Oxygen Tension Research Articles

Microstructural characteristics of the internal oxidation zone of ferritic/martensitic steel exposed to LBE at 550°C for 1000 h

The oxidation products formed on ferritic/martensitic (F/M) steel exposed to oxygen-saturated lead-bismuth eutectic (LBE) at 550 °C for 1000 h were investigated using various characterizations. The results indicate that the corrosion products consist of three distinct layers from the inside to the outside: the inner oxidation zone (IOZ), a middle oxide layer, and the growth front facing LBE. In the IOZ, although O has penetrated the entire oxidation layer, the martensite laths and ferrite grains remain visible. However, significant segregation of Cr and O along the laths and grain boundaries has occurred, resulting in the formation of strip-shaped Cr2O3 particles. In the matrix adjacent to the IOZ, Cr atoms have segregated at the grain boundaries and martensite laths, forming Cr-rich regions, while O atoms have not yet infiltrated. During the growth of Fe3O4 grains, the priority formed strip-shaped Cr2O3 particles are pushed toward the corrosion front until they detach from the F/M steel and disperse into the LBE, resulting in nearly pure Fe3O4 grains in the middle layer. The gradient three-layer structure of the oxidation product is closely associated with the segregation of Cr and the gradient distribution of oxygen partial pressure (PO2).

Case-control study on risk factors for in-hospital mortality in patients with severe COVID-19.

The purpose of this study was to identify independent risk factors affecting patient survival and explore predictors of severe cases of coronavirus disease 2019 (COVID-19). We conducted a retrospective, observational, case-control study on adult patients with severe COVID-19 who were admitted to affiliated hospitals in Tianjin between December 18, 2022, and January 31, 2023. We used univariate and multifactorial logistic regression analyses to analyze demographic indicators, comorbidity profiles, and laboratory parameters in two groups of patients (deceased and surviving) to identify independent risk factors for death in patients with severe COVID-19. Patients in the deceased group were older than those in the survival group (p = 0.018), and there were more cases of coexisting respiratory insufficiency in the deceased group (p = 0.002). Additionally, laboratory test results for white blood cell count (WBC) and creatine kinase (CK) showed significantly higher values in the deceased group (p = 0.047 and p = 0.029, respectively), while arterial oxygen partial pressure (PAO2) showed significantly lower values compared to the survival group (p = 0.021). Age, respiratory insufficiency, WBCH (highest WBC value), CKH (highest CK value), and PAO2F (first PAO2 value) had area under curve (AUC) values of 0.698, 0.838, 0.721, 0.744, and 0.633, respectively. The main risk factors for mortality in patients with severe COVID-19 that we identified in this study were the advanced age of patients, coexisting respiratory insufficiency, elevated levels of WBC and CK, and decreased levels of PAO2. Elevated WBC and CK laboratory parameters, in particular, demonstrated good predictive value for in-hospital mortality risk.

Effect of N-acetylcysteine in treatment of COPD with pulmonary interstitial fibrosis, inflammatory factors and VEGF levels

Purpose: To investigate the efficacy of N-acetylcysteine as an adjuvant therapy in chronic obstructive pulmonary disease (COPD) with pulmonary interstitial fibrosis (PIF), and its effect on inflammatory factors and serum vascular endothelial growth factor (VEGF) levels. Methods: A total of 94 patients with COPD-PIF from May 2020 to May 2022 in Wuhan Fourth Hospital, China were equally randomized into study and control groups. Control group was administered conventional treatment while the study group was given N-acetylcysteine in addition to conventional treatment. Therapeutic efficacy, forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), FEV1/FVC, blood gas, pulmonary fibrosis, and oxidative stress were evaluated. Changes in inflammatory factors, serum vascular endothelial growth factor (VEGF), and incidence of adverse drug reactions were compared. Results: The study group showed significantly higher efficacy, FEV1, FVC, FEV1/FVC compared to control group (p < 0.05). Also, study group showed significantly higher partial pressure of oxygen (PaO2), blood oxygen saturation, superoxide dismutase (SOD), and glutathione (GSH) levels after treatment compared to control group (p < 0.05). Platelet-derived growth factor (PDGF), transforming growth factor (TGF-β), vascular cell adhesion molecule (VCAM), tumor necrosis factor (TNF), interleukin-6 (IL-6), and vascular endothelial growth factor (VEGF) levels after treatment were significantly lower in the study group than in the control group (p < 0.05). Conclusion: N-acetylcysteine as an adjuvant therapy for COPD-IF is highly effective, improves lung function and oxidative stress, reduces airway inflammation, and VEGF, and attenuates the degree of hypoxia and pulmonary fibrosis with no serious adverse effects. A larger sample size, multicenter, randomized trials to validate these findings and evaluate the downstream regulatory mechanism of Nacetylcysteine in COPD-PIF.

MCM proteins are up-regulated in placentas of women with reduced insulin sensitivity.

In the first trimester of pregnancy the human placenta grows rapidly, making it sensitive to changes in the intrauterine environment. To test whether exposure to an environment in utero often associated with obesity modifies placental proteome and function, we performed untargeted proteomics (LC-MS/MS) in placentas from 19 women (gestational age 35-48 days, i.e. 5+0-6+6 weeks). Maternal clinical traits (body mass index, leptin, glucose, C-peptide and insulin sensitivity) and gestational age were recorded. DNA replication and cell cycle pathways were enriched in the proteome of placentas of women with low maternal insulin sensitivity. Driving these pathways were the minichromosome maintenance (MCM) proteins MCM2, MCM3, MCM4, MCM5, MCM6 and MCM7 (MCM-complex). These proteins are part of the pre-replicative complex and participate in DNA damage repair. Indeed, MCM6 and γH2AX (DNA-damage marker) protein levels correlated in first trimester placental tissue (r = 0.514, P<0.01). MCM6 and γH2AX co-localized to nuclei of villous cytotrophoblast cells, the proliferative cell type of the placenta, suggesting increased DNA damage in this cell type. To mimic key features of the intrauterine obesogenic environment, a first trimester trophoblast cell line, i.e., ACH-3P, was exposed to high insulin (10 nM) or low oxygen tension (2.5% O2). There was a significant correlation between MCM6 and γH2AX protein levels, but these were independent of insulin or oxygen exposure. These findings show that chronic exposure in utero to reduced maternal insulin sensitivity during early pregnancy induces changes in the early first trimester placental proteome. Pathways related to DNA replication, cell cycle and DNA damage repair appear especially sensitive to such an in utero environment.

Empiric gram-negative antibiotics usage among critically ill patients across 13 ICUs of Nepal: A retrospective cohort study

Background This study aims to investigate the associations between patient characteristics and the receipt of empiric broad-spectrum gram-negative antimicrobials among adult patients admitted to ICUs in Nepal. Methods A retrospective cohort study was conducted in 13 ICUs in Nepal between January 1st, 2020, and December 31st, 2022. Empiric antibiotic use was defined as receiving gram-negative antibiotics within the first two days of ICU admission without evidence of infection from culture. Patient characteristics between patients receiving narrow-spectrum antibiotics and broad-spectrum gram-negative antibiotics were compared. Continuous variables were compared using mean and standard deviation, with mean differences and 95% confidence intervals calculated. Categorical variables were compared using the chi-square test. A multi-level multivariable regression model assessed the relationship between selected variables and broad-spectrum antibiotic usage, treating admitting ICU as a random factor. Results Among 12,349 eligible patients, 8720 (70.6%) received Empiric gram-negative antibiotics. Of those, 3240 (37.15%) received empiric narrow-spectrum gram-negative antibiotics, and 5480 (62.8%) received Empiric broad-spectrum gram-negative antibiotics. Patients receiving broad-spectrum gram-negative antibiotics were older (57.4 vs 53.8 yrs); had higher mean heart rates (97.3 vs 89.5 bpm), respiratory rates (24 vs 21.9), a fraction of inspired oxygen ( 50% vs 40%), blood sugar levels (163.4 vs 153.9 mg/dl), total leucocyte counts (12,685 vs 10,647 cells/cu mm) and serum creatinine (2.06 vs 1.03 umol/l) compared to narrow spectrum antibiotics. Similarly, patients receiving broad-spectrum gram-negative antibiotics had lower systolic blood pressure (122.6 vs 126.5 mm Hg), partial pressure of oxygen (96.7 vs 105.3), and pH ( 7.33 vs 7.36) compared to narrow-spectrum antibiotics. On multivariable regression; patients with readmission, cardiac support, and mechanical ventilation were more likely to receive broad-spectrum antibiotics. Conclusion The rate of empiric broad-spectrum gram-negative antibiotics usage in intensive care units is significantly high and associated with features of increased severity of illness.

Colorimetric Oxygen Sensing by Analyzing Chromaticity Points for Polymer Cobalt Schiff Base in CIELAB

AbstractPolymer membranes of a copolymer ligand (L) coordinated to tetra‐coordinated N,N'‐ethylene bis(salicylideneiminato) cobalt(II) at the fifth coordinating site of the center cobalt(II), Co(II)S‐L, are prepared to measure colorimetrically the color changes in response to rapid reversible oxygen binding simultaneously with slow oxidation under moist conditions to yield Co(III)S‐L. The chromaticity point observed in CIELAB is the endpoint of the vector sum of the unit vectors for Co(II)S‐L, O2‐Co(II)S‐L, and Co(III)S‐L, scaled by their respective abundance ratios: (1 − m)(1 − n), m(1 − n), and n, where m is the ratio of O2‐Co(II)S‐L to the sum of Co(II)S‐L and O2‐Co(II)S‐L and n is the ratio of Co(III)S‐L to the total of the three cobalt complexes. The observed limited area in CIELAB as a stoichiometric Euclidean space is supported by the following two different reaction processes of the polymer membranes: an oxygen‐binding reaction under several different partial pressures of oxygen supplied to the membranes in a short period, during which oxidation of the cobalt(II) complexes is negligible, and an oxidation reaction over a long period at a constant partial pressure of oxygen. The chromaticity points in both processes progress linearly in three different two‐dimensional coordinates: a*b*, a*L*, and b*L*.

Effect of Temperature and Oxygen Concentration on Corrosion of J55 Steel in an O2/CO2 Environment

ABSTRACTThe corrosion product competition and transformation process of J55 under an O2/CO2 environment in the temperature range of 50–350°C and 0–1 MPa oxygen partial pressure range, respectively, were studied using electrochemical and surface analysis techniques as well as thermodynamic calculations to determine its corrosion rate change law and pitting corrosion phenomenon. This study demonstrates that the uniform corrosion rate of J55 with increasing temperature shows a trend of first increasing, then decreasing, and finally increasing. The transformation of its corrosion products, from FeCO3 into Fe3O4, is consistent with the altering corrosion rate law with increasing temperatures. J55 corrodes faster at 350°C as the O2 partial pressure increases. When the O2 partial pressure is low, the predominant kind of corrosion product that is obtained is FeCO3; when the O2 partial pressure exceeds 0.2 MPa, all corrosion products are transformed into iron oxides. As the oxygen partial pressure increases, J55's corrosion product film becomes increasingly less protective of the substrate, making the substance more vulnerable to corrosion reactions.

Local structure maturation in high entropy oxide (Mg,Co,Ni,Cu,Zn)1‐x(Cr,Mn)xO thin films

AbstractHigh entropy oxides (HEOs) have garnered much interest due to their available high degree of tunability. Here, we study the local structure of (MgNiCuCoZn)0.167(MnCr)0.083O, a composition based on the parent HEO (MgNiCuCoZn)0.2O. We synthesized a series of thin films via pulsed laser deposition at incremental oxygen partial pressures. X‐ray diffraction shows lattice parameters to decrease with increased pO2 pressures until the onset of phase separation. X‐ray absorption fine structure shows that specific atomic species in the composition dictate the global structure of the material as Cr, Co, and Mn shift to energetically favorable coordination with increasing pressure. Transmission electron microscopy analysis on a lower‐pressure sample exhibits a rock salt structure, but the higher‐pressure sample reveals reflections reminiscent of the spinel structure. In all, these findings give a more complete picture of how (MgNiCuCoZn)0.167(MnCr)0.083O forms with varying initial conditions and advances fundamental knowledge of cation behavior in high entropy oxides.

Element behavior during autoclave oxidation of polymetallic sulfide flotation concentrate containing tungsten and molybdenum

In this paper, we investigate the behavior of associated elements (tungsten, molybdenum, and bismuth) contained in a sulfide gold-bearing concentrate during its autoclave oxidation. The process is studied using a sulfide flotation concentrate, crushed to a particle sieve mesh size of minus 0.045 mm and containing 22.1 g/t of gold, 133.2 g/t of silver, 2.7% of tungsten, 13% of molybdenum, and 0.7% of bismuth. The process was carried out in a 2 dm3 autoclave at a temperature of 220ºC and an oxygen partial pressure of 0.7 MPa. The concentrations of sulfuric acid and iron ions in the solution were determined by titrimetric analysis. Inductively coupled plasma atomic emission spectroscopy was used to determine the concentrations of bismuth, tungsten, molybdenum, copper, silver, and arsenic in the solution, as well as the content of bismuth, tungsten, molybdenum, copper, arsenic, lead, and iron and sulfur forms in the cake. The cake was also examined using diffraction analysis. Experiments on cyanidation of oxidized cake were carried out in the pH range of 10.0–10.5 and a NaCN concentration of 1 g/dm3 with a PuroliteS992 ion exchange resin for 24 h. Autoclave oxidation experiments showed the sulfide oxidation degree to be higher than 99%. Extraction of molybdenum into solution in the form of [MoO2(SO4)n]-(2n-2) and MoO 2+ amounted to 95%. The decrease in the solid mass led to an increase in the concentration of bismuth and tungsten in the cake, with their contents reaching 1.66% and 12.7%, respectively. The main phases in the cake were established to be scheelite, anhydrite, plumboyarosite, and bedantite. The extraction of precious metals at the subsequent cyanidation stage amounted to 97.5% of gold and 91.6% of silver. Therefore, autoclave cyanide processing of sulfide gold-containing concentrates leads to a molybdenum extraction in the autoclave oxidation solution at the level of 95%. During cyanidation, more than 90% of gold and silver are extracted. Due to the significant amount of tungsten (17%), bismuth (0.9%), lead (5.3%), and molybdenum (3.3%), the obtained cake cannot be considered a waste product.

Combined optical measurement of dissolved oxygen tension (DOT), pH value, biomass and viscosity in shake flasks

Shake flasks are widely spread in microbial process development. Characterization of the processes by manual offline sampling is time-consuming, highly laborious and a contamination risk. Online monitoring of key parameters would provide deeper insights, while saving time and effort. In this study, a device for optical online monitoring of dissolved oxygen tension (DOT), biomass, pH value and viscosity in shake flasks is presented. DOT measurement relies on fluorescent oxygen sensitive nanoparticles. The fluorescence intensity signal of the nanoparticles is used to trigger the DOT and scattered light measurements inside the rotating bulk liquid. The scattered light signal (610 – 630 nm) can be correlated to offline measured optical density OD600, even at elevated viscosity. The pH value is monitored online by using pH sensor spots, fixed inside the shake flasks. The shift of the angle of the bulk liquid Θ-Θ0 is correlated to the offline measured viscosity. Detection of the leading edge of the bulk liquid, necessary for viscosity measurement, can be performed either using the fluorescence intensity signal of the oxygen nanoparticles or the scattered light signal.

Associations of arterial oxygen partial pressure with all‑cause mortality in critically ill ischemic stroke patients: a retrospective cohort study from MIMIC IV 2.2

BackgroundAs a supportive treatment, the effectiveness of oxygen therapy in ischemic stroke (IS) patients remains unclear. This study aimed to evaluate the relationships between arterial partial pressure of oxygen (PaO2) and both consciousness at discharge and all-cause mortality risk in ICU IS patients.MethodsBlood gas measurements for all patients diagnosed with IS were extracted from the MIMIC-IV database. Patients were classified into four groups based on their average PaO2 during the first ICU day: hypoxemia (PaO2 < 80 mmHg), normoxemia (PaO2 80–120 mmHg), mild hyperoxemia (PaO2 121–199 mmHg), and moderate/severe hyperoxemia (PaO2 ≥ 200 mmHg). The primary endpoint was 90-day all-cause mortality. Secondary outcomes included the level of consciousness at discharge, assessed by the Glasgow Coma Scale (GCS), and 30-day all-cause mortality. Multivariate Cox regression and Restricted cubic spline (RCS) analysis were used to investigate the relationship between mean PaO2 and mortality, and to assess the nonlinear association between exposure and outcomes.ResultsThis study included a total of 946 IS patients. The cumulative incidence of 30-day and 90-day all-cause mortality increased with decreasing PaO2 levels. RCS analysis revealed a nonlinear relationship between PaO2 and the risk of 30-day all-cause mortality (nonlinear P < 0.0001, overall P < 0.0001), as well as a nonlinear association between PaO2 and 90-day all-cause mortality (nonlinear P < 0.0001, overall P < 0.0001). The results remained consistent after excluding the small subset of patients who received reperfusion therapy. Sensitivity analysis indicated that the favorable impact on survival tends to increase with the extended duration of elevated PaO2.ConclusionsFor IS patients who do not receive reperfusion therapy or whose recanalization status is unknown, a lower PaO2 early during ICU admission is considered an independent risk factor for short-term and recent mortality. Adjusting respiratory parameters to maintain supraphysiological levels of PaO2 appears to be beneficial for survival, although this finding requires further validation through additional studies.Trial registrationNot applicable.

A compact machine perfusion device for whole blood perfusion in isolated rat liver.

We established a compact machine perfusion system for whole blood perfusion of rat liver by making use of oxygenation filters as an artificial lung. Livers removed from rats were divided into Krebs-Henseleit (control), 50% blood (hemoglobin: 7g/dL), and whole blood (hemoglobin: 14g/dL) groups, then perfused (total perfusate volume: 25ml) with a small oxygenation filter at 37°C for 120min. Blood or perfusate was collected over time, and blood gas and blood cell were measured. In addition, bile volume and portal venous pressure measurements were taken. In all groups, the partial pressure of oxygen was controlled to approximately 400mmHg. Flow rates were maintained at approximately about 20-30ml/min according to liver size. Portal venous pressure was normal in the 50% blood and whole blood groups, while lower than the reference value in the Krebs-Henseleit group. Twice as much bile was produced in the 50% blood and whole blood groups relative with the Krebs-Henseleit group. We observed no differences in hemoglobin and red blood cell levels. Lactate levels were normal in the 50% blood and whole blood groups, but were elevated in the Krebs-Henseleit group. Our compact perfusion system using oxygenation filters was able to maintain rat liver function by perfusing a small amount of extracorporeal blood. This system is simple and stable, and may contribute to the future development of machine perfusion systems.

Hemodynamic Disorders in Alcohol Withdrawal Syndrome

INTRODUCTION: The introduction of the study is determined by a high prevalence of alcoholism and a high incidence of complications from the cardiovascular system. AIM: To study the features of hemodynamics in patients with uncomplicated alcohol withdrawal syndrome (AWS) and in those with alcohol withdrawal delirium (delirium tremens). MATERIALS AND METHODS: The study enrolled 116 men, 58 of them with uncomplicated AWS, 78 with AWS and delirium. Basic hemodynamic parameters were studied: heart rate (HR), blood pressure (BP), and integral parameters — cardiac index (CI), total peripheral resistance (TPR), shock index (SI). Comparisons between the groups and correlation analysis were conducted to find relationships between hemodynamic parameters and clinical data. RESULTS: In patients with alcoholic delirium, hemodynamic parameters were statistically significantly higher than in patients with uncomplicated AWS: HR (р = 0.003), systolic BP (р = 0.02) and diastolic BP (р = 0.04), while no statistically significant differences in the integral parameters (CI, TPR, SI) were found between the groups. In patients of both groups, CI linearly decreased with age (p 0.0001). The same linearly CI decreased with increase in the duration of alcoholism (p = 0.02). With an increase in the amount of consumed alcohol during the binge period, a linear growth of CI was observed in withdrawal state (p = 0.001). The value of TPR increased with age (p = 0.005). Only in patients with delirium tremens, there was an inverse relationship between SI and partial tension of carbon dioxide in venous blood (r = -0.4; p = 0.014). Besides, only in patients with delirium tremens, by the 7th day of withdrawal, a direct relationship was established between the cardiac index and blood potassium level (r = 0.36; p = 0.03). CONCLUSIONS: There was no significant difference between hemodynamic parameters in uncomplicated AWS and in delirium tremens. CI in patients with uncomplicated AWS and in those with DT decreased with age and with increase in the alcohol load. The vessel tone was inversely proportional to CI throughout the entire period of observation. With the development of delirium, a correlation was noted between a decrease in the level of energy metabolism and the probability for decompensation of systemic circulation. At the stage of reduction of delirium tremens, a correlation was noted between CI and the blood potassium level that reflected the exhaustion of the cardiovascular system and reduction of its compensatory capacities.

NUPR1 modulates pulmonary embolism progression via smooth muscle cells phenotypic transformation

ObjectiveThis study aimed to investigate the role of Nuclear Protein 1 (NUPR1) in pulmonary embolism (PE) and its impact on the phenotypic transformation of pulmonary artery smooth muscle cells (PASMCs). MethodsA PE model was established via autologous pulmonary emboli infusion into the jugular vein. Partial Pressure of Oxygen (PaO2), Oxygenation Index (OI), Brain Natriuretic Peptide (BNP), and Troponin I (TnI) were measured, and lung tissue was subjected to hematoxylin-eosin (HE) staining. NUPR1 expression was assessed through Immunofluorescence and Western blot analyses. To investigate role of NUPR1, PE rats were treated with lentiviral vectors for NUPR1 knockdown (si-NUPR1) or overexpression (ov-NUPR1), and the effects on lung pathology were examined. NUPR1 expression was evaluated in human PASMCs. Additionally, PASMCs from SD rats were cultured under normoxic and hypoxic conditions to evaluate NUPR1 expression. Transfection of NUPR1 expression vectors into PASMCs allowed monitoring of phenotypic transformation-associated protein changes and PASMCs activity. ResultsIncreased NURP1 was observed in human-derived PASMCs. In PE rats, histological examination revealed ruptured pulmonary alveoli, exudate accumulation, interstitial edema, and infiltration of inflammatory cells, concomitant with elevated NUPR1 expression levels. Knockdown of NUPR1 in PE rats significantly improved lung tissue structure, reducing alveolar rupture and interstitial edema. Conversely, NUPR1 overexpression exacerbated lung damage, leading to increased inflammatory infiltration. NUPR1 expression in rat PASMCs remained stable under normoxic conditions; however, under hypoxic conditions, NUPR1 protein expression increased progressively over time. Subsequent upregulation of NUPR1 expression led to a decrease in the levels of contractile phenotype markers α-SMA and SM22α in PASMCs, accompanied by increased expression of synthetic phenotype markers Vimentin and OPN. This phenotypic shift was associated with enhanced cellular proliferation, invasion, and migration. ConclusionsElevated NUPR1 expression in PE exacerbates abnormal PASMCs proliferation by promoting their phenotypic transformation, thereby fostering the pathological progression of PE.

The atomic-level structure and stability of interfaces of Pt nanoparticles in alumina: An experimental and computational evaluation

The atomic-level structure of interfaces between Pt and a transition form of Al2O3 were studied using a combination of electron microscopy and first principles calculations. A model system of Pt nanoprecipitates in Al2O3 were formed in sapphire wafers via high-energy ion implantation of Pt followed by thermal annealing at 1000 °C in air. The Pt nanoparticles took the form of tetrahedra and truncated tetrahedra primarily bound by {111}Pt facets. The high prevalence of these facets motivated the development of density functional theory (DFT) based models of (111)Pt interfaces with six different chemical terminations of (2¯01) θ-alumina. The atomic-level structure of the Pt/Al2O3 interfaces was characterized with aberration-corrected scanning transmission electron microscopy (STEM) and the experimental images were compared to STEM image simulations of the DFT models. The model interface with Pt bonded to oxygen-terminated θ-Al2O3, with the Pt located on top of the O and with an underlying layer of octahedral Al, provided the best match to the experimental images. This interfacial termination is also the most stable for the thermal annealing conditions used based on thermodynamic calculations of the interfacial energy as a function of temperature and oxygen partial pressure. This experimentally verified model provides a basis for improving models of Pt/γ-alumina interfaces.

Advanced maternal age affects their frozen-thawed embryo susceptibility to high oxygen environment

Preimplantation embryos can experience stress from laboratory interventions and a sub-optimal culture environment. Though research has demonstrated advanced maternal age impairs oocyte quality, the response of embryos derived from such oocytes to vitrification-thawing and culture in a high oxygen (O2) environment in the assisted reproductive technology laboratory is unknown. Therefore, in this study, embryos produced by in vitro fertilization (IVF) using oocytes from two- and eight-month-old Swiss albino mice were vitrified and thawed during their 6–8 cell stage. and cultured at low oxygen (5%) tension (LOT) and high oxygen (20%) tension (HOT). Embryo development, apoptosis, inner cell mass (ICM) outgrowth proliferation ability in vitro and pluripotency were assessed. Embryos from advanced maternal age cultured at HOT showed reduced fertilizing ability (p < 0.05), poor survival post-thawing (p < 0.05), and increased apoptosis (p < 0.01) in comparison to sibling embryos cultured at LOT. Importantly, the extended culture of vitrified-thawed embryos from advanced maternal age led to a significant (p < 0.001) reduction in complete ICM outgrowth formation at HOT in comparison to the LOT environment. The findings of this study suggest that HOT is detrimental to embryos from advanced maternal age, and importantly, vitrified-thawed embryos are more susceptible to stress, which could have negative implications, especially during the peri-implantation developmental period.

A-342 Precision Evaluation of the pH, PO2 and PCO2 tests in the i-STAT® G3+ Cartridge using the i-STAT 1 System for Venous, Arterial and Capillary Whole Blood Specimens in Clinical Settings

Abstract Background Precise and accurate measurements of blood gases are important for the diagnosis, monitoring and treatment of respiratory, metabolic, and acid-base disturbances. This study demonstrates the precision of the pH, partial pressure of oxygen (PO2), and partial pressure of carbon dioxide (PCO2) tests in the i-STAT G3+ cartridge with the i-STAT 1 System in arterial, venous, and capillary whole blood specimens in point-of-care or clinical laboratory settings. Methods The precision of the i-STAT pH, PO2, and PCO2 tests in the i-STAT G3+ cartridge was assessed at external clinical sites by end-users using whole blood specimens across the measurement range for each test: pH (6.500 - 7.800 pH units), PO2 (5 - 700 mmHg), PCO2 (5.0 - 130.0 mmHg). The study included venous whole blood samples from ∼140 adult subjects (≥ 18 years) and arterial whole blood samples from ∼140 adult subjects at 3 clinical sites. Each whole blood sample was run in duplicate on the i-STAT G3+ cartridge. In addition, ∼140 specimens were collected in capillary tubes using two fingerstick draws from adult subjects and ∼20 capillary heel-stick specimens were collected into two capillary tubes from neonate subjects (birth - 28 days) at two clinical sites. Specimens used in this study were prospectively collected venous, arterial, or capillary specimens under an Institutional Review Board approved informed consent or were de-identified leftover venous or arterial specimens. For each specimen type, duplicates from each subject were grouped into subintervals based on their mean values. The subintervals included the medical decision levels of 7.300, 7.350 and 7.450 pH units for pH, 30, 45 and 60 mmHg for PO2 and 35, 45, 50 and 70 mmHg for PCO2. The estimates of the pooled standard deviation (SD) and pooled coefficient of variation (%CV), as well as their respective 95% confidence intervals were calculated for each subinterval. Results Across all specimen types (excluding outliers), the pooled SD for pH ranged from 0.00591 - 0.01747 pH units for subintervals 6.500 - 7.300, &amp;gt;7.300 - 7.450, &amp;gt;7.450 - 7.800 pH units. For PO2, the pooled SD ranged from 0.71 - 3.76 mmHg for subintervals 10 - 40 mmHg and &amp;gt;40 - 50 mmHg and the pooled %CV ranged from 1.63 - 8.76 %CV for subintervals &amp;gt;50 - 100 mmHg, &amp;gt;100 - 250 mmHg and &amp;gt;250 - 700 mmHg. For PCO2, the pooled SD ranged from 0.000 - 1.709 mmHg for subintervals 5.0 - 35.0 mmHg, &amp;gt;35.0 - 50.0 mmHg and &amp;gt;50.0 - 62.5 mmHg and the pooled %CV ranged from 1.10 - 3.62 %CV for subinterval &amp;gt;62.5 - 130.0 mmHg. Conclusions The precision study demonstrated that the pH, PO2 and PCO2 tests in the i-STAT G3+ cartridge when tested using the i-STAT 1 System deliver precise results within ∼2 minutes for venous, arterial, and capillary whole blood patient specimens when tested by end users in a point-of-care or clinical laboratory setting. These studies were funded by Abbott Laboratories.

A-329 Accuracy of the pH, PO2, and PCO2 Tests in the i-STAT® G3+ Cartridge Using the i-STAT 1 System for Venous, Arterial and Capillary Whole Blood Specimens in Clinical Settings

Abstract Background Precise and accurate measurements of blood gases are important for the diagnosis, monitoring and treatment of respiratory, metabolic, and acid-base disturbances. This study demonstrates the accuracy of the pH, partial pressure of oxygen (PO2), and partial pressure of carbon dioxide (PCO2) tests in the i-STAT G3+ cartridge with the i-STAT 1 System in arterial, venous, and capillary whole blood specimens in point of care or clinical laboratory settings. Methods The accuracy of the PO2, and PCO2 tests in the i-STAT G3+ cartridge was assessed at external clinical sites in a method comparison study using whole blood specimens across the measurement range for each test: pH 6.5-7.8, PO2 5-700 mmHg, PCO2 5.0-130.0 mmHg. Specimens used in this study were venous, arterial, and capillary specimens prospectively collected under Institutional Review Board-approved informed consent or were leftover de-identified venous or arterial specimens. The study included venous and arterial whole blood samples from ∼140 adult subjects (≥ 18 years) at 3 clinical sites, and capillary whole blood samples from ∼180 adult subject at 3 clinicals sites and ∼25 neonate subjects (birth to 28 days) at 2 clinical sites. The RapidPoint System was used as comparator. For venous and arterial whole blood, samples were collected and tested in duplicate on the i-STAT G3+ cartridge and in singlicate on the RapidPoint System. For capillary whole blood samples, adult fingerstick samples and neonate heel-stick samples were collected in capillary tubes and tested in singlicate on the i-STAT G3+ cartridge and on the RapidPoint System. Passing-Bablok regression was performed for venous and arterial whole blood samples combined, using the first replicate from the i-STAT G3+ cartridge versus the singlicate result from the comparator, and for capillary whole blood samples (adult and neonate combined) using the singlicate result from the i-STAT G3+ cartridge versus the singlicate result from the comparator. Results Passing-Bablok regression of i-STAT G3+ cartridge results versus the comparator was used to calculate slope and correlation coefficient (r). For adult venous and arterial whole blood results, pH had slope = 0.96 and r = 0.99, PO2 had slope = 1.05 and r = 1.00, and PCO2 had slope = 1.04 and r = 0.98. For adult and neonate capillary whole blood results, pH had slope = 1.02 and r = 0.98, PO2 had slope = 1.09 and r = 0.99, and PCO2 had slope = 1.07 and r = 0.96. Conclusions These results demonstrate that the i-STAT 1 System delivers accurate pH, PO2, and PCO2 test results with ∼2 minutes using the i-STAT G3+ cartridge for venous, arterial and capillary whole blood samples for adult and neonate subjects when tested by end-users in a point of care or clinical laboratory setting. This study was funded by Abbott Laboratories.

A-349 Evaluation of i-STAT® Point of Care Blood Gas Cartridges and Competitor Blood Gas Devices Against Reference Standard for PCO2 and PO2

Abstract Background The i-STAT System provides laboratory quality results in minutes at the patient’s bedside. Accurate and rapid test results are critical for clinical decision making in the presence of blood gas disorders, including oxygenation and acid-base status, where the partial pressure oxygen (PO2) and partial pressure carbon dioxide (PCO2) are needed. The purpose of this study was to compare the analytical performance of the PO2 and PCO2 tests in the i-STAT G3+ and i-STAT CG8+ cartridges to the theoretical PO2 and PCO2 in prepared reference standards. Two other blood gas instruments, a benchtop device and a laboratory device were also compared to the reference PO2 and PCO2. Methods Venous whole blood samples were contrived using saturation tonometry with U.S. NIST (National Institute of Science and Technology) traceable gas tanks to prepare the reference standards, which were value assigned to theoretical PO2 or PCO2 levels based on the molar composition of the gas mixture used. Eleven levels spanning the reportable range of each PO2 (5 mmHg - 800 mmHg) and PCO2 (5 mmHg - 130 mmHg) were prepared and tested in duplicate on the i-STAT G3+ and i-STAT CG8+ cartridges, benchtop device, and the laboratory device. Passing-Bablok linear regression analysis was performed to evaluate the slope and correlation coefficient, comparing each blood gas device against the reference PO2 and PCO2 values. Study designs followed CLSI (Clinical and Laboratory Standards Institute) EP09C-ED3:2018, Measurement Procedure Comparison and Bias Estimation using Patient Samples, 3rd Edition. Passing-Bablok regression analysis was also performed for the i-STAT cartridges and benchtop device against the laboratory device. Results The regression analysis was performed against the reference standards. For PO2, slopes for the i-STAT cartridges ranged from 0.93 - 0.97, the slope for the benchtop device was 0.99, and the slope for the laboratory device was 0.97. Correlation coefficients for all devices were 1.00. For PCO2, slopes for the i-STAT cartridges ranged from 0.98 - 1.02, the slope for the benchtop device was 0.85, and the slope for the laboratory device was 1.01. Correlation coefficients were 1.00 for the i-STAT cartridges and laboratory device, and 0.99 for the benchtop device. The regression analysis was also performed against the laboratory device. For PO2, slopes for the i-STAT cartridges ranged from 0.96 - 1.00, and the slope for the benchtop device was 1.02. Correlation coefficients for all devices were 1.00. For PCO2, slopes for the i-STAT cartridges ranged from 0.97 - 1.01, and the slope for the benchtop device was 0.85. Correlation coefficients were 1.00 for the i-STAT cartridges and 0.99 for the benchtop device. Conclusions The study demonstrated that the i-STAT G3+ and i-STAT CG8+ cartridges used with the i-STAT System were shown to provide laboratory quality results within 2 minutes, showing good agreement to both reference standards and laboratory quality devices. For PCO2, the i-STAT System was shown to have better agreement to both theoretical reference standards and the laboratory device than the benchtop device. These studies were funded by Abbott Laboratories.

Characterization of A-site doped PrBaCo2O5+δ perovskites as cathode materials for IT-SOFCs

Creating highly efficient and durable cathodes persists as a formidable task in the realm of intermediate temperature solid oxide fuel cells (IT-SOFCs). Hence, we present a double perovskite oxide, Pr0.6Sr0.4BaCo2O5+δ (PS0.4BC), and its electrocatalytic activity is thoroughly investigated. The XRD test is carried out and a notable transformation in the phase structure is observed upon the introduction of Sr2+ ions into the PBC matrix. That is, the phase structure of the material changes from double perovskite structure to single perovskite structure. Through the TG and TEC test that the introduction of Sr2+ ions into the lattice can create additional sites for oxygen vacancy formation and reduce TEC values. Further verify that Sr doping can enhance the concentration of oxygen vacancies of the material. The PS0.4BC cathode material exhibits remarkably low polarization resistance, achieving an impressive value of 0.027 Ω cm2 at an operating temperature of 800 °C. Oxygen partial pressure test shows that as the oxygen partial pressure decreases, there is a notable increase in impedance, particularly evident in the low frequency region of the Nyquist plots. This indicates that the oxygen content has obvious effects on the low-frequency processes. When the oxygen partial pressure exceeds 0.05 atm, the oxygen adsorption-dissociation and diffusion process is the rate-limiting step in the ORR. However, when the oxygen partial pressure is less than 0.05 atm, the formation of lattice oxygen through the combination of oxygen ions and oxygen vacancies processes is the rate-limiting step. Compared PBC cathode material, the more pronounced changes in the high frequency arc of the PS0.4BC cathode at the same oxygen content. It shows that Sr doping significantly changes the high frequency process. After doping, the oxygen vacancy concentration increases, which facilitates the occurrence of the charge transfer process at high frequency.