Increasing Oxygen Pressure Research Articles

Short-Term Effects of Heat Stress on Cow Behavior, Registered by Innovative Technologies and Blood Gas Parameters.

Heat stress (HS) is one of the key factors affecting an animal's immune system and productivity, as a result of a physiological reaction combined with environmental factors. This study examined the short-term effects of heat stress on cow behavior, as recorded by innovative technologies, and its impact on blood gas parameters, using 56 of the 1070 cows clinically evaluated during the second and subsequent lactations within the first 30 days postpartum. Throughout the experiment (from 4 June 2024 until 1 July 2024), cow behavior parameters (rumination time min/d. (RT), body temperature (°C), reticulorumen pH, water consumption (L/day), cow activity (h/day)) were monitored using specialized SmaXtec boluses and employing a blood gas analyzer (Siemens Healthineers, 1200 Courtneypark Dr E Mississauga, L5T 1P2, Canada). During the study period, the temperature-humidity index (THI), based on ambient temperature and humidity, was recorded and used to calculate THI and to categorize the data into four THI classes as follows: 1-THI 60-63 (4 June 2024-12 June 2024); 2-THI 65-69 (13 June 2024-18 June 2024); 3-THI 73-75 (19 June 2024-25 June 2024); and 4-THI 73-78 (26 June 2024-1 July 2024). The results showed that heat stress significantly reduced rumination time by up to 70% in cows within the highest THI class (73 to 78) and increased body temperature by 2%. It also caused a 12.6% decrease in partial carbon dioxide pressure (pCO2) and a 32% increase in partial oxygen pressure (pO2), also decreasing plasma sodium by 1.36% and potassium by 6%, while increasing chloride by 3%. The findings underscore the critical need for continuous monitoring, early detection, and proactive management to mitigate the adverse impacts of heat stress on dairy cow health and productivity. Recommendations include the use of advanced monitoring technologies and specific blood gas parameter tracking to detect the early signs of heat stress and implement more timely interventions.

Investigation on the Durability of a Polypropylene Geotextile under Artificial Aging Scenarios

Geosynthetics are widely used in various civil engineering applications, such as geotextiles in coastal protection, and display a sustainable alternative to natural mineral materials. However, the full benefits of using geosynthetics can only be gained with a long service lifetime of the products. With the use of added stabilizers to the polymers, service lifetimes can be achieved in the range of 100 years. Therefore, accelerated aging methods are needed for the assessment of the long-term performance of geotextiles. In the present study, the behavior of geosynthetic materials made of polypropylene was investigated under artificial aging conditions involving elevated temperatures ranging from 30 to 80 °C, increased oxygen pressures ranging from 10 to 50 bar in water-filled autoclaves, and UV irradiation under atmospheric conditions. ATR-IR spectroscopy was employed to detect the increase in the carbonyl index over various aging durations, indicating the oxidative degradation of the geotextile. The most pronounced increase was observed in the case of aging through UV irradiation, followed by thermal aging. Elevated pressure, on the other hand, had a lower impact on oxidation. High-temperature size exclusion chromatography was utilized to follow the reduction in molar mass under different degradation conditions, and the results were consistent with those obtained from ATR-IR spectroscopy. In polyolefins such as polypropylene, Hindered Amine Stabilizers (HAS) are used to suppress oxidation caused by UV radiation. The quantitative analysis of HAS was carried out using a UV/Vis method and HPLC. The degradation of UV stabilizers during the aging of geotextiles is responsible for the oxidation and the reduction in the molar mass of polypropylene. From the results, it can be concluded that applications of PP geotextile without soil or sand cover might cause the risk of the formation of microplastic particles. Material selection, design, and maintenance of the construction must follow best practices, including the system’s removal or replacement at end-of-life. Otherwise, a sustainable use of geotextiles in civil engineering is not possible.

Degradation Issues in Solid Oxide Electrolysers

One of the crucial aspects to achieving long lifetime and high-efficient SOCs (Solid oxide cells) is to enhance durability of the current devices.Degradation issues are typically associated with problems in both electrodes. For example, nickel-yttria stabilized zirconia (Ni-YSZ) hydrogen electrodes present under extreme conditions of high steam partial pressures, a low durability due to Ni oxidation resulting in lowered electronic conductivity and catalytic activity of the electrode. Ni agglomeration, depleting and micro crack in Ni-containing hydrogen electrode can also occur leading to a lower activity of the Ni-based electrodes as an SOEC fuel electrode. Furthermore, carbon deposition and sulfur poisoning on the Ni surface are also lead to cell performance degradation and poor durability.In addition, the performance of the oxygen electrode is also particularly more important in electrolysis mode than in fuel cell mode, as it is well established that electrochemically induced oxygen pressure increase at the electrolyte-oxygen electrode interface and subsequent membrane failure have been theoretically predicted and experimentally observed in SOEC mode. For example, several examples in the literature reported the presence on voids at the YSZ electrolyte, leading to delamination of the oxygen electrode. In this sense, lanthanide nickelates (Ln = La, Nd, Pr) have received considerable interest as materials for IT-SOFC electrodes and oxygen separation membranes, and they seem to be very attractive for electrolysis applications. The hyperstoichiometry of some oxygen electrode materials such as these Ruddlesden-Popper phases is believed to be favourable for effective oxygen evolution, as performance of these electrodes is enhanced in SOEC mode.Different strategies to develop optimized electrode structures as well as controlled operating conditions will be discussed in order to improve the durability of SOCs.

Realization of tunable fabrication from Cu nanoparticles film towards Cu2O thin film by pulse laser deposition method

In this paper, the tunable fabrication from Cu nanoparticles (NPs) film to Cu2O thin film on single-crystal MgO (100) substrates via pulse laser deposition (PLD) has been realized by precisely adjusting the oxygen pressure. In-situ X-ray photoelectron spectroscopy confirms that the chemical state of Cu is altered from Cu0 to mixed state of Cu0 and Cu1+, and then to Cu1+. X-ray diffraction results reveal the main crystal structure of the films is changed from Cu (200) to Cu2O (110) with the increase of oxygen pressure. The morphology of three typical samples (Cu NPs film, Cu@Cu2O core-shell NPs films and Cu2O thin film) was record by transmission electron microscopy. According to the analysis, the mechanism of oxygen is to absorb on the surface of MgO (100) substrate and act as an oxidant in the growth of the films. The increase of oxygen pressure is beneficial to the formation of Cu@Cu2O core-shell NPs with larger diameters and the transition from Cu@Cu2O core-shell NPs film to continuous Cu2O (110) thin film. This work provides essential information for the fabrication of Cu2O thin films by PLD with Cu target at low oxygen pressure.

PLD of α-Ga2O3 on m-plane Al2O3: Growth regime, growth process, and structural properties

Phase-pure α-Ga2O3 thin films with high surface quality and crystallinity have been grown on m-plane sapphire using pulsed laser deposition (PLD). Therefore, the influence of growth temperature, oxygen background pressure, and film thickness on the structural properties is investigated to determine the growth window for phase-pure corundum structured α-Ga2O3. Samples were analyzed using x-ray diffraction (XRD), atomic force microscopy (AFM), and spectroscopic ellipsometry measurements. A distinct growth window in favor of phase-pure (10.0)-oriented α-Ga2O3 for growth temperatures above 480 °C and low oxygen partial pressures p(O2) of 3 × 10−4 mbar is identified. The growth rate increases significantly with increasing oxygen pressure. Furthermore, it shows an Arrhenius-like decrease for lower temperatures, caused by the increasing desorption of volatile Ga2O suboxides. It was found that for thicker layers, the growth of monoclinic β-Ga2O3 is promoted likely facilitated by the c-facets of the α-Ga2O3 grains. This leads to a (010)-oriented island growth corroborated by stripe-like features in AFM scans and a corresponding in-plane orientation confirmed by XRD ϕ-scans. For oxygen partial pressures above 3 × 10−4 mbar and Tg < 540 °C, the formation of mixed (10.0) α-Ga2O3 and spinel-defective (110)-γ-Ga2O3 manifesting as defective inclusions was observed independent of the layer thickness d. A corresponding p(O2) − d − T phase diagram for the growth of Ga2O3 on m-plane sapphire by PLD is provided.

Why thermal laser epitaxy aluminum sources yield reproducible fluxes in oxidizing environments

Aluminum plays a central role in the world of electronic oxide materials. Yet, aluminum sources are very difficult to handle during oxide molecular-beam epitaxy, the main reason for which is the high oxidization potential of aluminum. In this work, we present a thorough study of the behavior of aluminum sources during oxide thermal laser epitaxy. We identify two distinct operating regimes. At high laser-beam fluences, the source emanates reproducible fluxes independent of an applied oxygen pressure of <10−1 hPa. At lower beam fluences, the flux increases with increasing oxygen pressure (<10−1 hPa) due to suboxide formation. We demonstrate reproducible rate control over a flux range of 5 orders of magnitude, which can be expanded further. These results demonstrate that thermal laser epitaxy does not present the challenges associated with the evaporation of aluminum during oxide molecular-beam epitaxy.

DETERMINATION OF TREATMENT TIME AND EFFICACY WITH OXYGEN IN EXPERIMENTAL METHEMOGLOBINEMIA MODEL

Introduction: Methemoglobin, an abnormal form of hemoglobin, is one of the causes that should be considered primarily in severe central cyanosis. Methylene blue and ascorbic acid are used as the first-line therapies in methemoglobinemia. Experience with the use of oxygen therapy is not sufficient to conclude the duration of therapy. The aim of the present study is to find out the effects of oxygen therapy on drug or toxic agent-induced methemoglobinemia. Material and Method: First group rats (n=6) were administered 100 mg/kg prilocaine intraperitoneally, and the rats were kept at room temperature. The second group of oxygen group rats (n=6) were administered 100% oxygen at 10 liters/min. All rats were observed for 180 minutes, and blood gas and biochemical analyses were performed at the end of the experiment period. Results: Fifty percent of the rats in the room air group (n=3) died spontaneously at the end of the trial period, while all rats in the oxygen group (n=6) survived to the end of the trial period. When evaluated in terms of survival, a statistical difference was found between the groups (p <0.05). In addition, although there was a significant difference in oxygen saturation levels between the groups (p <0.05), there was no significant increase in partial arterial oxygen pressure, the primary determinant of oxygenation. Conclusion: This study revealed that rats are not suitable for this type of experimental study. Prilocaine doses did not cause high levels of methemoglobinemia due to mortality, so the goal and target could not be met. It has been concluded that this study can serve as a guide for choosing methodologies to be employed in planned future investigations of the topic.

Effect of oxygen pressure on the structural and electrical properties of Bi2Mg2/3Nb4/3O7 thin films

Bismuth magnesium niobate (Bi2Mg2/3Nb4/3O7, BMN) films were prepared on indium-doped tin oxide glass substrates via pulsed laser deposition. The effect of oxygen pressure on the structural and electrical properties of the BMN films are investigated. The prepared BMN film presents monoclinic phase, and the surface of the films have good compactness without cracks and pores. With the increase of oxygen pressure, the energy storage density and dielectric constant of the films decrease and subsequently increase, which is related to the influence on the structure and surface morphology of BMN films. The BMN films prepared at 10Pa have the best surface uniformity, with a dielectric constant of 138, a loss tangent of 0.0043, a tunability of 16%, and an energy storage density of 0.749J/cm3.

Different methods of bone marrow harvesting influence cell characteristics and purity, affecting clinical outcomes

BackgroundBone marrow (BM)-derived stem cells were implanted to induce angiogenesis in patients with no-option critical limb-threatening ischemia. Considering the potential for this therapy, conflicting results related to BM harvesting methods have been reported that could affect stem cell concentrations and quality. MethodsA total of 75 patients with no-option critical limb-threatening ischemia were treated with BM implantation. For 58 patients, BM was harvested using a BM aspirate concentrate system (Harvest Technologies; group HT) with a standard aspiration needle, followed by an automated centrifugation process, to produce BM aspirate concentrate. For 17 patients, BM was harvested using the Marrow Cellution system (Aspire Medical Innovation; group MC). CD34+ cells/mL, CD117+ cells/mL, CD133+ cells/mL, CD309+ cells/mL, hematocrit, and BM purity were compared between the two BM preparations. ResultsThe retrospective analysis of a subset group after adjustment for age shows that the quality of BM obtained using the Marrow Cellution system is better, in terms of purity, than the classic harvesting method before centrifugation. Harvested BM before centrifugation is characterized by a higher percentage of CD133+ cells compared with BM after centrifugation. In contrast, the MC aspirate had a larger amount of very small embryonic-like cells, as indicated by the higher percentage of CD133+, CD34+, and CD45− cells. These differences translated into an increased occurrence of leg amputations in group HT than in group MC and an increase in transcutaneous oxygen pressure in patients treated with BM aspirated using MC. ConclusionsBM manipulation, such as centrifugation, affects the quality and number of stem cells, with detrimental consequences on clinical outcomes, as reflected by the different amputation rates between the two groups.

Modelling Nickel Metal Hydride Batteries for System Integrated Applications

The NiMH battery is resilient against mistreatment and can be charged in a large temperature window. It also has a high power-capability, which has made it popular in for instance power tools. Today, the battery is often found in large scale stationary energy storage, as well as applications which require high power capability.In large scale energy storage, small differences in run cycles can have large total effects on power efficiency and safety. It is therefore desirable to develop better methods of battery management. In recent years, development in system hardware has made it possible to implement on-line models in battery management systems. Such an implementation requires a model capable of working in dynamic conditions simulating voltage, temperature, and pressure. In this study, a model for this purpose is developed and verified.There are two major features that present a challenge when modelling a NiMH-system dynamically: Open Circuit Voltage (OCV) hysteresis and pressure build-up. Handling the hysteresis effect is important to accurately predict voltage and OCV.[1] OCV is especially important, as OCV is used to estimate the battery state of charge (SOC). Pressure build-up can be an important tool for charge termination, as it is the build-up of oxygen pressure and subsequent temperature increase that signal end of charge, Figure 1. In addition, the hydrogen pressure behavior changes with battery age and can be used to estimate end-of-life.OCV hysteresis is when the open circuit voltage at a certain SOC depends on the path taken to reach that charge state. This mean that a battery that has been charged to 50% will have a drastically different OCV than when the same battery has been discharged to 50%. This effect is believed to arise primarily from structural changes in the positive electrode, where the potential of the electrode surface is dependent on the material structure of the surface. An example of open circuit voltage hysteresis in a NiMH cell is found in Figure 1.The gas phase in the battery consists of four gases: nitrogen, hydrogen, oxygen and water. Nitrogen is an inert remnant from the battery manufacture.[2] Water is in equilibrium with the aqueous electrolyte. Hydrogen is in equilibrium with intercalated hydrogen in the negative metal hydride (MH) electrode. Finally, oxygen is the product of a side reaction that occurs at high potentials on the positive electrode. The production of oxygen at the positive electrode and ensuing oxygen recombination on the negative electrode produces a great deal of heat, which heats the battery and produces the temperature response that can be used to set a temperature derivative determined end of charge criteria. However, the presence of oxygen and high temperatures also drives the major aging mechanism: oxidation of the negative electrode. As the negative electrode is consumed, the capacity decreases. This leads to a difference in the hydrogen equilibrium pressure, as reaching a higher intercalation fraction increases the equilibrium pressure. [3]An implementation of a model for system battery management could help improve the following functions for a NiMH system: SOC estimation, SOH estimation, charge termination, fault detection and aging prevention. Therefore, development of a fully dynamic NiMH model has great value in improving over all system function for large scale energy storage applications. This study presents a fully dynamic and experimentally verified model for the NiMH battery that takes both pressure and OCV hysteresis into consideration. References Axén, J. B.; Ekström, H.; Zetterström, E. W.; Lindbergh, G. Evaluation of Hysteresis Expressions in a Lumped Voltage Prediction Model of a NiMH Battery System in Stationary Storage Applications. J. Energy Storage 2022, 48 (January). https://doi.org/10.1016/j.est.2022.103985.Mank, A. J. G.; Belfadhel-Ayeb, A.; Krüsemann, P. V. E.; Notten, P. H. L. In Situ Raman Analysis of Gas Formation in NiMH Batteries. Appl. Spectrosc. 2005, 59 (1), 109–114. https://doi.org/10.1366/0003702052940503.Tserolas, V.; Katagiri, M.; Onodera, H.; Ogawa, H. Thermodynamical Modeling of P-C Isotherms for Metal Hydride Materials. Trans. Mater. Res. Soc. Japan 2010, 35 (2), 221–226. https://doi.org/10.14723/tmrsj.35.221. Figure 1 Left: Open Circuit Voltage of a NiMH cell with exhibited hysteresis behavior. Right: Pressure and Temperature behavior of a NiMH module during a charge discharge cycle. Figure 1

Tunable the kondo effect at LaAlO3/SrTiO3 interface by oxygen vacancies

Complex oxide interfaces provide a platform for the study of electrical transport properties. In this work, high-quality LaAlO3/SrTiO3 heterostructures have been prepared under different oxygen partial pressure by pulsed laser deposition and monitored by in-situ reflection high energy electron diffraction. Based on X-ray photoelectron spectra and resistivity measurements, it is indicated that oxygen vacancy plays a pivotal role in the Kondo effect at LaAlO3/SrTiO3 interface. The formation of Ti3+ local moments related to oxygen vacancy can be controlled by oxygen partial pressure during the deposition of LaAlO3 films. With the increase of oxygen pressure, the Kondo temperature increased from 30 K to 80 K. This work may pave the way for studying the role of oxygen vacancy in the two-dimensional electron gas at the oxide interface.

Surface Morphology and Optical Mutation Properties of V2O5 Films Prepared with Different Oxygen Partial Pressures

vanadium pentoxide films(V2O5) were deposited on sapphire substrates under four different oxygen partial pressures by magnetron sputtering. Then the films’ crystallinity, surface morphology and optical mutation properties were researched. The results show that all the prepared films are polycrystalline V2O5, and the crystallization performance gets better with the oxygen pressure increases. In addition, the Root-Mean-Square(RMS) roughness decrease with the increase of oxygen pressure. Furthermore, with the oxygen pressure increases, the optical turn-off time and turn-on time are 2.2 and 36 ms, respectively down to 1.7 and 30 ms, and before/after phase-change transmittance, meanwhile, decreases from 75%/20% to 57%/11%, showing a great improvement in optical mutation properties.

Optimization of active antireflection ZnO films for p-GaAs-based heterojunction solar cells

We have optimized the photovoltaic properties of active ZnO/p-GaAs heterojunction solar cells by pulsed laser deposition method by varying the oxygen pressure from 0 to 50 mTorr during the fabrication process. We observed the crystallinity and grain size of ZnO enhanced with increasing oxygen pressure from 0 to 30 mTorr. In addition, with this increase of oxygen flux, the intensity of E1(LO) modes obtained by Raman measurements declines significantly and almost disappears under an oxygen pressure of 50 mTorr. The change of intensity is assumed to be the change of oxygen vacancy and zinc interstitial concentrations in ZnO films with oxygen pressures. Current-voltage measurements and extractions show that ZnO grown at 30 mTorr displays the best performance with the ISC of 24.3 mA/cm2, the efficiency of 8.746 %, and FF0 of 68.73 %. The high performance of the heterojunction solar cell grown at the oxygen partial pressure of 30 mTorr might be due to the reduction of oxygen vacancies by increasing oxygen during the deposition. The results reveal the importance of the oxygen processing gas in promoting devices performance.

Enhanced crystallization of α-(Cr, Al)2O3 coatings with increasing oxygen pressure

The synthesis of corundum structured α-Al2O3 coatings at relatively low temperatures has obsessed researchers for decades. Here, we propose an approach to promote the crystallization of α-(Cr, Al)2O3 by increasing the oxygen pressure during the deposition process. Specifically, cathodic arc evaporated (Cr, Al)2O3 coatings, synthesized from Al0.70Cr0.30 alloy targets under oxygen pressures of 0.8, 1.6, and 3.2 Pa, were investigated with reference to their microstructure, thermal stability, and mechanical properties. All three oxides exhibit an amorphous, cubic, and α-(Cr, Al)2O3 mixed structure. The latter crystallizes progressively with the increased oxygen pressure. Nevertheless, the (Cr, Al)2O3-3.2 coating containing most corundum constituents has the lowest hardness due to its uncompacted feature. Additionally, the transformation from metastable rock salt-type cubic-(Cr, Al)2O3 to α-(Cr, Al)2O3 upon annealing is accelerated with the elevated oxygen pressure, which leads to a strengthening in indentation hardness. This strengthening, together with the thermal-induced structural densification, results in a significant increase in hardness from ~19.0 to ~22.8 GPa for the corundum-containing coating after annealing at 1100 °C.

A Novel Mock Circuit to Test Full-Flow Extracorporeal Membrane Oxygenation.

Extracorporeal membrane oxygenation (ECMO) has become an important therapeutic approach in the COVID-19 pandemic. The development and research in this field strongly relies on animal models; however, efforts are being made to find alternatives. In this work, we present a new mock circuit for ECMO that allows measurements of the oxygen transfer rate of a membrane lung at full ECMO blood flow. The mock utilizes a large reservoir of heparinized porcine blood to measure the oxygen transfer rate of the membrane lung in a single passage. The oxygen transfer rate is calculated from blood flow, hemoglobin value, venous saturation, and post-membrane arterial oxygen pressure. Before the next measuring sequence, the blood is regenerated to a venous condition with a sweep gas of nitrogen and carbon dioxide. The presented mock was applied to investigate the effect of a recirculation loop on the oxygen transfer rate of an ECMO setup. The recirculation loop caused a significant increase in post-membrane arterial oxygen pressure (paO2). The effect was strongest for the highest recirculation flow. This was attributed to a smaller boundary layer on gas fibers due to the increased blood velocity. However, the increase in paO2 did not translate to significant increases in the oxygen transfer rate because of the minor significance of physically dissolved oxygen for gas transfer. In conclusion, our results regarding a new ECMO mock setup demonstrate that recirculation loops can improve ECMO performance, but not enough to be clinically relevant.

Lung perfusion during veno-venous extracorporeal membrane oxygenation in a model of hypoxemic respiratory failure

BackgroundVeno-venous extracorporeal membrane oxygenation (ECMO) provides blood oxygenation and carbon dioxide removal in acute respiratory distress syndrome. However, during ECMO support, the native lungs still play an important role in gas exchange, functioning as a second oxygenator in series with ECMO. The hypoxic vasoconstriction mechanism diverts regional blood flow within the lungs away from regions with low oxygen levels, optimizing ventilation/perfusion matching. ECMO support has the potential to reduce this adaptive pulmonary response and worsen the ventilation/perfusion mismatch by raising venous oxygen partial pressure. Thus, the objective of this study was to evaluate the effect of ECMO on regional pulmonary perfusion and pulmonary hemodynamics during unilateral ventilation and posterior lung collapse.MethodsFive Agroceres pigs were instrumented, monitored and submitted to ECMO. We used the Electrical Impedance Tomography (EIT) to evaluate lung ventilation and perfusion in all protocol steps. Effects of ECMO support on pulmonary hemodynamics and perfusion involving two different scenarios of ventilation/perfusion mismatch: (1) right-lung selective intubation inducing collapse of the normal left lung and (2) dorsal lung collapse after repeated lung lavage. Data including hemodynamics, respiratory, lung perfusion/ventilation, and laboratory data over time were analyzed with a mixed generalized model using the subjects as a random factor.ResultsThe initiation of ECMO support provided a significant reduction in Mean Pulmonary Artery Pressure (PAPm) in both situations of ventilation/perfusion mismatch. However, distribution of lung perfusion did not change with the use of ECMO support.ConclusionsWe found that the use of ECMO support with consequent increase in venous oxygen pressure induced a significant drop in PAPm with no detectable effect on regional lung perfusion in different scenarios of ventilation/perfusion mismatch.

Тhe role of the glutamatergic system in the mechanism of development of hyperbaric oxygen seizures

The purpose of the scientific article was to study the neurophysiological mechanisms of the occurrence of convulsive activity when breathing oxygen under high pressure under conditions of hyperbaric oxygen and the role of the glutamatergic system in this process.Research methods: Wistar rats, males, weighing 200–250 g. in the amount of 20 were used in the work. The animals were placed in a pressure chamber and compressed with medical oxygen up to 5 ATА. Behavioral reactions and signs of convulsive activity were recorded in animals during compression and during subsequent exposure. Two experimental groups were previously injected with a glutamine synthetase inhibitor at various concentrations 6 hours before compression.The main results showed that irreversible inhibition of glutamine synthetase in the rat brain under the action of increased oxygen pressure led to a significant decrease in the latent period of convulsions.

Influence of substrate temperature and oxygen pressure on the structural and optical properties of polycrystalline BaTiO3 thin films grown by PLD

The effect of substrate temperature and oxygen pressure on linear and nonlinear optical properties of pulsed laser deposited barium titanate BaTiO3 (BTO) thin films is reported in the present manuscript. BTO thin films have been deposited on n-type Si (100) and quartz substrates in the range of substrate temperatures from 400 to 700 °C and oxygen pressures from 0.005 to 1 mbar. The root means square (RMS) surface roughness is observed to decrease with the rise in substrate temperature and increased with an increase in oxygen pressure. The optimum background pressure and the substrate temperature are observed to be around ∼0.1 mbar and 700 °C, respectively. All the BTO thin films are found to be in the preferential (110) plane, from X-ray Diffraction (XRD), indicating the pseudocubic phase. Raman analysis also confirms the pseudocubic phase of BTO for all the thin films. The crystallite size, measured from XRD analysis is found to be increased with the increase in substrate temperature and is also affected by the background oxygen pressure. The thickness, linear absorption coefficient, and refractive index of the thin films are determined from UV–Visible–NIR spectroscopy. Transmission is observed to be 75–85% for all the thin films in the spectral range of 400–2000 nm. Nonlinear optical properties (NLO) are studied by an in-house assembled modified Z-scan set-up using continuous-wave (cw) Ar-Ion laser (λ = 488 nm) and found to be (57.54 ± 0.05) cm/W at the optimum deposition parameters.

Formation of ilmenite-type single-crystalline MgTiO3 thin films by pulsed-laser deposition

Ilmenite structure is a good playground to explore magnetism in honeycomb lattices owing to the existence of an intriguing variety of magnetism in 3d transition metal compounds. Because of the absence of magnetic ions, ilmenite-type MgTiO3 is a promising candidate for d0 transparent insulators to reveal general features of TiO6 honeycomb layers. In this study, we found an optimum growth condition to synthesize ilmenite-type single-crystalline MgTiO3 thin films on Al2O3(0001) substrates by pulsed-laser deposition. By increasing oxygen pressure from roughly 10−6 to 10−1 Torr, we obtained (0001)-oriented MgTiO3 thin films with suppression of segregation of a Mg2TiO4 phase. On the triangular lattice of Al2O3, twin-domain formation is suppressed with decreasing deposition rate, resulting in the synthesis of single-crystalline MgTiO3 thin films. The bandgap of the MgTiO3 film was evaluated to be about 4.4 eV by optical absorption spectra, which implies d0 transparent insulator.

Hyperbaric phototherapy augments blood carbon monoxide removal.

Carbon monoxide (CO) poisoning is responsible for nearly 50,000 emergency department visits and 1200 deaths per year. Compared to oxygen, CO has a 250-fold higher affinity for hemoglobin (Hb), resulting in the displacement of oxygen from Hb and impaired oxygen delivery to tissues. Optimal treatment of CO-poisoned patients involves the administration of hyperbaric 100% oxygen to remove CO from Hb and to restore oxygen delivery. However, hyperbaric chambers are not widely available and this treatment requires transporting a CO-poisoned patient to a specialized center, which can result in delayed treatment. Visible light is known to dissociate CO from carboxyhemoglobin (COHb). In a previous study, we showed that a system composed of six photo-extracorporeal membrane oxygenation (ECMO) devices efficiently removes CO from a large animal with CO poisoning. In this study, we tested the hypothesis that the application of hyperbaric oxygen to the photo-ECMO device would further increase the rate of CO elimination. We developed a hyperbaric photo-ECMO device and assessed the ability of the device to remove CO from CO-poisoned human blood. We combined four devices into a "hyperbaric photo-ECMO system" and compared its ability to remove CO to our previously described photo-ECMO system, which was composed of six devices ventilated with normobaric oxygen. Under normobaric conditions, an increase in oxygen concentration from 21% to 100% significantly increased CO elimination from CO-poisoned blood after a single pass through the device. Increased oxygen pressure within the photo-ECMO device was associated with higher exiting blood PO2 levels and increased CO elimination. The system of four hyperbaric photo-ECMO devices removed CO from 1 L of CO-poisoned blood as quickly as the original, normobaric photo-ECMO system composed of six devices. This study demonstrates the feasibility and efficacy of using a hyperbaric photo-ECMO system to increase the rate of CO elimination from CO-poisoned blood. This technology could provide a simple portable emergency device and facilitate immediate treatment of CO-poisoned patients at or near the site of injury.