Oxygen Transport Research Articles

Tailoring the Anisotropic Oxygen Transport Properties in Bulk Ceramic Membranes Based on a Ruddlesden-Popper Oxide by Applying Magnetic Fields.

Textured Nd2NiO4+ δ bulk ceramic membranes are fabricated via slip casting in a 0.9T magnetic field generated by neodymium magnets. This process aligns the oxide grains with their easy-magnetization c-axis parallel to the applied magnetic field. Depending on the magnetic field's direction relative to the slip casting, grains orient either with their a,b-plane or c-axis parallel to the normal direction of the disk-shaped ceramic, thus aligning with the oxygen permeation direction. Without the magnetic field, a non-textured bulk membrane is formed. The microstructure and texture of the ceramic membranes are meticulously analyzed using advanced techniques, including X-ray diffraction, scanning and transmission electron microscopy, as well as related methods. Evaluation of the texturing effect on the oxygen permeation performance shows that the a,b-plane textured Nd2NiO4+ δ bulk membrane achieves the highest oxygen permeation fluxes between 1023-1223K. Additionally, it demonstrates impressive CO₂ stability, maintaining effective performance for at least 140h due to preferential oxygen transport along the a,b-plane. These characteristics make Nd2NiO4+ δ an auspicious material for industrial applications as an oxygen transport membrane, outperforming more susceptible perovskite-based materials. Magnetic alignment thus proves to be an effective method for achieving membrane texturing, enabling precise regulation of oxygen transport properties.

Characteristics of biofilm layer in a bio-doubling reactor and their impact on aerobic denitrifying bacteria enrichment.

Microbial loss significantly affects wastewater treatment efficiency. This study simulated the inoculation area of a self-developed biological doubling reactor (BDR) to evaluate the retention efficiency of seven different fillers for aerobic denitrifying bacteria. Over 90 days of continuous operation, the porous filler R3 demonstrated excellent performance, with OD600 values consistently exceeding 1.0 and minimal fluctuation. On day 90, the seed liquid amplified with R3 achieved removal efficiencies of 100% for ammonia nitrogen, 97.75% for total nitrogen, and 96.4% for chemical oxygen demand, outperforming other fillers. Scanning electron microscopy and microscopic analysis revealed that R3's large large specific surface area and volume formed a unique meshed biofilm structure, enhancing oxygen and nutrient transport while minimizing detachment. This promoted effective enrichment and retention of aerobic denitrifying bacteria. Microbial diversity analysis confirmed that Acinetobacter, a key genus involved in aerobic denitrification, dominated the network biofilm on R3, accounting for an average of 35.63%. while granular fillers, due to oxygen limitation, promoted the growth of anaerobic ammonium-oxidizing Alcaligenes. The use of BDR-enhanced MBBR for treating synthetic wastewater resulted in a 29.6% increase in TN removal efficiency, with stable system operation. The use of porous fillers with a high specific volume supports stable biofilm formation and consistent seed liquid output, providing a viable solution to microbial loss in wastewater treatment processes.

Minimizing bulk oxygen transport resistance of PEMWE by adding PTFE to tuning wettability and pore size in the anode catalyst layer

Minimizing bulk oxygen transport resistance of PEMWE by adding PTFE to tuning wettability and pore size in the anode catalyst layer

Endurance Training for Cardiovascular Health: Insights into Risk Reduction and Heart Disease Prevention

Endurance training significantly benefits from strong cardiovascular health, as it relies on the efficient delivery of oxygen and nutrients to working muscles. A robust cardiovascular system enhances key factors such as cardiac output, stroke volume, and capillary density, which optimize oxygen transport and utilization during prolonged physical activity. This improved vascular efficiency reduces strain on the heart, allowing athletes to sustain higher intensities for longer durations. Endurance training also improves aerobic capacity (VO₂max) and accelerates recovery rates, enabling individuals to handle greater training loads and recover more effectively. Together, these adaptations create a positive feedback loop where endurance training strengthens cardiovascular health, further enhancing performance and resilience.

Вплив триптофану на гістоморфометричні зміни бурої жирової тканини щурів

Literature data on the effects of tryptophan on brown adipose tissue (BAT) are ambiguous. Its role in BAT with existing pathology in the body, primarily obesity, was mainly studied. However, the effect of the use of tryptophan on the functioning of a healthy BAT is little studied. The aim of this work was to study the effect of L-tryptophan on the histomorphometric parameters of the BAT in healthy rats. The study was conducted on male Wistar rats, whose age at the beginning of the experiment was 3 months. Rats were divided into 2 groups (12 animals in each): I group – control, II group – experimental animals, which received daily oral L-tryptophan at a dose of 80 mg/kg body weight. Work with rats was carried out in accordance with the principles of the Declaration of Helsinki. Histological preparations were made from the interscapular bodies of the BAT according to the standard me­thod. Micropreparations of the BAT were photographed using a digital camera. Morphometry of the BAT was carried out on digital images using the computer program “Image J”. Histomorphometric analysis of the BAT of rats treated with L-tryptophan revealed an increase in the number of adipocytes with one large lipid droplet (12 times more) and a smaller number of brown adipocytes (1.5 times less). The size of adipocytes increased due to an increase in the area of lipid droplets (by 174 %) located in the cytoplasm. A decrease in the area of the nucleus, the nuclear-cytoplasmic ratio, and the number of nucleolus indicates inhibition of the synthetic activity of adipocytes. An increase in the relative area of connective tissue (by 13 %) and a decrease in the area of blood vessels (by 27 %) were also found in the BAT of these rats, which indicates worse perfusion, inhibition of oxygen transport to parenchymal elements, deterioration of conditions for metabolic processes. Therefore, a 28-day exposure to L-tryptophan has morphological signs of a decrease in the functional activity of BAT in healthy rats and leads to the process of its «whitening» – transformation into white adipose tissue. Therefore, despite the researched positive effect of tryptophan on many organs, it should be taken carefully so as not to harm the functioning of the BAT.

Minerals and Human Health: From Deficiency to Toxicity

Minerals are essential nutrients that play critical roles in human health by regulating various physiological functions. Examples include bone development, enzyme function, nerve signaling, and the immune response. Both the deficiencies and toxicities of minerals can have significant health implications. Deficiencies in macrominerals such as calcium, magnesium, and phosphate can lead to osteoporosis (associated with falls and fractures), cardiovascular events, and neuromuscular dysfunction. Trace mineral deficiencies, such as iron and zinc. Selenium deficiency impairs oxygen transport, immune function, and antioxidant defenses, contributing to anemia, delaying wound healing, and increasing susceptibility to infectious diseases. Conversely, excessive intake of minerals can have severe health consequences. Hypercalcemia can cause kidney stones and cardiac arrhythmias as well as soft-tissue calcification, whereas excessive iron deposition can lead to oxidative stress and organ/tissue damage. Maintaining adequate mineral levels through a balanced diet, guided supplementation, and monitoring at-risk populations is essential for good health and preventing disorders related to deficiencies and toxicities. Public health interventions and education about dietary sources of minerals are critical for minimizing health risks and ensuring optimal well-being across populations. While a comprehensive analysis of all macro and micronutrients is beyond the scope of this article, we have chosen to focus on calcium, magnesium, and phosphate. We summarize the consequences of deficiency and the adverse events associated with the overconsumption of other minerals.

High-affinity VNARs targeting human hemoglobin: Screening, stability and binding analysis.

Hemoglobin, composed of α- and β-chains, is essential for oxygen transport and is key in diagnosing and treating gastrointestinal and blood disorders. It also aids in detecting blood contamination and estimating transfusion volumes. Immunological methods, based on antigen-antibody interactions, are distinguished by their high sensitivity and accuracy. Consequently, it is necessary to develop hemoglobin-specific antibodies characterized by high specificity and affinity to enhance detection accuracy. The variable domain of the new antigen receptor (VNAR) from sharks, the smallest antigen-binding unit, is ideal for disease diagnosis and treatment due to its small size, stability, and high affinity. In this study, Chiloscyllium plagiosum was immunized with human hemoglobin protein. Nine VNAR immune libraries with sizes ranging from 1 × 108 to 1.82 × 109 colony-forming units (CFU) were constructed and biopanned using phage display, resulting in three hemoglobin-specific VNAR sequences (5-10C, 7-11 A, T-12-4D). These sequences were inserted into pTT5-TEV-Fc vectors and transfected into HEK 293F cells. The resulting VNAR-Fc fusion proteins were purified from the cell culture supernatants. Binding activity, cross-reactivity, physicochemical stability, and epitope competition were evaluated using non-competitive enzyme-linked immunosorbent assay (ELISA) and biolayer interferometry (BLI). T-12-4D-Fc exhibited the highest affinity with a KD value of 7.59 nM and superior physicochemical stability. It maintained over 80 % binding activity at 90 °C, over 51 % in extreme pH conditions (pH 2 and 12), and above 65 % in urea concentrations up to 8 mol/L. Its binding activity remained largely unaffected after 6 h of incubation in human plasma-like medium (HPLM). The binding epitope competition results showed that 5-10C-Fc and T-12-4D-Fc targeted the same hemoglobin epitope. Molecular dynamics simulations revealed hydrogen bonds as the primary interaction force between VNARs and hemoglobin. Furthermore, a double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) method was established for the detection of human hemoglobin, utilizing T-12-4D-Fc as the coating antibody. This technique demonstrated high accuracy, reproducibility and specificity when applied to human whole blood samples. Hence, the identified VNARs, particularly T-12-4D, demonstrated good stability, specificity, and high affinity, filling the gap of hemoglobin-targeting shark-derived single-domain antibodies and offering a foundation for diagnosing and monitoring hemoglobin-related diseases.

Proteomic analysis of spinal dorsal horn in prior exercise protection against neuropathic pain

Neuropathic pain (NP) is a complex and prevalent chronic pain condition that affects millions of individuals worldwide. Previous studies have shown that prior exercise protects against NP caused by nerve injury. However, the underlying mechanisms of this protective effect remain to be uncovered. Therefore, the purpose of this study is to investigate how prior exercise affects protein expression in NP model rats and thus gain comprehensive insights into the molecular mechanisms involved. To achieve this objective, 6-week-old male Sprague–Dawley rats were randomly assigned into three groups, named as chronic constriction injury (CCI) of the sciatic nerve, CCI with prior 6-week swimming training (CCI_Ex), and sham operated (Sham). The CCI_Ex group underwent 6 weeks of swimming training before CCI surgery, while the CCI and sham groups had no intervention. Mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were used as the main observation indicators to evaluate the behavioral changes associated with pain. Tissues from the spinal dorsal horn of the rats in the three groups were collected at 4 weeks after operation. LC–MS/MS proteomic analysis based on the label-free approach was used to detect protein profiles, and volcano plots, Venn diagrams, and clustering heatmaps were used to identify differentially expressed proteins (DEPs). Gene Ontology (GO) annotations, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, and protein–protein interaction networks were employed to explore the biological importance of DEPs. At 14, 21, and 28 days following CCI, CCI rats with prior exercise showed a significant increase in the MWT and TWL of the injured lateral hind paw compared with those without exercise. A total of 122 proteins with significant changes in abundance were detected after CCI surgery, and 55 proteins were detected in the comparison between the CCI_Ex and CCI groups. GO and KEGG enrichment analysis revealed that oxygen transport capacity and the complement and coagulation cascades may be the critical mechanism by which prior exercise protects against NP. Serpina1, DHX9, and Alb are the key proteins in this process and warrant further attention, as confirmed by the results of Western blot analysis. In conclusion, this study provides new evidence that active physical activity can accelerate the relief of hyperalgesia after NP. Proteomic analyses revealed the potential target proteins and pathways for this process, offering valuable data resources and new insights into the pathogenesis and therapeutic targets of NP.

Exploring the pharmacological potential of Macrobrachium acanthurus hemocyanin: preliminary biological activity studies

Hemocyanin (Hc) is a copper-containing hemoprotein found in the hemolymph of invertebrates such as mollusks and arthropods. It plays essential roles in oxygen transport, immune defense, and molting processes. Due to their antiviral, antimicrobial, and phenoloxidase (PO) activities, Hcs hold significant potential in biotechnology. This study aims to obtain the Hc from the shrimp Macrobrachium acanthurus and perform preliminary biological activity tests (PO and antimicrobial activity) of this Hc. The results will serve as a basis for future structural and biological investigations of this unique protein. HcMac was purified using ultracentrifugation and size exclusion liquid chromatography (SEC). PO activity was induced by the surfactant SDS in the presence of dopamine hydrochloride, monitored by optical absorption at 475 nm using a spectrophotometer. Tests were performed to evaluate the inhibitory activity against Candida neoformans, Candida albicans and some fish pathogens. The results demonstrated that the surfactant SDS induced PO activity, with optimal formation observed at an SDS concentration of 1.0 mmol L-1. However, HcMac did not exhibit antimicrobial activity in the tests performed. Despite this, we cannot rule out the hypothesis that this Hc has biological activity and an immunological role, since it showed PO activity.

Oxygen transport across the lifespan of male Sprague Dawley rats.

Human populations are experiencing unprecedented growth and longevity with lingering knowledge gaps of the characteristics, mechanisms, and pathologies of senescence. Invasive measurements and long-term control conditions for longitudinal studies are infeasible, necessitating the need for surrogate animal models. Rats have short lifespans (2-3years) with translatable cardiovascular systems, and Sprague Dawley microcirculatory preparations are key to studying the oxygen transport mechanisms critical to the loss of skeletal muscle function in aging. Here we present baseline physiological data of 61 male, Sprague Dawley rats at 3, 6, 12, 18, and 24months of age. Anesthetized animals were surgically prepared for femoral arterial and venous cannulations, tracheal intubation, and exteriorization of the spinotrapezius muscle. Measurements included cardiovascular function, blood gases, and peripheral tissue interstitial oxygen tension (PISFO2) using phosphorescence quenching microscopy. Intrinsic heart rates decreased with age without significant changes to blood pressure. Arterial oxygen tension declined 17% by 18 and 24 Months (p < 0.05) while pACO2 and PISFO2 were unchanged. Lactate was elevated at 12 and 18 Months along with an alkaline shift in blood pH. Heart rate and decreased pAO2 decoupled from pACO2 are conserved phenomena in human aging. The continuity of resting PISFO2 despite an anaerobic shift in metabolism may be due to declining mitochondrial function and dysregulation of the vascular response to hypoxemia, which are also present in aged humans. These physiological and microcirculatory data offer a useful experimental model for investigating the detailed changes in oxygen supply and demand that affect senescing skeletal muscles in rats and humans.

Evaluation of Non-Invasive Hemoglobin Monitoring in Perioperative Patients: A Retrospective Study of the Rad-67TM (Masimo).

Background: Hemoglobin (Hb) is a crucial parameter in perioperative care due to its essential role for oxygen transport and tissue oxygenation. Accurate Hb monitoring allows for timely interventions to address perioperative anemia and, thus, prevent morbidity and mortality. Traditional Hb measurements rely on invasive blood sampling, which significantly contributes to iatrogenic anemia and poses discomfort and increased infection risks. The advent of non-invasive devices like Masimo's Rad-67™, which measures Hb using pulse CO-oximetry (SpHb), offers a promising alternative. This study evaluates the accuracy of SpHb compared to clinical standard blood gas analysis (BGA) in perioperative patients. Methods: This retrospective study analyzed 335 paired Hb measurements with an interval <15 min between SpHb and BGA in the operating theater and post-anesthesia care unit of a university hospital. Patients experiencing hemodynamic instability, acute bleeding, or critical care were excluded. Statistical analysis included Bland-Altman plots and Pearson correlation coefficients (PCCs) to assess the agreement between SpHb and BGA. Potential confounders, e.g., patient age, skin temperature, sex, perfusion index (PI), and atrial fibrillation, were also analyzed. Results: The bias of the SpHb compared to BGA according to Bland-Altman was 0.00 g/dL, with limits of agreement ranging from -2.70 to 2.45 g/dL. A strong correlation was observed (r = 0.79). Overall, 57.6% of the paired measurements showed a deviation between the two methods of ≤±1 g/dL; however, this applied to only 33.3% of the anemic patients. Modified Clark's Error Grid analysis showed 85.4% of values fell within clinically acceptable limits. Sex was found to have a statistically significant, but not clinically relevant, effect on accuracy (p = 0.02). Conclusions: The Rad-67TM demonstrates reasonable accuracy for non-invasive SpHb, but exhibits significant discrepancies in anemic patients with overestimating low values. While it offers potential for reducing iatrogenic blood loss, SpHb so far should not replace BGA in critical clinical decision-making.

The role of neutrophilia in hyperlactatemia, blood acidosis, impaired oxygen transport, and mortality outcome in critically ill COVID-19 patients.

COVID-19 severity and high in-hospital mortality are often associated with severe hypoxemia, hyperlactatemia, and acidosis, yet the key players driving this association remain unclear. It is generally assumed that organ damage causes toxic acidosis, but since neutrophil numbers in severe COVID-19 can exceed 80% of the total circulating leukocytes, we asked if metabolic acidosis mediated by the glycolytic neutrophils is associated with lung damage and impaired oxygen delivery in critically ill patients. Based on prospective mortality outcome, critically ill COVID-19 patients were divided into ICU- survivors and ICU-non-survivors. Samples were analyzed to explore if correlations exist between neutrophil counts, lung damage, glycolysis, blood lactate, blood pH, hemoglobin oxygen saturation, and mortality outcome. We also interrogated isolated neutrophils, platelets, and PBMCs for glycolytic activities. Arterial blood gas analyses showed remarkable hypoxemia in non-survivors with no consistent differences in PCO2 or [HCO3 -]. The hemoglobin oxygen dissociation curve revealed a right-shift, consistent with lower blood-pH and elevated blood lactate in non-survivors. Metabolic analysis of different blood cells revealed increased glycolytic activity only when considering the total number of neutrophils. This indicates the role of neutrophilia in hyperlactatemia and lung damage, subsequently contributing to mortality outcomes in severe SARS-CoV-2 infection.

Avian pathogenic Escherichia coli alters complement gene expression in chicken erythrocytes.

1. Avian Escherichia coli (E. coli) causes significant losses in livestock by inducing morbidity and mortality. Erythrocytes, the most abundant in blood, possess dual functions of oxygen transportation and immune regulation. In recent years, the interaction between erythrocytes and the complement system has gradually become a focal point of study. However, the transcription dynamics of the complement system in chicken erythrocytes post-E. coli invasion remains unclear.2. In this study, chicken erythrocytes and E. coli were co-cultured for 0.25-2 h to assess adhesion, analysed by indirect immunofluorescence (IIF) and scanning electron microscopy (SEM). Quantitative real-time PCR (qRT-PCR) examined differential expression of complement genes (CD93, C1q, C1s, C2, C3, C3AR1, C4, C4A, C5, C5AR1, C6, C7, C8G, CFI, MBL) in vitro using erythrocytes at 0.25-2 h and in vivo using chicks at 1, 3 and 7 d post-E. coli infection.3. E. coli adheres to chicken erythrocytes, as observed using IF and SEM. Gene expression analysis revealed early downregulation of C4, C4A, MBL and late upregulation of CD93, C1q, C1s, C3, C3AR1, C5AR1, C6, with C5, C7, C8G downregulated at 7 dpi. C2 expression varied at each time point.4. This study first showed E. coli adhering to erythrocytes, which activated complement genes rapidly. In vivo recovery from chickens with colibacillosis favours classical pathway activation, while lectin pathway may be inhibited, suggesting early immune down-regulation.

Oxygen Transport in Nanoporous SiN Membrane Compared to PDMS and Polypropylene for Microfluidic ECMO.

Extracorporeal Membrane Oxygenation (ECMO) serves as a crucial intervention for patients with severe pulmonary dysfunction by facilitating oxygenation and carbon dioxide removal. While traditional ECMO systems are effective, their large priming volumes and significant blood-contacting surface areas can lead to complications, particularly in neonates and pediatric patients. Microfluidic ECMO systems offer a promising alternative by miniaturizing the ECMO technology, reducing blood volume requirements, and minimizing device surface area to improve safety and efficiency. This study investigates the oxygen transport performance of three membrane types- polydimethylsiloxane (PDMS), polypropylene, and a novel nanoporous silicon nitride (SiN) membrane-in a microfluidic ECMO platform. While nanoporous membranes rely on pore-mediated diffusion and PDMS on polymer lattice diffusion, results show no significant differences in device oxygenation efficiency (p > 0.05). Blood-side factors, including the diffusion rate of oxygen through the red blood cell (RBC) membrane, RBC residence time, and hemoglobin binding kinetics, were identified as primary bottlenecks. Even computational models of a hypothetical infinitely permeable membrane corroborate the limited impact of membrane material. These findings suggest a shift in ECMO design priorities from membrane material to blood-side enhancements. This research provides a foundation for optimizing ECMO systems.

Computational Analysis of Flow and Transport Suggests Reduced Oxygen Levels Within Intracranial Aneurysms, Especially in Individuals With Sickle-Cell Disease.

Sickle cell disease (SCD) is a genetic condition characterized by an abundance of sickle hemoglobin in red blood cells. SCD patients are more prone to intracranial aneurysms (ICA) compared to the general population, with distinctive features such as multiple intracranial aneurysms: 66% of SCD patients with ICAs have multiples ICAs, compared to 20% in nonsickle patients. The exact mechanism behind these associations is not fully understood, but there is a hypothesized link between hypoxic conditions in blood vessels and impaired synthesis of extracellular matrix, which may weaken the vessel walls, favoring aneurysm formation and rupture. SCD patients experience reduced oxygen levels in their blood, potentially exacerbating hypoxia in intracranial aneurysms, and potentially creating a feedback loop that could contribute to aneurysm development and early onset in these patients. In this work, we performed a series of computational studies (Fluent) using idealized geometries to investigate the key differences in the oxygen transport and blood flow dynamics inside an aneurysm formation for sickle and nonsickle cases. We found that using sickle cell disease parameters resulted in a 14% to 68% reduction in blood flow and a 37% to 70% reduction in oxygen availability within the aneurysm, depending on the vessel curvature and the aneurysm throat diameter, due to factors including oxygen-dependent viscosity and alteration in the oxygen transport. The results indicate that depending on geometry and flow characteristics, some degree of hypoxia maybe present in aneurysm bulb and would be more severe in sickle-cell disease patients. This study hopes to bring into attention the potential presence of hypoxic environment in the aneurysm bulb.

Numerical Investigation of Proton Exchange Membrane Fuel Cells with Symmetrical Serpentine Channels Equipped with Baffles.

The design of the flow field structure for bipolar plates significantly influences the output performance of proton exchange membrane fuel cells (PEMFCs). Adding baffles in the flow channels can enhance the transportation of reactants and electrochemical performance of the PEMFCs. In this study, three types of baffles with different shapes and sizes were designed. Computational fluid dynamics (CFD) models for the PEMFCs with a symmetrical serpentine flow field (SSFF), both without baffles and with baffles, were established using the CFD method. Numerical simulations for the PEMFCs, both without baffles and with baffles, were performed by FLUENT software. The simulation results show that the PEMFCs with baffles demonstrated improved oxygen transport and increased reaction gas concentrations in the flow channels compared to the PEMFCs without baffles. The velocity magnitude exhibited abrupt changes as the fluid passed through the baffles due to their disturbance effect. Specially, the PEMFCs without baffles had a maximum power density of 0.601 W/cm2, while the PEMFCs with rectangular baffles reached a maximum power density of 0.755 W/cm2, which was enhanced by 25.6% due to the arrangement of baffles in the symmetrical serpentine flow channels.

Self-Sustained Micro-Reactor: Exploring the Potential of Iron Powder Combustion

Iron powder combustion presents a promising green energy alternative, relying on millions of tiny microreactors that burn in a fundamentally different way than conventional fuels. To fully harness this potential, a deeper understanding of the combustion process at the level of individual iron particles is crucial. Our research uncovers new insights into the mechanisms driving iron powder combustion, revealing that while oxygen transport is a key factor, unexpected mass loss occurs through vaporization, even at temperatures below the boiling point. This finding challenges previous assumptions about iron's zero-emission potential and expands the possibilities for sustainable energy.

Three-dimensional bioprinting utilizing sacrificial material support and longitudinal printability evaluation through volumetric imaging.

In three-dimensional (3D) bioprinting, the internal channel network is vital for nutrient and oxygen transport, crucial for cell survival and tissue construction. However, bioinks' poor mechanical properties hinder precise control over these networks. Advancements in 3D printing strategies, structure characterization, and deformation monitoring can improve hydrogel scaffolds with interconnected channels. Using label-free, non-invasive, in-situ optical coherence tomography (OCT) imaging, we monitored the dynamic deformation of 3D bioprinted hydrogel scaffolds. We validated sacrificial materials' role in enhancing internal channels and introduced deformation characteristics, lateral pore ratio and pore-specific surface area as new parameters. Results from cell-laden hydrogels show that 3D bioprinting with sacrificial materials achieves high fidelity, minimizing collapse, inter-filament fusion, and enhancing lateral porosity. Furthermore, these promote cell proliferation and cell viability.

Analytical Solutions for Steady‐State Oxygen Transport in Soil With Microbial and Plant Root Sinks

ABSTRACTA complete model using analytical solutions for one‐dimensional oxygen transport from the atmosphere into soil with microbial and root sinks that builds on work over 30 years is developed. This new model uses concepts from a previously published model for one distributed sink and two sinks with a distributed (microbial) and line (root) sink. It removes the problem, in previous publications, of matching the flux at the joining point between the two sink solution where the root sink ceases and the single sink at a finite depth. Analytical solutions are developed for integer values of p = Zr/Zm, where Zm is the scaling depth for microbial respiration and Zr is the scaling depth for root length density. The solutions allow two critical diffusivity (D) values to be defined (Dc) and (Dc2). When Dc2 ≤ D &lt; Dc, a procedure is presented to calculate the depth, z1, where C′ = 0 and this is the depth where root uptake of oxygen ceases and is shown to be related to D/Dc. When D &lt; Dc2, a procedure is presented to estimate the depth, Z0, at which the oxygen concentration = 0 and is shown to be related to D/Dc2. These results have useful applications in determining soil aeration, soil biogeochemical reactions, soil surface flux of oxygen and carbon dioxide, and the effect of climate change on these processes through the temperature dependence of the solution. These results suggest the oxygen diffusion rate (ODR) is likely to be the best estimator of soil aeration but there will not be a universal value for all plants. The surface flux density of oxygen into the soil for both the microbial sink (Sm) and total sink (f0) are presented and the ratio is shown to be related to ( is the diffusivity in air). The possible range in Sm/f0 is shown to be compatible with measured values from the literature. The solutions have many applications in environmental science.

Mechanisms of oxygen transport resistance of mesoporous carbon-supported catalysts in fuel cells

Origin of local oxygen transport resistance for water-Pt catalyst is revealed; Rads is significantly affected by the structure of dense layer on Pt surfaces; the dense effect of interior Pt catalysts leads to the remarkable increase of .