Reduction In Oxygen Research Articles

Effects of Temperature and Salt Catalysts on Depolymerization of Kraft Lignin to Aromatic Phenolic Compounds

Hydrothermal liquefaction (HTL) of Kraft lignin was investigated with different salt catalysts (namely, the basic salts K₂CO₃, CaCO₃; acidic salts ZrOCl₂·8H₂O and AlK(SO₄)₂·12H₂O, and neutral salt KCl) in the temperature range of 200–350 °C for 40 min in a batch reactor. With an increase in reaction temperature from 200 to 350 °C, the bio-oil yield first increased up to 300 °C and then decreased at 350 °C. The highest total bio-oil yield of ∼48.5 wt %, which involved ∼7.5 wt % water-soluble organics (WSO) and lowest char formation (∼19.1 wt %), was obtained at 300 °C over K₂CO₃ catalyst. The GC-MS results showed that WSO fractions were comprised of mainly guaiacol and catechol-type monomers, whereas the heavy bio-oil fractions contained mostly long-chain acids, aldehydes, and ketone-type compounds. In comparison with the other salt catalysts, the insertion of K₂CO₃ resulted in significant reduction in oxygen, nitrogen, and sulfur contents and consequently increased the high heating value (HHV) of 18.9 MJ/kg (in the original Kraft lignin) to 29.3 MJ/kg (in the bio-oil obtained with K₂CO₃ catalyst). The overall results suggested that K₂CO₃ in a subcritical water system was more efficient for the production of high-quality bio-oil in comparison to other tested acidic and neutral salt catalysts. The solid and liquid products obtained in different experiments were analyzed by FT-IR, SEM, GC-MS, and elemental analysis methods.

Biowaste-based biochar: A new strategy for fermentative bioethanol overproduction via whole-cell immobilization

This work explores the potential use of biochar as a microbial cell carrier enhancing the efficiency of alcoholic fermentations. Olive kernels, vineyard prunings, sewage sludge and seagrass residues were applied as biowaste for biochar production through pyrolysis at two different temperatures (250 °C and 500 °C), while a commercial type of non-biomass char was also employed for benchmarking purposes. Apart from vineyard prunings pyrolyzed at 250 °C, all other carbonaceous materials presented crystalline phases including halite, calcite, sylvite and/or silicon. Moreover, increase in pyrolysis temperature enhanced biochar’s porosity and BET-specific surface area, which reached 41.7 m2 g−1 for VP-based biochar remaining at lower levels (0.15–5.3 m2 g−1) in other specimens tested. Elemental analysis demonstrated reduction in oxygen and increase in the carbon content of biochars produced at elevated temperatures, while biochar from seagrass included residues of chloride (0.3–5.14%). Three major yeasts were immobilized on materials exhibiting the highest surface areas and applied in repeated batch fermentations using Valencia orange peel hydrolyzates as feedstock. The biocatalysts developed using S. cerevisiae and K. marxianus immobilized on vineyard prunings-based biochar exhibited exceptional ethanol productivities as compared to the relevant literature, which reached 7.2 g L−1 h−1 and 7.3 g L−1 h−1 respectively. Although the aforementioned strains improved biofuel production by 36–52% compared to the conventional process, P. kudriavzevii KVMP10 was not efficient following immobilization on biochar. The approach constitutes an innovative method for bioenergy production, demonstrating a novel application of biochar in industrial biotechnology which incorporates important technological advances such as enhanced biofuel production and biomass recycling.

The impact of implementing a preprinted order form for inpatient management of otherwise healthy children admitted to a tertiary care centre with a diagnosis of bronchiolitis.

To examine the effect on length of stay (LOS) of a preprinted order (PPO) set for children admitted to hospital with a diagnosis of bronchiolitis, as well as on quality improvement measures, medical errors, and resource utilization. A retrospective chart review was performed of children admitted to the inpatient units at the Children's Hospital of Eastern Ontario (CHEO) with a discharge diagnosis of bronchiolitis. Primary and secondary outcomes were compared between the pre-PPO (December 1, 2014 to June 30, 2015) and post-PPO (December 1, 2015 to June 30, 2016) periods. The primary outcome was LOS in days. Secondary outcomes included the proportion of quality improvement measures reached, the number of medical errors, and resource utilization. A total of 245 patients were included; 122 patients from the pre-PPO period (December 1, 2014 to June 30, 2015) and 123 patients from the post-PPO period (December 1, 2015 to June 30, 2016). Mean LOS was 3.1 days (2.7 to 3.5 days) and 2.8 days (2.4 to 3.2 days) in the pre- and post-PPO periods, respectively (multivariate analysis, P-value = 0.13). There were significant differences between the pre- and post-PPO periods in a number of quality improvement measures, although not in the number of medical errors. Significant reductions in oxygen, corticosteroid, antibiotic, and bronchodilator use were noted post-PPO implementation. Although our bronchiolitis PPO did not significantly shorten LOS, it led to important improvements in quality improvement measures and in resource utilization efficiency.

Atomic surface reduction of interfaces utilizing vapor phase approach: High energy LiNixMnyCoz oxide as a test case

In the present work, a simple and agile methodology for atomic surface reduction of interfaces is introduced. Using a surface directed vapor phase reaction, at relatively low temperature, we show that a highly reactive and volatile molecule can be used to selectively reduce the interface, without changing the bulk of the treated material, and without the need of alternating sequence of multiple precursors, normally involved in ALD. The model system we use to demonstrate the efficacy, and potential of our approach is trimethyl aluminum, and high energy Li and Mn rich cathode (HE-NCM) as the functional material of interest. We demonstrate that with the proposed method, the particles of HE-NMC were conformally coated with ~ 3 nm amorphous layer of the reduced surface in less than 1 h (including the cooling time),as witnessed using HR-TEM. XPS and solid-state NMR, further confirmed that surface treatment was successfully achieved using the proposed method and is well explained by DFT calculations. Utilizing online electrochemical mass spectrometry (OEMS), we show in-operando that this amorphous layer helps to suppress parasitic reactions under extreme electrochemical conditions as indicated by the significant reduction in oxygen and CO2 evolution. The surface treatment further resulted in enhancement in specific capacity during the first cycle. This methodology provides a non-conventional path to achieve thin layer surface modification under facile conditions, and opens a new way to meet the requirements of surface modification strategies for improving the performance of electrode materials without utilizing expensive instrumentation and high temperature processes.

Improved glass bonding with plasma treatment

Bonding of automotive glass is generally performed with 1C PUR adhesive on a primed ceramic frit or naked glass surface. The aim of this research was to replace the chemistry of the primer with an atmospheric pressure plasma treatment (APPT) with compressed air for cleaning and activation directly before bonding. Characterization of the glass surface was performed with surface energy through contact angle, XPS, TOF-SIMS and adhesive peel bead test. The results show that APPT treatment can clean the surface, improve the wetting, improve the bonding but reduce the number of non bridging oxygen for the adhesive to bond to. The highest measured spot temperature of the glass during APPT was measured up to 270 °C, but the temperature was depending on process parameters. A reduction in non bridging oxygen was also seen during heating of the reference glass at 100 °C. A further reaction was seen when measured after a 550 °C heating. A modified APPT treatment with deionized water as precursor was used. The results show that the APPT with water does not lower the level of non bridging oxygen and the bonding was further improved.

Effects of dairy shed effluent dry matter content on ammonia and nitrous oxide emissions from a pasture soil

AbstractAtmospheric emissions of nitrogen (N) from New Zealand dairy farms are significant but have the potential to be affected by manure management prior to land application. The current work examined whether reducing cattle manure dry matter (DM) from 0.16 high DM (HDM) to 0.06 low DM (LDM), to enhance infiltration and reduce ammonia (NH3) emissions when applied to grassland, would affect nitrous oxide (N2O) emissions. Pasture was cut, simulating grazing, and either amended with HDM (173 kg N/ha) or LDM manure (48 kg N/ha) or left unamended. Ammonia emissions from HDM manure were higher than from LDM manure, as a flux or as a percentage of total ammoniacal nitrogen (TAN, i.e. NH3 + NH4+) applied, due to more TAN being retained near the soil surface and the higher soil surface pH under HDM manure treatment. Cumulative N2O emissions over 37 days from HDM plots were higher than from the control but not from the LDM plots. After 5 days, the daily N2O emission rate was larger from HDM plots than from LDM and control plots. The N2O fluxes from LDM and HDM treatments did not differ, either as a proportion of TAN applied or as a proportion of total-N applied. Increasing DM contributed to reductions in both oxygen (O2) availability and relative gas diffusivity, and thus potentially N2O production. Under the conditions of the current study, lower manure DM content reduced NH3 emissions but did not increase cumulative losses of N2O.

Trans-Chalcone Attenuates Pain and Inflammation in Experimental Acute Gout Arthritis in Mice

Gouty arthritis is characterized by an intense inflammatory response to monosodium urate crystals (MSU), which induces severe pain and reduction in the life quality of patients. Trans-Chalcone (1,3-diphenyl-2-propen-1-one) is a flavonoid precursor presenting biological activities such as anti-inflammatory and antioxidant proprieties. Thus, the aim of this work was to evaluate the protective effects of trans-Chalcone in experimental gout arthritis in mice. Mice were treated with trans-Chalcone (3, 10, or 30 mg/kg, per oral) or vehicle (Tween 80 20% plus saline) 30 min before intra-articular injection of MSU (100 μg/knee joint, intra-articular). We observed that trans-Chalcone inhibited MSU-induced mechanical hyperalgesia, edema, and leukocyte recruitment (total leukocytes, neutrophils, and mononuclear cells) in a dose-dependent manner. Trans-Chalcone also decreased inflammatory cell recruitment as observed in Hematoxylin and Eosin (HE) staining and the intensity of fluorescence of LysM-eGFP+ cells in the confocal microscopy. Trans-Chalcone reduced MSU-induced oxidative stress as observed by an increase in the antioxidant defense [Glutathione (GSH), Ferric Reducing (FRAP), and 2,2’-Azinobis-3-ethylbenzothiazoline 6-sulfonic acid (ABTS assays)] and reduction in reactive oxygen and nitrogen species production [superoxide anion (NBT assay) and nitrite (NO assay)]. Furthermore, it reduced in vivo MSU-induced interleukin-1β (IL-1β), Tumor necrosis factor-α (TNF-α), and IL-6 production, and increased Transforming growth factor-β (TGF-β) production. Importantly, trans-Chalcone reduced nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation and thereby the mRNA expression of the inflammasome components Nlrp3 (cryopyrin), Asc (apoptosis-associated speck-like protein containing a CARD), Pro-caspase-1 and Pro-IL-1β. In vitro, trans-Chalcone reduced the MSU-induced release of IL-1β in lipopolysaccharide (LPS)-primed macrophages. Therefore, the pharmacological effects of trans-Chalcone indicate its therapeutic potential as an analgesic and anti-inflammatory flavonoid for the treatment of gout.

ACE inhibition for severe bronchopulmonary dysplasia - an approach based on physiology.

Premature infants have a high incidence of bronchopulmonary dysplasia (BPD). Systemic hypertension, arterial thickness and stiffness, and increased systemic afterload may all contribute to BPD pathophysiology by altering left ventricular (LV) function and increasing pulmonary venous congestion by lowering end‐diastolic compliance. This case series studied the usefulness of angiotensin‐converting enzyme (ACE) inhibition by measuring clinical and echocardiographic improvements in six consecutive infants with “severe” BPD unresponsive to conventional therapy. The range of gestation and birthweight were 23–29 weeks and 505–814 g, respectively. All required mechanical ventilation (including high‐frequency oscillation) and all but one were administered postnatal corticosteroids. Other treatments including sildenafil and diuretics made no clinical improvements. Captopril was started for systemic hypertension after cardiac and vascular ultrasounds which were repeated 5 weeks later. A significant reduction in oxygen (55 ± 25 to 29 ± 3%, two‐tailed P = 0.03) and ventilator requirements, and improved cardiovascular parameters were noted. This included a trend toward reduction in aorta intima media thickness [840 ± 94 to 740 ± 83 μm, P = 0.07] and an increased pulsatile diameter [36 ± 14 to 63 ± 25 μm, P = 0.04]). Improvements were observed for both systolic (increased LV output, 188 ± 13 to 208 ± 13 mL/kg/min, P = 0.046 and mean velocity of circumferential fiber shortening, 1.6 ± 0.2 to 2.5 ± 0.3 [circ/sec], P = 0.0004) and diastolic (decreased isovolumic relaxation time, 69.6 ± 8.2 to 59.4 ± 5 msec, P = 0.044) function which was accompanied by increased pulmonary vein flow. Right ventricular output increased accompanied by a significant lowering of pulmonary vascular resistance. These findings suggest that improving respiratory and cardiac indices (especially diastolic function) warrants further exploration of ACE inhibition in BPD infants unresponsive to conventional therapy.

Zooplankton drive diurnal changes in oxygen concentration at Tisler cold-water coral reef

Tisler Reef is a Norwegian cold-water coral reef in the Northeastern Skagerrak, which lies at an average depth of 120 m, is constructed principally of the scleractinian coral Lophelia pertusa and hosts a dynamic and diverse ecosystem. The availability of oxygen within Tisler Reef, recorded between 2006 and 2008, showed a decline during the summer months, caused by both the isolation of the reef from the atmosphere under conditions of seasonal stratification, and the enhanced respiration in the water column during the seasonal zooplankton proliferations. Concentrations of dissolved oxygen were replenished from high-current flows advecting water from off the reef. Low current flow conditions (< 0.05 m s−1) coincided with a short-term reduction in oxygen, the extent of which varied seasonally and were observed to be greatest during July and August, coinciding with the summer Calanus proliferation in the Skagerrak. Normalized acoustic backscatter amplitude during the summer months showed a strong signal of zooplankton diurnal vertical migration, coinciding with the lowest oxygen concentrations at the reef observed during, and lagging slightly after, the deep phase of the zooplankton vertical migration. This effect was most obvious during low-flow conditions; highlighting the importance of zooplankton and associated activity as a consumer of oxygen at the reef.

Subsurface processes influence oxidant availability and chemoautotrophic hydrogen metabolism in Yellowstone hot springs.

The geochemistry of hot springs and the availability of oxidants capable of supporting microbial metabolisms are influenced by subsurface processes including the separation of hydrothermal fluids into vapor and liquid phases. Here, we characterized the influence of geochemical variation and oxidant availability on the abundance, composition, and activity of hydrogen (H2 )-dependent chemoautotrophs along the outflow channels of two-paired hot springs in Yellowstone National Park. The hydrothermal fluid at Roadside East (RSE; 82.4°C, pH 3.0) is acidic due to vapor-phase input while the fluid at Roadside West (RSW; 68.1°C, pH 7.0) is circumneutral due to liquid-phase input. Most chemotrophic communities exhibited net rates of H2 oxidation, consistent with H2 support of primary productivity, with one chemotrophic community exhibiting a net rate of H2 production. Abundant H2 -oxidizing chemoautotrophs were supported by reduction in oxygen, elemental sulfur, sulfate, and nitrate in RSW and oxygen and ferric iron in RSE; O2 utilizing hydrogenotrophs increased in abundance down both outflow channels. Sequencing of 16S rRNA transcripts or genes from native sediments and dilution series incubations, respectively, suggests that members of the archaeal orders Sulfolobales, Desulfurococcales, and Thermoproteales are likely responsible for H2 oxidation in RSE, whereas members of the bacterial order Thermoflexales and the archaeal order Thermoproteales are likely responsible for H2 oxidation in RSW. These observations suggest that subsurface processes strongly influence spring chemistry and oxidant availability, which in turn select for unique assemblages of H2 oxidizing microorganisms. Therefore, these data point to the role of oxidant availability in shaping the ecology and evolution of hydrogenotrophic organisms.

Recent changes in chironomid communities and hypolimnetic oxygen conditions relate to organic carbon in subarctic ecotonal lakes

A key question in aquatic elemental cycling is related to the influence of bottom water oxygen conditions in regulating the burial and release of carbon under climate warming. In this study, we used head capsules of Chironomidae larvae to assess community and diversity change between the past (estimated as Pre-Industrial Period) and present and to reconstruct changes in hypolimnetic oxygen conditions from 30 subarctic ecotonal lakes (northeastern Lapland) using the top-bottom paleolimnological approach applying surface sediment (topmost 0–2 cm) and reference (4–5 cm) samples. Subsequently, we tested the findings against dissolved organic carbon (DOC) concentration of the sites. We found that the benthic communities were statistically dissimilar between the past and the present with largest changes occurring in the more transparent oligo-mesohumic lakes. However, murky polyhumic lakes displayed uniformly a decrease in diversity. The chironomid-inferred oxygen values showed a general decrease toward the present with largest shifts in low-DOC lakes, whereas no significant changes were found in the hypolimnetic oxygen conditions of high-DOC lakes, which were often located in wetland areas. These finding suggest that lakes associated with constant organic carbon inputs are more resilient toward climate-induced reductions in hypolimnetic oxygen.

An Open-Loop, Physiologic Model-Based Decision Support System Can Provide Appropriate Ventilator Settings.

To evaluate the physiologic effects of applying advice on mechanical ventilation by an open-loop, physiologic model-based clinical decision support system. Prospective, observational study. University and Regional Hospitals' ICUs. Varied adult ICU population. Advice were applied if accepted by physicians for a period of up to 4-8 hours. Seventy-two patients were included for data analysis. Acceptance of advice was high with 95.7% of advice applied. In 41 patients in pressure support ventilation, following system advice led to significant decrease in PS, with PS reduced below 8 cm H2O in 15 patients (37%), a level not prohibiting extubation. Fraction of end-tidal CO2 values did not change, and increase in respiratory rate/VT was within clinical limits, indicating that in general, the system maintained appropriate patient breathing effort. In 31 patients in control mode ventilation, pressure control and tidal volume settings were decreased significantly, with tidal volume reduced below 8 mL/kg predicted body weight in nine patients (29%). Minute ventilation was maintained by a significant increase in respiratory rate. Significant reductions in FIO2 were seen on elevated baseline median values of 50% in both support and control mode-ventilated patients, causing clinically acceptable reductions in oxygen saturation. The results indicate that during a short period, the clinical decision support system provided appropriate suggestions of mechanical ventilation in a varied ICU population, significantly reducing ventilation to levels which might be considered safe and beneficial.

Glutamate as a potential \u201csurvival factor\u201d in an in vitro model of neuronal hypoxia/reoxygenation injury: leading role of the Na+/Ca2+ exchanger

In brain ischemia, reduction in oxygen and substrates affects mitochondrial respiratory chain and aerobic metabolism, culminating in ATP production impairment, ionic imbalance, and cell death. The restoration of blood flow and reoxygenation are frequently associated with exacerbation of tissue injury, giving rise to ischemia/reperfusion (I/R) injury. In this setting, the imbalance of brain bioenergetics induces important metabolic adaptations, including utilization of alternative energy sources, such as glutamate. Although glutamate has long been considered as a neurotoxin, it can also be used as intermediary metabolite for ATP synthesis, and both the Na+/Ca2+ exchanger (NCX) and the Na+-dependent excitatory amino-acid transporters (EAATs) are essential in this pathway. Here we analyzed the role of NCX in the potential of glutamate to improve metabolism and survival of neuronal cells subjected to hypoxia/reoxygenation (H/R). In SH-SY5Y neuroblastoma cells differentiated into a neuron-like state, H/R produced a significant cell damage, a decrease in ATP cellular content, and intracellular Ca2+ alterations. Exposure to glutamate at the onset of the reoxygenation phase attenuated H/R-induced cell damage and evoked a significant raise in intracellular ATP levels. Furthermore, we found that in H/R cells NCX reverse-mode activity was reduced, and that glutamate limited such reduction. All the effects induced by glutamate supplementation were lost when cells were transfected with small interfering RNA against NCX1 and EAAT3, suggesting the need of a specific functional interplay between these proteins for glutamate-induced protection. Collectively, our results revealed the potential beneficial effect of glutamate in an in vitro model of H/R injury and focused on the essential role exerted by NCX1. Although preliminary, these findings could be a starting point to further investigate in in vivo systems such protective effect in ischemic settings, shedding a new light on the classical view of glutamate as detrimental factor.

Effect of rapid thermal annealing on bulk micro-defects and plastic deformation in silicon during high temperature processing

We studied how rapid thermal annealing (RTA) affects bulk micro-defects (BMDs) and plastic deformation in Si wafers processed at high temperatures. BMDs caused by oxygen precipitation at 1200 °C were investigated in Si wafers as a function of annealing time with and without RTA and pre-annealing. Only the pre-annealed RTA wafer revealed an average BMD size of ~50 nm after annealing at 800 °C for 2 h and subsequently at 1000 °C for 4 h, and such wafers retained BMDs after annealing at 1200 °C for 500 min. The relationship between BMDs and plastic deformation was investigated for Si wafers subjected to RTA at various temperatures. Dislocations were generated and propagated after the simulated CMOS heat treatment as RTA temperature increased because of the low dislocation pinning effect produced by the reduction in residual oxygen while precipitated oxygen concentration increased. Incident angle deviation in the rocking curve indicated a high degree of plastic deformation caused by high RTA temperature after performing a realistic device fabrication process. We propose that a combination of RTA and a pre-annealing process can improve the internal gettering efficiency during high temperature processing, which controls BMDs. This would balance the residual oxygen and preventing plastic deformation.

Neuroprotection Targeting Protein Misfolding on Chronic Cerebral Hypoperfusion in the Context of Metabolic Syndrome.

Metabolic syndrome (MetS) is a cluster of risk factors that lead to microvascular dysfunction and chronic cerebral hypoperfusion (CCH). Long-standing reduction in oxygen and energy supply leads to brain hypoxia and protein misfolding, thereby linking CCH to Alzheimer's disease. Protein misfolding results in neurodegeneration as revealed by studying different experimental models of CCH. Regulating proteostasis network through pathways like the unfolded protein response (UPR), the ubiquitin-proteasome system (UPS), chaperone-mediated autophagy (CMA), and macroautophagy emerges as a novel target for neuroprotection. Lipoxin A4 methyl ester, baclofen, URB597, N-stearoyl-L-tyrosine, and melatonin may pose potential neuroprotective agents for rebalancing the proteostasis network under CCH. Autophagy is one of the most studied pathways of proteostatic cell response against the decrease in blood supply to the brain though the role of the UPR-specific chaperones and the UPS system in CCH deserves further research. Pharmacotherapy targeting misfolded proteins at different stages in the proteostatic pathway might be promising in treating cognitive impairment following CCH.

Chloral Hydrate Administered by a Dedicated Sedation Service Can Be Used Safely and Effectively for Pediatric Ophthalmic Examination

To determine safety and efficacy of oral chloral hydrate sedation (CHS) for outpatient pediatric ophthalmic procedures. Prospective, interventional case series. Setting: King Khaled Eye Specialist Hospital. Children aged 1month to 5 years undergoing CHS for ocular imaging/evaluation. Details on chloral hydrate dose administered, sedation achieved, vital signs, and adverse events were recorded. Primary outcome was percentage of patients with a sedation level ≥ 4 at 45minutes post chloral hydrate administration. Secondary outcomes were time from sedation to discharge and adverse events, including changes in vital signs following chloral hydrate administration. A total of 324 children were recruited with a mean age of 2.2 (SD: 1.3) years and mean weight of 10.9 (SD: 3.3) kg. Adequate sedation was obtained with a mean chloral hydrate first dose of 77.4 (SD: 14.7) mg/kg in 306 (94.4%) patients, with an additional 6 patients (1.9%) achieving adequate sedation with a second dose (overall adequate sedation: 96.3%). Mean reductions in heart rate, respiratory rate, and oxygen (O2) saturation from pre-sedation to 25minutes post-sedation were 11.7 (SD: 14.3) beats per minute, 1.2 (SD: 2.4) breaths per minute, and 0.81% (SD: 1.2%), respectively (P<.001 for all). In multivariable regression, odds of remaining sedated 45minutes after chloral hydrate administration were 2.53 times higher for American Society of Anesthesiologists (ASA) class II or III patients than for ASA class I (95% confidence interval [CI]: 1.11-5.78, P= .03), 1.03 times higher per mg increase in initial dose of chloral hydrate (95% CI: 1.01-1.06, P= .006), and 2.70 times higher per unit increase in number of planned procedures (95% CI: 1.63-4.47, P < .001). Three patients developed minor adverse events: 2 cases of O2 desaturation and 1 paradoxical reaction, none requiring significant intervention. Patients were discharged a median of 90minutes after chloral hydrate administration. Chloral hydrate administered by a dedicated sedation service, as in this prospective assessment, can be used safely and effectively for outpatient pediatric ophthalmic procedures.

Sympathetic baroreceptor regulation during hypoxic hypotension in humans: new insights.

Baroreceptor activation by a continuous infusion of phenylephrine selectively abolishes the muscle sympathetic nerve activity (MSNA) response to hypoxia in humans. Baroreceptor deactivation enhances the MSNA rise during hypoxia in animals. Whether this is true in humans is unknown and was tested in the present study. We assessed MSNA responses elicited by isocapnic hypoxia (10% O2 in N2) during baroreflex loading and unloading with phenylephrine and nitroprusside, respectively, in 19 healthy volunteers. The study was randomized and placebo-controlled. Phenylephrine and nitroprusside increased and decreased, respectively, blood pressure during normoxia and hypoxia, whereas the reverse occurred for heart rate and MSNA (all P < 0.001 vs. placebo). As compared with normoxia, cardiac barosensitivity decreased during the infusion of placebo and nitroprusside in the presence of hypoxia, as well as sympathetic barosensitivity during the infusion of nitroprusside (all P < 0.05). Three patients even disclosed a reduction in arterial pressure, which became apparent at the third minute of hypoxia and worsened steadily thereafter (SBP: 91 ± 7 mmHg; DBP 47 ± 9 mmHg), in spite of a gradual rise in heart rate of 20 ± 4 bpm. Changes in baroreceptor loading conditions did not affect ventilation during normoxia and hypoxia. Cardiac and sympathetic baroreceptor sensitivity decrease during baroreceptor unloading in the presence of peripheral chemoreceptor activation. Normal humans have limited reflex capabilities to sustain simultaneous reductions in oxygen and pressure, and may experience hemodynamic instability episodes in such condition.

Prophylactic Riluzole Attenuates Oxidative Stress Damage in Spinal Cord Distraction.

Spinal cord injury (SCI) without radiographical abnormalities (SCIWORA) presents a significant challenge because of the loss of function despite an apparent normal anatomy. The cause of dysfunction is not understood, and specific treatment options are lacking. Some scoliosis corrective surgeries result in SCIWORA, where stretching of the spinal cord can lead to vascular compromise and hypoxia. The iatrogenic nature of this injury allows for the implantation of neuroprotective strategies that are designed to prevent damage. We utilized a model of atraumatic SCI to evaluate the efficacy of the sodium-channel blocker, riluzole, as a prophylactic neuroprotectant. As expected, the stretch injury caused a significant reduction in intraparenchymal oxygen in distraction (-53.09 ± 22.23%) and riluzole pre-treated distraction animals (-43.04 ± 22.86%). However, in contrast to the oxidative stress and metabolic impairments observed in vehicle-treated distraction animals, in which protein carbonylation increased significantly (5.88 ± 1.3 nmol/mL), riluzole kept these levels within the normal range (1.8 ± 1.0 nmol/mL). This neurprotection also prevented ventral motor neuron hypoplasia and pyknosis, characteristic features of this atraumatic SCI model, and maintained normal gait function (e.g., stride length and stance time). This study provides evidence for the use of prophylactic neuroprotective strategies in which thoracic or spine surgeries present the risk of causing atraumatic SCI.

A Polyanion Host as a Prospective High Voltage Cathode Material for Sodium Ion Batteries

It is essential to develop efficient electrode materials for sodium in batteries, which are currently being considered as a promising alternative to lithium-ion batteries. In this work, we are presenting NaMnBO3 nanoparticles with conductive carbon matrix (C-NMB) synthesized by urea-assisted hydrothermal method used as a potential cathode material in sodium ion batteries. The C-NMB electrode delivered discharge capacities of 116 mAh g−1, 97 mAh g−1, and 52 mAh g−1 at 0.2 C, 0.5 C, and 2 C rates, respectively and exhibited excellent cyclic behavior at all current densities. Further, the C-NMB electrode demonstrated the best electrochemical stability among other polyanion cathodes, with a capacity fade of 0.06% per cycle at 2 C after 250 cycles with more than 99% coulombic efficiency. X-ray photoelectron spectroscopy revealed that the reduction in oxygen containing surface functionalities (carboxyl groups) further increased the electrical conductivity of the NMB materials. The ex-situ XRD studies after first initial charge and discharge steps reveals that the hexagonal C-NMB electrode displays a topotactic sodium storage mechanism. These outcomes will contribute to the progress of developing low cost, eco-friendly electrode materials for sodium-ion batteries.

Anti-Inflammatory Activity of Marine Ovothiol A in an In Vitro Model of Endothelial Dysfunction Induced by Hyperglycemia.

Chronic hyperglycemia is associated with oxidative stress and vascular inflammation, both leading to endothelial dysfunction and cardiovascular disease that can be weakened by antioxidant/anti-inflammatory molecules in both healthy and diabetic subjects. Among natural molecules, ovothiol A, produced in sea urchin eggs to protect eggs/embryos from the oxidative burst at fertilization and during development, has been receiving increasing interest for its use as an antioxidant. Here, we evaluated the potential antioxidative/anti-inflammatory effect of purified ovothiol A in an in vitro cellular model of hyperglycemia-induced endothelial dysfunction employing human umbilical vein endothelial cells (HUVECs) from women affected by gestational diabetes (GD) and from healthy mothers. Ovothiol A was rapidly taken up by both cellular systems, resulting in increased glutathione values in GD-HUVECs, likely due to the formation of reduced ovothiol A. In tumor necrosis factor-α-stimulated cells, ovothiol A induced a downregulation of adhesion molecule expression and decrease in monocyte-HUVEC interaction. This was associated with a reduction in reactive oxygen and nitrogen species and an increase in nitric oxide bioavailability. These results point to the potential antiatherogenic properties of the natural antioxidant ovothiol A and support its therapeutic potential in pathologies related to cardiovascular diseases associated with oxidative/inflammatory stress and endothelial dysfunction.