Oxygen Content Difference Research Articles

Primary inflammatory disease in heart failure with preserved ejection fraction

Abstract Background Inflammation plays a fundamental role in the pathogenesis of heart failure (HF) with preserved ejection fraction (HFpEF). In most patients, inflammation develops secondary to cardiometabolic comorbidities, but in some, HFpEF develops in the setting of underlying systemic inflammatory diseases represented by rheumatoid arthritis. Purpose This study aimed to investigate the prevalence, pathophysiology, and outcome of patients with HFpEF and primary inflammatory diseases. Methods Consecutive patients undergoing hemodynamic exercise testing with concurrent expiratory gas analysis to evaluate dyspnea of unknown cause were identified. HFpEF was defined as left ventricular ejection fraction ≥50% and pulmonary capillary wedge pressure ≥15 mmHg (rest) or ≥25 mmHg (exercise). Patients with HFpEF were divided into groups with and without primary inflammatory diseases. Patients without inflammatory disease were divided into tertiles according to the value of C-reactive protein (CRP). Results Of 982 consecutively evaluated patients with HFpEF diagnosed (577 female, mean age 68 years), 79 (8%) had primary inflammatory disease. In multivariable logistic regression, female sex (OR 1.88; 95% CI 1.01-3.52), higher resting heart rate (OR 1.18; 95% CI 1.08-1.30), lower hemoglobin level (OR 0.84; 95% CI 0.70-0.99), absence of history of atrial fibrillation (OR 0.45; 95% CI 0.24-0.86) and absence of epicardial coronary artery disease (OR 0.45; 95% CI 0.22-0.93) were independently associated with inflammatory disease. Hemodynamics at rest and exercise did not differ between the groups, but peripheral oxygen extraction was lower in those with inflammatory disease, reflected by lower arterial-venous oxygen content difference (Ca-vO2) at rest (4.2±0.7 mL/dL vs 4.6±1.0 mL/dL, P<.001) and during exercise (9.3±2.2 mL/dL vs 10.4±2.2 mL/dL, P<.001) (Figure 1A), suggesting a greater peripheral deficit, and ventilatory efficiency (VE/VCO2 slope) was also more impaired (38.0±7.9 vs 36.2±7.3, P=.035). The HFpEF patients without inflammatory disease falling in the highest tertile of CRP) displayed lower Ca-vO2 during exercise, more closely resembling peripheral deficits observed in those with inflammatory disease (Figure 1B). During a median follow-up of 3.0 years, the composite outcome of all-cause deaths and HF hospitalization occurred in 127 patients (14%). Patients with HFpEF and inflammatory disease showed a higher incidence of composite outcome than those without (log-rank P=.030; Figure 2). Patients with inflammatory disease had higher risk of composite outcome compared to those without in adjusted analyses (HR 1.93; 95% CI 1.15-3.23), which was primarily attributable to higher risk of HF hospitalization (HR 2.85; 95% CI 1.08-7.52). Conclusion Patients with HFpEF and primary inflammatory disease have similar hemodynamic derangements but greater peripheral deficits in oxygen transport and higher risk for adverse outcome compared to those without.

STATE OF HAEMODYNAMICS AND OXYGEN BUDGET IN THE PERIOPERATIVE PERIOD IN PATIENTS WITH OSTEOARTHRITIS AND CONCOMITANT CARDIAC PATHOLOGY DURING TOTAL HIP ARTHROPLASTY SURGERY DEPENDING ON THE TYPE OF SURGICAL ACCESS

Summary. Aim. To compare the hemodynamic status and oxygen budget in patients with osteoarthritis and comorbid cardiac pathology during total hip arthroplasty, based on the type of surgical approach used. Materials and Methods. The study analyzed the treatment outcomes of 90 patients with stage 3-4 osteoarthritis of the hip who underwent total cemented hip arthroplasty. All patients were divided into two groups according to the surgical approach (traditional posterior or modified posterior). The study was conducted at the following stages: before surgery, immediately after surgery, 24 hours post-surgery, and one week after surgery. The following parameters were recorded: hemodynamic parameters (heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure, and central venous pressure) and oxygen budget parameters (hemoglobin (Hb), lactate, hematocrit (Ht), oxygen saturation of hemoglobin in arterial and venous blood (SaO2 and SvO2), partial pressure of oxygen in arterial and venous blood (paO2 and pvO2)). Based on these data, the following indices were calculated: left ventricular ejection fraction (LVEF), cardiac index (CI); oxygen content in arterial and venous blood (CaO2 and CvO2), arteriovenous oxygen content difference (C(a-v)O2), oxygen transport (TO2), oxygen consumption (VO2); systemic perfusion pressure (SPP), blood flow power (BFP), oxygen reserve (OR), and circulatory reserve (CR). Results. The use of the modified posterior approach positively influenced hemodynamic parameters. After the surgery and on the 7th day post-surgery, SPP was significantly lower with the modified posterior approach. The CI was also significantly affected by the modified posterior approach. Throughout the study, except for the first stage, CI was significantly higher when using the modified posterior approach. LVEF increased significantly with both approaches, but on the 7th day post-surgery, it was significantly higher in the second group. BFP did not statistically differ between the two groups throughout the study, but its energy efficiency was lower, primarily due to the arteriovenous oxygen content difference (C(a-v)O2). C(a-v)O2 was the same before surgery for both approaches. At subsequent stages of the study, the differences between the groups increased, and on the 7th day, they were the most significant, with C(a-v)O2 being lower after using the modified posterior approach. The energy efficiency of blood flow was assessed by calculating OR and CR. Both indicators were significantly higher during the study, except at the preoperative stage, when using the modified posterior approach. Conclusions. Our study clearly demonstrates the benefits of implementing the modified posterior approach in total hip arthroplasty for patients with osteoarthritis and comorbid cardiac pathology. This approach improves hemodynamic and oxygen budget parameters compared to the traditional approach, which can significantly impact treatment outcomes for patients with cardiac comorbidity and reduce the number of postoperative complications.

Air infiltration characteristics in oxygen-enhanced and heated chambers on the Qinghai-Xizang Plateau

The Qinghai-Xizang Plateau is characterized by a low-pressure and oxygen-deficient environment due to its high altitude, causing discomfort and major safety problems for the inhabitants. To address this, oxygen-enriched chambers can be used to alleviate the plateau reaction. However, little consideration has been given to air infiltration in these chambers, with a lack of information on the corresponding infiltration heat loss phenomenon. This paper addresses this by investigating the phenomenon of air flow in an oxygen-enriched chamber using experiments and simulations. The results highlight that when there is a difference in oxygen concentration between the interior and exterior of the chamber, mass transfer occurs due to both the molecular diffusion in addition to a flow due to the air density difference caused by the variation in concentration. Also, the simultaneous stack effect is roughly equivalent to 10 times the oxygen pressure, and the two pressure effects act in opposite directions. It is also noted that both the oxygen pressure and the stack effect decrease as the atmospheric pressure decreases. Overall, the oxygen-enriched chambers exhibit less infiltration in plateau areas with a low atmospheric pressure compared to plains areas with a relatively high atmospheric pressure. Finally, this study establishes formulas that can be used to calculate air infiltration rates in oxygen-enriched chambers. This study fills a gap in the existing literature regarding the air infiltration mechanism in oxygen-enriched chambers at high altitudes and low pressures, providing a theoretical foundation for improving indoor environments in the Qinghai-Xizang Plateau and other high-altitude regions.

Exercise intolerance and oxygen dynamics in nontuberculous mycobacteria with bronchiectasis

BackgroundNontuberculous mycobacterial pulmonary disease (NTM-PD) patients often have exercise intolerance. Pulmonary rehabilitation (PR) to improve such patients' conditions is often not based on its exercise pathophysiology. We have reported that the oxygen consumption (ΔFO2) by expiratory gas analysis, i.e., the inspired-expired-expiratory mean oxygen concentration difference, is related to the minute ventilation-carbon dioxide output (V′E-V′CO2)-slope and oxygen uptake (V′O2) independent of the V′E. The aim of this study was to investigate how ΔFO2 is related to dynamic ventilatory variables, chest computed tomography (CT), and echocardiography findings in NTM-PD patients to understand their pathophysiological conditions. MethodsClinical data of NTM-PD patients with exertional dyspnea (n = 29) who underwent incremental exercise testing, chest CT, and echocardiography at the same time were compared with those of control participants (n = 12). ResultsIn the NTM-PD group, 1) peak V′O2 decreased (NTM-PD: 17.6 vs. controls: 28.7 mL⋅min−1⋅kg−1), and 2) ΔFO2 at peak exercise was negatively correlated with respiratory frequency at peak exercise (correlation coefficient: r = −0.80, p < 0.0001), V′E-V′CO2-slope (r = −0.75, p < 0.0001), bronchiectasis CT score (r = −0.52, p = 0.0042), and the trans-tricuspid pressure gradient (r = −0.39, p = 0.0417), and positively correlated with peak V'O2 (r = 0.71, p < 0.0001) and the body mass index (r = 0.42, p = 0.0217), but it was not correlated with V′E at peak exercise and the cavity CT score. ConclusionsExertional oxygen consumption, independent of ventilatory ability, is associated with exercise tolerance and ventilatory efficiency, while being related to tachypnea and bronchiectasis rather than cavitation in NTM-PD patients. These findings may be useful in considering exercise physiology-based PR for NTM-PD patients with exertional dyspnea.

Characteristics of the fish food supply of the Uglich reservoir

The work on assessing the feed base of the Uglich Reservoir was carried out within the framework of annual monitoring studies by the Branch for Freshwater Fisheries of the Federal State Budgetary Scientific Institution “VNIRO” (VNIIPRH). Samples were taken in July 2021 and 2022 on three sections. During the year, 10 samples of zooplankton and benthic invertebrate communities were collected and processed. The purpose of the study is to evaluate the fish food supply of the Uglich Reservoir according to the indicators of zooplankton and benthic invertebrate communities in the period 2021–2022. The tasks of the study: to determine the number and biomass of zooplankton of the Uglich Reservoir in 2021–2022; to determine the number and biomass of benthic invertebrate communities of the Uglich Reservoir in 2021–2022. The Uglich Reservoir belongs to the Upper Volga cascade of hydro nodes. Located in the territory of two regions and having a length of more than a hundred kilometers, it has differences in water temperature and oxygen content in the water by reaches. Oxygen conditions in 2021 in the bottom layers, and in 2022 — both in the surface and in the bottom horizons, were unfavorable: deviations from the water quality standard were observed. The studies showed that the productivity of the Uglich Reservoir also varies by reaches. The maximum indicators of zooplankton development were observed in the channel part of the Upper reach of the reservoir. During the observation period (with incomplete determination), 21 taxa of planktonic organisms were recorded, including: Rotifera — 5, Cladocera — 12, Copepoda — 3 and Bivalvia — 1 species. In the composition of the plankton fauna, Cladocera dominated in number and biomass. The benthic invertebrate communities of the Uglich Reservoir is mainly represented by oligochaetes, chironomid larvae and bivalve molluscs. By the magnitude of the summer biomass of zooplankton and benthic invertebrate communities, in accordance with the generally accepted classification of Pidgayko (1968), the Uglich Reservoir in 2021 can be assessed as a high-feed reservoir, and in 2022 — as a medium-feed reservoir.

Relationships of Jugular Bulb Parameters with Cerebral Perfusion and Metabolism After Resuscitation from Cardiac Arrest: A Post-Hoc Analysis of Experimental Studies Using a Minipig Model.

Cerebral blood flow (CBF) decreases in the first few hours or days following resuscitation from cardiac arrest, increasing the risk of secondary cerebral injury. Using data from experimental studies performed in minipigs, we investigated the relationships of parameters derived from arterial and jugular bulb blood gas analyses and lactate levels (jugular bulb parameters), which have been used as indicators of cerebral perfusion and metabolism, with CBF and the cerebral lactate to creatine ratio measured with dynamic susceptibility contrast magnetic resonance imaging and proton magnetic resonance spectroscopy, respectively. We retrospectively analyzed 36 sets of the following data obtained during the initial hours following resuscitation from cardiac arrest: percent of measured CBF relative to that at the prearrest baseline (%CBF), cerebral lactate to creatine ratio, and jugular bulb parameters, including jugular bulb oxygen saturation, jugular bulb lactate, arterial-jugular bulb oxygen content difference, cerebral extraction of oxygen, jugular bulb-arterial lactate content difference, lactate oxygen index, estimated respiratory quotient, and arterial-jugular bulb hydrogen ion content difference. Linear mixed-effects models were constructed to examine the effects of each jugular bulb parameter on the %CBF and cerebral lactate to creatine ratio. The arterial-jugular bulb oxygen content difference (P = 0.047) and cerebral extraction of oxygen (P = 0.030) had a significant linear relationship with %CBF, but they explained only 12.0% (95% confidence interval [CI] 0.002-0.371) and 14.2% (95% CI 0.005-0.396) of the total %CBF variance, respectively. The arterial-jugular bulb hydrogen ion content difference had a significant linear relationship with cerebral lactate to creatine ratio (P = 0.037) but explained only 13.8% (95% CI 0.003-0.412) of the total variance in the cerebral lactate to creatine ratio. None of the other jugular bulb parameters were related to the %CBF or cerebral lactate to creatine ratio. In conclusion, none of the jugular bulb parameters appeared to provide sufficient information on cerebral perfusion and metabolism in this setting.

Identifying the Mechanisms of a Peripherally Limited Exercise Phenotype in Patients With Heart Failure With Preserved Ejection Fraction.

We identified peripherally limited patients using cardiopulmonary exercise testing and measured skeletal muscle oxygen transport and utilization during invasive single leg exercise testing to identify the mechanisms of the peripheral limitation. Forty-five patients with heart failure with preserved ejection fraction (70±7 years, 27 females) completed seated upright cardiopulmonary exercise testing and were defined as having a (1) peripheral limitation to exercise if cardiac output/oxygen consumption (VO2) was elevated (≥6) or 5 to 6 with a stroke volume reserve >50% (n=31) or (2) a central limitation to exercise if cardiac output/VO2 slope was ≤5 or 5 to 6 with stroke volume reserve <50% (n=14). Single leg knee extension exercise was used to quantify peak leg blood flow (Doppler ultrasound), arterial-to-venous oxygen content difference (femoral venous catheter), leg VO2, and muscle oxygen diffusive conductance. In a subset of participants (n=36), phosphocreatine recovery time was measured by magnetic resonance spectroscopy to determine skeletal muscle oxidative capacity. Peak VO2 during cardiopulmonary exercise testing was not different between groups (central: 13.9±5.7 versus peripheral: 12.0±3.1 mL/min per kg; P=0.135); however, the peripheral group had a lower peak arterial-to-venous oxygen content difference (central: 13.5±2.0 versus peripheral: 11.1±1.6 mLO2/dL blood; P<0.001). During single leg knee extension, there was no difference in peak leg VO2 (P=0.306), but the peripherally limited group had greater blood flow/VO2 ratio (P=0.024), lower arterial-to-venous oxygen content difference (central: 12.3±2.5 versus peripheral: 10.3±2.2 mLO2/dL blood; P=0.013), and lower muscle oxygen diffusive conductance (P=0.021). A difference in magnetic resonance spectroscopy-derived phosphocreatine recovery time was not detected (P=0.199). Peripherally limited patients with heart failure with preserved ejection fraction identified by cardiopulmonary exercise testing have impairments in oxygen transport and utilization at the level of the skeletal muscle quantified by invasive knee extension exercise testing, which includes an increased blood flow/V̇O2 ratio and poor muscle diffusive capacity. URL: https://www.clinicaltrials.gov; Unique identifier: NCT04068844.

Quantifying oxygen diffusion during thermal degradation of combustible porous media

Oxygen diffusion controlled combustion occurs when local oxygen transport is slower than the chemistry, commonly found in porous combustible material or combustible material embedded within an inert porous medium. This mode of combustion, such as smouldering, can pose dangerous fire risks and also be harnessed in environmentally beneficial applications. However, the oxygen diffusion limitation is poorly understood in all contexts and persists as a key knowledge gap. Quantitative analysis of oxygen diffusion effects is therefore crucial for understanding the combustion behavior of combustible porous media and developing precise smouldering simulation models. In this paper, a reactive transport model incorporating both oxygen diffusion and chemical consumption was developed. Using coal as the model fuel, the impacts of key parameters on global mass loss during the one-dimensional diffusion combustion of coal samples were simulated and compared with TGA experiments conducted within a range of oxygen concentrations between 3–21%. Using this method, key kinetic and oxygen diffusion parameters were obtained within reasonable ranges by using a genetic algorithm optimization method. With these optimized parameters, the local oxygen distribution profiles in the samples at different inlet oxygen concentrations were simulated. The results indicate that oxygen diffusion can lead to large oxygen concentration differences within the coal samples, exceeding 63% of the inlet oxygen concentration. These oxygen differences can impact the local chemistry throughout the sample, and lead to fundamental errors in analyzing global kinetic analyses, if the transport effects are not considered. Altogether, this study delivers new insights into a potentially rate-limiting phenomenon that is relevant in progressing knowledge on many fire problems and engineering applications.

Evidence for direct CO2 -mediated alterations in cerebral oxidative metabolism in humans.

How the cerebral metabolic rates of oxygen and glucose utilization (CMRO2 and CMRGlc, respectively) are affected by alterations in arterial PCO2 (PaCO2) is equivocal and therefore was the primary question of this study. This retrospective analysis involved pooled data from four separate studies, involving 41 healthy adults (35 males/6 females). Participants completed stepwise steady-state alterations in PaCO2 ranging between 30 and 60 mmHg. The CMRO2 and CMRGlc were assessed via the Fick approach (CBF × arterial-internal jugular venous difference of oxygen or glucose content, respectively) utilizing duplex ultrasound of the internal carotid artery and vertebral artery to calculate cerebral blood flow (CBF). The CMRO2 was altered by 0.5 mL × min-1 (95% CI: -0.6 to -0.3) per mmHg change in PaCO2 (p < 0.001) which corresponded to a 9.8% (95% CI: -13.2 to -6.5) change in CMRO2 with a 9 mmHg change in PaCO2 (inclusive of hypo- and hypercapnia). The CMRGlc was reduced by 7.7% (95% CI: -15.4 to -0.08, p = 0.045; i.e., reduction in net glucose uptake) and the oxidative glucose index (ratio of oxygen to glucose uptake) was reduced by 5.6% (95% CI: -11.2 to 0.06, p = 0.049) with a + 9 mmHg increase in PaCO2. Collectively, the CMRO2 is altered by approximately 1% per mmHg change in PaCO2. Further, glucose is incompletely oxidized during hypercapnia, indicating reductions in CMRO2 are either met by compensatory increases in nonoxidative glucose metabolism or explained by a reduction in total energy production.

Changes in temporal lobe activation during a sound stimulation task in patients with sensorineural tinnitus: a multi-channel near-infrared spectroscopy study

BackgroundThe subjective sign of a serious pandemic in human work and life is mathematical neural tinnitus. fNIRS (functional near-infrared spectroscopy) is a new non-invasive brain imaging technology for studying the neurological activity of the human cerebral cortex. It is based on neural coupling effects. This research uses the fNIRS approach to detect differences in the neurological activity of the cerebral skin in the sound stimulation mission in order to better discriminate between the sensational neurological tinnitus.MethodsIn the fNIRS brain imaging method, 14 sensorineural tinnitus sufferers and 14 healthy controls listened to varied noise and quiet for fNIRS data collection. Linear fitting was employed in MATLAB to eliminate slow drifts during preprocessing and event-related design analysis. The false discovery rate (FDR) procedure was applied in IBM SPSS Statistics 26.0 to control the false positive rate in multiple comparison analyses.ResultsWhen the ill group and the healthy control group were stimulated by pink noise, there was a significant difference in blood oxygen concentration (P < 0.05), and the healthy control group exhibited a high activation, according to the fNIRS measurement data. The blood oxygen concentration level in the patient group was dramatically enhanced after one month of acupuncture therapy under the identical stimulation task settings, and it was favorably connected with the levels of THI and TEQ scales.ConclusionsUsing sensorineural tinnitus illness as an example, fNIRS technology has the potential to disclose future pathological study on subjective diseases throughout time. Other clinical disorders involving the temporal lobe and adjacent brain areas may also be examined, in addition to tinnitus-related brain alterations.

Autoimmune Disorders in Heart Failure With Preserved Ejection Fraction

BackgroundInflammation plays a fundamental role in the pathogenesis of heart failure with preserved ejection fraction (HFpEF). In most patients, inflammation develops secondary to cardiometabolic comorbidities, but in some, HFpEF develops in the setting of an underlying systemic inflammatory disease such as rheumatoid arthritis or systemic lupus erythematosus. ObjectivesThis study aimed to investigate the prevalence, pathophysiology, and outcome of patients with HFpEF and autoimmune or primary inflammatory disorders. MethodsOf 982 consecutively evaluated patients with HFpEF diagnosed, 79 (8.0%) had autoimmune disorders. HFpEF was defined by invasive cardiopulmonary hemodynamic exercise testing. ResultsFemale sex, higher heart rate, lower hemoglobin, absence of atrial fibrillation, and absence of coronary artery disease were independently associated with autoimmune disorders. Hemodynamics at rest and exercise did not differ between the groups, but peripheral oxygen extraction was lower in those with autoimmune disorders, reflected by lower arterial-venous oxygen content difference at rest (4.2 ± 0.7 mL/dL vs 4.6 ± 1.0 mL/dL; P < 0.001) and during exercise (9.3 ± 2.2 mL/dL vs 10.4 ± 2.2 mL/dL; P < 0.001), suggesting a greater peripheral deficit, and ventilatory efficiency (VE/VCo2 slope, regression slope relating minute ventilation to carbon dioxide output) was also more impaired (38.0 ± 7.9 vs 36.2 ± 7.3; P = 0.043). Patients with autoimmune disorders had a higher risk of death or heart failure (HF) hospitalization compared with those without in adjusted analyses (HR: 1.95 [95% CI: 1.17-3.27]; P = 0.011) over a median follow-up of 3.0 years, which was primarily attributable to higher risk of HF hospitalization (HR: 2.87 [95% CI: 1.09-7.57]; P = 0.033). ConclusionsPatients with HFpEF and autoimmune disorders have similar hemodynamic derangements but greater peripheral deficits in oxygen transport and higher risk for adverse outcome compared with those without.

Effect of horizontal magnetic field position on oxygen distribution in CZ silicon crystal growth

The horizontal magnetic field-assisted Czochralski(CZ) method is gaining significant popularity in the semiconductor industry for producing 200 mm semiconductor-grade silicon wafers. In this study, the impact of the horizontal magnetic field position on the oxygen content and radial uniformity of semiconductor-grade silicon crystals produced by the CZ method was investigated. Three-dimensional simulations were conducted using finite element software to calculate the melt convection and oxygen content before and after adjustment of the magnetic field position, respectively. The simulations results predicted a decrease in the oxygen content of the crystals following the adjustment of the magnetic field position from 0 to 75 mm below the free surface, and this was experimentally verified. The velocity distribution of the free melt surface exhibits better uniformity when lowering the magnetic field position. The influence of the magnetic field position on the temperature distribution and Marangoni flow in the melt was investigated, and the result of oxygen concentration difference identified the adjustment of the magnetic field position promoted the greater Marangoni flow below the free melt surface, which promoted the volatilization of SiO gas and thus reduced the oxygen concentration in the silicon ingot. Therefore, adjusting the position of the magnetic field is an effective way to increase the Marangoni flow and to obtain semiconductor-grade silicon crystal with lower oxygen content and better oxygen radial homogeneity.

Leakage of water-cooled wall tube in subcritical boiler

Usually, heating surfaces used in thermal power plant boilers include economizers, water-cooled walls, superheaters, and reheaters, abbreviated as the “four tubes” of boilers. The leakage of the heating surface is a common form of unplanned shutdown in thermal power plants, accounting for more than 50% of abnormal shutdown accidents of units. Once the heating surface explosion occurs, the thermal power plant needs to shut down for treatment, resulting in huge losses in power generation and fuel consumption during startup and shutdown. This has a huge impact on the safety production and economic benefits of the enterprise. In this paper, the leaked water-cooled wall tube in the subcritical boiler was studied by means of microstructure analysis, hardness test, energy spectrum analysis, chemical composition test, macro-morphology inspection, and tensile test. The results revealed that the oxygen concentration difference between the area installed in ceiling pouring material and the area exposed to the air can result in significant differences in electrode potential between different areas of the front water wall tube passing through the ceiling. An oxygen concentration difference battery is formed. In this way, the water-cooled wall steel pipe continuously corroded and thinned. Finally, perforation leakage occurred under the pressure of the internal high-temperature medium.

Controlling splat boundary network evolution towards the development of strong and ductile cold sprayed refractory metals: The role of powder characteristics

Feedstock powder characteristics such as composition (specific alloying elements and concentrations and impurity levels), microstructure, thickness/composition of surface oxide layers, and particle size distribution play a crucial role in determining the overall mechanical properties of cold sprayed deposits. Herein, we report on two deposits consolidated via cold spray processing from differently-sourced batches of nominally identical elemental refractory powders under identical spraying conditions, which exhibit bending strength and ductility values that differ by more than a factor of two – and with the weakest sample displaying negligible effective ductility. Through chemical, microstructural and micromechanical characterization of both the feedstock powders and cold sprayed deposits, we consider the possible influences of feedstock characteristics on the mechanical performance of cold spray consolidated deposits. It is shown that while differences in interstitial oxygen and hydrogen content may result in differences in the intrinsic yield characteristics of the feedstock material, both feedstocks maintain the ductile behavior required to induce good metallurgical bonding upon impact of optimally sized powder particles. We conclude that the deposits formed from the two feedstock powders are indistinguishable and exhibit high ductility when characterized locally within the relatively undeformed bulk of a single particle or splat. However, the two sprayed deposits show low ductility or brittle behavior when loaded in tension across intersplat boundary domains comprising material that has undergone extensive deformation. In addition, one feedstock incorporates a broader particle size distribution, with a long tail of larger-than-optimal particles. These larger particles are accelerated below the critical impact velocity, resulting in observed imperfect metallurgical bonding at splat interfaces and higher porosity at such intersplat boundaries. This result, combined with the overall differences in the morphology of the intersplat boundary network between the two deposits, explains the difference in macroscopic mechanical behavior. We conclude that accurate control of the powder feedstock particle size distribution is essential for optimizing the mechanical integrity of cold sprayed refractory elements and alloys.

Research progress of diagnostic and therapeutic value of carbon dioxide-derived indicators in patients with sepsis

Effectively assessing oxygen delivery and demand is one of the key targets for fluid resuscitation in sepsis. Clinical signs and symptoms, blood lactic acid levels, and mixed venous oxygen saturation (SvO2) or central venous oxygen saturation (ScvO2) all have their limitations. In recent years, these limitations have been overcome through the use of derived indicators from carbon dioxide (CO2) such as mixed veno-arterial carbon dioxide partial pressure difference (Pv-aCO2, PCO2 gap, or ΔPCO2), the ratio of mixed veno-arterial carbon dioxide partial pressure difference to arterial-mixed venous oxygen content difference (Pv-aCO2/Ca-vO2). Pv-aCO2, PCO2 gap or ΔPCO2 is not a purely anaerobic metabolism indicator as it is influenced by oxygen consumption. However, it reliably indicates whether blood flow is sufficient to carry CO2 from peripheral tissues to the lungs for clearance, thus reflecting the adequacy of cardiac output and metabolism. The Pv-aCO2/Ca-vO2 may serve as a marker of hypoxia. SvO2 and ScvO2 represent venous oxygen saturation, reflecting tissue oxygen utilization. When oxygen delivery decreases but tissues still require more oxygen, oxygen extraction rate usually increases to meet tissue demands, resulting in decreased SvO2 and ScvO2. But in some cases, even if the oxygen delivery rate and tissue utilization rate of oxygen are reduced, it may still lead to a decrease in SvO2 and ScvO2. Sepsis is a classic example where tissue oxygen utilization decreases due to factors such as microcirculatory dysfunction, even when oxygen delivery is sufficient, leading to decrease in SvO2 and ScvO2. Additionally, the solubility of CO2 in plasma is approximately 20 times that of oxygen. Therefore, during sepsis or septic shock, derived variables of CO2 may serve as sensitive markers for monitoring tissue perfusion and microcirculatory hemodynamics. Its main advantage over blood lactic acid is its ability to rapidly change and provide real-time monitoring of tissue hypoxia. This review aims to demonstrate the principles of CO2-derived variables in sepsis, assess the available techniques for evaluating CO2-derived variables during the sepsis process, and discuss their clinical relevance.

ВЛИЯНИЕ МИКРООКСИДАЦИИ МЕЗГИ НА ХИМИЧЕСКИЕ И ОРГАНОЛЕПТИЧЕСКИЕ ПОКАЗАТЕЛИ КРАСНЫХ ВИН

An urgent problem in modern wine-making is to ensure long-term preservation of the color of red wine, including when it is stored in bottles. The problem is associated with the oxidation of phenolic substances under the influence of oxygen. One of the ways to prevent oxidation is the use of microoxidation – introducing a certain amount of oxygen in order to oxidize labile fractions of polyphenols at an early stage of the wine production process. However, oxygen dosages require clarification and further research. The purpose of the research is to study the effect of microoxidation with various doses of oxygen on physical and chemical parameters, including the mass concentration of phenolic substances, of wine materials from the Cabernet Sauvignon grape variety. The objects of the study were production and experimental batches of wines made from the Cabernet Sauvignon grape variety. The oxygen dosage varied from 2 to 10 mg/dm3 . A significant difference in the mass concentration of oxygen in industrial samples was established – from 0.5 to 4.3 mg/dm3 . A correlation was revealed between the color of the wine and the oxygen content: the test samples with the highest mass concentration of oxygen had garnet-red shades of color. It was shown that the concentration of all groups of phenolic substances depended on the location of the grapes and the wine producer. The greatest accumulation of the amount of phenolic substances was in wine produced in the geographical area of Novorossiysk. A general trend of changes in the concentration of various groups of phenolic compounds depending on the dosage of oxygen was revealed: with an increase in the dosage of oxygen, the concentration of the components of the phenolic complex decreases, with anthocyanins undergoing the greatest change. The concentration of catechins decreased gradually with increasing oxygen dosage. For procyandins, dosing 2-4 mg/dm3 immediately led to a decrease in their concentration by 10-15 %. A further increase in the oxygen dosage did not cause a change in the concentration of procyanidins. It has been proven that an oxygen dosage of 2-4 mg/dm3 ensures high organoleptic properties of red wine. Key words: RED WINES, PHENOLIC COMPOUNDS, MICROOXIDATION, OXIDATION, ORGANOLEPTIC EVALUATION

145 The effect of a plant secondary metabolite blend on energy metabolism and nutrient balance of beef cattle consuming low-quality warm season grass hay

Abstract Plant secondary metabolites (PSM) such as condensed tannins, hydrolysable tannins, saponins and essential oils purportedly impact rumen fermentation at low inclusion rates in beef cattle diets. Twelve steers (347 ± 23 kg BW) of British and continental influence were allocated to 1 of 4 replicated 3 x 3 Latin squares. Latin squares each had 14 d periods (10 d adaptation and 4 d for sample collection). All cattle were fed ground warm-season hay (89.5% DM, 92.8% OM, 65.9% NDF, 43.6% ADF, 6.70% CP) at 1.5% of BW (DM-basis) and supplemented with soybean meal at 0.18% of BW (DM-basis) once daily. Treatments consisted of a blend of tannins, saponins and essential oils provided at 0% (Control), 0.1% (Low) and 0.3% (High) of hay offering. Treatments were mixed with daily soybean meal allotment and provided before feeding of hay. Urine and feces were completely collected from d 11 through 14 at 0730 h and daily amounts of urine and feces produced were measured gravimetrically. Measures of gaseous exchange were determined via indirect calorimetry on d 13 and 14. Open-circuit respiration calorimeters (91.4 × 91.4 × 191.2 cm) were used to collect respired gas and ruminal methane production. Total oxygen consumption and production of carbon dioxide and methane were calculated from the difference in concentration of oxygen, carbon dioxide, and methane from air exhausted from each calorimeter and concentration of oxygen, carbon dioxide, and methane in ambient air and multiplied by amounts of air flowing from each calorimeter standardized for temperature, pressure, and humidity. Data were analyzed for a Latin square using the MIXED procedure of SAS with fixed effect of treatment, period and square and random effect of steer. Linear and quadratic contrast coefficients were assigned using PROC IML for uneven spacing of treatments. Significance was declared when P ≤ 0.05. Per experimental design, forage N and OM intake did not differ (P ≥ 0.77). Apparent total tract digestion of OM, NDF and ADF did not differ (P ≥ 0.66) among treatments. Fecal nitrogen excretion, and the percentage of N excreted in feces increased linearly (P = 0.01). N balance tended (P = 0.08) to decrease linearly with increasing PSM supplemented. Methane (L/kg DMI) was not affected (P = 0.28) by treatments. Methane, GE, DE, and ME (mcal/kg DMI) was unaffected (P = 0.19) by treatment. Under the conditions of this experiment, a blend of PSM had little effect on rumen fermentation or energy metabolism in beef steers.

Overdot and overline annotation must be understood to accurately interpret O2MAX physiology with the Fick formula.

Few formulas have been used in exercise physiology as extensively as the Fick formula, which calculates the rate of oxygen consumption (i.e., V.O2) as the product of cardiac output (Q.) and the difference in oxygen content in arterial and mixed venous blood (ΔaO2). Unfortunately, the physiology of maximum V.O2 (V.O2MAX) is often misinterpreted due to a lack of appreciation for the limitations represented by the oft-ignored superscript annotations in the Fick formula. The purpose of this perspective is to explain the meaning of the superscript annotations and highlight how such annotations influence proper interpretation of V.O2MAX physiology with the Fick formula. First, we explain the significance of the overdots above V.O2 and Q., which indicate a measure per unit of time. As we will show, the presence of an overdot above Q. and lack of one above ΔaO2 denotes they are different types of ratios and should be interpreted in the context of one another-not in contrast to each other as is commonplace. Second, we discuss the significance of the overline above the "" in ΔaO2, which indicates the venous sample is an average of blood that comes from mixed sources. The mixed nature of the venous sample has major implications for interpreting the influence of oxygen diffusion and blood flow heterogeneity on V.O2MAX. Ultimately, we give recommendations and insights for using the Fick formula to calculate V.O2 and interpret V.O2MAX physiology.

A Multi-Center Randomized Controlled Study Using ΔPCO2/Ca-vO2 as the Target to Guide Early Tissue Hypoperfusion in Sepsis in Plateau Areas

Objective: To explore the value of using the venous-arterial carbon dioxide partial pressure difference and the arterial-venous oxygen content difference ratio (ΔPCO2/Ca-vO2) as targets to guide early tissue hypoperfusion in sepsis in plateau areas. Methods: 90 sepsis patients admitted to the Third People’s Hospital of Xining and Golmud People’s Hospital from June 2017 to December 2022 were selected as the research subjects, and they were divided into the ScvO2 (central venous oxygen saturation) group and the ΔPCO2/Ca-vO2 group, with 45 cases in each group. The two groups were treated with early shock resuscitation according to different protocols. The hemodynamic characteristics of the two groups of patients before and after resuscitation were observed, and the volume responsiveness was evaluated. The ROC (receiver operating characteristic) curve was used to analyze the significance of ΔPCO2/Ca-vO2, ScvO2, lactate, lactate clearance, and urine output in evaluating patient prognosis and the correlation between ΔPCO2/Ca-vO2 and the above indicators was explored. Results: Compared with before resuscitation, after fluid resuscitation, the heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), cardiac index (CI), lactate, lactate clearance rate, and urine output of the two groups of patients were significantly improved (P &lt; 0.05); in terms of therapeutic effect, the 28-day mortality rate, 6-hour fluid balance, and lactic acid clearance of the ΔPCO2/Ca-vO2 group were better than the ScvO2 group. The ROC characteristic curve showed that the ΔPCO2/Ca-vO2 value can effectively predict the prognosis of patients (AUC = 0.907, sensitivity was 97%, specificity was 72.4%, and critical value was 1.84). ΔPCO2/Ca-vO2 significantly correlated with ScvO2, lactic acid, and lactic acid clearance rate. Conclusion: The ΔPCO2/Ca-vO2 value can be used to guide fluid resuscitation in early hypoperfusion in sepsis in plateau areas, improve patients’ hemodynamics, reduce lactate indicators, and increase urine output. ΔPCO2/Ca-vO2 level &gt; 1.84 can effectively improve patient prognosis.&#x0D; Corrigendum available at: https://www.doi.org/10.26689/jcnr.v8i2.6467

Recent Advances in MR Imaging-based Quantification of Brain Oxygen Metabolism.

The metabolic rate of oxygen (MRO2) is fundamental to tissue metabolism. Determination of MRO2 demands knowledge of the arterio-venous difference in hemoglobin-bound oxygen concentration, typically expressed as oxygen extraction fraction (OEF), and blood flow rate (BFR). MRI is uniquely suited for measurement of both these quantities, yielding MRO2 in absolute physiologic units of µmol O2 min-1/100 g tissue. Two approaches are discussed, both relying on hemoglobin magnetism. Emphasis will be on cerebral oxygen metabolism expressed in terms of the cerebral MRO2 (CMRO2), but translation of the relevant technologies to other organs, including kidney and placenta will be touched upon as well. The first class of methods exploits the blood's bulk magnetic susceptibility, which can be derived from field maps. The second is based on measurement of blood water T2, which is modulated by diffusion and exchange in the local-induced fields within and surrounding erythrocytes. Some whole-organ methods achieve temporal resolution adequate to permit time-series studies of brain energetics, for instance, during sleep in the scanner with concurrent electroencephalogram (EEG) sleep stage monitoring. Conversely, trading temporal for spatial resolution has led to techniques for spatially resolved approaches based on quantitative blood oxygen level dependent (BOLD) or calibrated BOLD models, allowing regional assessment of vascular-metabolic parameters, both also exploiting deoxyhemoglobin paramagnetism like their whole-organ counterparts.