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BACKGROUND AND OBJECTIVES: Oxygen (O2) use during neonatal cardiopulmonary resuscitation (CPR) remains a subject of controversy. The inspired O2 concentration during neonatal CPR, that hastens return of spontaneous circulation (ROSC), allows adequate cerebral and myocardial O2 delivery, and enhances survival to discharge, is not known. The optimal FiO2 during CPR should decrease incidence of hypoxia but also avoid hyperoxia, and ultimately lead to improved neurodevelopmental outcomes. Due to infrequent need for extensive resuscitation, and emergent circumstances surrounding neonatal CPR, conducting randomized clinical trials continues to be a challenge. The goal of this study was to review the evolution of oxygen use during neonatal CPR, the evidence from animal and clinical studies on oxygen use during neonatal CPR and after ROSC, the pertinent physiology including myocardial oxygen consumption and cerebral oxygen delivery during CPR, and outcomes following CPR in the DR and in the neonatal intensive care unit. METHODS: This narrative review is based on recent and historic English literature in PubMed and Google scholar over the past 35 years (January 1, 1985 - May 1, 2021). KEY CONTENT AND FINDINGS: Several studies in animal models have compared ventilation with different inspired O2 concentrations (mostly 21% and 100%) during chest compressions and after ROSC. These studies reported no difference in short-term outcomes, even with as low as 18% O2. However, in lamb models of cardiac arrest and CPR, 100% O2 during chest compressions is associated with better oxygen delivery to the brain compared to 21% O2. Abrupt weaning to 21% O2 following ROSC followed by titration to achieve preductal SpO2 of 85-95% minimizes systemic hyperoxia and oxidative stress compared to slow weaning from 100% O2 following ROSC. CONCLUSIONS: Clinical research is needed to arrive at the best strategy for assessment of oxygenation and choice of FiO2 during neonatal CPR that lead to improved survival and outcomes. In this article, we have reviewed the literature on evidence behind O2 use during neonatal advanced CPR and after ROSC.

Non-cyanobacterial diazotrophs (NCDs) are widespread and active in marine waters. The carbon and low-oxygen (O2) conditions required for their N2 fixation may be encountered on marine particles, while a putative role of light remains uninvestigated. This study explored factors that regulate N2 fixation in Rhodopseudomonas sp. BAL398--a anoxygenic phototrophic bacterium isolated from low-salinity surface waters. Light (250 µmol photons m-2 s-1) and anoxia (0 µM O2) stimulated growth and N2 fixation; however, diazotrophy in light was dependent on high organic carbon levels (35 mM, glucose:succinate). Immunolabeling revealed that cellular nitrogenase levels increased with light, decreasing inorganic nitrogen (N) and ambient O2 (250 µM). Light and O2 stimulated motility and biofilm formation on surfaces, and N2 fixation rates increased compared to the control treatment. N2 fixation rates were positively correlated with the formation of rosette-like cellular structures, and an increased concentration of nitrogenase was observed toward the center of these structures, which increased their occurrence 600 times when cultures reached maximum N2 fixation rates vs when they had low rates. Interestingly, N2 fixation was not completely inhibited under oxic conditions and was accompanied by increased formation of capsules and cysts. Rosettes, as well as capsules and cysts, may thus serve as protection against O2. Our study reveals the physiological adaptations that underlie N2 fixation in an anoxygenic phototroph, emphasizing the significance of biofilm formation for utilizing light and fixing N2 under oxic conditions, and underscores the need for deciphering the importance of light for marine NCDs. IMPORTANCE The contribution of non-cyanobacterial diazotrophs (NCDs) to total N2 fixation in the marine water column is unknown, but their importance is likely constrained by the limited availability of dissolved organic matter and low O2 conditions. Light could support N2 fixation and growth by NCDs, yet no examples from bacterioplankton exist. In this study, we show that the phototrophic NCD, Rhodopseudomonas sp. BAL398, which is a member of the diazotrophic community in the surface waters of the Baltic Sea, can utilize light. Our study highlights the significance of biofilm formation for utilizing light and fixing N2 under oxic conditions and the role of cell plasticity in regulating these processes. Our findings have implications for the general understanding of the ecology and importance of NCDs in marine waters. [ABSTRACT FROM AUTHOR]

Bronchopulmonary dysplasia (BPD) is the most common complication of extreme prematurity. Its etiology is multifactorial and is attributed to genetic susceptibility to prenatal and postnatal factors. As advancements in neonatology have led to the increased survival of premature infants, a parallel increase in the incidence of BPD has occurred. Over time, the definition and diagnostic criteria for BPD have evolved, as have management strategies. However, challenges continue to exist in the management of these infants, which is not surprising given the complexity of the disease. We summarize the key diagnostic criteria and provide insight into the challenges related to various aspects of BPD definitions, data comparisons, and clinical care implementation. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H2S) is a primary cause of odor and corrosion in sewer systems. In drop structures, falling wastewater impinges the surface of bottom water pool as a jet or numerous drops, triggering a high level of turbulence and thus enhancing the emission of H2S and the absorption of oxygen (O2) at the pool surface. In this study, laboratory experiments were conducted to study the mass transfer at the pool surface with falling water drops or a single jet of water. In the test range of falling flow rate of 49–223 mm/h and falling velocity of 3.1–5.2 m/s [kinetic energy flux (KEF)=0.11–0.80 J/(m2·s)] , the mass transfer coefficient KL for the pool surface was found to be 2.6–14.8×10−5 m/s for H2S. In addition, KL was found to be 76% larger when the pool surface was impinged by water drops than by a single jet. KL was 27%−47% larger in the half of the water surface directly receiving the drops or jet than the other half. The increase of water depth in the pool promoted the mass transfer, especially for the scenario of falling jet. Equations were proposed to predict KL under drops or jet. Moreover, KL for H2S and for O2 was found almost the same, indicating O2 can be a safe surrogate gas for H2S. Finally, the research results were applied to estimate H2S emissions at the pool surface of a prototype drop structure with a falling height of up to 10 m, which showed that turbulent wastewater surface can enhance mass transfer over 100 times compared with a quiescent surface. [ABSTRACT FROM AUTHOR]

Nonthermal plasma (NTP) is a promising technology for the decomposition of chlorobenzene (CB), but many conditions will affect the performance of NTP. The effects of gas temperature, relative humidity, oxygen content, sulfur dioxide (SO2), and nitric oxide (NO) on the removal of CB in dielectric barrier discharge (DBD) were studied in this study. The results showed that the gas temperature with the highest CB removal rate was 50°C at 14 kV and 200°C at 18 kV. With the addition of water vapor, the removal efficiency of CB first increased and then decreased, reaching the highest (52.94%) when the relative humidity was 20% at 14 kV. The presence of oxygen inhibited the degradation of CB. At 14 kV, when the oxygen concentration increased from 0% to 25%, the degradation efficiency of CB decreased from 71.93% to 32.54%. In the discharge process, the addition of SO2 promoted the removal of CB, while NO inhibited under the same conditions. The addition of SO2 and NO did not change the specific energy density. For ozone (O3), the addition of water molecules, SO2 , and NO inhibited the formation of O3. It is of great significance to study the influence of relevant gas conditions on the degradation of CB by NTP technology, so as to provide a reference for industrial application. [ABSTRACT FROM AUTHOR]

This study showed that the dark muscle of yellowtail stored in pure O2 had almost unchanged redness, pH, and MetMb formation during 72-hour storage, while the N2 and air groups had significantly lower redness and pH, and significantly higher MetMb formation indices. Lactic acid content showed a significant negative correlation with pH. Pearson correlation analysis demonstrated that the lower redness was correlated with the lower pH and higher MetMb formation index. Thus, pure O2 could inhibit the MetMb accumulation and decrease pH, thereby suppressing discoloration and making the dark muscle more likely to gain bright red color. [ABSTRACT FROM AUTHOR]

The majority of rail vehicles worldwide use diesel as a primary fuel source. Diesel engine carbon emissions harm the environment and human health. Although railway electrification can reduce emissions, it is not always the most economical option, especially on routes with low vehicle demand. As a result, interest in hydrogen-powered trains as a way to reduce greenhouse gas (GHG) emissions has steadily grown in recent years. In this paper, we discuss advancements made in hydrogen-powered freight and commuter trains, as well as the technology used in some aspects of hydrogen-powered vehicles. It was observed that hydrogen-powered trains are already in use in Europe and Asia, unlike most developing countries in Africa. Commuter trains have received most of the research and development (R&D) attention, but interest in hydrogen-powered freight trains has recently picked up momentum. Despite the availability and use of gray and blue hydrogen, green hydrogen is still the preferred fuel for decarbonizing the rail transport sector.

• A O 2 -LITES sensor was reported. • A diode laser with high output power was adopted as the excitation source. • A minimum detection limit of 583 ppm was realized. Oxygen (O 2) is a fundamental element in the atmosphere. It is important to detect it in various fields. In this paper, a sensitive O 2 sensor based on light-induced thermoelastic spectroscopy (LITES) with a high power diode laser is reported. A distributed feedback (DFB) diode laser emitting at 760 nm with output power of 16.8 mW was employed as the light source. The O 2 absorption line at 13144.54 cm−1 was selected for the investigation. Wavelength modulation spectroscopy (WMS) technique and second harmonic signal demodulation (2 f) were adopted to improve the sensing performance. For the concentration dynamic range from 20 % to 80 %, a linear relationship between the amplitude of 2 f signal and O 2 concentration was demonstrated. Allan deviation analysis was conducted to evaluate the long-term stability of the sensor system and the minimum detection limit (MDL) was measured to be 583 ppm at the optimum integration time of 100 s. Further improvement of this O 2 -LITES sensor system was also discussed. [ABSTRACT FROM AUTHOR]

Highlights • The accuracy and dynamic range of a dual-wavelength laser-based DIAL measurement extend with simultaneously transmission and detection the spectrally closed "on" and "off" wavelengths; in addition to size, weight, and cost reduction. • Differential absorption lidar (DIAL) equipped with the dual-wavelength laser at 762 nm (on-wavelength) and 773 nm (off-wavelength) on 3D remote measurement of oxygen molecules, O 2. • A concentration of less than 1 ppm by volume is detectable by the system if a path length of 1 km is used. • The system can be used from a satellite to quickly characterize O 2 in H 2 O matrices on outer solar system bodies. • The wavelengths 762 nm and 773 nm lay in the water-window region (650–1350 nm) enabling system for laser remote sensing dissolved oxygen in water. Abstract Recently, we have demonstrated a longitudinally pumped tunable dual-wavelength Ti:sapphire laser that can operate at simultaneous dual-wavelength (765.0, 771.3 nm), (763.9, 772.2 nm), (763.5, 772.2 nm) and (762.4, 773.7 nm) with a pulse width of ∼20 ns and a maximum average power of ∼2.98 W at 1-kHz pulse repetition rate, corresponding to a slope efficiency of ∼34.7% [1]. In this paper, the feasibility of the contactless differential absorption lidar (DIAL) equipped with the dual-wavelength laser emitting at 762 nm (on-wavelength) and 773 nm (off-wavelength) on remote 3D-measurement of molecular oxygen, O 2 , has been investigated. Absorption by atmospheric oxygen A-band at 761.9 nm corresponds to the magnetic dipole transition b 1 Σ b + (v ′ = 0) ← X 3 Σ g − (v ″ = 0) with absorption cross section of 5.749 × 10−3 cm−2 atm−1 at STP. The accuracy and dynamic range of the DIAL measurement can be extended by simultaneous transmission and detection the spectrally close "on" and "off" wavelengths generated in a compact single laser, in addition to reduce the cost, volume, and weight of the system. The results demonstrate that a concentration of less than 1 ppm by volume is detectable by the system if a path length of 1 km is used. It is noticeable that the wavelengths 762 nm and 773 nm in the near-infrared window spectral range (650–950 nm) allow lidar system to monitor dissolved oxygen in ambient water. This system can also be used from a satellite to quickly characterize O 2 in H 2 O matrices in the outer solar system bodies. [ABSTRACT FROM AUTHOR]

Background and Objectives: Oxygen (O 2 ) use during neonatal cardiopulmonary resuscitation (CPR) remains a subject of controversy. The inspired O 2 concentration during neonatal CPR, that hastens return of spontaneous circulation (ROSC), allows adequate cerebral and myocardial O 2 delivery, and enhances survival to discharge, is not known. The optimal FiO 2 during CPR should decrease incidence of hypoxia but also avoid hyperoxia, and ultimately lead to improved neurodevelopmental outcomes. Due to infrequent need for extensive resuscitation, and emergent circumstances surrounding neonatal CPR, conducting randomized clinical trials continues to be a challenge. The goal of this study was to review the evolution of oxygen use during neonatal CPR, the evidence from animal and clinical studies on oxygen use during neonatal CPR and after ROSC, the pertinent physiology including myocardial oxygen consumption and cerebral oxygen delivery during CPR, and outcomes following CPR in the DR and in the neonatal intensive care unit., Methods: This narrative review is based on recent and historic English literature in PubMed and Google scholar over the past 35 years (January 1, 1985 - May 1, 2021)., Key Content and Findings: Several studies in animal models have compared ventilation with different inspired O 2 concentrations (mostly 21% and 100%) during chest compressions and after ROSC. These studies reported no difference in short-term outcomes, even with as low as 18% O 2 . However, in lamb models of cardiac arrest and CPR, 100% O 2 during chest compressions is associated with better oxygen delivery to the brain compared to 21% O 2 . Abrupt weaning to 21% O 2 following ROSC followed by titration to achieve preductal SpO 2 of 85-95% minimizes systemic hyperoxia and oxidative stress compared to slow weaning from 100% O 2 following ROSC., Conclusions: Clinical research is needed to arrive at the best strategy for assessment of oxygenation and choice of FiO 2 during neonatal CPR that lead to improved survival and outcomes. In this article, we have reviewed the literature on evidence behind O 2 use during neonatal advanced CPR and after ROSC.

Oxygen (O2) concentration inside the substrate is an important measurement for silage-research and-practical management. In the laboratory gas chromatography is commonly employed for O2 measurement. Among sensor-based techniques, accurate and reliable in situ measurement is rare because of high levels of carbon dioxide (CO2) generated by the introduction of O2 in the silage. The presented study focused on assessing three types of commercial O2 sensors, including Clark oxygen electrodes (COE), galvanic oxygen cell (GOC) sensors and the Dräger chip measurement system (DCMS). Laboratory cross calibration of O2 versus CO2 (each 0-15 vol.%) was made for the COE and the GOC sensors. All calibration results verified that O2 measurements for both sensors were insensitive to CO2. For the O2 in situ measurement in silage, all O2 sensors were first tested in two sealed barrels (diameter 35.7 cm; height: 60 cm) to monitor the O2 depletion with respect to the ensiling process (Test-A). The second test (Test-B) simulated the silage unloading process by recording the O2 penetration dynamics in three additional barrels, two covered by dry ice (0.6 kg or 1.2 kg of each) on the top surface and one without. Based on a general comparison of the experimental data, we conclude that each of these in situ sensor monitoring techniques for O2 concentration in silage exhibit individual advantages and limitations. [ABSTRACT FROM AUTHOR]

Three-dimensional periodic molecular models of amorphous cis-1,4-polybutadiene ( cis-PBD) were constructed using the Materials Studio (MS)® software to study the effects of temperature on the diffusion of oxygen (O2). The radial distribution function, solubility parameter and others clearly proved the three-dimensional periodic molecular model was able to reproduce bulk experimental data of the authentic materials. The volume fraction of accessible oxygen was reckoned by fractional free volume with a probe radius of 1.8 Å. The diffusion coefficients (D) of O2 were calculated, and researches on the diffusion mechanism were made. Data obtained corresponded with the trend from available experiments and previously published simulation work. The results confirmed the accelerating effect of high temperatures on the diffusion of O2 and meanwhile suggested the favourable binding sites of thermo-oxidative aging reactions. Our findings have an important significance for promoting the development of membrane separation technology and provide valuable guidance for further research on thermo-oxidative aging of cis-PBD. [ABSTRACT FROM AUTHOR]

To reiterate from above, glycolysis occurs during sleep, while eating and procreating as well as below the first or second threshold; over 70% of the La SP - sp produced in heavy intensity exercise is removed through oxidation (Brooks I et al i . 1984), and I R i SB a sb matches I R i SB d sb . Therefore, a rise in blood La SP - sp concentration ([La SP - sp ]) during exercise indicates neither anaerobiosis (an O SB 2 sb lack) nor a threshold of O SB 2 sb lack. Critical power, gas exchange threshold, glycolysis, lactate, lactate threshold, oxygen (O2) Keywords: critical power; gas exchange threshold; glycolysis; lactate; lactate threshold; oxygen (O2) EN critical power gas exchange threshold glycolysis lactate lactate threshold oxygen (O2) 1711 1712 2 03/03/21 20210301 NES 210301 We thank Dr MacIntosh and colleagues (MacIntosh I et al i . 2021) for revisiting concerns surrounding nomenclature and the use of the term "anaerobic threshold" (AT), in response to our recent review (Poole I et al i . 2021). [Extracted from the article]

Oxygen (O₂) concentration inside the substrate is an important measurement for silage-research and-practical management. In the laboratory gas chromatography is commonly employed for O₂ measurement. Among sensor-based techniques, accurate and reliable in situ measurement is rare because of high levels of carbon dioxide (CO₂) generated by the introduction of O₂ in the silage. The presented study focused on assessing three types of commercial O₂ sensors, including Clark oxygen electrodes (COE), galvanic oxygen cell (GOC) sensors and the Dräger chip measurement system (DCMS). Laboratory cross calibration of O₂ versus CO₂ (each 0-15 vol.%) was made for the COE and the GOC sensors. All calibration results verified that O₂ measurements for both sensors were insensitive to CO₂. For the O₂ in situ measurement in silage, all O₂ sensors were first tested in two sealed barrels (diameter 35.7 cm; height: 60 cm) to monitor the O₂ depletion with respect to the ensiling process (Test-A). The second test (Test-B) simulated the silage unloading process by recording the O₂ penetration dynamics in three additional barrels, two covered by dry ice (0.6 kg or 1.2 kg of each) on the top surface and one without. Based on a general comparison of the experimental data, we conclude that each of these in situ sensor monitoring techniques for O₂ concentration in silage exhibit individual advantages and limitations.