Total Oxidation Rates Research Articles

Differential Effects of Chronic Ethanol Use on Mouse Neuronal and Astroglial Metabolic Activity.

Chronic alcohol use disorder, a major risk factor for the development of neuropsychiatric disorders including addiction to other substances, is associated with several neuropathology including perturbed neuronal and glial activities in the brain. It affects carbon metabolism in specific brain regions, and perturbs neuro-metabolite homeostasis in neuronal and glial cells. Alcohol induced changes in the brain neurochemical profile accompany the negative emotional state associated with dysregulated reward and sensitized stress response to withdrawal. However, the underlying alterations in neuro-astroglial activities and neurochemical dysregulations in brain regions after chronic alcohol use are poorly understood. This study evaluates the impact of chronic ethanol use on the regional neuro-astroglial metabolic activityusing 1H-[13C]-NMR spectroscopy in conjunction with infusion of [1,6-13C2]glucose and sodium [2-13C]acetate, respectively, after 48h of abstinence. Besides establishing detailed 13C labeling of neuro-metabolites in a brain region-specific manner, our results show chronic ethanol induced-cognitive deficits along with a reduction in total glucose oxidation rates in the hippocampus and striatum. Furthermore, using [2-13C]acetate infusion, we showed an alcohol-induced increase in astroglial metabolic activity in the hippocampus and prefrontal cortex. Interestingly, increased astroglia activity in the hippocampus and prefrontal cortex was associated with a differential expression of monocarboxylic acid transporters that are regulating acetate uptake and metabolism in the brain.

In Vivo Threonine Oxidation Rate Is Dependent on Threonine Dietary Supply in Growing Pigs Fed Low to Adequate Levels

Threonine oxidation was examined in 12 growing pigs fed a well-balanced control diet or a threonine-deficient diet supplemented (Glu) or not (LT) with glutamic acid during constant infusion of L-[1-13C]-threonine, [1-14C]glycine and [1-14C]α-ketobutyrate for 10 h. During these infusions, liver glycine enrichment was significantly lower than plasma enrichment. Moreover, the pancreas to plasma glycine enrichment ratio was higher than the liver to plasma ratio (70–89%), showing that an important part of glycine de novo synthesis in pancreas occurred through the threonine dehydrogenase (TDG) pathway. These results imply that calculation of threonine oxidation into glycine should be made with the assumption of both hepatic and extrahepatic oxidation. Plateau values of plasma threonine, glycine and α-ketobutyrate enrichments and specific radio activities allowed estimations of threonine oxidation through the TDG and threonine dehydratase (TDH) pathways. Threonine oxidation into glycine was 12.16 ± 2.06, 2.89 ± 0.61 and 2.13 ± 0.44 µmol/(kg·h), respectively, in pigs fed the control, LT and Glu diets, and threonine oxidation into α-ketobutyrate was 1.80 ± 0.31, 0.88 ± 0.02 and 0.55 ± 0.06 µmol/(kg·h) for the control, LT and Glu groups, respectively. Total threonine oxidation rates were 75 and 81% lower in the LT and Glu groups, respectively, than in the control group. Liver TDG and TDH activity measured in vitro were not affected by either the level of dietary threonine supply the addition of glutamic acid. On the basis of plasma data, it may be concluded that the addition of glutamic acid to a threonine-deficient diet had no significant effect on threonine oxidation but did reduce the rate of threonine release from protein breakdown. Oxidation appears to be related to plasma threonine concentration.

Iron precipitation under controlled oxygen flow: Mineralogical implications for BIF precursors in the Archean ocean

Banded iron formation (BIF) deposition in the Archean ocean is thought to have been initiated by the oxidation of dissolved iron into ferric primary precursor phases that descended through the water column and were deposited on the seafloor. Effective interpretation of the trace element and isotopic composition of BIFs in the geologic record requires an understanding of the identity and longevity of those precursor phases. Temporal and spatial variation in oxidant concentration and ocean chemistry may have driven precursor mineralogy. Furthermore, precursor phases may undergo transitions during descent and burial. This experimental study follows the evolution of iron mineralogy, speciation, and redox state during the precipitation of iron under variable oxygen fluxes and in fluids containing different iron-complexing anions (chloride, sulfate, and phosphate). Additionally, suspensions collected after incomplete oxidation were anoxically aged to simulate changes to precursor mineralogy during descent below the seawater redoxcline.Results from X-ray diffraction, sequential dissolution, colorimetric determination of Fe redox state, and Fe K-edge X-ray absorption fine structure spectroscopy showed that under all experimental conditions, intermediate precipitates collected before complete iron uptake contained mineralized ferrous iron. Purely ferric mineral assemblages were not observed until iron was removed from solution. In low-oxygen experiments, intermediate precipitates contained phases with stoichiometric Fe2+, including magnetite, vivianite, and green rust (GR). Chloride green rust (GR1) had more ferric iron than sulfate green rust (GR2) and more readily transitioned to magnetite via disproportionation. GR2 was stable over a broader range of iron uptake; magnetite appeared mainly as an additional oxidation product in sulfate solution. In high oxygen experiments, mineralized ferrous iron occurred in amorphous phases or as a non-stoichiometric component in ferric oxides; final ferric assemblages were less crystalline than in low-oxygen equivalents.Low concentrations of phosphate increased the total iron oxidation rate, but also increased the ferrous content of intermediate precipitates. The incorporation of phosphate stabilized GR2 and facilitated GR2 precipitation over a larger range of iron uptake. In higher concentrations of phosphate, vivianite and poorly crystalline ferric hydroxides formed in place of GR. These findings suggest that over a range of possible ocean chemistries, mixed-valence phases may have been short lived but relevant precursors to BIF. Additionally, anionic chemistry and oxidant concentration are shown to influence the crystallinity and chemical resistivity of final ferric assemblages, affecting their reactivity during later anoxic burial.

Thermodynamics of oxygen-containing intermediates and their role in coal spontaneous combustion

Oxygen-containing intermediates (OCIs) play an important role in low-temperature oxidation of coal. However, since they are in a dynamic intermediate state, it is difficult to test their thermodynamic properties, and their mechanism of action in coal spontaneous combustion(CSC) are not clear. Therefore, this paper proposed a method to measure the thermodynamics of the OCIs. Furthermore, the reasons for the variation laws of the thermodynamics of the OCIs and their mechanisms of action in CSC were investigated from both macro and micro perspectives. According to the experimental results, thermodynamic parameters of the OCIs can be obtained using the proposed method. And the heating rate of OCIs calculated by the mathematical model based on this method is closer to the total rate of coal oxidation before 70 °C, indicating that OCIs play an important role in the starting process of CSC. Besides, the activation energy of OCIs presents different variation characteristics in different stages. The segmentation can be attributed to the stability of OCIs, which is also critical to the prevention and control of CSC. Hence, the risk of CSC can be reduced by improving the stability of OCIs.

Phenolics in buckwheat hull extracts and their antioxidant activities on bulk oil and emulsions.

Buckwheat hulls are discarded as waste, although they have more phenolic compounds than buckwheat groats. The antioxidant activities of buckwheat hull extracts prepared with water, 50% ethanol, and 100% ethanol were investigated in bulk oil, oil-in-water (O/W), and water-in-oil (W/O) emulsions. The relationship between the phenolic compositions of the extracts and their antioxidant activities in the three different lipid systems was also evaluated. Fifty percent ethanol extract had the highest total phenolic content (327mg gallic acid equivalent [GAE]/g extract) followed by water and 100% ethanol extracts (211 and 163mg GAE/g extract, respectively). The total oxidation rate (k) was not significantly different among the bulk oils added with the buckwheat hull extracts. However, in the O/W emulsion, the k was more reduced by the 50% and 100% ethanol extracts than by the water extract at the concentration of 100µg GAE/g (2.9, 2.8, and 3.7 Totox/day, respectively). The k of the W/O emulsion was more reduced by the 100% ethanol extract than by the water and 50% ethanol extract at the concentration of 100µg GAE/g (3.8, 4.7, and 4.5 Totox/day, respectively). Multivariate statistical analysis revealed that the contents of phenolic acids and their derivatives were the highest in the water extract among the extracts, while the contents of flavonoid glycosides and methylated polyphenols were the highest in the 50% and 100% ethanol extracts, respectively. The results suggest that flavonoid glycosides and methylated polyphenols could be potential candidates for retarding the oxidation of the emulsion system. PRACTICAL APPLICATION: Buckwheat hull extracts could retard lipid oxidation. Flavonoid glycosides and methylated polyphenols in buckwheat hull extracts may have an antioxidative effect on lipids. Thus, buckwheat hulls could be used as an antioxidant in lipid systems, as flavonoid glycosides and methylated polyphenols are properly extracted from buckwheat hulls.

Nitrogen removal performance and bacterial flora analysis of a partial nitrification-anaerobic ammonium oxidation-denitrification system treating rare earth element tailings wastewater

In this study, the start of partial nitrification (activated sludge)-anaerobic ammonia oxidation (immobilized fillers)-denitrification (immobilized fillers) and stable nitrogen removal in the treatment of rare earth element tailings wastewater were explored. The results showed that, at 25–30 °C, partial nitrification could be rapidly established by controlling the combination of average free ammonia concentration (25.4–60.2 mg/L) and dissolved oxygen concentration (0.5 mg/L). Adopting the stepwise substrate (three stages) and shortening hydraulic retention time (HRT) methods, the total nitrogen removal rate of anaerobic ammonia oxidation (anammox) immobilized fillers reached up to 0.99 kg N•(m3•d)−1. Adopting the C/N ratio of 4.5:1 and shorter HRT methods, the total nitrogen removal rate of denitrification immobilized fillers reached up to 1.07 kg N•(m3•d)−1. The activities of the anammox and denitrification immobilized fillers were increased by 8.39 and 4.46 times, respectively. At steady state operation, the average effluent ammonia nitrogen concentration was 3.01 mg/L, with an average effluent total nitrogen concentration of 5.11 mg/L, which met the requirements of the "Emission Standard for Pollutants from Rare Earth Industry" GB 26451–2011. High-throughput sequencing technology showed that the relative abundance ratios of Nitrosomonas and Nitrospira changed from 0.36:1–108.05:1. The dominant bacterial genera of the anammox immobilized fillers was Candidatus Kuenenia, and that of denitrification immobilized fillers were Pseudomonas and Thauera. This process provides a new technical approach for rare earth element tailings wastewater treatment, with high significance in engineering.

Effect of virgin olive oil nanoemulsion combined with ajowan (Carum copticum) essential oil on the quality of lamb loins stored under chilled condition

This survey was conducted to evaluate the impact of virgin olive oil nanoemulsion (ONE) combined with ajowan (Carum copticum) essential oil (AEO) on quality of lamb loin under refrigerated condition. The treatments were control, ONE, ONE + 1% AEO, and ONE + 2% AEO. The treatments caused a delay in growth of mesophilic and psychrotrophic bacteria, Enterobacteriaceae, and lactic acid bacteria during chilled storage. The increasing rate of total volatile nitrogen content, lipid and protein oxidation, metmyoglobin formation, and color deterioration was more retarded in treatment groups. The treatments including ONE + 1% AEO and ONE + 2% AEO were more efficient than ONE alone to delay microbial flora growth, slow down oxidative processes, and improve color in the loins. According to the results of microbial, chemical, and sensory parameters, shelflife of lamb loins was 4 days in control, 8 days in ONE, and at least 16 days in ONE + 1% AEO and ONE + 2% AEO groups. In conclusion, combination of ONE and AEO is appropriate as natural preservative to extend the shelflife of lamb loins stored under chilled condition.

13C-glucose-fructose labeling reveals comparable exogenous CHO oxidation during exercise when consuming 120 g/h in fluid, gel, jelly chew, or coingestion

We examined the effects of carbohydrate (CHO) delivery form on exogenous CHO oxidation, gastrointestinal discomfort, and exercise capacity. In a randomized repeated-measures design [after 24 h of high CHO intake (8 g·kg-1) and preexercise meal (2 g·kg-1)], nine trained males ingested 120 g CHO·h-1 from fluid (DRINK), semisolid gel (GEL), solid jelly chew (CHEW), or a coingestion approach (MIX). Participants cycled for 180 min at 95% lactate threshold, followed by an exercise capacity test (150% lactate threshold). Peak rates of exogenous CHO oxidation (DRINK 1.56 ± 0.16, GEL 1.58 ± 0.13, CHEW 1.59 ± 0.08, MIX 1.66 ± 0.02 g·min-1) and oxidation efficiency (DRINK 72 ± 8%, GEL 72 ± 5%, CHEW 75 ± 5%, MIX, 75 ± 6%) were not different between trials (all P > 0.05). Despite ingesting 120 g·h-1, participants reported minimal symptoms of gastrointestinal distress across all trials. Exercise capacity was also not significantly different (all P > 0.05) between conditions (DRINK 446 ± 350, GEL 529 ± 396, CHEW 596 ± 416, MIX 469 ± 395 s). Data represent the first time that rates of exogenous CHO oxidation (via stable isotope methodology) have been simultaneously assessed with feeding strategies (i.e., preexercise CHO feeding and the different forms and combinations of CHO during exercise) commonly adopted by elite endurance athletes. We conclude that 120 g·h-1 CHO (in a 1:0.8 ratio of maltodextrin or glucose to fructose) is a practically tolerable strategy to promote high CHO availability and oxidation during exercise.NEW & NOTEWORTHY We demonstrate comparable rates of exogenous CHO oxidation from fluid, semisolid, solid, or a combination of sources. Considering the sustained high rates of total and exogenous CHO oxidation and relative lack of gastrointestinal symptoms, consuming 120 g CHO·h-1 appears to be a well-tolerated strategy to promote high CHO availability during exercise. Additionally, this is the first time that rates of exogenous CHO oxidation have been assessed with feeding strategies (e.g., coingestion of multiple CHO forms) typically reported by endurance athletes.

Effect of Toluene Content on Soot Particle Morphology and Evolution in Coflow Diffusion Flames of Diesel Surrogate Fuels

ABSTRACT Toluene is a representative of aromatics in diesel surrogate fuels, and its influence mechanism on the formation and evolution of soot particles has attracted much attention. In this work, the evolution of the microscopic morphology of soot particles in n-heptane laminar diffusion flame doped with toluene of 0% to 30% was investigated experimentally, and the effects of toluene ratio on particle dynamics such as inception, surface growth and oxidation were analyzed numerically. The experimental results showed that as the toluene ratio increases, the primary particle size increases, and the aggregates first grows from short chains to long chains, then develops to multi-branched chains, which results in Df first decreasing and then increasing, reaching the minimum at 10% toluene. The numerical results showed that the peak inception rate increases linearly with the increase of toluene ratio. The peak rate of HACA surface growth increases slightly due to the increase of particles that could provide active sites and reaches the maximum at ratio of 10% toluene, then decreases slightly due to the limited production of H and C2H2. On the other hand, the PAHs condensation rate increases monotonously, which makes the aggregates more likely to form a loose multi-branched chain structure, and in the subsequent oxidation process, the weak points of the connections between the particles are more likely to be oxidized, resulting in the fracture and fragmentation of the aggregates. For particles oxidation, toluene blending has an opposite effect on soot oxidation by O2 and OH. As the toluene ratio increases, the O2 oxidation rate increases gradually due to the increase of soot volume fraction, while the OH oxidation rate decreases due to the inhibited production of OH. However, the total oxidation rate of particles increases with the increase of toluene ratio.

Feeding Tolerance, Glucose Availability, and Whole-Body Total Carbohydrate and Fat Oxidation in Male Endurance and Ultra-Endurance Runners in Response to Prolonged Exercise, Consuming a Habitual Mixed Macronutrient Diet and Carbohydrate Feeding During Exercise.

Using metadata from previously published research, this investigation sought to explore: (1) whole-body total carbohydrate and fat oxidation rates of endurance (e.g., half and full marathon) and ultra-endurance runners during an incremental exercise test to volitional exhaustion and steady-state exercise while consuming a mixed macronutrient diet and consuming carbohydrate during steady-state running and (2) feeding tolerance and glucose availability while consuming different carbohydrate regimes during steady-state running. Competitively trained male endurance and ultra-endurance runners (n = 28) consuming a balanced macronutrient diet (57 ± 6% carbohydrate, 21 ± 16% protein, and 22 ± 9% fat) performed an incremental exercise test to exhaustion and one of three 3 h steady-state running protocols involving a carbohydrate feeding regime (76–90 g/h). Indirect calorimetry was used to determine maximum fat oxidation (MFO) in the incremental exercise and carbohydrate and fat oxidation rates during steady-state running. Gastrointestinal symptoms (GIS), breath hydrogen (H2), and blood glucose responses were measured throughout the steady-state running protocols. Despite high variability between participants, high rates of MFO [mean (range): 0.66 (0.22–1.89) g/min], Fatmax [63 (40–94) % V̇O2max], and Fatmin [94 (77–100) % V̇O2max] were observed in the majority of participants in response to the incremental exercise test to volitional exhaustion. Whole-body total fat oxidation rate was 0.8 ± 0.3 g/min at the end of steady-state exercise, with 43% of participants presenting rates of ≥1.0 g/min, despite the state of hyperglycemia above resting homeostatic range [mean (95%CI): 6.9 (6.7–7.2) mmol/L]. In response to the carbohydrate feeding interventions of 90 g/h 2:1 glucose–fructose formulation, 38% of participants showed breath H2 responses indicative of carbohydrate malabsorption. Greater gastrointestinal symptom severity and feeding intolerance was observed with higher carbohydrate intakes (90 vs. 76 g/h) during steady-state exercise and was greatest when high exercise intensity was performed (i.e., performance test). Endurance and ultra-endurance runners can attain relatively high rates of whole-body fat oxidation during exercise in a post-prandial state and with carbohydrate provisions during exercise, despite consuming a mixed macronutrient diet. Higher carbohydrate intake during exercise may lead to greater gastrointestinal symptom severity and feeding intolerance.

The Effects of an Acute "Train-Low" Nutritional Protocol on Markers of Recovery Optimization in Endurance-Trained Male Athletes.

This study aimed to determine the effects of an acute "train-low" nutritional protocol on markers of recovery optimization compared to standard recovery nutrition protocol. After completing a 2-hour high-intensity interval running protocol, 8 male endurance athletes consumed a standard dairy milk recovery beverage (CHO; 1.2g/kg body mass [BM]of carbohydrate and 0.4g/kg BM of protein) and a low-carbohydrate (L-CHO; isovolumetric with 0.35g/kg BM of carbohydrate and 0.5g/kg BM of protein) dairy milk beverage in a double-blind randomized crossover design. Venous blood and breath samples, nude BM, body water, and gastrointestinal symptom measurements were collected preexercise and during recovery. Muscle biopsy was performed at 0hour and 2hours of recovery. Participants returned to the laboratory the following morning to measure energy substrate oxidation and perform a 1-hour distance test. The exercise protocol resulted in depletion of muscle glycogen stores (250mmol/kg dry weight) and mild body-water losses (BM loss = 1.8%). Neither recovery beverage replenished muscle glycogen stores (279mmol/kg dry weight) or prevented a decrease in bacterially stimulated neutrophil function (-21%). Both recovery beverages increased phosphorylation of mTORSer2448 (main effect of time = P < .001) and returned hydration status to baseline. A greater fold increase in p-GSK-3βSer9/total-GSK-3β occurred on CHO (P = .012). Blood glucose (P = .005) and insulin (P = .012) responses were significantly greater on CHO (618mmol/L per 2h and 3507μIU/mL per 2h, respectively) compared to L-CHO (559mmol/L per 2h and 1147μIU/mL per 2h, respectively). Rates of total fat oxidation were greater on CHO, but performance was not affected. A lower-carbohydrate recovery beverage consumed after exercise in a "train-low" nutritional protocol does not negatively impact recovery optimization outcomes.

Impact of slow versus rapid digesting carbohydrates on substrate oxidation in pre-pubertal children: A randomized crossover trial

Consumption of rapid digesting sugars by children are under increased scrutiny because of their contribution to unhealthy weight gain. Previous studies in adults and children have suggested that altering the blend of carbohydrates (CHOs) consumed may cause shifts in substrate utilization. The purpose of this study was to examine the effects of consuming a slow digesting carbohydrate (SDC) and rapid digesting carbohydrate (RDC) on CHO and fat oxidation, glucose, and insulin responses at rest, during exercise, and post-exercise rest in pre-pubescent children. A randomized, double-blind, crossover design was used. Nineteen pre-pubescent children (n=10 boys, n=9 girls, mean±standard error, age=9.84±0.37-yrs) participated. Visits to the laboratory began with a 30-min measurement of resting metabolism followed by consumption of either an RDC or SDC drink. Postprandial resting metabolism was recorded for 60-min, immediately followed by 60-min of submaximal cycling exercise while metabolism was recorded, which was immediately followed by another 60-min recording of post-exercise metabolism. Total CHO and fat oxidation, endogenous and exogenous CHO oxidation, blood glucose, and insulin were assessed. Total CHO oxidation rate (g∙min-1) was greater after the RDC drink at 60min (p=0.032). Endogenous CHO oxidation rate (g∙min-1) was greater after the SDC drink at 15min (p≤0.010). Cumulative endogenous CHO oxidation (g) was greater after the SDC drink at 45min (p=0.009). Endogenous CHO oxidation accounted for a greater proportion of substrate oxidation after the first 60-min rest period (p=0.028), while exogenous CHO oxidation accounted for a greater proportion of substrate oxidation for the RDC at all time points (p≤0.019). The present study provides novel data suggesting that an SDC promotes greater endogenous substrate utilization in pre-pubertal children, which may have beneficial health impacts on energy intake and carbohydrate regulation/metabolism during growth and development. NCT03185884, clinicaltrials.gov.

Effect of safflower oil nanoemulsion and cumin essential oil combined with oxygen absorber packaging on the quality and shelf-life of refrigerated lamb loins

In this research, we assessed the efficacy of safflower oil nanoemulsion (SNE) and cumin essential oil (CEO) in combination with oxygen absorber (OA) packaging on the quality of lamb loins over 20-day chilled storage. The applied treatments were SNE, OA, SNE + OA, SNE +1% CEO, SNE +1% CEO + OA, and the control. The treatments delayed the growth of mesophilic and psychrotrophic bacteria, Enterobacteriaceae, and lactic acid bacteria during the storage period. The increasing rate of total volatile nitrogen content, lipid and protein oxidation, metmyoglobin formation, and color and sensory deterioration was more retarded in treatment groups. The binary treatments were more efficient than single treatments to postpone microbial growth and retard physicochemical and sensory changes in loin samples, while ternary treatment was the most efficient treatment. Considering various parameters, loins shelf-life was 8 days in control, 12 days in SNE and OA, 16 days in SNE + OA and SNE +1% CEO, and at least 20 days in SNE +1% CEO + OA group. In conclusion, a combination of SNE and CEO followed by OA packaging is the most appropriate treatment to enhance chilled lamb loins' shelf-life.

Algal blooms modulate organic matter remineralization in freshwater sediments: A new insight on priming effect

This study provides a novel insight into the degradation of sediment organic matter (SOM) regulated by algae-derived organic matter (AOM) based on priming effect. We tracked the dynamics of SOM mineralization products and pathways, together with priming effects (PE) using the compound-specific stable isotope (δ13C) technique following addition of low- and high-density algal debris in sediments. We found that algal debris increased the total carbon oxidation rate, and resulted in denitrification and methanogenesis-dominated SOM mineralization. While iron reduction and sulphate reduction played important roles in the early period of algal accumulation. Total carbon oxidation rate and anaerobic rates (Ranaerobic) were higher in the amended treatments compared with that in the control. Analysis indicated that algal debris had a positive PE on SOM mineralization, which caused an intensified mineralization in the initial phase with over 80% of dissolved inorganic carbon deriving from SOM degradation. Total carbon oxidation rate of SOM deduced from priming effect (RTCOR-PE) was similar to Ranaerobic, further indicating SOM mineralization was a critical source of the end products. These findings deviate the causal focus from the decomposition of AOM, and confirm the accumulation of AOM as the facilitator of SOM mineralization. Our study offers empirical evidences to advance the traditional view on the effect of AOM on SOM mineralization.

Response of ammonia‐oxidizing archaea and bacteria to streptomycin sulfate and penicillin in coastal wetlands along the Bohai Rim

Antibiotics are pollutants that are constantly discharged into ocean and coastal wetlands and affect the growth and activity of microorganisms. Ammonia-oxidizing archaea (AOA) and bacteria (AOB), which are very important in the global nitrogen cycle, are affected by antibiotics in the environment as well. Antibiotics have different influences on AOA and AOB microbial communities due to their different biochemical compositions and metabolic mechanisms, which change the ammonia-oxidizing process in different environments. In this study, 62 samples from four typical coastal wetland types along the Bohai Rim were collected and treated with streptomycin sulfate and penicillin in the laboratory. The total ammonia oxidation rate decreased by 61.2–84.0% with streptomycin sulfate and decreased by 50.0–74.5% with penicillin. The significant change in abundance and community structure indicated that AOB were more inhibited than AOA by streptomycin sulfate and penicillin. Nevertheless, ecological network analysis verified that the internal association in the AOA community was more fragile than that in the AOB community. Moreover, the relationship between AOA and other nitrogen-transforming functional archaea weakened in the presence of antibiotics, while AOB established relationships with more nitrogen-transforming functional bacteria in the presence of antibiotics. Streptomycin sulfate had a stronger effect than penicillin due to the different inhibiting mechanisms of these antibiotics and the promotion of interspecific cooperation induced by penicillin in AOA.

No effect of 10 weeks erythropoietin treatment on lipid oxidation in healthy men.

Studies indicate that erythropoietin (EPO) has effect on lipid and energy metabolism; however, the impact of EPO on lipid oxidation in vivo has not been well documented. Here, we evaluate whether long-term erythropoiesis-stimulating agent (ESA) treatment affects the oxidation of plasma very low-density lipoprotein triglycerides (VLDL-TG) fatty acids (FA), plasma free fatty acids (FFA) and non-plasma (residual) FA in healthy, young, sedentary men. Infusion of [1-14C]VLDL-TG and [9,10-3H]palmitate was used in combination with indirect calorimetry to assess resting lipid fuel utilization and kinetics, and resting energy expenditure (REE) before and after 10 weeks of ESA exposure compared with placebo. REE increased significantly during ESA compared with placebo (P = 0.023, RM-ANOVA). Oxidation rates of VLDL-TG FA, FFA, and residual FA remained unchanged during ESA compared with placebo. The relative contribution of the lipid stores was greatest for FFA (47.1%) and the total lipid oxidation rate and was not significantly different between ESA and placebo-treated subjects. We conclude that long-term ESA treatment of healthy young men increases REE but does not alter the oxidation rates of plasma and non-plasma FA sources.

Fast redox kinetics of a perovskite oxygen carrier measured using micro-fluidized bed thermogravimetric analysis

Redox kinetics of oxygen carrier in chemical looping combustion (CLC) is important for reactor design and its oxidation enthalpy is important in order to establish auto thermal demonstration. Most published redox kinetics of oxygen carrier has been measured by thermogravimetric analysis (TGA) which can include additional diffusion limitations and thus underestimate the overall kinetics. In this study, the redox kinetics of a new perovskite oxygen carrier (CaMn0.375Ti0.5Fe0.125O3-δ) was measured by a novel micro-fluidized bed thermogravimetric analysis (MFB-TGA) method which can achieve real-time weight measurement of oxygen carrier in a fluidizing state with similar mass and heat transfer characteristics as in a CLC reactor. The experimental data from MFB-TGA were analyzed with a reactor model. The redox kinetics was described by a two-stage model of gas-solid reaction. The effect of temperature, O2 concentrations and reducing gas type (H2 and CH4) on the redox kinetics in MFB-TGA was investigated and compared with other oxygen carriers such as natural manganese ore and ilmenite. It is observed that the oxidation of both manganese ore and ilmenite can be divided into two stages, a fast initial stage followed by a second slower stage, resulting in slower total oxidation rates. A very interesting finding is that there is only the fast initial stage for the oxygen carrier of CaMn0.375Ti0.5Fe0.125O3-δ, and the full oxidation of CaMn0.375Ti0.5Fe0.125O3-δ can be finished within ∼4 s which is ∼7.5 and ∼30 times faster than that of manganese ore and ilmenite. The reduction kinetics of CaMn0.375Ti0.5Fe0.125O3-δ by H2 is also ∼5 and ∼2.2 times faster than that of manganese ore and ilmenite, respectively. The kinetic parameters of three oxygen carriers were compared and the redox mechanism of CaMn0.375Ti0.5Fe0.125O3-δ was discussed.

Muscle Glycogen Utilization during Exercise after Ingestion of Alcohol.

Ingested ethanol (EtOH) is metabolized gastrically and hepatically, which may influence resting and exercise metabolism. Previous exercise studies have provided EtOH intravenously rather than orally, altering the metabolic effects of EtOH. No studies to date have investigated the effects of EtOH ingestion on systemic and peripheral (e.g., skeletal muscle) exercise metabolism. Eight men (mean ± SD; age = 24 ± 5 yr, body mass = 76.7 ± 5.6 kg, height = 1.80 ± 0.04 m, V˙O2peak = 4.1 ± 0.2 L·min) performed two bouts of fasted cycling exercise at 55% V˙O2peak for 2 h, with (EtOH) and without (control) prior ingestion of EtOH 1 h and immediately before exercise (total dose = 0.1 g·kg lean body mass·h; 30.2 ± 1.1 g 40% ABV Vodka; fed in two equal boluses) in a randomized order, separated by 7-10 d. Muscle glycogen use during exercise was not different between conditions (mean [normalized 95% confidence interval]; EtOH, 229 [156-302] mmol·kg dm, vs control, 258 [185-331] mmol·kg dm; P = 0.67). Mean plasma glucose concentrations during exercise were similar (control, 5.26 [5.22-5.30], vs EtOH, 5.34 [5.30-5.38]; P = 0.06). EtOH ingestion resulted in similar plasma nonesterified fatty acid concentrations compared with rest (control, 0.43 [0.31-0.55] mmol·L, vs EtOH, 0.30 [0.21-0.40] mmol·L) and during exercise. Plasma lactate concentration was higher during the first 30 min of rest after EtOH consumption (mean concentration; control, 0.83 [0.77-0.90] mmol·L, vs EtOH, 1.00 [0.93-1.07] mmol·L), but the response during exercise was similar between conditions. Muscle glycogen utilization was similar during exercise with or without prior EtOH ingestion, reflected in similar total whole-body carbohydrate oxidation rates observed.

Influence of electron acceptor availability and microbial community structure on sedimentary methane oxidation in a boreal estuary

Methane is produced microbially in vast quantities in sediments throughout the world’s oceans. However, anaerobic oxidation of methane (AOM) provides a near-quantitative sink for the produced methane and is primarily responsible for preventing methane emissions from the oceans to the atmosphere. AOM is a complex microbial process that involves several different microbial groups and metabolic pathways. The role of different electron acceptors in AOM has been studied for decades, yet large uncertainties remain, especially in terms of understanding the processes in natural settings. This study reports whole-core incubation methane oxidation rates along an estuarine gradient ranging from near fresh water to brackish conditions, and investigates the potential role of different electron acceptors in AOM. Microbial community structure involved in different methane processes is also studied in the same estuarine system using high throughput sequencing tools. Methane oxidation in the sediments was active in three distinct depth layers throughout the studied transect, with total oxidation rates increasing seawards. We find extensive evidence of non-sulphate AOM throughout the transect. The highest absolute AOM rates were observed below the sulphate-methane transition zone (SMTZ), strongly implicating the role of alternative electron acceptors (most likely iron and manganese oxides). However, oxidation rates were ultimately limited by methane availability. ANME-2a/b were the most abundant microbial phyla associated with AOM throughout the study sites, followed by ANME-2d in much lower abundances. Similarly to oxidation rates, highest abundances of microbial groups commonly associated with AOM were found well below the SMTZ, further reinforcing the importance of non-sulphate AOM in this system.

A 3-day dietary manipulation affects muscle glycogen and results in modifications of carbohydrate and fat metabolism during exercise when hyperglycaemic

The effect of hyperglycaemia on exercise with low and elevated muscle glycogen on glucose utilization (GUR), carbohydrate and fat oxidation, hormonal and metabolite responses, as well as rating of perceived exertion (RPE) were explored. Five healthy trained males were exercised for 90min at 70% V̇O2max in two trials, while glucose was infused intravenously at rates to "clamp" blood glucose at 12mM. On one occasion, participants were 'loaded' with carbohydrate (CHO-L), whilst on a separate occasion, participants were glycogen depleted (CHO-D). Prior exercise and dietary manipulations produced the 'loaded' and 'depleted' states. The CHO-L and CHO-D conditions resulted in muscle glycogen concentrations of 377 and 159mmol/g dw, respectively. Hyperglycaemia elevated plasma insulin concentrations with higher levels for CHO-L than for CHO-D (P < 0.01). Conversely, CHO-D elevated plasma adrenaline and noradrenaline higher than CHO-L (P < 0.05). Plasma fat metabolites (NEFA, β-hydroxybutyrate, and glycerol) were higher under CHO-D than CHO-L (P < 0.01). The resultant was that the rates of total carbohydrate and fat oxidation were elevated and depressed for loaded CHO-L vs CHO-D respectively (P < 0.01), although no difference was found for GUR (P > 0.05). The RPE over the exercise period was higher for CHO-D than CHO-L (P < 0.05). Hyperglycaemia during exercise, when muscle glycogen is reduced, attenuates insulin but promotes catecholamines and fat metabolites. The effect is a subsequent elevation of fat oxidation, a reduction in CHO oxidation without a concomitant increase in GUR, and an increase in RPE.