Equivalents For Carbon Dioxide Research Articles

Abstract 4138282: Effect of cardiopulmonary exercise testing parameters and global longitudinal strain on survival after surgery for severe primary mitral regurgitation

Background: Optimum timing of surgery for severe primary mitral regurgitation (MR) particularly in the absence of significant symptoms or echo evidence of LV impairment remains unclear. Other modalities of assessment include cardiopulmonary exercise testing (CPET) and novel echo measurements, such as LV global longitudinal strain (LVGLS). We sought to evaluate whether pre-op CPET or LVGLS are associated with survival after surgery. Methods: We identified consecutive patients who had surgery for severe primary MR between 2007 and 2017 and had pre-op CPET. Clinical and mortality data were collected from chart review and our institutional database. LVGLS was retrospectively collected by a single person blinded to patient outcomes. Primary outcome was post surgery all cause death, and we used univariable analysis to identify variables associated with all cause death. Results: We included 176 patients with median age 63 (IQR 51, 71) years, 63 patients (35.8%) were female and 31 patients (14.8%) had a history of atrial fibrillation. 165 patients (93.8%) had mitral repair, 18 (10.2%) had concomitant CABG, 22 (12.5%) had concomitant ablation procedure and 14 (8.0%) had concomitant tricuspid procedure. 114 patients (64.8%) were in NYHA Class I and 56 (31.8%) were in NYHA Class II. There was no operative mortality. Median % predicted peak VO2 (ppVO2) was 89 (74, 101), median ventilatory equivalent of carbon dioxide (VE/VCO2) was 28.0 (25.7, 31.0) l/min/l/min and median respiratory exchange ratio was 1.2 (1.1, 1.2). 73 patients (41.5%) had abnormal CPET (defined as ppVO2<85%). Median LVEF was 65 (60, 68) %, median LVESD was 35 (32, 38) mm and median LVGLS was 18.5 (16.6, 20.3) %. 45 patients (25.9%) had abnormal LVEF (defined as ≤ 60%), 11 patients (6.7%) had abnormal LVESD (defined as ≥45mm) and 35 patients (20.8%) had abnormal LVGLS (defined as <16%). At a median follow up of 10.2 (6.8, 13.2) years, there were 19 (10.8%) deaths. In the univariate analysis, age at surgery (HR 1.12, p<0.001), LVESD (HR 1.11, p=0.009), LVGLS (HR 1.11, p=0.013) and VE/VCO2 (HR 1.08, p=0.044) were associated with all cause mortality. Conclusion: A significant proportion of patients with no or mild symptoms exhibit echocardiographic evidence of LV impairment when having surgery for severe primary MR. CPET parameters such as VE/VCO2 and novel echocardiographic measurements such as LVGLS may predict risk of long term mortality and potentially inform timing of surgery in these patients.

The effectiveness of various intensity interval training compared to continuous training in patients with heart failure: a systematic review and network meta-analysis

Abstract Background/Introduction Cardiac rehabilitation including exercise therapy is beneficial for improving exercise tolerance, physical function, quality of life (QOL), and life expectancy in patients with heart failure. High-intensity interval training (HIIT) is increasingly reported as a new training modality to improve exercise tolerance more effectively than conventional moderate-intensity continuous aerobic training (MCT). However, the optimal intensity of HIIT for achieving the greatest effects in patients with heart failure remain controversial. Purpose This systematic review and network meta-analysis aimed to examine the effectiveness of HIIT compared to MCT on exercise tolerance in patients with heart failure. Methods We searched for studies published up to 30 January 2024 in Embase, MEDLINE via Ovid SP, PubMed, and the Cochrane Library via Wiley Online Library with no limitations on data, language, or publication status. We included randomised controlled trials comparing the efficacy of HIIT and MCT on peak oxygen uptake (VO2), as a measure of exercise tolerance, aerobic threshold (AT) VO2, ventilatory equivalent of carbon dioxide (VE/VCO2) slope, and QOL. We categorized HIIT into three different intensities [> 80% heart rate max (HRM), 60-80% HRM, < 60% HRM] and compared the outcomes with those of MCT. Results We identified 15 randomised controlled trials with 557 patients from a total of 27,931 records. Our network meta-analysis revealed that the following results of peak VO2 from the comparisons among the three intensities of HIIT and MCT: > 80% HRM (10 studies, mean difference 1.27 ml/min/kg, 95% confidence interval -0.20 to 2.73), 60-80% HRM (3 studies, 1.47, -0.89 to 3.83), < 60% HRM (2 studies, 2.10, -1.22 to 5.43) (Fig. 1). Regarding AT VO2, HIIT at 60-80% HRM demonstrated significant improvements compared to MCT: > 80% HRM (8 studies, 0.18, -0.83 to 1.18), 60-80% HRM (2 studies, 2.50, 0.72 to 4.28), < 60% HRM (2 studies, 1.14, -0.93 to 3.20) (Fig. 2). Regarding VE/VCO2 slope, HIIT at 60-80% HRM also demonstrated significant improvements compared to MCT: > 80% HRM (7 studies, 0.29, -1.89 to 2.47), 60-80% HRM (2 studies, -3.26, -6.18 to -0.35), < 60% HRM (no study). The network meta-analysis did not reveal any significant differences in QOL between the various intensities of HIIT and MCT. Conclusions Our systematic review and network meta-analysis revealed that HIIT prescribed at a sub-maximal intensity, 60-80% heart rate max, is most effective in improving exercise tolerance. Higher intensity does not necessarily yield better outcomes, and future research on interval training should include detailed methodologies that account for the training intensity.Fig.1 Network meta-analysis on peak VO2Fig.2 Network meta-analysis on AT VO2

Cardiopulmonary exercise testing predicts risk of progressive heart failure and long term mortality in ambulatory patients awaiting isolated heart transplant

Abstract Introduction Cardiopulmonary exercise testing (CPET) parameters such as peak VO2 ≤ 14ml/kg/min, percentage predicted peak VO2 (ppVO2) ≤ 50% and ventilation equivalent of carbon dioxide (Ve/VCO2) >35 l/min/l/min are recommended thresholds to list for isolated heart transplant. There is minimal data on clinical events after listing to guide clinical management or priority in organ allocation. Purpose To assess the effect of peak VO2, ppVO2, Ve/VCO2 on clinical events after listing for isolated heart transplant. Methods In a single centre retrospective study, we identified patients who were status 6 or status 2 prior to 2018 at time of listing for isolated heart transplant between 2007 and 2021. Clinical data were collected by chart review. Primary outcome of progressive heart failure was defined as death or upgrade in transplant priority status (new inotropes or mechanical circulatory support). Comparison was made between peak VO2 strata (> 14 vs ≤ 14 ml/kg/min), ppVO2 strata (> 50% vs 40-50% vs <40%) and Ve/VCO2 strata (<35 vs >35 l/min/l/min). Secondary outcome was time dependent survival after listing for heart transplant. Results We identified 141 patients of which 133 underwent CPET and follow up was available for 130 who were included in the analysis. Median age was 53 years (interquartile range 41-59 years), 29.1% of patients were female. Median peak VO2 was 14.0 ml/kg/min (11.2-15.7), ppVO2 was 44% (36-52), Ve/VCO2 slope was 34.0 (31.0-37.0) and RER was 1.1 (1.1-1.2). 87 patients had progressive heart failure consisting of 34 deaths and 83 patients having upgrade in priority status. There was a significant difference in risk of progressive heart failure comparing peak VO2 strata (Figure 1) (freedom from event at one year 71.4% with peak VO2 > 14 vs 46.5% with peak VO2 ≤ 14, p=0.00061) and ppVO2 strata (Figure 2) (freedom from event at one year 75.0% with ppVO2 >50% vs 61.2% with ppVO2 40-50% vs 42.6% with ppVO2 <40%, p=0.0015). There was no significant difference with Ve/VCO2 strata (freedom from event at one year 59.8% with Ve/VCO2 <34 vs 54.9% with Ve/VCO2 >34, p=0.52). There were 34 deaths before transplant and 23 deaths after transplant. 87 patients underwent transplant. In a time dependent survival analysis, age, gender and ppVO2<50% (HR 1.65 (0.87-3.12)) were not significant predictors of mortality. Both early transplant (defined as < 1 year after listing, HR 0.14 (0.06-0.34) and late transplant (defined as > 1 year after listing, HR 0.16 (0.08-0.32)) were significant predictors of lower mortality whilst Ve/VCO2>35 (HR 2.09 (1.19-3.68)) was a significant predictor of higher mortality. Conclusions Peak VO2 and ppVO2 stratify risk of progressive heart failure in ambulatory patients awaiting isolated heart transplant. However, Ve/VCO2 is a predictor of significantly higher mortality. These findings should affect clinical management and transplant priority status; and influence revision of future guidelines.Freedom from event by peak VO2 strataFreedom from event by ppVO2 strata

Effect of Sarcobesity Index and Body Adipose Tissue Variables on Cardiopulmonary Exercise Testing Performance in Colorectal Surgery Setting: A Retrospective Cohort Study.

Aims/Background The prognostic significance of body composition variables has become a popular area of research over the recent years. This study aimed to determine whether adipose tissue variables and sarcobesity index measured by computed tomography (CT) could predict cardiopulmonary exercise testing (CPET) performance and long-term mortality in patients undergoing major colorectal surgery. Methods The Strengthening the Reporting of Cohort Studies in Surgery (STROCSS) statement standards were followed to conduct a retrospective cohort study of consecutive patients who had CPET prior to major colorectal surgery between January 2011 and January 2017. Receiver Operating Characteristic curve analysis was conducted to assess the discriminative performances of adipose tissue variables. The association between CT-derived adipose tissue variables (sarcobesity index, visceral adipose tissue, subcutaneous adipose tissue, and total adipose tissue) and CPET performance and mortality were assessed using regression analyses. Results 457 patients were included. Total adipose tissue evaluated via 2-dimensional (2D) and 3-dimensional (3D) approaches predicted oxygen uptake (V̇O2) Rest, V̇O2 anaerobic threshold (AT), ventilatory equivalents for carbon dioxide (V̇E/V̇CO2) AT, ventilatory equivalents for oxygen (V̇E/V̇O2) AT, V̇O2 peak, exercise time, maximum work, peak metabolic equivalents (METS), peak respiratory rate (RER), and peak oxygen pulse. Sarcobesity index (2D and 3D) predicted V̇O2 Rest, V̇O2 AT, V̇E/V̇CO2 AT, V̇O2 peak, maximum work, peak METS, maximum heart rate, and peak RER. Neither total adipose tissue nor sarcobesity index (2D and 3D) predicted 1-year, 3-year, or 5-year mortality. There was no difference in the discriminative performance of adipose tissue variables in predicting mortality. Conclusion The CPET performance may be predicted by radiologically measured adipose tissue variables and sarcobesity index. However, the prognostic value of the variables may not be significant in this setting.

Cardiopulmonary Response to Acute Exercise before Hemodialysis: A Pilot Study.

Disparities in physical fitness between immediately before dialysis (pre-D) and the day following dialysis (non-D) have not been investigated despite potential adverse factors such as fluid status, uremia, and electrolyte levels in the pre-dialysis period. The effect of acute exercise immediately before hemodialysis (HD) on HD-related hypotension remains unclear. We hypothesized that cardiopulmonary performance and muscular strength would be inferior in the immediate pre-D period compared to those non-D. Twenty patients receiving chronic HD treatments underwent symptom-limited incremental cardiopulmonary exercise testing (CPET) and isokinetic testing both 1-2 h prior to dialysis (pre-D) and non-D. This investigation was a sub-study of a clinical trial assessing the efficacy of a pre-D exercise training program. Blood pressure profiles during HD post-CPET and pre-D exercise training were compared with those during usual HD sessions. No adverse events were observed during the 80 exercise tests. Prior to dialysis, the nadir of the ventilatory equivalent of CO2 was slightly elevated, the resting heart rate was lower, and the peak systolic blood pressure was higher than those non-D. Contrary to our hypothesis, peak <inline-formula><mml:math id="m1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mover accent="true"><mml:mi mathvariant="normal">V</mml:mi><mml:mo>˙</mml:mo></mml:mover><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math></inline-formula> and quadriceps peak torque showed no differences. Blood pressure profiles during HD post-exercise were similar to those during sessions without prior exercise, except for a lower resting systolic blood pressure at the beginning of HD. Cardiopulmonary response and muscular strength in the 1-2 h prior to HD were comparable with those on the day following HD, with only minor clinically insignificant differences. Acute exercise prior to HD did not affect the magnitude of hypotension during HD. This study suggests a potential alternative timing for exercise training or testing in patients undergoing chronic HD.

Analysis of energy input-output in direct seeded and transplantation cultivation of rice under different irrigation systems

Energy input-output assessment for crop production processes is becoming increasingly important due to increased energy demand. This study explored the energy consumption for puddled transplanted (PTR), un-puddled transplanted (UPTR), and direct-seeded rice (DSR) cultivation methods under sprinkler, flood and drip irrigation systems in Golestan province, Iran, during 2019 and 2020. The energy of inputs and outputs were calculated using energy equivalents. Then, using input energy values, the global warming potential (GWP) was determined based on the equivalent of carbon dioxide (CO2). According to the results, the highest amount of yield was obtained for permanent flood irrigation with PTR. The results of mean comparison of cultivation method showed that the highest and lowest amounts of energy input were obtained for PTR (32418 MJ/ha) and UPTR (28175 MJ/ha), respectively. Also, the amounts of indices of energy use efficiency (EUE), energy productivity (EP) and net energy (NE) in DSR were lower than transplanted treatments. The results of mean comparison showed that the lowest amount of GWP was related to UPTR. The results of this study showed that drip irrigation with UPTR cultivation (due to less energy input and a yield close to PTR) can be a technology to save water and energy.

Effect of Off-Season Iron Supplementation on Aerobic Capacity of Female Handball Player: A Randomized, Double-Blinded, Placebo-Controlled Study

BackgroundIron supplementation, especially in female athletes, is 1 of the influential factors in aerobic capacity, and its deficiency can lead to significant problems related to reduced aerobic capacity. ObjectivesThis study aimed to investigate the effect of 3 wk of iron supplementation on the aerobic capacity of female handball players. MethodsIn this randomized, double-blinded, and placebo control trial, 14 elite handball players (age: 21.6 ± 5.68 y; height: 169.5 ± 4.9 cm; weight: 62.2 ± 9.25 kg; body mass index (in kg/m2): 21.5 ± 2.9) randomly divided into 2 supplement groups (receiving a 100 mg/d of poly-maltose tri hydroxide iron complex in the form of tablets) and the placebo group (receiving a tablet containing 100 mg/d starch which is the same color and shape as iron tablets). The supplementation protocol was performed for 3 wk during the off-season. Maximal oxygen consumption (VO2max), amounts of carbon dioxide at the first ventilatory threshold, amounts of carbon dioxide at the second ventilatory threshold, time to exhaustion (TTE), pulmonary ventilation (VE), ventilatory equivalents for oxygen, amounts of oxygen at the first ventilatory threshold, amounts of oxygen at the second ventilatory threshold, time to reach first ventilatory threshold, end-tidal partial pressure of oxygen at the first ventilatory threshold, end-tidal partial pressure of carbon dioxide at the first ventilatory threshold and ventilatory equivalents for carbon dioxide were measured using the Bruce test and gas analyzer in 2 pretest and posttest stages. ResultsThere were significant improvements in oxygen at the first ventilatory threshold, time to reach first ventilatory threshold, and end-tidal partial pressure of carbon dioxide at the first ventilatory threshold and a significant decrease in end-tidal partial pressure of oxygen at the first ventilatory threshold (P < 0.05). Also, no significant changes were found in VO2max, carbon dioxide at the first ventilatory threshold, carbon dioxide at the second ventilatory threshold, oxygen at the second ventilatory threshold, TTE, VE, ventilatory equivalents for oxygen, and ventilatory equivalents for carbon dioxide after 3 wk of iron supplementation (P > 0.05). ConclusionsThe study found that 3 wk of off-season iron supplementation positively impacted female handball players’ aerobic capacity; however, it did not significantly improve their VO2max.

Cardiopulmonary Exercise Testing Predicts Postoperative Morbidity after Major Abdominal Cancer Surgeries: A Prospective Observational Study

Background and Aim: Cardiopulmonary exercise testing (CPET) has been shown to predict outcomes after major surgery. However, CPET performance and risk thresholds may vary geographically due to different body composition, nutritional status, anaemia, etc. This study aimed to investigate the relationship between preoperative CPET variables and in-hospital morbidity after abdominal cancer surgeries. Methods: In this prospective observational study, 142 patients aged 18–70 years, American Society of Anesthesiologists Physical Status II–III, underwent CPET preoperatively within 7 days of planned surgery. Oxygen uptake (VO2), ventilatory equivalents for carbon dioxide, heart rate (HR) and oxygen pulse (VO2/HR) were measured at anaerobic threshold (AT) and peak exercise (PE). Morbidity was assessed using the postoperative morbidity survey (POMS) postoperatively on days 3, 5 and 7. Receiver operating characteristic (ROC) curves were constructed to assess the optimal cut-offs for various CPET parameters. A multivariate logistic regression model was applied to test the relationship between CPET and postoperative morbidity. Results: After excluding patients who met the exclusion criteria, data from 109 participants were available for analysis. Forty-two patients (39%) suffered some morbidity postoperatively. VO2@AT (univariate odds ratio (OR) 1.36 [1.11–1.67] P = 0.002), sex (0.40 [0.17–0.99] P = 0.04), HR@AT (0.91 [0.94–0.99] P = 0.01), VO2/HR@AT (2.00 [1.42–2.80] P &lt; 0.001) and VO2/HR@PE (2.04 [1.45–2.87] P &lt; 0.001] were associated with postoperative morbidity. The final multivariate regression model contained VO2@AT (multivariate OR 1.25 [1.00–1.56] P = 0.04) and VO2/HR@PE (1.89 [1.34–11.09] P = 0.001). ROC curves revealed the optimal cut-off for VO2@AT as 11.9 ml/kg/min and VO2/HR@PE at 6.1 ml/beat. Conclusion: CPET parameters of oxygen uptake at AT and oxygen pulse at PE can predict morbidity in patients undergoing major abdominal onco-surgeries.

The oral contraceptive cycle and its influences on maximal and submaximal endurance parameters in elite handball players.

The usage of the oral contraceptive pill is widespread among athletes of various levels. However, there is limited knowledge on how the intake of the pill alters the submaximal and maximal endurance parameters between the oral contraceptive phases. Therefore, the aim of this study was to examine potential differences between the pill intake and withdrawal phase on endurance-related parameters in first-division handball players. In total, 15 female team handball players performed two graded exercise tests until volitional exhaustion on a motorized treadmill. Tests were performed during the pill intake (days 16-17) and withdrawal phase (day 2-3). Throughout the test, respiratory gases were measured breath-by-breath, and the heart rate was measured continuously. Before and after the graded exercise test, blood samples were obtained in order to assess the blood lactate concentration. Before each test, venous blood samples were taken to determine endogenous sex hormone levels. Ventilatory parameters (O2, CO2, and E, and respiratory equivalents for O2 and CO2) were measured, and the oxidation of fat and carbohydrates was calculated. A paired-sample t-test was used to assess differences between the two time points, and the significance was accepted as p < 0.050. Significant differences with lower values during the consumption phase were found for absolute (mean difference ± SD: 88 ± 131mL∙min-1; p = 0.021) and relative O2peak (mean difference ± SD: 1 ± 2mL∙min-1∙kg-1; p = 0.012). Higher values during the consumption phase were found for submaximal respiratory equivalents for O2 (mean difference ± SD: -1.1 ± 1.7; p = 0.028) and CO2 (mean difference ± SD: -0.9 ± 1.5; p = 0.032). No differences were found for all other parameters, including differences for endogenous sex hormones (p > 0.050). The results of the current study suggest only marginal and physiologically insignificant differences in endurance-related parameters between oral contraceptive phases.

Soil Carbon: Pool, Loss, Emission and Climate Change Sources and Knowledge Level of Some Land Use Systems in Sudan Savanna, Kwara State

This research work was carried out in Sudan savanna of Kwara State to determine the effects of land use types on soil carbon pool, loss, emission and to determine the farmer’s knowledge level and sources of information on climate change. Six villages were selected randomly and in each Local Government Area, three villages were visited and three farms planted each with maize/cassava intercrop, cashew plantation and natural forest were sampled. Soil samples were collected from the farmland randomly at the depth of 0–20cm and analysed for physical and chemical properties in the laboratory. Carbon pool index was higher under cashew plantation. The mass of carbon lost recorded was higher under maize/cassava intercrop and cashew plantation recorded the lowest mass of carbon lost. Equivalent Carbon dioxide emitted recorded was lower under cashew plantation and maize/cassava intercrop recorded higher equivalent of carbon dioxide emitted. Natural forest had the highest organic carbon. Simple random sampling of 126 respondents were interviewed. Results revealed majority (71.4%) are willing to invest in residue retention and 92.9% are willing to engage in climate change mitigation practices free of charge. Maize/cassava intercrop recorded the lowest carbon pool due to burning of plant residues and the use of tillage practices. The highest carbon pool index recorded under cashew plantation was due to leaves litter decomposition. Carbon emitted was generally higher under maize/cassava intercrop as a result of continuous and vigorous cultivation leading to loss of carbon. Some farmers are not fully aware of climate change mitigation practices, therefore, more observation should be given to afforestation scheme to mitigate climate change and government and nongovernmental organization (NGOs) should educate and encourage farmers to practice crop residue retention and also minimize bush burning.

Preoperative aerobic fitness and perioperative outcomes in patients undergoing cystectomy before and after implementation of a national lockdown

BackgroundLower fitness is a predictor of adverse outcomes after radical cystectomy. Lockdown measures during the COVID-19 pandemic affected daily physical activity. We hypothesised that lockdown during the pandemic was associated with a reduction in preoperative aerobic fitness and an increase in postoperative complications in patients undergoing radical cystectomy. MethodsWe reviewed routine preoperative cardiopulmonary exercise testing (CPET) data collected prior to the pandemic (September 2018 to March 2020) and after lockdown (March 2020 to July 2021) in patients undergoing radical cystectomy. Differences in CPET variables, Postoperative Morbidity Survey (POMS) data, and length of hospital stay were compared. ResultsWe identified 267 patients (85 pre-lockdown and 83 during lockdown) who underwent CPET and radical cystectomy. Patients undergoing radical cystectomy throughout lockdown had lower ventilatory anaerobic threshold (9.0 [7.9–10.9] vs 10.3 [9.1–12.3] ml kg−1 min−1; P=0.0002), peak oxygen uptake (15.5 [12.9–19.1] vs 17.5 [14.4–21.0] ml kg−1 min−1; P=0.015), and higher ventilatory equivalents for carbon dioxide (34.7 [31.4–38.5] vs 33.4 [30.5–36.5]; P=0.030) compared with pre-lockdown. Changes were more pronounced in males and those aged >65 yr. Patients undergoing radical cystectomy throughout lockdown had a higher proportion of day 5 POMS-defined morbidity (89% vs 75%, odds ratio [OR] 2.698, 95% confidence interval [CI] 1.143–6.653; P=0.019), specifically related to pulmonary complications (30% vs 13%, OR 2.900, 95% CI 1.368–6.194; P=0.007) and pain (27% vs 9%, OR 3.471, 95% CI 1.427–7.960; P=0.004), compared with pre-lockdown on univariate analysis. ConclusionsLockdown measures in response to the COVID-19 pandemic were associated with a reduction in fitness and an increase in postoperative morbidity among patients undergoing radical cystectomy.

The influence of Ti/Ni metallic phase content on the microstructure and environmental interactions of gradient Al2O3-based composites

Al2O3/Ti/Ni composites, enhanced with the inclusion of NiAl2O4 and TiAl2O5 phases, represent a novel class of advanced materials with multifaceted properties suitable for diverse engineering applications. Centrifugal slip casting method was used for preparation of two series of gradient Al2O3/Ti/Ni composite samples with different content of the metallic Ti and Ni phases. Series I containing 0.5 vol.% of Ni and 0.5 vol.% of Ti and Series II containing 2.5 vol.% of Ni and 2.5 vol.% of Ti. Each series contained 55 vol.% of a solid phase. Rheological properties of the suspensions as well as microstructure of the obtained composites were studied, with special attention paid to the analysis of the formed spinel phases. Both series in the green form were characterized by 3-zone structure with different metallic phase content. The widths of individual zones for the Series I and Series II, after sintering at 1450?C, were 0.53mm (zone I), 3.26mm (zone II), 0.8mm (zone III) and 1.27mm (zone I), 1.47mm (zone II), 1.87mm (zone III), respectively. The results showed that after sintering two spinel phases were formed. The NiAl2O4 spinel phase consists only of small grains with a size of approximately 1.3- 1.8 ?m, which form larger clusters with or without a void inside. The TiAl2O5 phase consists of grains with an average size of 4.3 to 4.5 ?m. The Life Cycle Assessment analysis revealed that the values of the global warming potential indicator in phase A1 are 0.16 kg and 0.20 kg equivalent of CO2 per sintered sample for the Series I and Series II, respectively.

Reactivity of NHI-Stabilized Heavier Tetrylenes towards CO2 and N2 O.

A heteroleptic amino(imino)stannylene (TMS2 N)(It BuN)Sn: (TMS=trimethylsilyl, It Bu=C[(N-t Bu)CH]2 ) as well as two homoleptic NHI-stabilized tetrylenes, (It BuN)2 E: (NHI=N-heterocyclic imine, E=Ge, Sn) are presented. VT-NMR investigations of (It BuN)2 Sn: (2) reveal an equilibrium between the monomeric stannylene at room temperature and the dimeric form at -80 °C as well as in the solid state. Upon reaction of the homoleptic tetrylenes with CO2 , both compounds insert two equivalents of CO2 , however differing bonding modes can be observed. (It BuN)2 Sn: (2) inserts one equivalent of CO2 into each Sn-N bond, giving carbamato groups coordinated κ2 O,O' to the metal center. With (It BuN)2 Ge: (3), the Ge-N bonds stay intact upon activation, being bridged by one molecule of CO2 respectively, forming 4-membered rings. Furthermore, the reactivity of 2 towards N2 O was investigated, resulting in partial oxidation to form stannylene dimer [((It BuN)3 SnO)(It BuN)Sn:]2 (6).

CO2-Sensitive Porous Magnet: Antiferromagnet Creation from a Paramagnetic Charge-Transfer Layered Metal-Organic Framework.

Porous magnets that undergo a magnetic phase transition in response to gaseous adsorbates are desirable for the development of sustainable sensing and memory devices. Familiar gases such as O2 and CO2 are one class of target adsorbates because of their close association with life sciences and environmental issues; however, it is not easy to develop magnetic devices that respond to these ubiquitous gases. To date, only three examples of gas-responsive magnetic phase transitions have been demonstrated: (i) from a ferrimagnet to an antiferromagnet, (ii) its vice versa (i.e., change of magnetic phase), and (iii) from a ferrimagnet to a paramagnet (i.e., erasure of the magnetic phase). However, the creation of a magnet, meaning the change from a nonmagnet to a magnet by O2 or CO2 gas adsorption and magnetic switching by this phenomenon have not yet been explored. Herein, we report a CO2-induced antiferromagnet modified from a paramagnetic charge-flexible layered compound, [{Ru2(2,4-F2PhCO2)4}2TCNQ(OEt)2] (1; 2,4-F2PhCO2- = 2,4-difluorobenzoate; TCNQ(OEt)2 = 2,5-diethoxy-7,7,8,8-tetracyanoquinodimethane), where three molar equivalents of CO2 was accommodated at a CO2 pressure of 100 kPa. The magnetic change originates from charge fluctuation due to the transfer of electrons moving from the electron-donor to the electron-acceptor unit or vice versa, resulting in a change in the electron distribution induced by CO2 adsorption/desorption in the donor-acceptor-type charge transfer framework. Owing to the reversible electronic state change upon CO2 adsorption/desorption, these magnetic phases are switched, accompanied by modification of the electrical conductivity, which is boosted by the CO2 accommodation. This is the first example of the creation of a CO2-responsive magnet, which is promising for novel molecular multifunctional devices.

The effectiveness of high-intensity interval training compared to moderate-intensity continuous training in patients with heart failure: a systematic review and meta-analysis

Abstract Background/Introduction Cardiac rehabilitation including exercise therapy is beneficial for improving exercise tolerance, physical function, quality of life (QOL), and life expectancy in patients with heart failure. High-intensity interval training (HIIT) has attracted attention as a new training modality in heart failure, whereas moderate-intensity continuous aerobic training (MCT) is recommended as the main training modality to improve exercise tolerance. However, the effects of HIIT in patients with heart failure remain controversial. Purpose This systematic review and meta-analysis aimed to examine the effectiveness of HIIT compared to MCT on exercise tolerance in patients with heart failure. Methods We searched for studies published up to 4 March 2022 in EMBASE, MEDLINE via Ovid SP, PubMed, and the Cochrane Library via Wiley Online Library with no limitations on data, language, or publication status. We included randomised controlled trials comparing the effectiveness of HIIT and MCT on peak oxygen uptake (VO2), as a measure of exercise tolerance, aerobic threshold (AT) VO2, ventilatory equivalent of carbon dioxide (VE/VCO2), and QOL. We pooled the data on peak VO2, compared HIIT to MCT, and conducted a sub-analysis if there was heterogeneity in the result. Results We identified 15 randomised controlled trials with 557 patients from a total of 23,272 records. Our meta-analysis showed that participants who underwent HIIT achieved a significantly higher peak VO2 than those who underwent MCT (mean difference 1.46 ml/kg/min, 95% confidence interval 0.39 to 2.53; I2 = 65.7%; very low-quality evidence) (Figure 1). Participants who underwent HIIT had no statistically significant difference in AT VO2, VE/VCO2, and QOL compared to those who underwent MCT. The meta-regression analysis, conducted as a sub-analysis to explore possible causes of heterogeneity, revealed that the effect size of HIIT compared to MCT was inversely associated with body mass index (r = -0.508, p = 0.028, 95% confidence interval -0.95 to -0.07) (Figure 2). Conclusions Our systematic review showed that HIIT achieved a higher peak VO2 than MCT in patients with heart failure. In addition, HIIT may be more effective in improving exercise tolerance in patients with low body mass index.

Abstract 15275: Cardiac Magnetic Resonance Ventricular Function and Hemodynamic Multivariable Model Predictors of Exercise Performance in Tetralogy of Fallot Using Machine Learning and Multivariable Modelling: A Substudy of the Single Center Cardiac Magnetic Resonance Outcomes Registry-Tetralogy of Fallot

Background: There are no robust predictors of exercise performance in repaired tetralogy of Fallot (rTOF) using both ventricular function and hemodynamics. Aim: To utilize machine learning and multivariable modeling to determine cardiac magnetic resonance (CMR) and other metrics predictive of exercise performance. Methods: We retrospectively reviewed data of all rTOF pts undergoing CMR from 2005-2020. Those who had cardiopulmonary exercising testing (CPET) within 6 months of CMR were analyzed using the machine learning technique LASSO to choose candidate variables for subsequent testing with multivariable modeling. CMR parameters included right (RV) and left ventricular (LV) function and hemodynamics. Significance P&lt;0.05. Results: 266 of 761 pts with rTOF met the inclusion criteria (age at CMR 16.1 + 9.7 years old, age at repair 0.36 years old, 56% male). Higher RV mass, RV global function index and lower pulmonary regurgitant fraction (PR) were independently associated with higher % predicted (%P) maximum oxygen consumption (VO 2 max). In addition, females and non-syndromic pts were also associated with higher %P VO 2 max (table). Those with a higher LV end-diastolic volume (EDV), females and pts without pulmonary atresia performed better at %P work. Those with a higher RV mass/volume demonstrated a worse ventilatory equivalent of carbon dioxide (VE/VCO 2 ). See table. Conclusion: RV ventricular functional parameters, PR (hemodynamics), gender and syndromic status are all independently associated with %P VO 2 max. Those with larger LV volumes were able to perform more work and those with a higher RV mass/volume had a worse VE/VCO 2 . Our findings shed some light into the etiology of poor rTOF exercise performance.

Cardiorespiratory Reactions During Submaximal Exercise in Humans after 14-Day Simulated Lunar Gravity

The paper presents main results of a study on the influence of the physiological effects of simulated lunar gravity on cardiorespiratory responses to exercise in humans. Twelve healthy male volunteers aged 19–31 years (M ± SD: 22.5 ± 4.0 years) took part in the study. They were under 14-day head-up bed rest at +9.6° angle (HUBR) relative to the horizon as a model for the physiological effects of lunar gravity. Cardiopulmonary exercise testing (CPET) was performed 7 days before the onset of HUBR and on the next day after the end of the experimental exposure. A 3-stage cycle ergometer test with 5-minute platforms at 125, 150, and 175 watts was used as a CPET protocol. Exposure of subjects to simulated lunar gravity reduced their tolerance to physical load. This was indicated by more pronounced changes for such parameters of cardiorespiratory system as heart rate, minute ventilation of the lungs, ventilatory equivalents for oxygen and carbon dioxide, as well as a less pronounced increase in oxygen consumption and oxygen pulse during CPET after 14 days of exposure to HUBR.

Long-term effects of physical training on cardiopulmonary exercise parameters in young patients with congenital heart diseases.

Physical activity is recognised as an important intervention in patients with CHD. However, more data on the actual magnitude of physical training impact on functional capacity in this group of patients are still warranted. We aim to assess effort tolerance in a contemporary cohort of patients with congenital heart disease, regularly following a training programme, in comparison with a matched control group. Patients with CHD followed at the sports medicine department, who had undergone cardiopulmonary exercise test between 2011 and 2019, were included. Variables recorded were maximum workload, absolute and indexed maximum oxygen consumption, maximum heart rate, absolute and indexed maximum O2 pulse, ventilatory equivalent of CO2 and oxygen consumption/Work. Trend of cardiopulmonary parameters was analysed over time. Maximal workload, maximum oxygen consumption and ventilatory equivalent of CO2 were compared with a control group of patients with a more sedentary lifestyle, matched for diagnosis, gender, age, and body mass index. Among one hundred and eleven patients, 73 males (66%) were analysed. Median age was 14 (12-17) years. Twenty-nine patients (27%) were practising sports at competitive level. Maximum oxygen consumption and oxygen consumption % of maximum predicted were not significantly different at follow-up as compared with baseline. Follow-up of maximum oxygen consumption was 38.2 ± 9 ml/kg/min versus 38.6 ± 9.2 ml/kg/min (p = NS) and follow-up of %oxygen consumption was 88 ± 20 versus 87 ± 15 (p = NS). Ventilatory equivalent of CO2 significantly improved in the last test as compared with the baseline: 30 ± 4 versus 33 ± 5 (p = 0.002). As compared with the control group, trained patients displayed a significantly higher maximum workload and oxygen consumption, while ventilatory equivalent of CO2 was not significantly different. In our cohort, patients following a regular training programme displayed a significantly higher functional capacity as compared with not trained control group, irrespective of NYHA class. Objective functional capacity was stable over a median follow-up of 3 years.

Analysis of Greenhouse Gas Emissions Characteristics and Emissions Reduction Measures of Animal Husbandry in Inner Mongolia

Global warming has had a profound impact on human life, with animal husbandry being a significant contributor to greenhouse gas emissions and playing a crucial role in the global greenhouse gas budget. Inner Mongolia is a major contributor to these emissions, making it vital to study the link between greenhouse gas emissions and animal husbandry in this region for the purpose of reducing emissions. In this study, the emissions of greenhouse gases (CH4, N2O, and CO2) from livestock and poultry breeding from 2010 to 2020 and the emissions of each city from 2020 were estimated, the emissions characteristics were analysed, and the low carbon emissions reduction technical measures were proposed. The results show that (1) the overall greenhouse gas emissions from 2010 to 2020 in Inner Mongolia showed a fluctuating trend; the main emissions sources were gastrointestinal fermentation and faecal management. The annual average CH4 emissions were 994,400 ta−1, and the annual average N2O emissions were 35,100 ta−1. (2) In 2020, the total emissions of each league city were 38.05 million t equivalent of CO2, and the emissions gradually decreased from east to west, with a significant emissions reduction potential. Based on these findings, this study also proposed technical measures for reducing carbon emissions, offering theoretical support to drive the industrial transformation and upgrading of the livestock industry, and promoting green economic development in Inner Mongolia as part of its carbon peaking and neutrality goals.

Cardiovascular capacity in adults with obstructive sleep apnoea.

BACKGROUND: Obstructive sleep apnoea (OSA) patients have a decreased exercise capacity. Potential cardiovascular capacity in patients with OSA with different severity without known cardiovascular disease has not been described.OBJECTIVE: To evaluate impaired potential exercise cardiovascular capacity during cardiopulmonary exercise testing (CPET) in OSA patients and to compare cardiovascular performance reaction with different severity during graded exercise stages.DESIGN: All participants were accompanied without cardiovascular disease, especially hypertension and arrhythmia. Parameters of different stages were compared between subjects with and without OSA, and among OSA patients with varied severity.RESULTS: Despite having significantly higher peak exercise diastolic blood pressure (DBP) and ventilatory equivalent for CO2 (EQCO₂), patients with OSA had a lower peak oxygen uptake (VO₂), heart rate (HR), heart rate recovery (HRR) and respiratory reserve (BR) than normal subjects. Furthermore, significant correlations were found between VO₂, DBP, EQCO₂, HRR, BR and the apnoea-hypopnea index. In severe OSA, there was a greater difference in HR and HRR during the anaerobic threshold stages.CONCLUSIONS: OSA patients demonstrate reduced potential cardiovascular capacity, even without documented cardiovascular disease. Patients with severe OSA develop impaired exercise capacity at early stage during exercise. These data point to exaggerated haemodynamic response to graded exercise and delayed post-exercise cardiovascular response recovery in OSA patients. CPET can be a supplement for assessment of OSA severity.