Oxygen System Research Articles

Oxygen Reduction Reaction Coupled Electro‐Oxidation for Highly‐Efficient and Sustainable Water Treatment

AbstractElectro‐oxidation (EO) technology demonstrates significant potential in wastewater treatment. However, the high energy consumption has become a pivotal constraint hindering its large‐scale implementation. Herein, we design an EO and 4‐electron oxygen reduction reaction coupled system (EO‐4eORR) to replace the traditional EO and hydrogen evolution reaction (HER) coupled system (EO‐HER). The theoretical cathodic potential of the electrolytic reactor is tuned from 0 V (vs. RHE) in HER to 1.23 V (vs. RHE) in 4eORR, which greatly decreases the required operation voltage of the reactor. Moreover, we demonstrate that convection can improve the mass transfer of oxygen and organic pollutants in the reaction system, leading to low cathodic polarization and high pollutant removal rate. Compared with traditional EO‐HER system, the energy consumption of the EO‐4eORR system under air aeration for 95 % total organic carbon (TOC) removal is greatly decreased to 2.61 kWh/kgTOC (only consider the electrolyzer energy consumption), which is superior to previously reported EO‐based water treatment systems. The reported results in this study offer a new technical mode for development of highly efficient and sustainable EO‐based treatment systems to remove organic pollutants in waste water.

Oxygen Reduction Reaction Coupled Electro-Oxidation for Highly-Efficient and Sustainable Water Treatment.

Electro-oxidation (EO) technology demonstrates significant potential in wastewater treatment. However, the high energy consumption has become a pivotal constraint hindering its large-scale implementation. Herein, we design an EO and 4-electron oxygen reduction reaction coupled system (EO-4eORR) to replace the traditional EO and hydrogen evolution reaction (HER) coupled system (EO-HER). The theoretical cathodic potential of the electrolytic reactor is tuned from 0 V (vs. RHE) in HER to 1.23 V (vs. RHE) in 4eORR, which greatly decreases the required operation voltage of the reactor. Moreover, we demonstrate that convection can improve the mass transfer of oxygen and organic pollutants in the reaction system, leading to low cathodic polarization and high pollutant removal rate. Compared with traditional EO-HER system, the energy consumption of the EO-4eORR system under air aeration for 95 % total organic carbon (TOC) removal is greatly decreased to 2.61 kWh/kgTOC (only consider the electrolyzer energy consumption), which is superior to previously reported EO-based water treatment systems. The reported results in this study offer a new technical mode for development of highly efficient and sustainable EO-based treatment systems to remove organic pollutants in waste water.

Ferroptosis Induction Enhances Photodynamic Therapy Efficacy for OLK.

Oral leukoplakia (OLK) is the most representative oral potentially malignant disorder, with a high risk of malignant transformation and unclear mechanisms of occurrence. Recently, photodynamic therapy (PDT) has exhibited great potential in the treatment of OLK. However, the efficacy of PDT is difficult to predict and varies from person to person. Ferroptosis-related pathways are upregulated in many cancers, and ferroptosis induction is considered to be a potential synergistic strategy for various antitumor therapies, but its role in OLK treatment remains unclear. This study aimed to determine whether ferroptosis induction can enhance the efficacy of PDT in OLK treatment. Our study revealed that solute carrier family 7 member 11 (SLC7A11), a component of a crucial amino acid transporter and a key negative regulator of ferroptosis, was found to be highly expressed in OLK patients with no response to PDT. 5-Aminolevulinic acid (ALA)-PDT is known to cause apoptosis and necrosis, but ferroptosis also occurred under ALA-PDT in OLK cells in our study. Using erastin to induce ferroptosis enhanced the efficacy of ALA-PDT on OLK cells by disrupting the antioxidant system and further elevating intracellular reactive oxygen species levels, leading to increased apoptosis. Furthermore, this combined modality also enhanced the efficacy of ALA-PDT on 4-nitroquinoline-1-oxide (4NQO)-induced OLK lesions in mice. In summary, ferroptosis induction may serve as a potential strategy to enhance the efficacy of ALA-PDT for OLK treatment.

Methylphenidate and the risk of acute central nervous system oxygen toxicity: a rodent model and observational data in human divers.

The effects of methylphenidate, a stimulant often prescribed for the treatment of attention-deficit/hyperactivity disorder (ADHD), on the development of central nervous system oxygen toxicity (COT) have not been experimentally evaluated. The records of all pure-oxygen-rebreather divers evaluated at our institution from 1975-2022 were assessed. Cases of COT were defined as a new onset of tinnitus, tunnel vision, myoclonus, headache, nausea, loss of consciousness, or seizures resolving within 15 minutes from breathing normobaric air, and matched 4:1 with similar controls. Any medications issued to the diver in the preceding three months, including methylphenidate, were recorded. In the animal arm of this study, male mice were exposed to increasing doses of methylphenidate orally, with subsequent exposure to hyperbaric O₂ until clinically evident seizures were recorded. Seventy-five cases of COT were identified in divers, occurring at a median of 80 (range 2-240) minutes after dive initiation at a median depth of 5 m (2-13). Hypercarbia was documented in 11 (14.7%) cases. Prescription of methylphenidate in the preceding three months was not associated with increased risk (OR 0.72, 95% CI 0.16-3.32) of COT. In mice, increasing methylphenidate exposure dose was associated with significantly longer mean COT latency time being 877 s (95% CI 711-1,043) with doses of 0 mg·kg⁻¹; 1,312 s (95% CI 850-1,773) when given 0.75 mg·kg⁻¹; and 1,500 s (95% CI 988-2,012) with 5 mg·kg⁻¹ (F = 4.635, P = 0.014). Observational human data did not demonstrate an association between methylphenidate and an increased risk of COT. Methylphenidate exposure in mice prolongs COT latency and may have protective effects against COT.

Modeling nitrogen behavior in Tigris River using system dynamics approach

Nitrogen behavior across multimedia environment like Tigris River is complex process resulting in a number of interactions of the biogeochemical processes. A solid understanding of the interacted processes is critical to evaluate river system performance. Inorganic nitrogen including ammonium ion (NH4+), free ammonia (NH3), total ammoniacal nitrogen (NHx), nitrite (NO2−), nitrate (NO3−), total oxidized nitrogen (NOx), and total inorganic nitrogen (TIN) in Tigris River were examined from April 2018 to March 2020. A simple system model was implemented to simulate and to help interpret the trend of inorganic N forms based on datasets collected from the river system. It is indicated that the obtained results revealed that the dynamic model was able to represent and predict NHx and NOx behavior in Tigris River. Root mean squared errors between actual and predicted concentrations for NHx and NOx were 0.053 and 0.312 g m−3, respectively. Modeling analysis confirmed the steady-state dynamics of NHx and NOx over the course of the study. Average concentration for NHx was 0.37 ± 0.05 g m−3, while mean value of NOx levels was 2.18 ± 0.33 g m−3 in the Tigris river water. The results from this study also supported by the changes of the water budget, chemical oxygen demand, pH, dissolved oxygen, electrical conductivity, and water temperature in the river system. The results suggest that the microbial mechanisms are the principal N transformation processes in the river system. Findings presented in this research could help to improve conceptual understanding of N behavior in Tigris River, and therefore could assist decision makers to select best management practices and to develop mitigation strategies to sustain water quality in Tigris River.

Coenzyme Q10 Improves the Post-Thaw Sperm Quality in Dwarf Surfclam Mulinia lateralis.

Previous studies have shown that post-thaw sperm performance is affected by multiple stressors during cryopreservation, such as those induced by physical, chemical, mechanical and physiological changes. One of these is the balance disturbance between the antioxidant defense system and reactive oxygen species (ROS) production. This study investigated whether this disturbance could be alleviated by the addition of different antioxidants to cryoprotective solution [8% dimethyl sulfoxide (DMSO) in 1 µm filtered seawater] optimized for the sperm in dwarf surf clam Mulinia lateralis, the model bivalve species used in many different types of studies. Results showed that the addition of 20 μM coenzyme Q10 (Q10) to 8% DMSO achieved a D-stage larval rate similar to that of the fresh control at a sperm-to-egg ratio at least 50% less than the 8% DMSO treatment alone. The addition of other antioxidants (glycine, melatonin and polyvinylpyrrolidone) did not have any positive effects. The improvement in post-thaw sperm quality by Q10 could be due to its ability to significantly decrease ROS production and lipid peroxidation and significantly increase the motility, plasma membrane integrity, mitochondrial membrane potential, acrosome integrity, DNA integrity and activities of catalase and glutatione. In this study, 37 fatty acids (FAs) were quantified in dwarf surf clam sperm, with 21 FAs being significantly impacted by the cryopreservation with 8% DMSO. Thirteen of these 21 FAs were changed due to the addition of 20 μM Q10 to 8% DMSO, with approximately half of them being improved significantly toward the levels of fresh control, while the remaining half extended further from the trends shown with 8% DMSO treatment. However, no significant difference was found in the percentage of each FA category sum and the ratio of unsaturated/saturated FAs between the two treated groups. In conclusion, the antioxidant Q10 has shown the potential to further improve the sperm cryopreservation technique in bivalves.

Removal of levofloxacin by H2O2 and PMS co-activation by sulfide-supported oxalate zero-valent iron enhanced with simultaneous catalysis of SO4-• and 1O2: Major free radicals, synergistic effects and mechanism exploration

It is reported in the literature that sulfide and oxalate are promising ways to modify zero-valent iron (ZVI) for the degradation of antibiotics, but the synergistic activation mechanism of H2O2 and PMS is still unclear. In order to explore this effect, a new type of oxalated and sulfided ZVI (OA-S-ZVI) was synthesized in this study, and levofloxacin (LEV) was degraded in H2O2, PMS and H2O2/PMS systems. The batch experiments confirmed that the removal ability of OA-S-ZVI/H2O2/PMS was 1.65–10 times that of other systems. This result was achieved by modifying ZVI surface catalytic sites and cooperating with H2O2/PMS. At the same time, the synergistic factor S (1.74) confirmed that the composite system H2O2/PMS can capture electrons from the catalyst Fe0 to Fe2+ and adsorb active sites of the catalyst, such as ≡Fe-C2O4-, ≡Fe-OH/OOH and ≡Fe-S. Further calculation and analysis revealed that the binding energy of singlet oxygen (1O2) and sulfate radical (SO4-•) in the composite system decreased and multiple molecular orbitals participated in the removal process. The characterization experiments and EPR experiments explained the transfer free radicals to non-free radicals from a single system to a composite system. This study provides a new perspective on modifying ZVI and utilizing multi-system synergy to effectively remove organic micropollutants from water.

Efficacy study of hyperbaric oxygen therapy for the treatment of central retinal artery occlusion: a systematic review

Central Retinal Artery Occlusion (CRAO) is a rare ophthalmology emergency caused by central retinal artery embolism. Many CRAO management strategies exist. However, no treatment has consistently improved visual outcomes following CRAO. These medicines have many negative effects and unclear efficacy. HBOT has been considered for CRAO management. HBOT may minimize ischemia damage between CRAO and retinal artery recanalization, which normally occurs within 72 hours.9 There is continuous disagreement about whether this treatment procedure achieves the desired visual target. The method use is PRISMA principles were followed for a systematic review. This systematic review examines HBOT's efficacy in CRAO. The search terms were “Hyperbaric Oxygen Therapy” (“HBOT”) and “Central Retinal Artery Occlusion” (“CRAO”). The 5 investigations were primarily cohort retrospective. Four studies found no link between onset-to-HBOT time and visual outcome, two found no correlation between HBOT session and VA improvement, and three found no correlation between first therapy before HBOT and VA improvement. All said this therapy produced side effects. The conclusion is in this study is more investigations showed no significant link between onset-to-HBOT time, initial treatment before HBOT, and VA improvement. HBOT can produce barotrauma, ear pain, tympanic membrane rupture, and central nervous system oxygen poisoning seizures, so these must be considered.

The introduction of pyrochar boosts the generation of singlet oxygen in a ferrihydrite-based Fenton-like system to facilitate the Cr(III)-citrate decomplexation under Cr(VI) inhibition

Cr(III)-organic complexes are frequently detected in tanning effluent, but they are challenging to elimination. Ferrihydrite (Fh)/carbon materials (CMs) composites showed superior performance in Fenton-like oxidation process, but their effectiveness and mechanism in Cr(III)-organic complex treatment need to be deep explored. In this study, pyrochar (PC)/Fh compounds were successfully synthesized and the experimental results found that the 5%-PC/Fh/H2O2 system exhibited efficient elimination of Cr(III)-citrate complexes with 89% reduction in TOC and almost 100% elimination of total Cr. The cooperation of PC with Fh promoted the decomposition of H2O2 by accelerating the electron transfer between Fe(III)/Fe(II) pairs. In contrast to the traditional Fenton-like catalysts, 5%-PC/Fh equipped with Fe–O–C bond could boost the production of 1O2, resulting in decomplexation of Cr(III)-citrate rather than direct attack of the Cr(III) site in the Cr(III)-citrate complex. Consequently, Cr(VI) could not be produced in the 5%-PC/Fh/H2O2 system. Moreover, the developed 5%-PC/Fh/H2O2 system exhibited enhanced reusability and excellent stability when applied to natural water and real wastewater. Finally, the oxidation intermediates could even promote the growth of C. vulgaris, indicating the structure of Cr(III)-citrate was destroyed and their toxicity was decreased. All these phenomena suggested the great potential of the 5%-PC/Fh/H2O2 system for practical wastewater treatment. This study has provided theoretical guidance and technical support for the efficient treatment of Cr(III)-organic complexes in real wastewater.

Factors Associated With Unplanned Readmissions and Prolonged Length of Stay in Patients Undergoing Primary Fusion for Congenital Scoliosis.

Approximately 50% of patients with congenital scoliosis will require surgical treatment to prevent further progression. Outcomes following congenital scoliosis are sparse in the literature. The purpose of this study was to identify independent risk factors associated with unplanned readmission and prolonged length of stay (LOS) in patients undergoing primary surgical treatment for congenital scoliosis. The National Surgical Quality Improvement Database-Pediatric was queried for database years 2016-2018 to identify patients with congenital scoliosis who underwent primary posterior fusion of the spine. Patient demographics, comorbidities, and operative variables, such as the number of levels fused and the American Society of Anesthesiologists (ASA) classificaiton, were collected. Univariate and multivariate analyses of patient factors were performed to test for association with readmission within 30 days and prolonged LOS (>4 days). Eight hundred sixteen patients were identified. The average age was 11.3 ± 4.02 years, and the mean postoperative LOS was 4.64 ± 3.71 days. Forty-three patients (5.40%) were readmitted, and 73 patients (8.96%) had prolonged LOS. Independent risk factors associated with prolonged LOS included chronic lung disease (P < 0.001), presence of a tracheostomy (P < 0.001), structural central nervous system abnormality (P = 0.039), oxygen support (P < 0.001), and number of levels fused (P = 0.008). The factors independently associated with unplanned readmission were fusion to the pelvis (P = 0.004) and LOS >4 days (P = 0.008). Prolonged LOS and readmission are widely being used as quality and performance metrics for hospitals. Congenital scoliosis, which often progresses rapidly resulting in significant deformity, frequently requires surgery at an earlier age than idiopathic and neuromuscular deformity. Nevertheless, 30-day outcomes for surgical intervention have not been thoroughly studied. The present study identifies risk factors for prolonged LOS and readmission, which can facilitate preoperative planning, patient/family counseling, and postoperative care. Congenital scoliosis management poses certain challenges that may be mitigated by understanding the risk factors for adverse outcomes following primary fusion surgery.

Systemic hemodynamics and pediatric lung disease: mechanistic links and therapeutic relevance.

Chronic lung disease, also known as bronchopulmonary dysplasia, affects thousands of infants worldwide each year. The impact on resources is second only to bronchial asthma, with lung function affected well into adolescence. Diagnostic and therapeutic constructs have almost exclusively focused on pulmonary architecture (alveoli/airways) and pulmonary hypertension. Information on systemic hemodynamics indicates major artery thickness/stiffness, elevated systemic afterload, and/or primary left ventricular dysfunction may play a part in a subset of infants with severe neonatal-pediatric lung disease. Understanding the underlying principles with attendant effectors would aid in identifying the pathophysiological course where systemic afterload reduction with angiotensin-converting enzyme inhibitors could become the preferred treatment strategy over conventional pulmonary artery vasodilatation.NEW & NOTEWORTHY Extremely preterm infants are at a higher risk of developing severe bronchopulmonary dysplasia. In a subset of infants, diuretic and pulmonary vasodilator therapy is ineffective. Recent information points toward systemic hemodynamic disease (systemic arterial stiffness and left ventricular dysfunction) as a contributor via back-pressure changes. Mechanistic links include heightened renin angiotensin aldosterone system activity, inflammation, and oxygen toxicity. Angiotensin-converting enzyme inhibition may be operationally more suited compared with induced pulmonary artery vasodilatation.

Transformations in phenylboronic acid at high pressures and temperatures

A recent report on obtaining the n-type conductivity in diamonds doped with boron–oxygen complexes in a metal solvent (X. Liu et al., PNAS 2019) stimulates interest in the synthesis of diamonds in heterohydrocarbon systems with oxygen and boron. The simultaneous effect of boron and oxygen heteroatoms on phase transitions in a hydrocarbon system is examined in phenylboronic acid C6H5B(OH)2 at pressures of 7–8.5 GPa and temperatures up to 1600 °C. At pressures of about 7 GPa and temperatures up to 1100 °C, the transformation of the precursor occurs through the stage of polymerization into a graphane-like phase with the subsequent formation of nanographite. Micro- and nanodiamonds are synthesized at 8.5 GPa and 1600 °C from the initial precursor and nanographite, which is a product of preliminary carbonization, respectively. Despite the presence of oxygen and boron in the growth system, the n-type conductivity in diamonds and nanographite is not detected. It is found that the degree of boron doping of diamond in hydrocarbon systems decreases in the presence of oxygen with a high chemical affinity to boron and that nanodiamonds in the carbonized product can be obtained when volatile components leave the system.

The removal and transformation of fipronil using a photoelectrochemical device combined with a carbonized TiO2 nanocomposite electrode

Fipronil has been a critical environmental concern due to its potential risks to aquatic environments. However, research on the effective removal of fipronil using photoelectrochemical (PEC) devices is still limited. This study represents the pioneering application of a PEC device for the efficient removal of pesticides. A carbonized titanium dioxide nanocomposite electrode was employed as the electrode in the PEC device. The extent of fipronil degradation in the PEC device was also monitored. The PEC device demonstrated higher efficiencies than the reported oxidation treatments. The applied voltage and illumination from the light source initiated the formation of various reactive species, which exhibited the ability to degrade fipronil in the PEC device. Importantly, the presence of singlet oxygen and ozone in the PEC device was demonstrated for the first time, providing new insights into the degradation mechanism in the PEC system. Furthermore, this study unveiled four byproducts that were previously unreported. The presence of fipronil chlorinated byproducts in the device resulted in the generation of reactive chlorine species, which contributed to fipronil decomposition. When the detoxification of fipronil was compared between the PEC and electrochemical devices, the PEC device demonstrated higher degradation efficiencies and more effective detoxification, providing valuable insight into removing pesticides. Novelty statementThe degradation of fipronil and the identification of its degradation byproducts, along with toxicity testing, have been extensively investigated. Previous studies have indicated that many oxidation processes for fipronil degradation lead to the formation of byproducts with higher toxicity or require extended periods to reduce toxicity. In this study, a photoelectrochemical advanced oxidation process was applied for the first time to degrade pesticides. The developed PEC degradation process demonstrated the ability to rapidly remove fipronil and effectively reduce its toxicity, showing significant potential for various applications. Furthermore, our research revealed the formation of singlet oxygen and ozone in a PEC degradation system, providing novel insights into the degradation mechanism within the PEC system. Utilizing the carbonized titanium dioxide nanocomposite electrode developed in this study, successful fipronil decomposition was achieved for the first time through a PEC device.

PEG300 Protects Mitochondrial Function By Upregulating PGC-1α to Delay Central Nervous System Oxygen Toxicity in Mice.

Central nervous system oxygen toxicity (CNS-OT) is a complication of hyperbaric oxygen (HBO) treatment, with limited prevention and treatment options available. In this study, we aimed to explore the effect of polyethylene glycol 300 (PEG300) on CNS-OT and underlying mechanisms. Motor and cognitive functions of mice in normobaric conditions were evaluated by Morris water maze, passive active avoidance, and rotarod tests. HBO was applied at 6 atmospheres absolute (ATA) for 30min after drug administration. The latency period of convulsion in mice was recorded, and hippocampal tissues were extracted for biochemical experiments. Our experimental results showed that PEG300 extended the convulsion latencies in CNS-OT mice, reduced oxidative stress and inflammation levels in hippocampal tissues. Furthermore, PEG300 preserved mitochondrial integrity and maintained mitochondrial membrane potential in hippocampal tissue by upregulating Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha (PGC-1α). This protective effect was enhanced following the administration of ZLN005, an agonist of PGC-1a. Hence, our study suggests that PEG300 might exert protective effects by upregulating PGC-1α expression and preserving mitochondrial health, offering promising prospects for CNS-OT treatment.

Research on control strategy of PEMFC air supply system for power and efficiency improvement

Proton exchange membrane fuel cell (PEMFC) is considered as a type of clean and efficient energy device. Fuel cell air supply system is a key component to maintaining the system output efficiency. In this paper, a dynamic control model for PEMFC system oxygen excess ratio (OER) management is built, and an OER control strategy is designed based on Fractional-Order PID. An OER control index mapping the relationship between the OER and the optimal net power under different load currents is proposed to improve the output performance of the system. The results show that Fractional-Order PID can achieve high accuracy and fast response real-time OER regulation under the step current in comparison to the traditional PID and Fuzzy PID control. Furthermore, under the dynamic load current of vehicle, the average relative error of OER is 2.81 % under optimal OER control based on Fractional-Order PID and the power generation efficiency of the PEMFC system can be increased to 52.55 %.

Getting outside of ourselves: Towards an other-oriented model of psychological health

This paper examines key assumptions about the benefits of self-oriented care and other-oriented care that have been guiding considerable amounts of research and applications in psychology. More specifically, the paper questions the importance of what can be referred to as the ‘Oxygen Mask Assumption,’ the belief that it is often best to take care of oneself to better take care of others. Based on mounting evidence of the benefits of prosocial behaviour, both for the giver and the receiver, this paper proposes an explicitly other-oriented model of wellbeing. The paper first outlines the Oxygen Mask Assumption and research demonstrating the importance of self-oriented care and the implicit model guiding much of this research. This is followed by examining recent research on the benefits of prosocial behaviour, and the introduction of an other-oriented model of wellbeing. Predictions based on both models are evaluated in light of current research. Theoretical and practical implications of adopting an other-oriented model are discussed.

Interaction of macro- and microvascular function underlies brachial artery flow-mediated dilation in humans.

Brachial artery flow-mediated dilation (BAFMD) is induced by hyperemic wall shear rate (WSR) following forearm ischemia. In older adults, there appears to be a reduced brachial hyperemic WSR and altered stimulus-response relationship compared with young adults. However, it is unclear if an altered forearm microvascular response to ischemia influences brachial hyperemic WSR in older adults. We determined associations between brachial hyperemic WSR and forearm skeletal muscle oxygen saturation in young and older adults. Healthy young (n = 17, 29 ± 7 yr) and older (n = 32, 65 ± 4 yr) adults participated in the study. BAFMD by a multigate spectral Doppler system and forearm skeletal muscle oxygen saturation by near-infrared spectroscopy were concurrently measured. When compared with the young, older adults showed reduced oxygen extraction kinetics (OE, 0.15 [0.12-0.17] vs. 0.09 [0.05-0.12]%s-1) and magnitude (So2deficit, 3,810 ± 1,420 vs. 2,723 ± 1,240%s) during ischemia, as well as oxygen resaturation kinetics (So2slope, 2.5 ± 0.7 vs. 1.7 ± 0.7%s-1) upon reperfusion (all P < 0.05). When OE in the young and So2slope in older adults were stratified by their median values, young adults with OE above the median had greater hyperemic WSR parameters compared with those below the median (P < 0.05), but So2slope in older adults did not show clear differences in hyperemic WSR parameters between those above/below the median. This study demonstrates that, in addition to a reduced microvascular response to ischemia, there may be a dissociation between microvascular response to ischemia and brachial hyperemic WSR in older adults, which may result in a further impairment of BAFMD in this cohort.NEW & NOTEWORTHY Microvascular response to ischemia and subsequent reperfusion is diminished in older adults compared with the young. Furthermore, there appears to be a dissociation between the microvascular response to ischemia and brachial hyperemic WSR in older adults, which may further disturb the BAFMD process in this cohort. A reduced BAFMD in older adults may be a result of multiple alterations occurring both at macro- and microcirculation.

The Effects of Slow Breathing during Inter-Set Recovery on Power Performance in the Barbell Back Squat.

Slow breathing (SB) reduces sympathetic nervous system activity, the heart rate (HR), and blood pressure (BP) and increases parasympathetic nervous system activity, HR variability, and oxygen saturation which may lead to quicker recovery between bouts of exercise. Therefore, the purpose of this study was to examine whether a SB technique using the 4-7-8 method between sets of barbell back squats (SQs) would attenuate drops in power and bar velocity. In a randomized, crossover design, 18 healthy resistance-trained college-aged males (age: 20.7 ± 1.4 years, body height: 178.6 ± 6.4 cm, body mass: 82.2 ± 15.0 kg, 4.5 ± 2.4 years of experience) performed 5 sets of 3 repetitions of SQs with normal breathing (CON) or SB during the 3-min recovery between sets. Peak and average power and bar velocity were assessed using a linear positioning transducer. HR recovery (RHR), systolic BP recovery (RBP), the rating of perceived exertion (RPE) and the rating of perceived recovery score (RS) were assessed after each set. There were no significant differences between conditions for peak and average power and bar velocity, RBP, RPE, and RS (p > 0.211). SB led to a greater RHR after set 2 (SB: 51.0 ± 14.9 bpm vs. CON: 44.5 ± 11.5 bpm, p = 0.025) and 3 (SB: 48.3 ± 13.5 bpm vs. CON: 37.7 ± 11.7 bpm, p = 0.006) compared to the CON condition. SB was well tolerated, did not hinder nor improve training performance and improved RHR after the middle sets of SQs. Further investigations are warranted to examine the effects of other SB techniques and to determine SB's effects on different training stimuli as well as its effects over an entire workout and post-workout recovery metrics.

Exposure to hyperbaric O2 levels leads to blood-brain barrier breakdown in rodents

IntroductionHyperbaric oxygen has been used as a medical treatment tool in hyperbaric chambers and is an integral part of professional and combat divers’ activity. In extreme cases, exposure to hyperbaric oxygen can develop central nervous system oxygen toxicity (CNS-OT), which leads to seizures and eventually death. CNS-OT is caused by neuronal hyperactivity due to high oxygen levels, potentially damaging brain cells including the blood-brain barrier (BBB). However, the effect of hyperbaric oxygen levels on the healthy BBB has not been characterized directly yet.MethodsSix or three different groups of ~ eight rats or mice, respectively, were exposed to increasing levels of partial pressure of oxygen (0.21 to 5 ATA) in a hyperbaric chamber, followed by MRI scanning with gadolinium. Statistical significance (adjusted p-value ≤ 0.05) was assessed using linear regression and ordinary one-way (rats) or two-way (mice) ANOVA with correction of multiple comparison tests. In rats, the effect of 100% oxygen at 5 ATA was independently validated using FITC-Dextran (5 kDa). Statistical significance (p-value ≤ 0.05) was assessed using Welch’s t-test and effect size was calculated by Cohen’s D.ResultsIn rats, analyzed MRI scans showed a significant trend of increase in the % gadolinium in brain tissues as a result of hyperbaric oxygen pressures (p-value = 0.0079). The most significant increase was measured at 4 ATA compared to air (adjusted p-value = 0.0461). Significant increased FITC-Dextran levels were measured in the rats’ brains under 100% oxygen at 5 ATA versus air (p-value = 0.0327; Effect size = 2.0). In mice, a significant increase in gadolinium penetration into the hippocampus and frontal cortex was measured over time (adjusted p-value < 0.05) under 100% oxygen at 3 and 5 ATA versus air, and between the treatments (adjusted p-value < 0.0001).ConclusionsThe BBB is increasingly disrupted due to higher levels of hyperbaric oxygen in rodents, indicating a direct relation between hyperbaric oxygen and BBB dysregulation for the first time. We suggest considering this risk in different diving activities, and protocols using a hyperbaric chamber. On the other hand, this study highlights the potential therapeutic usage of hyperbaric oxygen for controlled drug delivery through the BBB into brain tissues in different brain-related diseases.

Remotely controlled smart monitoring system of hermetic paddy storage to reduce postharvest losses in Bangladesh

In Bangladesh, where agriculture forms the backbone of the economy, efficient grain storage is crucial, particularly for paddy storage. Traditional methods like gunny bags and plastic containers are common, but the recent introduction of hermetic storage technologies, such as GrainPro bags and hermetic cocoons, have significantly reduced postharvest losses paddy. However, most research focuses on oxygen (O2) and carbon dioxide (CO2) levels in those open storage systems. This study introduces an innovative, cost-effective remote monitoring system for hermetically sealed grain storage, designed using locally sourced components, including a Digital Hygrometer, WiFi Mini IP Camera, and a Remote Controller unit. Tested over a 125-day period at Advanced Storage Lab, Bangladesh Agricultural University, the system effectively monitored the internal environment of the storage units. Key findings show that the internal temperature of the storage bags varied between 16.7°C and 29.2°C, demonstrating lesser fluctuation compared to the ambient temperature range of 16.1°C to 33.5°C. The relative humidity inside the storage units remained stable between 45 % and 54 %, in contrast to the external humidity range of 45 % to 81.2 %. Additionally, using the Steffe and Singh equation, an increase of 0.512 % in Equilibrium Moisture Content (EMC) of paddy was recorded. Notably, there was no evidence of insect or mold growth after 125 days of storage. This study's remote monitoring system not only marks a significant advancement in hermetic grain storage technology but also contributes to sustainable agricultural practices. It provides a practical, real-time solution to monitor and manage key environmental parameters, ensuring the preservation of grain quality over time.