Oxygen Supply Research Articles

Whether hypoxia tolerance improved after short-term fasting is closely related to phylogeny but not to foraging mode in freshwater fish species.

The combined stresses of fasting and hypoxia are common events during the life history of freshwater fish species. Hypoxia tolerance is vital for survival in aquatic environments, which requires organisms to down-regulate their maintenance energetic expenditure while simultaneously preserving physiological features such as oxygen supply capacity under conditions of food deprivation. Generally, infrequent-feeding species who commonly experience food shortages might evolve more adaptive strategies to cope with food deprivation than frequent-feeding species. Thus, the present study aimed to test whether the response of hypoxia tolerance in fish to short-term fasting (2 weeks) varied with different foraging modes. Fasting resulted in similar decreases in maintenance energetic expenditure and similar decreases in Pcrit and Ploe between fishes with different foraging modes, whereas it resulted in decreased oxygen supply capacity only in frequent-feeding fishes. Furthermore, independent of foraging mode, fasting decreased Pcrit and Ploe in all Cypriniformes and Siluriformes species but not in Perciformes species. The mechanism for decreased Pcrit and Ploe in Cypriniformes and Siluriformes species is at least partially due to the downregulated metabolic demand and/or the maintenance of a high oxygen supply capacity while fasting. The present study found that the effect of fasting on hypoxia tolerance depends upon phylogeny in freshwater fish species. The information acquired in the present study is highly valuable in aquaculture industries and can be used for species conservation in the field.

Debulking the Myth of the ‘Social’ Admission – A Retrospective Review of Acutely Admitted Medical Patients in Wexford General Hospital

Abstract Background “Acopia”, “social admission” and other synonymous terms are frequently provided reasons requiring admission to acute hospitals and represent a common encounter for the Geriatric clinician. These cases are usually so called when the patient’s social circumstances are felt to need urgent attention, yet their medical health has not acutely deteriorated. Such non-diagnostic labels often mask underlying complex medical issues which can have detrimental health outcomes if not addressed appropriately. Despite this, they persist in the vernacular of modern medicine with almost half of doctors, junior and senior, finding the term useful (43.5%) and acceptable as a diagnosis (30.9%)1. We sought to examine what percentage of adult medical patients admitted to an acute hospital did not have an appreciable medical cause for their presentation. Methods We conducted a retrospective review of 191 patients admitted under medical teams in Wexford General Hospital across a 13-day period. Inclusion criteria included adult patients admitted under a medical team from the Emergency Department. Exclusion criteria applied to any patient admitted from OPD or by non-medical specialities. Results 191 cases were analysed. The average age was 65.8, median age was 70 and majority were male (n=105, 55%). There were only 2 patients (1%) who had no acute medical concerns following medical review. In one, the patient’s home oxygen supply had run out and the intended delivery of oxygen had been delayed. Another patient required increased home care supports however their medical status had not changed. Conclusion Our findings suggest that most patients presenting to acute hospitals following a robust medical review will evidence an acute medical issue. Dismissive phrases such as “acopia” and “social admission” need to be challenged for the superficial assessment that they are, and this reductive approach must be expunged from clinical practice to avoid misdiagnosis and malpractice in the care of the older adult.

Penerapan Kolaborasi Pemberian Inhalasi dengan Close Suction untuk Bersihan Jalan Napas Tidak Efektif pada Pasien Ny. R Terpasang Endotracheal Tube di Ruang ICU RSUD Sidoarjo

Ineffective airway clearance is a condition where the patient is unable to cough effectively, often caused by thick or excessive secretions due to infection. The objective of this intervention is to address ineffective airway clearance in patients with an endotracheal tube in the ICU of RSUD Sidoarjo. After inhalation and close suction procedures, observations showed improvements in vital signs and respiratory rate, along with significant reduction of secretions. This led to an increase in peripheral oxygen saturation (SpO2), improving oxygen supply to the body. Based on the case study, the nursing intervention for ineffective airway clearance conducted over 2 x 8 hours showed partial success in resolving the issue. Following a thorough nursing assessment, the diagnosis for patient Mrs. R was determined as ineffective airway clearance related to airway spasms, evidenced by inability to cough, excessive sputum, and ronchi sounds.

Use of Extraterrestrial Resources and Recycling Water: Curb Your Enthusiasm

The NASA approach for technology development for missions is to (1) wait for a mission need, and (2) upgrade the technology available at that time, however inadequate. This is illustrated with two important NASA technologies: in situ resource utilization (ISRU) and recycling wastewater. It also serves as a review with 49 references provided. NASA funding for ISRU has been sporadic and minimal, probably because no mission was being implemented that used ISRU. The state of the technology remains underdeveloped. For example, CO2 in the Mars atmosphere supplies carbon and oxygen. However, we still do not have a viable system to acquire CO2 and compress it with acceptable power requirements and adequate lifetime. NASA technology for recycling wastewater was developed for the International Space Station. It requires frequent attention with replenishment and replacement of subsystems. This system appears to be inadequate for Mars missions and there is no evidence that NASA has a viable plan to fix that.

Injectable, oxygen-releasing, thermosensitive hydrogel promotes vascularized bone formation with prolonged oxygen delivery and improved osteoinductivity

The failure or delay in healing of critical bone defects is primarily due to early local anoxic conditions and reduced osteogenic activity. In this research, we integrated calcium peroxide (CPO) embedded polycaprolactone (PCL) microspheres and osteoinductive nanoparticles (Hydroxyapatite/Laponite) into a thermosensitive hydrogel (Pluronic F127), thereby formulating an injectable oxygen-releasing osteogenic thermosensitive hydrogel. Notably, the oxygen-releasing microspheres (ORMs) within the composite hydrogel provide stable oxygen release for up to 21 days, ensuring the survival, migration, and bioactivity of both mesenchymal stem cells and endothelial cells under anoxic conditions. Additionally, the composite hydrogel significantly augments the osteogenic potential of bone marrow mesenchymal stem cells by providing a biomimetic microenvironment with the incorporation of nano-hydroxyapatite/laponite. Ultimately, the injectable composite hydrogel successfully stimulated bone regeneration within a cranial defect in a rat model after 8 weeks, with enhanced vascularization and bone quality. The engineered hydrogel provides a minimally invasive approach to stimulate bone regeneration with a sustained oxygen supply and osteogenic microenvironment provision, underlining its potential for treating critical bone defects.

Boosting Electrochemical Performance via Extra-Role of La-Doped CeO2-δ Interlayer for "Oxygen Provider" at High-Current SOFC Operation.

Utilizing rare earth doped ceria in solid oxide cells (SOCs) engineering is indeed a strategy aimed at enhancing the electrochemical devices' durability and activity. Particularly, Gd-doped ceria (GDC) is actively used for barrier layer and catalytic additives in solid oxide fuel cells (SOFCs). In this study, experiments are conducted with La-doped CeO2 (LDC), in which the Ce sites are predominantly occupied by La, to prevent the formation of the Ce-Zr solid solution. This LDC is comparably used as a functional interlayer between the electrolyte and cathode if sintered at lower temperatures to avoid La2Zr2O7 impurity. In addition, the high substitution of La3+ into the ceria lattice improves the oxygen non-stoichiometry of LDC, leading to accelerated electrochemical high performance by the additional role of LDC for oxygen supplier capacitance at high current operation. Thus, it is confirmed that the improved SOFC high performance is achieved at the maximum power density (MPD) of ≈2.15W cm-2 at 800°C when the optimized LDC buffer layer is hired at the anode-supported typed-Samsung's SOFC by lowering the sintering temperature to prevent LDC's impurity reaction.

Extra Virgin Olive Oil from Stoned Olives with Oxygen Supply during Processing: Impact on Volatile and Phenolic Fraction and Sensory Characteristics.

The improvement of the extra virgin olive oil (EVOO) extraction process involves the proper management of endogenous enzymes of the olive fruit and all the technological conditions that can affect their activities. Coratina and Peranzana cultivars were processed to assess the influence of different technologies for fruit breaking (crushing and stoning) with and without controlled oxygen addition during this critical phase. The study of volatile compounds revealed that the enzymes that are responsible for their genesis during the technological process were significantly affected by oxygen addition in both the systems of fruit crushing. The results from the stoning technology proved that the quality improvement was a consequence of the prevention of the seed breaking and the oxidation catalyzed by the olive stone enzymes. In Peranzana EVOOs, it was possible to increase the aldehyde concentration up to 97% using stoning technology with a 0.2 L/min oxygen addition compared with traditional crushing. At the same time, non-significant reductions in phenolic compounds were detected when comparing crushing and stoning with and without the addition of oxygen, and similar trends were observed for the two studied cultivars. The sensory analyses confirmed the differences in phenolic and volatile composition detected in the EVOO samples.

Exogenous ketosis attenuates acute mountain sickness and mitigates normobaric high-altitude hypoxemia.

Acute mountain sickness (AMS) represents a considerable issue for individuals sojourning to high altitudes with systemic hypoxemia known to be intimately involved in its development. Based on recent evidence that ketone ester (KE) intake attenuates hypoxemia, we investigated whether exogenous ketosis might mitigate AMS development and to identify underlying physiological mechanisms. Fourteen healthy, male participants were enrolled in two 29h protocols (simulated altitude of 4,000-4,500m) receiving either KE or a placebo (CON) at regular timepoints throughout the protocol in a randomized, crossover manner. Physiological responses were characterized after 15min and 4h in hypoxia, and the protocol was terminated prematurely upon development of severe AMS (Lake Louise Score ≥ 10). KE ingestion induced a consistent diurnal ketosis ([ßHB] of ~3 mM), whereas blood [ßHB] remained low (<0.6 mM) in CON. Each participant tolerated the protocol equally long or longer (n=6 or n=8, resp.) in KE. Protocol duration increased by 32% on average with KE, and doubled upon KE for severe AMS-developing participants (n=9). Relative to CON, KE induced a mild metabolic acidosis, hyperventilation, and relative sympathetic dominance. KE also inhibited the progressive hypoxemia that was observed between 15min and 4h in hypoxia in CON, while concomitantly increasing cerebral oxygenation and capillary pO2 within this timeframe despite a KE-induced reduction in cerebral oxygen supply. These data indicate that exogenous ketosis attenuates AMS development. The key underlying mechanisms include improved arterial and cerebral oxygenation, in combination with lowered cerebral blood flow and oxygen delivery, and increased sympathetic dominance.

Rational Construction of Cyanide‐Functionalized D‐A‐π‐D Covalent Organic Framework for Highly Efficient Overall H2O2 Photosynthesis from Air and Water

Sacrificial‐agent‐free overall photosynthesis of H2O2 from water and air represents currently a promising route to reform the industrial anthraquinone production manner, but, still blocks by the requirement of pure O2 feedstock, due to the insufficient oxygen supply from water under air. Herein, we report a rational molecule design on COFs (covalent organic frameworks) equiped with cyanide‐functionalized D‐A‐π‐D system for highly efficient overall H2O2 production from air and water through photocatalytic oxygen reduction reactions (ORR) and water oxidation reaction (WOR). Without using any sacrificial agent, the as‐synthesized D‐A‐π‐D COF is found to enable a H2O2 production rate as high as 4742 μmol h‐1 g‐1 from water and air and an O2 utilization and conversion rate up to 88%, exceeding the other D‐A‐π‐A COF by respectively 1.9‐ and 1.3‐fold. Such high performance is attributed to the tuned electronic structure and prolonged charge lifetime facilitated by the unique D‐A‐π‐D structure and cyanide groups. This work highlights a fundamental molecule design on advanced photocatalytic COFs with complicated D‐A system for low‐cost and massive H2O2 production.

Study on the Spontaneous Combustion Law of Coal Body around a Borehole Induced by Pre-extraction of Coalbed Methane.

To address the challenges associated with the high gas content, high pressure, and low permeability coefficient in deep coal seams, strategies such as infilling boreholes and increasing the negative pressure of extraction are commonly implemented to alleviate issues related to coalbed methane extraction. However, long-term mining pressure can lead to the development of cracks in the coal seam near the borehole, thereby creating air leakage channels, which could potentially impact the oxygen supply during the extraction process. This leads to secondary disasters such as the spontaneous combustion of coal and gas explosions, considerably impacting the life and health of underground workers. To solve this issue, a thermal-fluid-solid coupling model for the working surface was constructed based on numerical simulation software, taking into account the multimechanism coupling effect of coal seam gas. The laws of coal oxidation and spontaneous combustion induced by coalbed methane extraction around boreholes were studied. The variation laws of the oxygen concentration, coal temperature, and oxidation heating zone around the borehole under different extraction conditions were simulated and analyzed. The findings demonstrate that the negative extraction pressure enables the gas to penetrate the fracture zone of the borehole, leading to an increase in the oxygen consumption rate and coal temperature around the borehole with an increase in negative extraction pressure. The coal gas leakage surrounding the borehole reduces as the sealing depth increases, and both the heating rate of coal and oxygen volume fraction show a downward trend. The fitting relationship between the negative pressure of drainage, depth of sealing, and temperature change in the coal body surrounding the boreholes was identified. It was determined that the negative pressure of 13 kPa for borehole drainage and a sealing depth >18 m are the optimal extraction parameters. The range of the oxidation zone and the position of the boundary line under this parameter were predicted, and the position function of the dangerous area of oxidation heating was defined. The research results have remarkable implications for the coordinated prevention and control of gas and coal spontaneous combustion in coalbed methane predrainage boreholes, as well as for efficient prevention and control of CO in on-site gas extraction boreholes, thus ensuring efficient and safe gas extraction.

Hypoglycaemia in screening oral glucose tolerance test in pregnancy with low birth weight fetus.

Maternal hypoglycemia, a condition characterized by lower than normal blood glucose levels in pregnant women, has been increasingly associated with adverse pregnancy outcomes, including low birth weight (LBW) in neonates. LBW, defined as a birth weight of less than 2500 g, can result from various factors, including maternal nutrition, health status, and metabolic conditions like hypoglycemia. Maternal hypoglycemia may affect fetal growth by altering the supply of essential nutrients and oxygen to the fetus, leading to restricted fetal development and growth. This condition poses significant risks not only during pregnancy but also for the long-term health of the child, increasing the likelihood of developmental delays, health issues, and chronic conditions later in life. Research in this area has focused on understanding the mechanisms through which maternal hypoglycemia influences fetal development, with studies suggesting that alterations in placental blood flow and nutrient transport, as well as direct effects on fetal insulin levels and metabolism, may play a role. Given the potential impact of maternal hypoglycemia on neonatal health outcomes, early detection and management are crucial to minimize risks for LBW and its associated complications. Further investigations are needed to fully elucidate the complex interactions between maternal glucose levels and fetal growth, as well as to develop targeted interventions to support the health of both mother and child. Understanding these relationships is vital for improving prenatal care and outcomes for pregnancies complicated by hypoglycemia.

Enhancing prediction of elemental composition through machine learning decision tree models for biomass gasification optimization

Abstract The worldwide transition to cleaner, sustainable energy sources, prompted by population growth and industrialization, responds to uncertain fossil fuel prices and environmental concerns, highlighting the substantial benefits of renewable energy in reducing greenhouse gas emissions and addressing climate change. Derived from non-fossilized organic materials, biomass emerges as a significant and sustainable contributor to renewable energy. Its diverse nature is complemented by a range of conversion technologies, encompassing combustion, pyrolysis, gasification, and liquefaction, providing versatile avenues for biomass energy transformation. Gasification, the transformative process of converting organic matter into combustible gases under controlled oxygen levels, is accomplished through direct oxygen supply or pyrolysis. This method yields a dependable gaseous fuel versatile for heating, industrial processes, power generation, and liquid fuel production. Machine learning employs advanced statistical techniques for modeling across diverse industries, showcasing particular efficacy in optimizing thermochemical processes by precisely identifying the optimal operating conditions required for achieving desired product properties. These models utilize proximate biomass data to predict the elemental compositions of N2 and H2. Assessment of both single and two hybrid models indicated that the introduced optimizers significantly enhanced the estimation of N2 and H2 when combined with Decision Tree (DT), with Decision Tree Coupled with Artificial Hummingbird Algorithm (DTAH) proving particularly effective. Notably, DTAH demonstrated outstanding performance with remarkable R 2 values of 0.990 for N2 and 0.992 for H2. Additionally, the minimal Root Mean Square Error (RMSE) values of 1.291 and 1.550 for N2 and H2 predictions respectively underscore the precision of DTAH, establishing it as a suitable choice for practical real-world applications.

Internal oxidation behavior and its effect on the surface crack formation in a Fe-Mn-Al-C high Mn steel

The correlation between internal oxidation and surface crack was investigated in high Mn steel. Time- and temperature-dependent internal oxidation behaviors are examined in the temperature ranges of 1000– 1250 °C, revealing faster and deeper oxidation along grain boundaries than in grain. Oxides at the internal oxidation layer are confirmed to be MnO and MnAl2O4. The grain boundary penetration depths of the internal oxide increase from 13 to 34 μm as the temperature increases. The tensile crack on the surface of the specimen was evaluated after 5 % straining with 10−3/s strain. Temperature-dependent crack formation probability (LAC/LT) increases also from 0.4 to 1.6 % as the temperature increases. The evolution of the internal oxidation layer during the hot compression test was investigated to clarify its role in surface crack formation. The transition of the internal oxide layer to the external oxide layer was observed. Exfoliation of the external oxidation layer was also confirmed by further compression. Driving force calculation on the internal and external oxides reveals that the abundant oxygen supply originating from the cracking of oxide and thickness reduction of the internal oxide layer transforms the internal oxide layer to scale during the compression. High-resolution analysis of the grain boundary crack reveals the cracking of grain boundary MnAl2O4. The comparison between the grain boundary oxides’ penetration depth and the crack formation behavior clarifies the grain boundary internal oxide’s crucial role in the surface crack formation in a high Mn steel. This study provides vital insights into the surface crack formation mechanism in a Fe-Mn-Al-C-based high Mn steel during hot-rolling processes, highlighting the significance of grain boundary internal oxidation in production.

Porous Organic Polymer-Based Nanocomposites for Hypoxia Relieving and Enhanced Chemotherapy in Hepatocellular Carcinoma.

Uncontrolled proliferation and altered metabolism of cancer cells result in an imbalance of nutrients and oxygen supply, and persuade hypoxia. Hypoxia, in turn, activates the transcription gene HIF-1α, which eventually upregulates the efflux transporter P-gp and induces multidrug resistance (MDR). Thus, hypoxia leads to the development of resistance to conventional therapies. Therefore, the fabrication of a nanoscale porous system enriched with upconversion nanoparticles to target cancer cells, evade hypoxia, and enhance anticancer therapy is the key goal of this article. Herein, upconversion nanoparticles are embedded in a nanoscale porous organic polymer (POP) and further conjugated with a targeting moiety and a catalase molecule. The nanoscale POP embedded in UCNPs is generated at room temperature. The targeting ligand, lactobionic acid, is attached after polymer coating, which effectively targets liver cancer cells. Then, catalase is grafted effectively to produce oxygen. Endogenously generated oxygen alleviates hypoxia in liver cancer cells. The drug- and catalase-loaded composite exhibit greater cytotoxicity in hypoxic liver cells than in normal cells by overcoming hypoxia and downregulating the hypoxia-inducible factors.

An Approximate Bayesian Computation Approach for Embryonic Astrocyte Migration Model Reduction.

During embryonic development of the retina of the eye, astrocytes, a type of glial cell, migrate over the retinal surface and form a dynamic mesh. This mesh then serves as scaffolding for blood vessels to form the retinal vasculature network that supplies oxygen and nutrients to the inner portion of the retina. Astrocyte spreading proceeds in a radially symmetric manner over the retinal surface. Additionally, astrocytes mature from astrocyte precursor cells (APCs) to immature perinatal astrocytes (IPAs) during this embryonic stage. We extend a previously-developed continuum model that describes tension-driven migration and oxygen and growth factor influenced proliferation and differentiation. Comparing numerical simulations to experimental data, we identify model equation components that can be removed via model reduction using approximate Bayesian computation (ABC). Our results verify experimental studies indicating that the choroid oxygen supply plays a negligible role in promoting differentiation of APCs into IPAs and in promoting IPA proliferation, and the hyaloid artery oxygen supply and APC apoptosis play negligible roles in astrocyte spreading and differentiation.

233 Exploring the impact of intrauterine growth restriction on fecal microbiota and metabolome in pigs

Abstract Intrauterine growth restriction (IUGR) poses a significant challenge in swine production, affecting approximately 20% of piglets and resulting in increased mortality rates, metabolic disturbances, compromised intestinal development, and altered microbial colonization. This phenomenon arises as the IUGR fetus adapts to limited oxygen and nutrient supply in utero by reallocating blood flow towards vital organs, particularly the brain, consequently leading to a greater brain-to-liver weight ratio (BrW/LW) at birth. Our study aimed to comprehensively investigate the repercussions of IUGR on fecal microbiota composition and plasma metabolome profiles in pigs from birth through to slaughter. To elucidate these effects, we conducted computed tomography scans on piglets within 24 h of birth to assess brain and liver weights accurately. Subsequently, we selected two groups of piglets based on the BrW/LW. Specifically, 12 piglets with the greatest BrW/LW (IUGR; BrW/LW: 1.00 ± 0.09) and 12 with the least BrW/LW (NORM; BrW/LW: 0.36 ± 0.04). From these piglets we collected fecal and blood samples at specific time points: during lactation (T1: d 16 ± 0.6), after the starter period (T2: d 63 ± 8.6), and at the onset (T3: d 119 ± 11.4) and conclusion (T4: d 162 ± 14.3) of the finisher period. Throughout the study, all pigs received identical diets to eliminate dietary confounders. In the lactation, starter and grower but not finisher period, IUGR piglets grew 47, 19 and 14% slower, respectively compared with their NORM littermates. Our findings revealed that fecal microbial α-diversity remained unaffected by IUGR across all time points examined, indicating a stable microbial richness within the gut microbiota of IUGR and NORM pigs. However, β-diversity, reflecting inter-group microbial community variation, exhibited significant differences at T1 (P = 0.002), T2 (P = 0.079), and T3 (P = 0.027), suggesting distinct microbial compositions between IUGR and NORM pigs at these stages. Specifically, IUGR pigs displayed a greater abundance of Clostridium sensu stricto 1 and Romboutsia at T1, Prevotellaceae NK3B31 group, Rikenellaceae RC9 gut group, and Alloprevotella at T2, and p-2534-18B5 gut group at T3. Conversely, the NORM group exhibited increased concentrations of Ruminococcus at T1, HT002 at T2, and Prevotella_9 at T3. Furthermore, while plasma metabolite analysis revealed no significant differences between IUGR and NORM pigs at T1, decreased arginine levels were observed in the IUGR group compared with NORM at T2 (P &amp;lt; 0.05). In conclusion, our study underscores the profound and persistent impact of IUGR on fecal microbiota composition in pigs from birth to the initial stages of the finisher period, while suggesting minimal alterations in the blood metabolome profile throughout various growth stages. These findings provide valuable insights into the long-term consequences of IUGR on swine health and production. This research received funding from the European Union’s Horizon 2020 research and innovation program under a Marie Sklodowska-Curie grant (agreement no. 955374).

Artificial Meshed Vessel-Induced Dimensional Breaking Growth of Human Brain Organoids and Multiregional Assembloids.

Brain organoids are widely used to model brain development and diseases. However, a major challenge in their application is the insufficient supply of oxygen and nutrients to the core region, restricting the size and maturation of the organoids. In order to vascularize brain organoids and enhance the nutritional supply to their core areas, two-photon polymerization (TPP) 3D printing is employed to fabricate high-resolution meshed vessels in this study. These vessels made of photoresist with densely distributed micropores with a diameter of 20 μm on the sidewall, are cocultured with brain organoids to facilitate the diffusion of culture medium into the organoids. The vascularized organoids exhibit dimensional breaking growth and enhanced proliferation, reduced hypoxia and apoptosis, suggesting that the 3D-printed meshed vessels partially mimic vascular function to promote the culture of organoids. Furthermore, cortical, striatal and medial ganglionic eminence (MGE) organoids are respectively differentiated to generate Cortico-Striatal-MGE assembloids by 3D-printed vessels. The enhanced migration, projection and excitatory signaling transduction are observed between different brain regional organoids in the assembloids. This study presents an approach using TPP 3D printing to construct vascularized brain organoids and assembloids for enhancing the development and assembly, offering a research model and platform for neurological diseases.

Impact of anatomic variability and other vascular factors on lamina cribrosa hypoxia.

Insufficient oxygenation in the lamina cribrosa (LC) may contribute to axonal damage and glaucomatous vision loss. To understand the range of susceptibilities to glaucoma, we aimed to identify key factors influencing LC oxygenation and examine if these factors vary with anatomical differences between eyes. We reconstructed 3D, eye-specific LC vessel networks from histological sections of four healthy monkey eyes. For each network, we generated 125 models varying vessel radius, oxygen consumption rate, and arteriole perfusion pressure. Using hemodynamic and oxygen supply modeling, we predicted blood flow distribution and tissue oxygenation in the LC. ANOVA assessed the significance of each parameter. Our results showed that vessel radius had the greatest influence on LC oxygenation, followed by anatomical variations. Arteriole perfusion pressure and oxygen consumption rate were the third and fourth most influential factors, respectively. The LC regions are well perfused under baseline conditions. These findings highlight the importance of vessel radius and anatomical variation in LC oxygenation, providing insights into LC physiology and pathology. Pathologies affecting vessel radius may increase the risk of LC hypoxia, and anatomical variations could influence susceptibility. Conversely, increased oxygen consumption rates had minimal effects, suggesting that higher metabolic demands, such as those needed to maintain intracellular transport despite elevated intraocular pressure, have limited impact on LC oxygenation.

Maternal physical activity in healthy pregnancy: Effect on fetal oxygen supply.

We review evidence for effects of physical activity before and during gestation on the course of pregnancy and ask if there are circumstances where physical activity can stress the fetus due to competition for oxygen and energy substrates. We first summarize physiological responses to exercise in nonpregnant people and known physiological adaptations to pregnancy. Comparing the two, we conclude that physical activity prior to and continuing during gestation is beneficial to pregnancy outcome. The effect of starting an exercise regimen during pregnancy is less easy to assess as few studies have been undertaken. Results from animal models suggest that the effects of maternal exercise on the fetus are transient; the fetus can readily compensate for a short-term reduction in oxygen supply. In general, we conclude that physical activity before and during pregnancy is beneficial, and exercise started during pregnancy is unlikely to affect fetal development. We caution, however, that there are circumstances where this may not apply. They include the intensive exercise regimens of elite athletes and pregnancies at high altitudes where hypoxia occurs even in the resting state.

Crocetin Delays Brain and Body Aging by Increasing Cellular Energy Levels in Aged C57BL/6J Mice.

Aging is usually accompanied by mitochondrial dysfunction, reduced energy levels, and cell death in the brain and other tissues. Mitochondria play a crucial role in maintaining cellular energy through oxidative phosphorylation (OXPHOS). However, OXPHOS is impaired as the mitochondrial oxygen supply decreases with age. We explored whether pharmacologically increased oxygen diffusion by crocetin can restore OXPHOS and help delay the aging of the brain and other vital organs. We found that aged mice treated with crocetin for four months displayed significantly improved memory behavior, neuromuscular coordination, and ATP and NAD+ levels in the brain and other vital organs, leading to an increased median life span. The transcriptomic analysis of hippocampi from crocetin-treated mice revealed that enhanced brain energy level was caused by the upregulation of genes linked to OXPHOS, and their expression was close to that in young mice. The chronic treatment of aged astrocytes also showed improved mitochondrial membrane potential and energy state of the cells. Moreover, chronic treatment with crocetin did not cause any oxidative stress. Our data suggest that restoring OXPHOS and the normal energy state of the cell can delay aging and enhance longevity. Therefore, molecules such as crocetin should be further explored to treat age-related diseases.