Oxygenation Status Research Articles

Assessment of hypoxia and its dynamic evolution in glioblastoma via qBOLD MRI: a comparative study with metformin treatment

BackgroundTo investigate the accuracy of quantitative blood oxygen level-dependent (qBOLD) magnetic resonance imaging (MRI) in identifying hypoxia within glioblastoma and explore dynamic changes in oxygenation status of glioblastoma with and without metformin administration.MethodsThree healthy and seven C6-bearing rats underwent 7-T qBOLD MRI. Oxygen extraction fraction (OEF) and cerebral metabolism rate of O2 (CMRO2) were calculated from qBOLD data. Tumor tissues were stained using hypoxia-inducible factor-1α (HIF-1α) and pimonidazole. The correlation between the hypoxia markers and corresponding qBOLD-based parameters was analyzed. Six C6-bearing rats were divided into metformin-treated and control groups for a longitudinal study of qBOLD imaging changes, with scans conducted on the 12th, 15th, and 18th day post-tumor implantation.ResultsIn healthy rats, gray matter showed higher values than white matter in T2, T2*, cerebral blood volume (CBV), and cerebral blood flow (CBF), whereas OEF was lower. Glioblastoma tissues exhibited elevated T2, T2*, CBV, and CBF but decreased OEF and CMRO2 relative to normal-appearing white matter. No significant correlation was found between staining scores from HIF-1α and pimonidazole. T2* and T2 values were negatively correlated with pimonidazole scores in tumor regions. As the tumor progressed, OEF values increased with intra-tissue variations, whereas CMRO2 decreased. Metformin delayed the reduction of T2 and T2* values, with significant differences in OEF and CMRO2 values compared to controls on day 18.ConclusionT2* and T2 values were significantly associated with the hypoxia status in glioma. Metformin could potentially mitigate the progression of hypoxia in glioblastoma, which can be tracked by qBOLD parameters.Relevance statementThis study demonstrates the potential of qBOLD parameters in assessing glioma dynamic oxygen metabolism and the efficacy of metformin as an anti-hypoxic agent, providing insights into improving glioblastoma treatment strategies.Key PointsThe study investigated qBOLD imaging’s accuracy in identifying hypoxia status within glioblastoma.qBOLD effectively assesses hypoxia and its dynamic evolution in glioblastoma.qBOLD parameters assist in identifying a suitable patient demographic for metformin treatment.Graphical

Mutual Neutralization in Collisions of Li+ with O−

The total and differential cross-sections and final state distribution for mutual neutralization in collisions of Li+ with O− were calculated using an ab initio quantum mechanical approach based on potential energy curves and non-adiabatic coupling elements computed with the multi-reference configuration interaction method. The final state distributions favored channels with excited oxygen states, indicating a strong effect of electron correlation, and the electron transfer could not be described by a simple one-electron exchange process.

Dynamics of Biomarkers in COVID-19 Patients Treated with Anakinra

Background: SARS-CoV-2 can trigger hyperinflammation, leading to severe COVID-19, presenting with pneumonia, acute respiratory distress syndrome (ARDS), and multiple organ failure. Specific biomarkers like leukocytes, CRP, NLR, AST, LDH, D-dimer, ferritin, and IL-6 are associated with disease severity. Anakinra, an IL-1 receptor antagonist, has been proposed to mitigate hyperinflammation, but its clinical efficacy remains uncertain. This study aimed to evaluate the effect of Anakinra on inflammatory biomarkers, oxygenation status, and survival outcomes in hospitalized patients with moderate to severe COVID-19 (according to the National Institute of Health severity scale), compared to standard treatment. Methods: A retrospective analysis included 65 patients (mean age 75.51 ± 9.54 years; 58.5% male, 41.5% female) hospitalized with moderate to severe COVID-19. Patients were divided into two groups: a control group receiving standard treatment (n = 24) and a target group treated with Anakinra (n = 41). Biomarkers and oxygenation status were assessed on Days 0, 3, and 7. Statistical analyses compared the groups for changes in leukocytes, NLR, CRP, AST, LDH, D-dimer, ferritin, and IL-6. Results: Anakinra treatment was associated with significant reductions in leukocytes, NLR, D-dimer, ferritin, IL-6, and CRP by Days 3 and 7. Improvements in oxygenation status were observed, although no survival benefits were noted. The control group showed no significant biomarker changes except for AST and LDH on Day 7. Conclusions: Anakinra demonstrated favorable effects on biomarkers and oxygenation in moderate to severe COVID-19 but did not improve survival. Further studies are needed to validate these findings.

A Complex Oxide Containing Inherent Peroxide Ions for Catalyzing Oxygen Evolution Reactions in Acid.

Proton exchange membrane water electrolyzers powered by sustainable energy represent a cutting-edge technology for renewable hydrogen generation, while slow anodic oxygen evolution reaction (OER) kinetics still remains a formidable obstacle that necessitates basic comprehension for facilitating electrocatalysts' design. Here, we report a low-iridium complex oxide La1.2Sr2.7IrO7.33 with a unique hexagonal structure consisting of isolated Ir(V)O6 octahedra and true peroxide O22- groups as a highly active and stable OER electrocatalyst under acidic conditions. Remarkably, La1.2Sr2.7IrO7.33, containing 59 wt % less iridium relative to the benchmark IrO2, shows about an order of magnitude higher mass activity, 6-folds higher intrinsic activity than the latter, and also surpasses the state-of-the-art Ir-based oxides ever reported. Combined electrochemical, spectroscopic, and density functional theory investigations reveal that La1.2Sr2.7IrO7.33 follows the peroxide-ion participation mechanism under the OER condition, where the inherent peroxide ions with accessible nonbonded oxygen states are responsible for the high OER activity. This discovery offers an innovative strategy for designing advanced catalysts for various catalytic applications.

The diagnositic value of dynamic contrast-enhanced ultrasound for evaluation of tissue oxygen status in rat hepatoma model

BackgroundHypoxia is a characteristic of solid tumors, but whether significant hypoxia exists in the hepatocellular carcinoma remains unclear. This animal study aims to explore the value of dynamic contrast-enhanced ultrasound (CEUS) quantitative parameters to evaluate the oxygen status in two rat hepatoma models.Materials and methodsN1S1 and McA-RH7777 S-D rat orthotopic hepatoma models were established. Once the tumors reached a diameter of 10–15 mm, CEUS and oxygen partial pressure (pO2) polarography were performed. Immunohistochemical staining for HIF-1α and pimonidazole was conducted after euthanizing the rats. Correlation between quantitative CEUS parameters, pO2, and the immunohistochemical integrated optical density (IOD) was analyzed to assess the predictive ability of CEUS quantitative parameters for the tissue oxygen environment.ResultEleven N1S1 models and ten McA-RH7777 models were established successfully. There was no significant difference in pO2 (35.5 mmHg vs 32.2 mmHg, P = 0.917), IOD of HIF-1α (13.4 vs 20.0, P = 0.159) and pimonidazole (0.70 vs 1.30, P = 0.926) between the tumor and the peritumoral liver tissue. The pO2 values were correlated with CEUS quantitative parameters including mean time-intensity curves (mTIC) (P = 0.003), peak intensity (PKI) (P = 0.010), area under the curve (AUC) (P = 0.009), area under the wash-in curve (WiAUC) (P = 0.006), and arrival time (AT) (P = 0.033). The IOD of HIF-1α correlated with AUC (P = 0.022), WiAUC (P = 0.009), ascending slope (AS) (P = 0.044), and falling time (FT) (P = 0.009). Multiple linear regression indicated that the “short AT” was an independent protective factor for hypoxia (β = -2.347, 95% CI: -4.948, -0.394, P = 0.022), and CEUS had the ability to predict the tumor pO2 (P = 0.003).ConclusionNo evidence of significant hypoxia was identified in two rat orthotopic hepatoma models. Quantitative CEUS parameters correlated with the oxygen status of the tumor, which could be utilized to predict the tumor tissue pO2.

A Single Night in Hypoxia Either with or without Ketone Ester Ingestion Reduces Sleep Quality Without Impacting Next Day Exercise Performance

ABSTRACT Background Sleeping at altitude is highly common in athletes as an integral part of altitude training camps or sport competitions. However, concerns have been raised due to expected negative effects on sleep quality, thereby potentially hampering exercise recovery and next-day exercise performance. We recently showed that ketone ester (KE) ingestion beneficially impacted sleep following strenuous, late evening exercise in normoxia, and alleviated hypoxemia. Therefore, we hypothesized that KE ingestion may be an effective strategy to attenuate hypox(em)ia-induced sleep dysregulations. Methods Eleven healthy, male participants completed three experimental sessions including normoxic training and subsequent sleep in normoxia or at a simulated altitude of 3,000 m while receiving either KE or placebo post-exercise and pre-sleep. Sleep was evaluated using polysomnography, while next-day exercise performance was assessed through a 30-min all-out time trial (TT30’). Physiological measurements included oxygen status, heart rate variability, ventilatory parameters, blood acid-base balance and capillary blood gases. Results Hypoxia caused a ~3% drop in sleep efficiency, established through a doubled wakefulness after sleep onset and a ~22% reduction in slow wave sleep. KE ingestion alleviated the gradual drop in SpO2 throughout the first part of the night, but did not alter hypoxia-induced sleep dysregulations. Neither KE, nor nocturnal hypoxia affected TT30’ performance, but nocturnal hypoxia hampered heart rate recovery following TT30’. Conclusions We observed that sleeping at 3,000 m altitude impairs sleep efficiency. Although this hypoxia-induced sleep disruption was too subtle to limit exercise performance, we for the first time indicate that sleeping at altitude might impair next-day exercise recovery. KE alleviated nocturnal hypoxemia only when SpO2 values dropped below ~85%, but this did not translate into improved sleep or next-day exercise performance.

Antepartum Cardiotocography and Feto-maternal Outcome Among Admitted Patients in Bangabandhu Sheikh Mujib Medical University (BSMMU) Dhaka, Bangladesh

Background: Admission Cardiotocography (CTG) a noninvasive procedure, is used to indicate the state of oxygenation of the fetus on admission into the labor ward. This study is performed to assess the association of admission CTG findings with feto-maternal outcome at a tertiary health facility in Bangladesh. Materials and methods: A prospective, observational study of 50 pregnant women who were admitted into the labor ward with singleton live pregnancies in Bangabandhu Sheikh Mujib Medical University. Information on the demographic characteristics, obstetrics and medical history, admission CTG tracing and neonatal outcome was obtained using a structured data collection form. Data were analyzed using the SPSS software version 20.0 with the level of significance set at p< 0.05. Results: The admission CTG findings were normal in 72% and abnormal in 28% of the women. The occurrence of low birth weight, asphyxiated neonates and Special Care Neonatal Unit (SCANU) admission was significantly more frequent among those with abnormal admission CTG results compared with normal results (p<0.001 for each). The incidence of cesarean delivery was more common when the CTG findings were abnormal, whereas all women with normal CTG result had a vaginal delivery (p<0.001). Conclusion: Admission CTG was effective in identifying fetuses with a higher incidence of perinatal asphyxia. Neonatal outcome such as low birth weight, APGAR score and SCANU admission was significantly associated with pathological CTG findings. In the absence of facilities for further investigations, prompt intervention for delivery should be ensured if admission CTG is pathological. IAHS Medical Journal Vol 7(1), June 2024; 50-53

A mechanistic integration of hypoxia signaling with energy, redox and hormonal cues.

Oxygen deficiency (hypoxia) occurs naturally in many developing plant tissues but can become a major threat during acute flooding stress. Consequently, plants as aerobic organisms must rapidly acclimate to hypoxia and the associated energy crisis to ensure cellular and ultimately organismal survival. In plants, oxygen sensing is tightly linked with oxygen-controlled protein stability of group VII ETHYLENE-RESPONSE FACTORs (ERFVII) which, when stabilized under hypoxia, act as key transcriptional regulators of hypoxia-responsive genes (HRGs). Multiple signaling pathways feed into hypoxia signaling to fine-tune cellular decision making under stress. First, ATP shortage upon hypoxia directly affects the energy status and adjusts anaerobic metabolism. Secondly, altered redox homeostasis leads to reactive oxygen and nitrogen species (ROS and RNS) accumulation, evoking signaling and oxidative stress acclimation. Finally, the phytohormone ethylene promotes hypoxia signaling to improve acute stress acclimation, while hypoxia signaling in turn can alter ethylene, auxin, abscisic acid, salicylic acid and jasmonate signaling to guide development and stress responses. In this Update, we summarize the current knowledge on how energy, redox and hormone signaling pathways are induced under hypoxia and subsequently integrated at the molecular level to ensure stress-tailored cellular responses. We show that some HRGs are responsive to changes in redox, energy and ethylene independently of the oxygen status, and propose an updated HRG list that is more representative for hypoxia marker gene expression. We discuss the synergistic effects of hypoxia, energy, redox and hormone signaling and their phenotypic consequences in the context of both environmental and developmental hypoxia.

Cation Migration‐Induced Lattice Oxygen Oxidation in Spinel Oxide for Superior Oxygen Evolution Reaction

Activating the lattice oxygen can significantly improve the kinetics of oxygen evolution reaction (OER), however, it often results in reduced stability due to the bulk structure degradation. Here, we develop a spinel Fe0.3Co0.9Cr1.8O4 with active lattice oxygen by high‐throughput methods, achieving high OER activity and stability, superior to the benchmark IrO2. The oxide exhibits an ultralow overpotential (190 mV at 10 mA cm–2) with outstanding stability for over 170 h at 100 mA cm–2. Soft X‐ray absorption‐ and Raman‐spectroscopies, combined with 18O isotope‐labelling experiments, reveal that lattice oxygen activation is driven by Cr oxidation, which induces a cation migration from CrO6 octahedrons to CrO4 tetrahedrons. The geometry conversion creates accessible non‐bonding oxygen states, crucial for lattice oxygen oxidation. Upon oxidation, peroxo O–O bond is formed and further stabilized by Cr6+ (CrO4 tetrahedra) via dimerization. This work establishes a new approach for designing efficient catalysts that feature active and stable lattice oxygen without compromising structural integrity.

Cation Migration-Induced Lattice Oxygen Oxidation in Spinel Oxide for Superior Oxygen Evolution Reaction.

Activating the lattice oxygen can significantly improve the kinetics of oxygen evolution reaction (OER), however, it often results in reduced stability due to the bulk structure degradation. Here, we develop a spinel Fe0.3Co0.9Cr1.8O4 with active lattice oxygen by high-throughput methods, achieving high OER activity and stability, superior to the benchmark IrO2. The oxide exhibits an ultralow overpotential (190 mV at 10 mA cm-2) with outstanding stability for over 170 h at 100 mA cm-2. Soft X-ray absorption- and Raman-spectroscopies, combined with 18O isotope-labelling experiments, reveal that lattice oxygen activation is driven by Cr oxidation, which induces a cation migration from CrO6octahedrons toCrO4tetrahedrons. The geometry conversion creates accessible non-bonding oxygen states, crucial for lattice oxygen oxidation. Upon oxidation, peroxo O-O bond is formed and further stabilized by Cr6+ (CrO4 tetrahedra) via dimerization. This work establishes a new approach for designing efficient catalysts that feature active and stable lattice oxygen without compromising structural integrity.

Analysis of Iron Status in Sickle Cell Disease Patients During Steady State at the Center de Recherche et de Lutte contre la Drépanocytose (CRLD) Bamako.

Sickle cell disease (SCD) is a prevalent inherited blood disorder arising from a single point mutation that results in substitution of valine with glutamic acid in the Beta hemoglobin chain, making red blood cells assume a banana shape under low oxygen state. It is most prevalent in sub-Saharan Africa, affecting approximately 2% of the population in Mali. This study aimed to evaluate the iron status and associated hematological parameters in SCD patients at steady state in an environment with a high prevalence of iron deficiency. A cross-sectional study was conducted at the Center de Recherche et de Lutte contre la Drépanocytose (CRLD) in Bamako, Mali, involving 757 SCD patients aged 10 to 29 years. Iron deficiency was defined as serum ferritin < 20 ng/mL, while iron overload was associated with serum ferritin > 500 ng/mL. The study population consisted of 171 (22.6%) hemolytic phenotypes (SS and Sβ0) and 586 (77.4%) viscous phenotypes (SC and Sβ+). Iron deficiency was found in 19 SCD patients (2.5%), with a higher prevalence in the SC phenotype (68.4%). All iron-deficient subjects exhibited microcytosis (MCV < 80 fL) and hypochromia (MCH < 26 pg). Hemoglobin levels < 12 g/dL were observed only in homozygous SCD patients. Low reticulocyte counts were noted in iron-deficient subjects with SC and Sβ+ phenotypes, but not in iron-deficient SS subjects. Serum C-reactive protein (CRP) was normal (< 10 mg/L) in all iron-deficient subjects, excluding iron deficiency due to chronic inflammation. Iron deficiency was observed among 2.5% of the study population, with a predominant occurrence among those with SC phenotype. All iron deficient subjects had microcytosis and hypochromia. Hemoglobin levels below 12 g/dL were only found in homozygous SCD patients. Additionally, low reticulocyte counts were noted in iron deficient patients with SC and Sβ+ phenotypes, though not in those with the SS phenotype. These findings contribute to the understanding of iron status in SCD patients in an African context and highlights the importance of monitoring iron levels in these population to prevent complications associated with iron deficiency or overload.

A collisional-radiative model for atmospheric-pressure low-temperature air discharges

Plasma-assisted combustion technology has been a hot spot in aero-engines and scramjet-engines. The electron density is a key discharge parameter related to the active-particle density. The latter has been considered playing an important role in the above applications by the kinetic effect. In this work, an atmospheric pressure air plasma collisional-radiative model considering the excited states of atomic nitrogen and oxygen is built based on previous widely kinetic investigations of molecules and radicals, as well as their excited states. The excited states, especially the atomic nitrogen and oxygen states were less investigated in previous works. The emission intensity distributions from the model have a good agreement with those measured in the glide arc plasma with two discharge modes, as well as the microwave plasma. Based on the kinetics of molecular and atomic emitting states, the line-ratio method is presented to determine the electron density. The N2(337 nm)/O(844 nm) and N2(337 nm)/NO(γ) line ratios are used for the glide arc plasma and microwave plasma torch, respectively. Besides, the kinetics of the excited states involved with two line-ratios are also investigated in the two types of discharges. Combined with the atmospheric pressure actinometry method, the kinetic effect of the plasma-assisted combustion can be revealed quantitatively in the future.

Formation of reactive nitrogen species promoted by iron ions through the photochemistry of a neonicotinoid insecticide

Abstract. Nitrous acid (HONO) and nitrogen oxides (NOx=NO+NO2) are important atmospheric pollutants and key intermediates in the global nitrogen cycle, but their sources and formation mechanisms are still poorly understood. Here, we investigated the effect of soluble iron (Fe3+) on the photochemical behavior of a widely used neonicotinoid (NN) insecticide, nitenpyram (NPM), in the aqueous phase. The yields of HONO and NOx increased significantly when NPM solution was irradiated in the presence of iron ions (Fe3+). We propose that the enhanced HONO and NO2 emissions from the photodegradation of NPM in the presence of iron ions result from the redox cycle between Fe3+ and Fe2+ and the generated reactive oxygen species (ROS) by electron transfer between the excited triplet state of NPM and molecular oxygen (O2). Using the laboratory-derived parameterization based on kinetic data and gridded downward solar radiation, we estimate that the photochemistry of NPM induced by Fe3+ releases 0.50 and 0.77 Tg N yr−1 of NOx and HONO, respectively, into the atmosphere. This study suggests a novel source of HONO and NOx during daytime and potentially helps to narrow the gap between field observations and model outcomes of HONO in the atmosphere. The suggested photochemistry of NPM can be an important contribution to the global nitrogen cycle affecting the atmospheric oxidizing capacity and climate change.

Long-Term Selective Photoelectrochemical Glycerol Oxidation via Oxygen Vacancy Modulated Tungsten Oxide with Self-Healing.

The photoelectrochemical selective oxidation of biowaste glycerol into the high value-added material, along with hydrogen production, holds significant promise for advancing renewable and sustainable energy technologies. Here, the surface oxygen state of tungsten oxide is modified to selectively oxidize glycerol into glyceraldehyde, a high-value-added material, and the selectivity is maintained over a prolonged period using the photo-stimulated self-recovery capability. The surface-coordinated photoelectrode exhibits high charge transfer efficiency to glycerol and favorable glycerol adsorption capacity, enabling the selective conversion of glycerol. At 1.2 VRHE in a 2m glycerol electrolyte adjusted to pH 2, the tungsten oxide photoelectrode achieves a photocurrent density of 2.58mA cm-2 and a production rate of 378.8mmol m-2h-1 with selectivity of 86.1%. The high selectivity is preserved for 18 h by utilizing the self-healing capability of tungsten oxide to restore initial states modified by photoelectrochemical oxidation. This work sheds light on the design of highly efficient metal oxide photoelectrodes for selective biomass oxidation over extended periods.

Expansion of d-spacing of boehmite for enhanced phosphate adsorption via hydrogen bond network

The optimization of the interlayer water content to increase the d-spacing of layered materials has recently attracted interest in pollutant removal. Several studies have explored phosphate adsorption onto boehmite considering its high surface area; however, the influence of its d-spacing on the adsorption performance remains unexplored. Therefore, our study aimed to investigate the impact of the synthesis pH of boehmite on the d-spacing and adsorption performance of phosphate ions. For this purpose, boehmite samples were synthesized under various pH conditions at 100°C to be tested for phosphate adsorption. As a result of this mild synthesis condition, the number of reactive hydroxyl groups in boehmite samples ranged from 7.02 – 9.02 mmol/g, nearly four times higher than the reported boehmites. Boehmite prepared under acidic conditions exhibits a relatively high interlayer water content and an enlarged d-spacing from 0.640 to 0.996 nm, resulting in superior phosphate adsorption (215 mg/g) within one minute. We also confirmed that phosphate adsorption increased the binding energy states of aluminum and oxygen in boehmite, indicating a robust hydrogen bond network with phosphate ions in the inner space. In contrast, the adsorption decreased the binding energy for other types of boehmite, indicating charge interaction. Competitive adsorption tests also showed the strong affinity of boehmite for phosphate ions, even in the presence of fluoride ions. These findings highlight the importance of the interlayer water molecules in controlling the d-spacing of boehmite, indicating their critical role in removing anions from water.

Genetic Variation and Metabolic Basis of Kidney Cancer: New Opportunities for Targeted Therapy

Renal cell carcinoma (RCC) has previously been considered as a single disease. However, it is currently characterized as a heterogeneous group of tumors that differ in histological features, genetic abnormalities, and variable clinical course. In normal cells, energy is produced by the cleavage of chemical bonds in nutrients through the oxidation of fats, proteins, or carbohydrates. Mutational alterations in genes associated with RCC, including VHL, FLCN, PTEN and SDH, lead to abnormal cellular adaptation to changes in oxygen status, iron metabolism and nutrients. The present paper reviews the known genetic abnormalities observed in RCC and their impact on metabolic alterations. Understanding the genetic and metabolic mechanisms underlying RCC is crucial for the development of effective therapies. Targeting specific genetic abnormalities or metabolic pathways represents a promising approach to the RCC treatment. In addition, studies into the metabolic basis of RCC contribute to the development of new biomarkers for early diagnosis and monitoring of the disease. Moreover, investigating the role of VHL, FLCN, PTEN, and SDH genes in the development of RCC provides valuable information on the molecular mechanisms behind the disease. As a result, it may lead to the development of new treatment strategies aimed at restoring the normal function of these genes or compensating for their abnormalities. Overall, an integrated approach to the study of RCC that considers genetic, metabolic, and clinical aspects will ensure that more effective treatments are developed and prognosis for patients with this disease are improved.

Promoting Surface Reconstruction in Spinel Oxides via Tetrahedral-Octahedral Phase Boundary Construction for Efficient Oxygen Evolution.

Understanding the origin of surface reconstruction is crucial for developing highly efficient lattice oxygen oxidation mechanism (LOM) based spinel oxides. Traditionally, the reconstruction has been achieved through electrochemical procedures, such as cyclic voltammetry (CV), linear sweep voltammetry (LSV). In this work, we found that the surface reconstruction in LOM-based CoFe0.25Al1.75O4 catalyst was an irreversible oxygen redox chemical reaction. And a lower oxygen vacancy formation energy (EO-V) could benefit the combination of the activated lattice oxygen atoms with adsorbed water molecular. Motivated by this finding, a strategy of phase boundary construction from Co tetrahedral to octahedral was employed to decrease EO-V in CoFe0.25Al1.75O4. The results showed that as the Co octahedral occupancy ratio rose to 64 %, a 3.5 nm-thick reconstructed layer formed on the catalyst surface with a 158 mV decrease in overpotential. Further experiments indicated that the coexistence of tetrahedral-octahedral (O-T) phase would result in lattice mismatch, promoting non-bonding oxygen states and lowering EO-V. Then more active lattice oxygen combined with H2O molecules to generate hydroxide ions (OH-), followed by soluble cation leaching, which enhanced the reconstruction process. This work provided new insights into the relationship between the intrinsic structure of pre-catalysts and surface reconstruction in LOM-based spinel electrocatalysts.

Conditions for reproduction of juvenile salmon fish in Sakhalin fish hatcheries: oxygen, temperature regimes and sanitary state of factory water sources

Conditions for reproduction of juvenile salmon fish in Sakhalin fish hatcheries: oxygen, temperature regimes and sanitary state of factory water sources

Direct and indirect photodegradation mechanism of ractopamine in aquatic environment

As a kind of typical lean meat essences and veterinary drugs, ractopamine (RAC) has been frequently detected in agricultural sewage and livestock, posing potential risk to both aquatic ecosystems and human health. Despite its widespread occurrence, the environmental fate of RAC remains unclear. Here, the mechanisms underlying the direct and indirect photodegradation of RAC was investigated under UV light irradiation at wavelengths of 275 and 365 nm, respectively. The effect of pH, initial concentration, and co-existing ions were examined. For direct photodegradation, the quantum yield of RAC increased with increasing pH values. In solutions containing dissolved organic matter (DOM), indirect photodegradation of RAC intensified with increasing pH values, and the initial concentration of DOM accelerated the process. The presence of Cu2+ was found to inhibit both direct and indirect photodegradation of RAC. Electron spin resonance (ESR) spectrometry and quenching experiments revealed that direct photodegradation was primarily attributed to the decomposition of the triplet state of RAC. Both the triplet state of DOM (3DOM*) and singlet oxygen contributed to the indirect photodegradation of RAC. LC-MS/MS analysis indicated that oxidation of the phenol group and subsequent decarboxylation were the principal photodegradation processes. The energies of each state of RAC and the active sites of RAC molecules were computed using frontier molecular orbitals and Fukui indices based on density functional theory. Combining the analysis of photoproducts with energy calculation, pathways of the direct and indirect photodegradation of RAC were proposed. These findings unveiled the photochemical behaviors of RAC concerning the removal and attenuation in aquatic environment.

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.