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The microalga Scenedesmus sp. (Chlorophyceae) was cultured in a raceway pond (RWP) placed in a greenhouse. The objective of this case study was to monitor the photosynthesis performance and selected physicochemical variables (irradiance, temperature, dissolved oxygen concentration) of microalgae cultures in situ at various depths of RWP. The data of actual photochemical yield Y(II), the electron transport rate monitored by in vivo chlorophyll fluorescence and photosynthetic oxygen production both in situ and ex situ revealed that (i) even in diluted cultures (0.6 g DW L−1), the active photic layer in the culture was only about 1 cm, indicating that most of the culture was "photosynthetically" inactive; (ii) the mechanism of non-photochemical quenching may not be fast enough to respond once the cells move from the surface to the deeper layers; and (iii) even when cells were exposed to a high dissolved oxygen concentration of about 200% sat and higher, the cultures retained a relatively high Y(II) > 0.35 when monitored in situ. The presented work can be used as exemplary data to optimize the growth regime of microalgae cultures in large-scale RWPs by understanding the interplay between photosynthetic activity, culture depth and cell concentration. [ABSTRACT FROM AUTHOR]

Reliable net primary production (NPP) estimations of kelp forests are important to evaluate their C-fixation potential. Photosynthetic oxygen measurements can be converted to C-fixation using photosynthetic quotients (PQs). Although there is a known high variability in PQs, the extent and the consequences for NPP is understudied in kelp species. Thus, the present study aimed (i) to quantify the variability of PQs, (ii) to model NPP and (iii) to assess the impact of warming on both. The kelp, Laminaria hyperborea, was studied near the island of Helgoland (North Sea, Germany) along a depth gradient (2, 4, 6 m below mean low water spring tide) across all four seasons. Blade discs were cultivated during at least 6 days per season under simulated ambient photosynthetic photon flux density (PPFD) and temperature conditions and, in parallel, in a warming scenario (+ 4°C). PQs were calculated from parallel oxygen production and 14C-fixation measurements at saturating PPFD at the end of the incubation period. Seasonal PQs varied between 1.7 and 4.4, with highest values in summer due to increased oxygen production. The warming scenario stimulated C-fixation in most seasons, lowering the PQ in comparison to ambient temperature conditions, while collection depth had no significant effect on PQs. The seasonal PQs were used to model daily NPP rates for kelp standing stock at 4 m depth. These daily NPP rates were compared between temperature treatments and with daily NPP rates based on fixed PQs. The warming scenario had a stimulating effect on daily NPP rates in the high-light season spring. In the low-light season autumn, warming resulted in negative daily NPP rates, as the high respiration rates could not be compensated by gross photosynthesis. Overall, annual NPP rate under warming conditions (347 g C m-2 yr-1) was 14% higher than the annual NPP rate under ambient conditions (303 g C m-2 yr-1). Modelling daily NPP with fixed PQs, which neglects the seasonal variation of the PQs, led to a high overestimation of up to 255%. We, therefore, recommend modelling NPP rates not with a fixed PQ, but with seasonal PQs determined under different temperature scenarios in order to obtain reliable future predictions. [ABSTRACT FROM AUTHOR]

Oxygen conditioning on a large scale could effectively improve living and working conditions to relieve the hypoxia of plateau environment. Industrial-scale pressure swing adsorption (PSA) and vacuum pressure swing adsorption (VPSA) medical oxygen production systems are designed for supplying oxygen at high altitude of 3800 m areas. The effects of process parameters and key steps on the performance of PSA and VPSA processes have been experimentally compared and analyzed. The results show that the adsorption time, pressure equalization and purge step are key factors of affecting the oxygen production performance. The PSA cycle with pressure equalization of product end and continuous purge could produce ~ 93% O2 with recovery of 45.4% from compressed air and the minimum energy consumption is 1.21 kW·Nm− 3. The VPSA cycle with pressure equalization of product end and intermittent purge could produce ~ 93% O2 with recovery of 54% from super-atmospheric air and the minimum energy consumption is 0.68 kW·Nm− 3. [ABSTRACT FROM AUTHOR]

Electrocatalytic water-splitting is one of the promising processes for producing hydrogen as a renewable and ecologically friendly fuel replacing fossil fuel. Achieving cost-efficient, stable, and active bifunctional electrocatalysts through water electrolysis is the highest challenge as the highest rate of hydrogen and oxygen production is desired. The role of copper vanadium oxide in different annealing conditions, as a possible electrocatalyst for water splitting was investigated in terms of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Structural and morphological characterizations were done by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The electrocatalytic efficiency and stability were assessed by linear sweep voltammetry (LSV) and chronoamperometry (CA). The LSV measurements show that the copper vanadium oxide catalyst with 700 °C annealing temperature exhibited overpotentials of 232 mV and 260 mV to attain a cathodic current density of 10 mAcm−2 and anodic current density of 20 mAcm−2, respectively. A Tafel slope of 68 mVdec−1 was required for the HER and for OER a Tafel slope of 72 mVdec−1 was needed. In addition, stability tests regarding CA yield very good stability of the material. The high annealing temperatures are important as they restructure crystal structures, increase the number of active sites, and thus improve electrical conductivity. Consequently, the overpotentials for OER and HER decrease due to enhanced electron transfer efficiency causing favorable interactions between electrocatalysts and reactants. The current research highlights the capability of the copper vanadium oxide catalyst for water water-splitting process which is cost-effective and efficient for renewable hydrogen production. Highlights: Copper vanadium oxide was fabricated using the microwave irradiation method. The prepared materials underwent annealing at three different temperatures to investigate the impact of annealing temperature on electrochemical performances. Electrocatalyst annealed at 700 °C, requires overpotentials of 232 mV and 260 mV to achieve a cathodic current density of 10 mAcm−2 and an anodic current density of 20 mAcm−2, respectively. The copper vanadium oxide, annealed at 700 °C, is an excellent material for both OER and HER applications. [ABSTRACT FROM AUTHOR]

Reliable net primary production (NPP) estimations of kelp forests are important to evaluate their C-fixation potential. Photosynthetic oxygen measurements can be converted to C-fixation using photosynthetic quotients (PQs). Although there is a known high variability in PQs, the extent and the consequences for NPP is understudied in kelp species. Thus, the present study aimed (i) to quantify the variability of PQs, (ii) to model NPP and (iii) to assess the impact of warming on both. The kelp, Laminaria hyperborea, was studied near the island of Helgoland (North Sea, Germany) along a depth gradient (2, 4, 6 m below mean low water spring tide) across all four seasons. Blade discs were cultivated during at least 6 days per season under simulated ambient photosynthetic photon flux density (PPFD) and temperature conditions and, in parallel, in a warming scenario (+ 4°C). PQs were calculated from parallel oxygen production and 14C-fixation measurements at saturating PPFD at the end of the incubation period. Seasonal PQs varied between 1.7 and 4.4, with highest values in summer due to increased oxygen production. The warming scenario stimulated C-fixation in most seasons, lowering the PQ in comparison to ambient temperature conditions, while collection depth had no significant effect on PQs. The seasonal PQs were used to model daily NPP rates for kelp standing stock at 4 m depth. These daily NPP rates were compared between temperature treatments and with daily NPP rates based on fixed PQs. The warming scenario had a stimulating effect on daily NPP rates in the high-light season spring. In the low-light season autumn, warming resulted in negative daily NPP rates, as the high respiration rates could not be compensated by gross photosynthesis. Overall, annual NPP rate under warming conditions (347 g C m–2 yr–1) was 14% higher than the annual NPP rate under ambient conditions (303 g C m–2 yr–1). Modelling daily NPP with fixed PQs, which neglects the seasonal variation of the PQs, led to a high overestimation of up to 255%. We, therefore, recommend modelling NPP rates not with a fixed PQ, but with seasonal PQs determined under different temperature scenarios in order to obtain reliable future predictions.

In the field of ecology, more and more attention is paid to the analysis of the interaction of herbaceous plants with the structure of ecosystems, including forests. The aim of the study was to determine the impact of herbaceous plants on the biodiversity and stability of pine plantations in Western Polissia of Ukraine. To achieve this goal, in 2010-2023, the State Enterprise “Research Farm “Horodetske” assessed the diversity of herbaceous plant species, measured their number and cover, evaluated soil physical properties and biometric parameters of pine trees, and assessed how changes in the pine plantation ecosystem caused by herbaceous plants can affect carbon sequestration and oxygen productivity. The study found that herbaceous species among pine plantations in Western Polissia perform important ecological functions that contribute to the conservation and restoration of ecosystems. The presence of these plants enriches the soil with organic matter and helps maintain the structural and functional stability of ecosystems. The study showed that herbaceous plants contribute to the restoration of pine plantations by providing protection and support for young trees, and have a positive impact on their biometric parameters, increasing the total phytomass. Herbaceous plants also improve soil physical properties, such as pH, humus content, aggregate water resistance and water permeability, which can contribute to soil structural stability and the health of pine stands. In addition, the presence of herbaceous plants contributes to more efficient carbon sequestration and oxygen production, which is important for the balance of the air environment in the ecosystem. The results obtained are of great importance for environmental management and conservation of natural resources in the Western Polissia region, as they provide scientific basis for developing strategies for the conservation and restoration of forest ecosystems, taking into account the role of herbaceous plants in their functioning

Molten Regolith Electrolysis, as an in situ resource utilization (ISRU) technology, has the potential to enable the production of oxygen and metallic alloys on the Lunar surface; opening new doors in Cis-Lunar, and eventually Martian space exploration. This research studies the fundamental physics which govern the formation, growth, detachment, and rise of electrolytic bubbles. To this end, computational fluid dynamic (CFD) models were developed and run, to simulate water electrolysis, molten salt electrolysis (MSE), and molten Lunar regolith (MRE) electrolysis across multiple reduced gravity levels. The results demonstrate that reduced gravity, electrode surface roughness (possibly due to surface degradation), fluid properties, and electrode orientation can all affect electrolytic efficiency and possibly even stall electrolysis by delaying bubble detachment. The findings of this research must be considered when designing and operating electrolysis systems at reduced gravity levels. [ABSTRACT FROM AUTHOR]

In the field of ecology, more and more attention is paid to the analysis of the interaction of herbaceous plants with the structure of ecosystems, including forests. The aim of the study was to determine the impact of herbaceous plants on the biodiversity and stability of pine plantations in Western Polissia of Ukraine. To achieve this goal, in 2010-2023, the State Enterprise "Research Farm "Horodetske" assessed the diversity of herbaceous plant species, measured their number and cover, evaluated soil physical properties and biometric parameters of pine trees, and assessed how changes in the pine plantation ecosystem caused by herbaceous plants can affect carbon sequestration and oxygen productivity. The study found that herbaceous species among pine plantations in Western Polissia perform important ecological functions that contribute to the conservation and restoration of ecosystems. The presence of these plants enriches the soil with organic matter and helps maintain the structural and functional stability of ecosystems. The study showed that herbaceous plants contribute to the restoration of pine plantations by providing protection and support for young trees, and have a positive impact on their biometric parameters, increasing the total phytomass. Herbaceous plants also improve soil physical properties, such as pH, humus content, aggregate water resistance and water permeability, which can contribute to soil structural stability and the health of pine stands. In addition, the presence of herbaceous plants contributes to more efficient carbon sequestration and oxygen production, which is important for the balance of the air environment in the ecosystem. The results obtained are of great importance for environmental management and conservation of natural resources in the Western Polissia region, as they provide scientific basis for developing strategies for the conservation and restoration of forest ecosystems, taking into account the role of herbaceous plants in their functioning. [ABSTRACT FROM AUTHOR]

The microalga Scenedesmus sp. (Chlorophyceae) was cultured in a raceway pond (RWP) placed in a greenhouse. The objective of this case study was to monitor the photosynthesis performance and selected physicochemical variables (irradiance, temperature, dissolved oxygen concentration) of microalgae cultures in situ at various depths of RWP. The data of actual photochemical yield Y(II), the electron transport rate monitored by in vivo chlorophyll fluorescence and photosynthetic oxygen production both in situ and ex situ revealed that (i) even in diluted cultures (0.6 g DW L−1), the active photic layer in the culture was only about 1 cm, indicating that most of the culture was “photosynthetically” inactive; (ii) the mechanism of non-photochemical quenching may not be fast enough to respond once the cells move from the surface to the deeper layers; and (iii) even when cells were exposed to a high dissolved oxygen concentration of about 200% sat and higher, the cultures retained a relatively high Y(II) > 0.35 when monitored in situ. The presented work can be used as exemplary data to optimize the growth regime of microalgae cultures in large-scale RWPs by understanding the interplay between photosynthetic activity, culture depth and cell concentration.

At present, commercial systems are usually used in pressure swing adsorption (PSA) experiments. However, the purchased equipment has disadvantages such as large size, complicated tubing design and high price, which are not conducive to undergraduate laboratory teaching. In this paper, a low-cost benchtop design of PSA system is proposed, with which students can build their own PSA equipment with common laboratory materials and conduct the testing and operation on their own. Using Li-exchanged zeolite as the adsorbent, the system can produce high-purity oxygen with a concentration up to 95.8%, which is comparable to that of commercial oxygen concentrator. The designed system can be disassembled and reassembled repeatedly and the process of building and testing is safe and fun. The proposed design can be used in the PSA experimental teaching for undergraduate students who major in applied chemistry, chemical engineering and other related subjects. We believe that students' interest in creating experimental equipment can be intrigued and their ability to solve practical problems can be improved during the build and testing process of the proposed PSA system. [ABSTRACT FROM AUTHOR]

The effect of adsorption time on the performance of pressure swing adsorption (PSA) oxy- gen production process was experimentally investigated and a concentration wave model was proposed for analyzing the mass transfer characteristics and calculating the optimal adsorption time during the PSA process. The results showed that the shape of N₂ loading profile at adsorption step changed with time and axial position, and the propagation velocity of the N₂ concentration wave with ideal conditions was greater than the practical propagation velocity. The limited heat and mass transfer resistance slowed down the propagation of the concentration wave during the practical adsorption process, and the reduction degree of the concentration wave velocity was about 26%. The errors between the opti- mal adsorption time calculated though the concentration wave model and the experimental adsorption time were within 0. 5 s. [ABSTRACT FROM AUTHOR]

Bone defects can interfere with bone healing by disrupting the local environment, resulting in vascular damage and hypoxia. Under these conditions, insufficient oxygen availability is a significant factor that exacerbates disease by blocking angiogenesis or osteogenesis. Exosomes play a crucial role in intercellular communication and modulation of inflammation to aid bone regeneration. However, the distance between exosomes and areas of damage can hinder efficient bone generation and cell survival. To overcome this limitation, we fabricated a continuous oxygen-supplying composite scaffold, with the encapsulation of calcium peroxide in a polylactic acid three-dimensional (3D) printing construct (CPS), as both an oxygen source and hydroxyapatite (HAP) precursor. Furthermore, bone marrow mesenchymal stem cell (BMSC)-derived exosomes were incorporated into hyaluronic acid (HA) hydrogels to stimulate cell growth and modulate inflammation. The release of exosomes into cells leads to an increase in alkaline phosphatase production. In vivo results demonstrated that the composite scaffold regulated the inflammatory microenvironment, relieved tissue hypoxia, and promoted new bone formation. These results indicate that the synergistic effect of exosomes and oxygen promoted the proliferation of BMSCs, alleviated inflammation and exhibited excellent osteogenic properties. In conclusion, this osteogenic functional composite scaffold material offers a highly effective approach for bone repair. • The reaction of calcium peroxide can generate oxygen, releasing calcium ions can help promote the growth of new bones. • Oxygen and exosomes synergistically promote bone repair. • In vivo , the composite scaffold allows bone repair to be promoted, and angiogenesis to be accelerated. [ABSTRACT FROM AUTHOR]

• Oxygen storage capacity is improved as temperature higher than 550 °C. • Desorption rates were obtained by fitting the curves with a kinetic model. • Desorption rate constant rises with temperature but decreases with Al doping amount. • Ideal oxygen production rate is proposed to evaluate sorbent performance. Perovskite-type oxides are extensively studied as oxygen sorbents in pressure swing adsorption (PSA) for air separation at elevated temperatures. However, quantitative analysis of desorption kinetics and the basis of material optimization are rarely reached on a fixed bed. In this study, the effects of Al doping on the oxygen absorption/desorption behaviors of Sr 0.72 Ca 0.28 Fe 1-x Al x O 3-δ (SCFA, x = 0, 0.03, 0.05, 0.07, 0.1) were investigated by temperature programmed desorption (TPD) and fixed bed absorption/desorption experiments. The desorption kinetics were analyzed by a Geometrical contraction model. O 2 -TPD results show that Al doping reduces the total absorption amount of Sr 0.72 Ca 0.28 FeO 3-δ (SCF). Through the peak-differentiation-imitating analysis, it was found that the SCFA series materials have three different oxygen desorption sites, and the desorption peak area and temperature corresponding to each site are different. CO 2 -TPD results reveal that Al doping improves the CO 2 resistance of the perovskite oxides. Compared with SCF, Al doped materials show enhanced equilibrium oxygen absorption capacity at temperature higher than 550 °C. The oxygen desorption rates of SCFA series were calculated by fitting the desorption curves with Geometrical contraction model (R2). Both initial oxygen desorption concentration and oxygen desorption rate constants increase with temperature but decrease with the Al doping amount. The similar apparent activation energies of the desorption rate constant of the SCFA series reveal that the desorption mechanism not changes with Al doping. Ideal oxygen production rate, equaling to the multiplication of equilibrium oxygen absorption capacity and the desorption rate constant, is suggested to evaluate the performance of an oxygen sorbent. The x = 0.03 sample shows the highest ideal oxygen production rate among the SCFA series. [ABSTRACT FROM AUTHOR]

Macrophages became BMB@M1 after internalizing BMB nanoparticles. About 15 hours after intravenous injection, BMB@M1 accumulated at the tumor site. Exogenous oxygen supplementation enhanced photodynamic therapy. The tumor fragments generated by photodynamic therapy recruited immune cells such as DCs, and increased oxygen content in TME were conducive to the infiltration of T cells. [Display omitted] • Macrophages were activated by BMB nanoparticles. • Nanoengineered macrophages transformed into activated oxygen rich "Trojan horse" • "Trojan horse" alleviated hypoxia in TME while preventing the exhaustion of T cells. • Nanoengineered macrophages enhanced photodynamic therapy. • Macrophages and photodynamic therapy stimulated immune response synergistically. Photodynamic therapy (PDT) is an emerging treatment for melanoma stimulating antitumor immune responses. However, oxygen consumption by PDT exacerbates hypoxia and immunosuppression in the tumor microenvironment. This issue could potentially be addressed by M1 macrophages with high hydrogen peroxide concentrations, which can be catalyzed to oxygen, thereby increasing oxygen level and enhancing intrinsic immune response of M1 macrophages and their ability to stimulate adaptive immunity. Herein, biocompatible photosensitizer-containing nanoparticles were designed by combining bovine serum albumin and manganese dioxide (BMB). These nanoparticles were internalized by M1 macrophages in vitro to form nanoengineered macrophages (BMB@M1). BMB@M1 demonstrated various ways to transfer nanoparticles in melanoma with high tumor site accumulation. Within the tumor microenvironment characterized by hydrogen peroxide and acidity, BMB underwent Mn2+ transformation and generated oxygen. The paramagnetic property of Mn2+ was used for magnetic resonance imaging, enabling visualization of the melanoma enrichment process of BMB@M1. Oxygen supplementation enhanced the therapeutic effect of PDT and stimulated the secretion of IL-12 and IFN-γ by macrophages, synergistically promoting the infiltration of T cells and dendritic cells into the tumor. These findings showed that nanoengineered M1 macrophage could be used as a delivery system to enhance immune effects of PDT. [ABSTRACT FROM AUTHOR]

• Integrating large-scale PSA units in local hospitals in Morocco to improve of medical oxygen supply systems and to enhance healthcare services. • Designing the PSA system tailored to meet the specific oxygen needs of hospitals. • Performing numerical simulations to validate and optimize the PSA system design. • Evaluating the performance of the system. To enhance the availability and accessibility of medical oxygen in local hospitals in Morocco, a solid approach has been conducted for upscaling PSA unit. This comprehensive research involves the design, simulation, and performance evaluation of the PSA unit to confirm the functioning and efficiency of the system. The design phase meticulously considers hospital oxygen requirements, utilizing data from multiple local hospitals. Objectives include using PSA technology to produce high-purity oxygen, providing autonomy for 30–35 patients at 5 L/min. Although, the hospital needs 650 L/min of medical oxygen in order to supply all the patients. The study reveals promising results for oxygen concentration which reaches a maximum of 96 % of oxygen under 29 mol/min of flowrate which give an equivalent to 660 L/min volumetric flow rate that can supply the needs of local hospitals within a short time. These findings will enable hospitals decision makers to consider large PSA over cryogenic separation unit that has been known with major drawbacks in delivery and pose logistical and environmental problems and to ensure a steady and reliable supply of medical oxygen, ultimately contributing to improved healthcare services and patient care. [ABSTRACT FROM AUTHOR]

Getting rid of the biofilms is a major challenge when treating skin and soft tissue infections (SSTI), an inflammatory illness brought on by bacteria. Traditional magnetic materials have a limited dispersibility and a biofilm permeable property, making it challenging to remove biofilms and causing infection to linger. To solve these problems, we developed a kind of magnetic composite nanoplatform coated with indocyanine green carbon dots and modified with chitosan modification (Fe-ICGCDs@CS). Fe-ICGCDs@CS has high dispersibility and improves the conductivity of biofilms under magnetic action. Fe-ICGCDs@CS can adsorb bacteria via the positive charge and achieve precise photothermal sterilization and photodynamic therapy (PDT). Moreover, by catalyzing hydrogen peroxide (2 mM), Fe-ICGCDs@CS can produce oxygen to relieve the anoxic state in the deep layer of biofilms and activate dormant bacteria to make them sensitive to external stimuli. All in all, unlike the common "just kill" sterilization model, Fe-ICGCDs@CS can accurately kill bacteria and be recovered by an external magnetic field at the end of treatment, thus reducing the potential biological toxicity of nanomaterials. Therefore, the proposed Fe-ICGCDs@CS provides a new antibacterial method with low biotoxicity for clinical application in the treatment of biofilm infections. • Fe-ICGCDs@CS has high dispersibility and improves the conductivity of biofilms under magnetic action. • Fe-ICGCDs@CS can adsorb bacteria via the positive charge and achieve precise PTT and PDT. • Fe-ICGCDs@CS can produce O 2 to relieve the anoxic state in the deep layer of biofilms and activate dormant bacteria. • Fe-ICGCDs@CS provides a new antibacterial method for clinical application in the treatment of biofilm infections. [ABSTRACT FROM AUTHOR]