Maximum Oxidation Rate Research Articles

Synergistic effect of reinforced cellulose nanofibrils/polyethylene glycol embedded particles in ammonia nitrogen wastewater: An in-depth microbial denitrification analysis

The encapsulation and immobilization technology provide a good growth environment for bacteria, strong protection ability, improved survival rate, and resistance to adverse environmental factors. Cellulose nanofibrils (CNF) with polyhydroxyl structure improve the elasticity, tensile properties, mechanical strength and gel strength of embedded particles through non-covalent forces. Polyethylene glycol (PEG) is a water-soluble polymer with unique carbon‑oxygen chain as the core skeleton. The ether bonds present in each unit give PEG extremely strong hydrophilicity and solubility. CNF and PEG to reinforce SA (sodium alginate) and PVA (polyvinyl alcohol)-SA embedded particle were adopted to treat ammonia nitrogen wastewater. The ammonia diffusion coefficients and oxygen diffusion coefficients of the CNF/PEG/SA and CNF/PEG/PVA-SA were 0.454 × 10−9, 0.286 × 10−9, 0.672 × 10−9 and 0.493 × 10−9 m2/s, respectively. The physicochemical properties of embedded particles were characterized by mass transfer characterization, SEM, XRD, FTIR, and BET analysis. The specific surface areas of CNF/PEG/SA and CNF/PEG/PVA-SA increased to 2.583 m2/g and 3.962 m2/g, respectively. The removal efficiency of NH4+-N, COD and TN in the CNF/PEG/PVA-SA system was 90 %, 74 % and 80 % at 30 °C. By HRT 8 h, the removal efficiency of NH4+-N, chemical oxygen demand (COD)and total nitrogen (TN) by the reinforced system was 94.35 %, 63.07 % and 73.84 %, respectively. The neutral to weakly alkaline pH range showed the highest removal efficiencies of NH4+-N, COD, and TN, at 88.51 %, 74.95 %, and 77.56 %, respectively. The half-saturation constant K was 82.98 mg/L, and the maximum ammonia oxidation rate (Vmax) was 358.92 mgN/(L-particles-h). The reinforced system showed zero-order reaction kinetics. Nonlinear fitting of each initial NH4+-N concentration and ammonia oxidation rate was carried out using the Michaelis-Menten equation. In reinforced embedded particles, microbial genomic data (KEGG; MetaCyc database annotation) analysis was conducted. The reinforced system demonstrated enhanced strength, specific surface area, mass transfer properties, resistance to adverse external environmental factors, and microbial survival rate for the effective treatment of NH4+-N wastewater.

Optimize the ratio of immobilized gel materials to improve gel performance and oxygen mass transfer rate: Achieve rapid start-up and efficient and stable operation of partial nitration

A gel filler with diatomaceous earth, activated carbon, and CaCO3 compounded with polyvinyl alcohol was prepared and optimized. Rapid start-up and efficient and stable operation of partial nitrification (PN) was achieved by immobilization of conventional activated sludge. The results showed that the proper material proportion synergistically improved the performance and oxygen mass transfer rate of the gel. The continuous flow reactor was operated for 10d to successfully start PN, and the maximum ammonia oxidation rate of this filler was 58.30 mg·(L·h)−1 during the stable operation, and the nitrite accumulation rate was maintained above 90 %. However, due to the greater mass transfer resistance of unoptimized fillers, more dissolved oxygen waste and nitrogen loss were caused, resulting in delayed expression of biological activity. Based on the kinetic characterization of ammonia-oxidizing bacteria (AOB) within the filler and high-throughput sequencing, it was demonstrated that the rapid start-up and efficient and stable operation of the PN system was due to the highly oxygenophilic and community-dominant position of AOB within this filler. This study provides new options and insights at the level of immobilization technology for the realization and efficient and stable operation of PN.

Effect of nano-graphene lubricating oil on particulate matter of a diesel engine

Nano-graphene lubricating oil with appropriate concentration shows excellent performance in reducing friction and wear under different working conditions of diesel engines, and has been widely concerned. Lubricating oil has a significant impact on particulate matter (PM) emissions. At present, there are few studies on the impact of nano-graphene lubricating oil on the physicochemical properties of PM. In order to comprehensively evaluate the impact of nano-graphene lubricating oil on diesel engines, this paper mainly focused on the effects of lubricating oil nano-graphene additives on the particle size distribution and physicochemical properties of PM. The results show that, compared with pure lubricating oil, the total number of nuclear PM and accumulated PM of nano-graphene lubricating oil is significantly increased. The fractal dimension of PM of nano-graphene lubricating oil increases and its structure becomes more compact. The average fringe separation distance of basic carbon particles decreases, the average fringe length increases. The degree of ordering and graphitization of basic carbon particles are higher. The fringe tortuosity of basic carbon particles decreases, and the fluctuation of carbon layer structure of basic carbon particles decreases. Aliphatic substances in PM are basically unchanged, aromatic components and oxygen functional groups increase. The initial PM oxidation temperature and burnout temperature increase, the maximum oxidation rate temperature and combustion characteristic index decrease, and the activation energy increases, making it more difficult to oxidize. This was mainly caused by the higher graphitization degree of PM of nano-graphene lubricating oil and the increased content of aromatic substances.

Optimized production of invasive animal biochar for arsenic immobilization and methane oxidation in contaminated soils using response surface methodology

The apple snail (Pomacea canaliculata Lamarck) is among the 100 worst invasive alien species worldwide. Apple snail residues discarded during daily management are potential raw materials for biochar production. This study optimized the factors for producing apple snail biochar (ASB) using response surface methodology (RSM) and analyzed the As removal capacity and soil remediation effects of the optimal ASB. The optimal ASB occurred for 348.63 °C pyrolysis temperature, 2.19 h pyrolysis time, and 2.53 Fe3+/Fe2+ molar ratio. For the optimal ASB, the maximum experimental As(III) removal ratio was 98.72%. Temperature and the Fe3+/Fe2+ molar ratio were essential factors affecting the As removal ratio of ASB. The ASB had a rough surface, and As (1.09%) was evident on its surface after adsorption. The As(III) adsorption capacity on ASB was 10.59 mg/g at 288 K, 9.75 mg/g at 298 K, and 11.82 mg/g at 308 K. The As immobilization efficiency in the 3% and 5% ASB treatments exceeded 50% after 15 d. The 5% ASB treatment increased the soil organic matter, total N, available N, total P, and available P content by 120%, 245%, 47%, 62%, and 154%, respectively. Within 15 d, the soil methane oxidation potential peaked at 4.05 μg/g/h in the 5% ASB treatment. The maximum methane oxidation rate occurred after 10 d in the 5% ASB treatment. ASB has multiple benefits for As immobilization, quality improvement, and methane oxidation in soil. This study provides a reference for optimized production and application of invasive animal biochar in contaminated soil.

High efficiency and stable partial nitration achieved via gel immobilization

Long-term high efficiency and stable partial nitrification (PN) performance was achieved using gel-immobilized partial nitrifying bacteria. The PN characteristics of the filler under high and low ammonia nitrogen concentrations and low temperature were comprehensively studied and the rapid reactivation was achieved after reactor breakdown or long stagnation period. The results showed that the maximum ammonia oxidation rate was 66.8 mg•(L•h)−1 and the nitrite accumulation rate was above 95 % for the filler. Efficient and stable PN performance depends on the high abundance of ammonia-oxidizing bacteria (AOB) inside the filler and dynamically microbial community. In addition, the oxygen-limited zone and competition between the microorganisms inside the filler effectively inhibited the growth of nitrite oxidizing bacteria, and the sludge outside the filler assisted in this process, which supported the dominant position of AOB in fillers. This study provides a reliable technology for the practical application of the PN nitrogen removal process.

Influence of gadolinium content on magnetic property and oxidation mechanism of Fe-B-Nb-Gd metallic glass

In this work, we use the rapid solidification technique to prepare five kinds of metallic glasses with different Gd content, and investigate in depth the influences of Gd content on the amorphous formation capability, thermal stability, and magnetic properties of (Fe<sub>73</sub>B<sub>22</sub>Nb<sub>5</sub>)<sub>100–<i>x</i></sub>Gd<sub><i>x</i></sub> (<i>x</i> = 0, 0.5, 1.0, 1.5, 2.0) alloys. By comparing the microstructural morphology and solute distribution of oxidation products before adding Gd and those after adding Gd, the amorphous oxidation mechanism is analyzed systematically. With the addition of Gd, the atomic size difference of the alloys exceeds 13%, and the configuration entropy increases from 7.27 kJ/(mol·K) to 9.44 kJ/(mol·K). The glass-forming ability of the alloy is significantly improved. The increase of Gd content can increase the glass transition temperature of the alloy to 864 K, and the undercooled liquid region can reach 73 K, significantly enhancing the thermal stability of the metallic glasses. The Gd limits the local anisotropy of the alloy and reduces the density of quasi-dislocation dipole defects. This can effectively reduce the pinning sites that hinder the rotation of magnetic domain walls, thereby improving the soft magnetic property. By comparing with the metallic glasses without Gd, only 2% (atomic percentage) Gd can reduce the coercivity by 8%. Moreover, the Gd makes the metallic glasses more sensitive to temperature variation in the oxidation process, and the temperature of the maximum oxidation rate is reduced by 15 K. However, their antioxidant performance does not deteriorate. The Gd atoms are influenced by binding energy and migrate to the surface, forming Gd-rich oxides. They fill surface defects and occupy a large part of the top space, leading to the structure becoming more compact near the surface. This structure reduces the channels for oxygen atoms to diffuse through the microstructure interface, which helps to improve antioxidant capability. This work provides a new approach for designing high performance Fe-based metallic glasses.

Experimental timing of pyrite oxidation under various leaching conditions: consequences for rates of weathering in geological profiles

Pyrite (FeS2) is one of the most abundant sulfides on Earth and has already been studied in numerous ways for decades because of its rapid oxidation and the associated environmental impacts. This study proposes a new experimental physico-chemical approach (air, tridistilled water and water drip exposure) to determine the oxidation rate of pyrite using surface and depth data via XPS (X-ray Photoelectron Spectroscopy) analyses. Our experimental study of almost pure pyrite reveals a maximum oxidation rate of 11.7 ± 1.8 nm day−1 for drip exposure with precipitation of sulfates or Fe-oxides depending on the experimental condition. The oxidation rates obtained under various experimental conditions may be extrapolated to weathering rates of different zones of supergene profiles/ores (leached zone, saprolite and cementation zone). The extrapolation suggests a maximum rate of 4.3 ± 0.6 m Ma−1, which is consistent with data obtained by isotope dating of weathering profiles. Under geological conditions however, the oxidation rate of pyrite may be influenced by additional parameters, such as the nature of the host rock, its porosity/permeability, the climate, the influence of an oxidizing environment, and the mineralization of secondary minerals.

Adverse bioenergetic effects of N-acyl amino acids in human adipocytes overshadow beneficial mitochondrial uncoupling

ObjectiveEnhancing energy turnover via uncoupled mitochondrial respiration in adipose tissue has great potential to improve human obesity and other metabolic complications. However, the amount of human brown adipose tissue and its uncoupling protein 1 (UCP1) is low in obese patients. Recently, a class of endogenous molecules, N-acyl amino acids (NAAs), was identified as mitochondrial uncouplers in murine adipocytes, presumably acting via the adenine nucleotide translocator (ANT). Given the translational potential, we investigated the bioenergetic effects of NAAs in human adipocytes, characterizing beneficial and adverse effects, dose ranges, amino acid derivatives and underlying mechanisms. MethodNAAs with neutral (phenylalanine, leucine, isoleucine) and polar (lysine) residues were synthetized and assessed in intact and permeabilized human adipocytes using plate-based respirometry. The Seahorse technology was applied to measure bioenergetic parameters, dose-dependency, interference with UCP1 and adenine nucleotide translocase (ANT) activity, as well as differences to the established chemical uncouplers niclosamide ethanolamine (NEN) and 2,4-dinitrophenol (DNP). ResultNAAs with neutral amino acid residues potently induce uncoupled respiration in human adipocytes in a dose-dependent manner, even in the presence of the UCP1-inhibitor guanosine diphosphate (GDP) and the ANT-inhibitor carboxyatractylate (CAT). However, neutral NAAs significantly reduce maximal oxidation rates, mitochondrial ATP-production, coupling efficiency and reduce adipocyte viability at concentrations above 25 μM. The in vitro therapeutic index (using induced proton leak and viability as determinants) of NAAs is lower than that of NEN and DNP. ConclusionNAAs are potent mitochondrial uncouplers in human adipocytes, independent of UCP1 and ANT. However, previously unnoticed adverse effects harm adipocyte functionality, reduce the therapeutic index of NAAs in vitro and therefore question their suitability as anti-obesity agents without further chemical modifications.

Higher mitochondrial oxidative capacity is the primary molecular differentiator in muscle of rats with high and low intrinsic cardiorespiratory fitness

ObjectiveCardiorespiratory fitness (CRF) is tightly linked with health and longevity and is implicated in metabolic flexibility and substrate metabolism. The high capacity runner (HCR) and low capacity runner (LCR) rat lines are a genetically heterogeneous rat model selected and bred for CRF that reflect CRF in humans by exhibiting differences in nutrient handling. This study aims to differentiate the intrinsic substrate preference of the HCR compared to LCR rats to better understand the intersection of mitochondrial respiration and intrinsic CRF. MethodsWe performed bulk skeletal muscle RNA-Sequencing on male and female HCR and LCR rats and assessed the effect of rat line on mitochondrial gene expression pathways using the MitoCarta3.0 database. In a separate cohort of rats, mitochondria were isolated from skeletal and cardiac muscle and maximal oxidation rates were measured using an Oroboros O2k when provided either pyruvate or fatty acid substrates. ResultsThe expression of mitochondrial genes are significantly upregulated in HCR skeletal muscle in both male and female rats. In respirometry experiments, fatty acid oxidative capacities were greater in HCR compared to LCR, and male compared to female rats, as a function of both mitochondrial quality and mitochondrial density. This effect was greater in the skeletal muscle than in the heart. Pyruvate oxidation did not differ significantly between lines. ConclusionsThe capacity for increased fatty acid oxidation in the HCR rat is a result of selection for running capacity and is likely a key contributor to the healthy metabolic phenotype of individuals with high CRF.

Impact of temperature on the performance of compost-based landfill biocovers

Methane (CH4) emissions from landfills are a major contributor to global greenhouse gas emissions. Compost-based biocovers offer a viable approach to reduce CH4 emissions from landfills; however, the effectiveness in climates with varying temperatures is not well understood. The methane removal performances of two compost-based biocover materials (food and yard waste compost) were examined under different temperature conditions using laboratory column experiments. A reactive transport model was used to simulate the experimental results to develop a better quantitative understanding of the effect of temperature on overall methane removal efficiency. As expected, experimental results indicated that the oxidation rate was influenced by temperature, as it was reduced when the temperature decreased from 22 °C to 8 °C. However, some oxidation was observed at a lower temperature, which was confirmed by CO2 concentrations above the initial level and the observed temperatures above the exposure temperature along the height of biocover column. Furthermore, results showed that when the compost-based materials were subjected to 8 °C and then increased to 22 °C, methane oxidation within the material recovered quickly and returned to similar oxidation rates as observed before the temperature was reduced, suggesting that compost-based biocovers may not be affected by cyclic temperature variations when used in colder climates. Methane oxidation capacity was limited by the maximum oxidation rate, the biocover porosity, and the gas saturation profile that affects residence time and overall methane oxidation in the columns. The model results show that the CH4 oxidation rate was reduced by one order of magnitude when the temperature decreased from 22 °C to 8 °C. Therefore, the calculated Q10 values were 4.19 and 5.18 for the food and yard waste compost, respectively. Overall, compost-based landfill biocovers, such as food and yard waste compost, are capable of mitigate CH4 emissions from old and small landfills under different temperature conditions.

Discrepancy between predicted and measured exercise intensity for eliciting the maximal rate of lipid oxidation

Background and aimsEctopic lipid storage is implicated in type 2 diabetes pathogenesis; hence, exercise to deplete stores (i.e., at the intensity that allows for maximal rate of lipid oxidation; MLO) might be optimal for restoring metabolic health. This intensity (“Fatmax”) is estimated during incremental exercise (“Fatmax test”). However, in “the field” general recommendations exist regarding a range of percentages of maximal heart rate (HR) to elicit MLO. The degree to which this range is aligned with measured Fatmax has not been investigated. We compared measured HR at Fatmax, with maximal HR percentages within the typically recommended range in a sample of 26 individuals (Female: n = 11, European ancestry: n = 17). Methods and resultsSubjects completed a modified Fatmax test with a 5-min warmup, followed by incremental stages starting at 15 W with work rate increased by 15 W every 5 min until termination criteria were reached. Pulmonary gas exchange was recorded and average values for V˙ o2 and V˙ co2 for the final minute of each stage were used to estimate substrate-oxidation rates. We modeled lipid-oxidation kinetics using a sinusoidal model and expressed MLO relative to peak V˙ o2 and HR. Bland-Altman analysis demonstrated lack of concordance between HR at Fatmax and at 50%, 70%, and 80% of age-predicted maximum with a mean difference of 23 b·min−1. ConclusionOur results indicate that estimated “fat-burning” heart rate zones are inappropriate for prescribing exercise to elicit MLO and we recommend direct individual exercise lipid oxidation measurements to elicit these values.

Activation of the combustion of low-reactivity solid fuels with metal-rolling production waste

The effect of the addition of different amounts of metal-rolling production waste (metal scale in amount of 1–10 wt%) on combustion characteristics of low-reactive solid fuels (anthracite and semi-coke) was studied. XRD analysis of the metal scale identified Fe3O4 and Mn3O4 phases along with a cubic Fe phase. The characteristics of ignition and combustion of the samples were studied via thermal analysis and high-speed video recording at heating medium temperatures of 600–800 °C (with 100 °C step) using a combustion chamber. It was experimentally found that the addition of a metal scale, regardless of its weight content, increases the fuel reactivity, as evidenced by the drop in temperature of the onset of intense oxidation (ΔTi) by 2–32 °C and the decrease in the ignition delay time (Δτi) by 0.2–2.2 s. The metal scale additive also increases the fuel combustion rate, which was evidenced by the maximum rate of oxidation (Δwmax) increasing by 0.1–2.0 wt%/min and, hence, the temperature of the end of oxidation (ΔTf) reducing by 13–68 °C. Due to combustion intensification, the carbon content in ash decreased by 55 rel% on average. The amount of CO and NOx contained in gas-phase combustion products diminished as well.

Inoculation Effect of Methanotrophs on Rhizoremediation Performance and Methane Emission in Diesel-Contaminated Soil.

During the rhizoremediation of diesel-contaminated soil, methane (CH4), a representative greenhouse gas, is emitted as a result of anaerobic metabolism of diesel. The application of methantrophs is one of solutions for the mitigation CH4 emissions during the rhizoremediation of diesel-contaminated soil. In this study, CH4-oxidizing rhizobacteria, Methylocystis sp. JHTF4 and Methyloversatilis sp. JHM8, were isolated from rhizosphere soils of tall fescue and maize, respectively. The maximum CH4 oxidation rates for the strains JHTF4 and JHM8 were 65.8 and 33.8 mmol·g-DCW-1·h-1, respectively. The isolates JHTF4 and JHM8 couldn't degrade diesel. The inoculation of the isolate JHTF4 or JHM8 significantly enhanced diesel removal during rhizoremediation of diesel-contaminated soil planted with maize for 63 days. Diesel removal in the tall fescue-planting soil was enhanced by inoculating the isolates until 50 days, while there was no significant difference in removal efficiency regardless of inoculation at day 63. In both the maize and tall fescue planting soils, the CH4 oxidation potentials of the inoculated soils were significantly higher than the potentials of the non-inoculated soils. In addition, the gene copy numbers of pmoA, responsible for CH4 oxidation, in the inoculated soils were significantly higher than those in the non-inoculated soils. The gene copy numbers ratio of pmoA to 16S rDNA (the ratio of methanotrophs to total bacteria) in soil increased during rhizoremediation. These results indicate that the inoculation of Methylocystis sp. JHTF4 and Methyloversatilis sp. JHM8, is a promising strategy to minimize CH4 emissions during the rhizoremediation of diesel-contaminated soil using maize or tall fescue.

Crystalline multilayer graphene nanoflakes synthesized by catalytic chemical vapor deposition using reduced nanostructured hematite as catalyst precursor and 1,2-dichlorobenzene and benzylamine mixture as carbon source

Carbon solubility in the catalyst for the growth of graphene-type nanomaterials is an essential issue for their large-scale fabrication. Iron compounds are fundamental catalysts for the synthesis of carbon materials. The carbon solubility of ferrite (α-Fe) is ∼0.1% at 700 °C, which is enough to promote the growth of graphene nanomaterials. In this work, we synthesized crystalline multilayer graphene flakes (MLGFs) by a two-step catalytic chemical vapor deposition method using an α-Fe catalyst derived from the reduction of nanostructured hematite at 950 °C under an Ar–H2 environment. In the first step, nitrogen-doped multi-walled carbon nanotubes were synthesized by a benzylamine-ferrocene mixture at 850 °C and oxidized at 620 °C in air. In the second step, the reduced nanostructured hematite was exposed to a mixture of a 1:9 benzylamine-1,2- dichlorobenzene at 950 °C. Raman spectroscopy confirmed the presence of MLGFs with a G band and a significant 2D band intensity. The results of the thermogravimetric analysis show that the maximum oxidation rate was at 643.5 °C. Additional functional density calculations were performed considering graphene growth on the oriented (110) α-Fe surface. This work reasserts the possibility of using alternative carbon sources for graphene growth.

A classical modelling of abandoned mine tailings' bioleaching by an autochthonous microbial culture

The aim of this study was to study and model the bioleaching of abandoned mine tailings at different pulp densities 1–20% w/v by using an autochthonous mesophilic microbial culture. Because of the importance of the ferrous-iron oxidation as sub-process on the bioleaching of sulphide mineral ores, the ferrous-iron oxidation process by the autochthonous microbial culture was studied at different ferrous-iron concentrations. A mathematical model fitted to the experimental results and the main kinetic and stoichiometric parameters were determined, being the most relevant the maximum ferrous-iron oxidation rate 5.1 (mmol Fe2+/mmol C·h) and the biomass yield, 0.01 mmol C/mmol Fe2+, values very similar to that of mixed cultured dominated by Leptospirillum strains. This autochthonous culture was used in the bioleaching experiment carried out at different pulp densities, obtaining a maximum metal recovery in the tests carried out at 1% w/v, recovering a 90% of Cd, 60% of Zn, 30% of Cu, 25% Fe and 6% of Pb. Finally, the different leaching mechanisms were modelled by using the pyrite as ore model obtaining a bioleaching rate of 0.316 mmol Fe2+/(L·h) for the direct mechanisms and a bioleaching rate for the indirect and cooperative leaching mechanisms of 0.055 Fe2+/(L·h).

NIRS-Estimated Muscle Oxidative Capacity And Capillary-To-Fiber Ratio Differs By Sex And Muscle In Endurance Trained Athletes

The relationship between muscle oxidative capacity and muscle diffusing capacity (DmO2), and how this differs among muscles or by sex in endurance trained athletes in vivo is unknown. Estimates of muscle oxidative capacity and capillary-to-fiber ratio (C:F; a mediator of DmO2) can be assessed by near infra-red spectroscopy (NIRS): muscle oxidative capacity is proportional to the recovery rate constant (k) of muscle V̇O2, and C:F is proportional to the change in k (∆k) when tissue saturation (TSI) is reduced. PURPOSE: To determine the role of sex on k and ∆k in the vastus lateralis (VL) and medial gastrocnemius (GS) in endurance trained athletes. METHODS: Twenty-six competitive college-level endurance athletes volunteered: 14 women (20 ± 1 yrs) and 12 men (27 ± 7 yrs). The NIRS assessments were administered using controlled arterial occlusions to maintain TSI in ±5% bands at each of HIGH (averaging 87% of functional range) and LOW (24%) TSI. k was measured in HIGH and ∆k was calculated from the difference in k between HIGH and LOW. RESULTS: k was lower in females than males (mean difference [95% confidence interval]: -0.61[-0.12,-1.08] min-1, p = 0.014, partial ηp2 = 0.13) and lower in VL than GS (-0.83[-0.35,-1.31] min-1, p = 0.001, ηp2 = 0.22), but there was no muscle-by-sex interaction (p = 0.860) (Table). ∆k tended to be greater in females (-0.43[-0.98,0.13] min-1, p = 0.131, ηp2 = 0.05) and in GS (-0.40[0.95,0.16] min-1, p = 0.159, ηp2 = 0.05), but there was no interaction (p = 0.676). CONCLUSIONS: Overall, both GS and VL muscle oxidative capacity was lower in female than male endurance trained athletes with similar training history. We also found that oxidative capacity in medial GS was greater than VL in these endurance-trained athletes. In females, there was a trend towards greater NIRS-derived estimates of C:F, a mediator of DmO2, suggesting potential differential training adaptations in muscle oxidative capacity and DmO2 to achieve maximal myocellular oxidation rates between sexes.

Effect of Sports Energy Drink on Fat Metabolism and Weight Loss of College Students

In order to solve the problem of fat metabolism and weight loss of college students, this paper puts forward a problem of the influence of sports energy drinks. Energy drink is a combination of sports drinks, energy drinks, and other special functional drinks (such as nutrient drinks with added vitamins and minerals; herbal drinks with Chinese herbal ingredients), a general term for a large category of drinks that provide specific health and nutritional functions for special groups of people. With the continuous improvement of people's consumption level and their constant attention to their own health, the consumption of energy drinks is also increasing. Energy drinks have become a new generation of drinks after carbonated drinks, drinking water, fruit and vegetable juice, and tea. At present, the total annual output of beverages in the world exceeds 300 billion liters, and functional beverages have become the fastest growing beverage varieties. Fat is the main energy supply material for endurance sports. The catabolism of fat during sports is the key link for the body to obtain energy. For the general population, abnormal fat metabolism is the main cause of obesity. In this paper, 10 healthy male and female college students without training experience were used to determine the maximum fat metabolism intensity FATmax. Based on this, the exercise prescription of maximum fat oxidation intensity for 8 weeks was formulated. The functional ability, maximum oxygen uptake, body fat percentage, quiet heart rate, blood pressure, and vital capacity before and after the experiment were measured to observe the exercise effect. The fitness effect of maximum fat metabolism intensity was studied to provide theoretical support for college students’ fitness exercise. The study found that there was no significant difference between boys and girls in the maximum fat oxidation rate and FATmax, and girls’ E. C. and running speed corresponding to FATmax were significantly lower than those of boys. After 8 weeks of exercise prescription exercise of maximum fat metabolism intensity, the E. C. and maximum oxygen uptake of boys and girls increased significantly; quiet heart rate, vital capacity index, and body fat percentage were significantly improved; and the changes in girls were more significant than boys. The results show that there is no gender difference in FATmax. The corresponding exercise intensity (7.22 METs for boys and 5.25 METs for girls) and running speed (9.73 km/h for boys and 8.65 km/h for girls) can be used as a reference for formulating college students’ fitness exercise prescriptions. The fitness exercise prescription based on FATmax can improve cardiopulmonary function and body composition, especially for girls. FATmax can be used as a reference standard for formulating fitness exercise prescriptions.

Induced blood oxidation in myocardial revascularization

Background: The use of artificial circulation in surgical myocardial revascularization is one of the key pathogenetic factors in the development of the oxidative stress and systemic inflammatory response in the postoperative period. Aims: the purpose of the study was to describe the dynamics of the induced blood oxidation parameters during coronary artery bypass surgery in the conditions of artificial circulation and on the working heart. Methods: The study included 64 patients who underwent coronary bypass surgery, with 31 (48.4%) on-pump patients and 33 (51.6%) off-pump patients. The oxidative stress simulations were conducted under the in vitro conditions. The blood oxidation-induced values were studied using a biological oxygen monitor. Results: In patients with coronary heart disease, regardless of the choice of the revascularization method (on-pump / off-pump), we observed statistically significantly (p 0.05) higher initial and maximum blood oxidation rates, the oxidative activity factor, and a shorter initiation period than those in healthy volunteers. No significant differences were found by the inter-group comparison analysis both 10 days and 6 months post-surgery. Conclusion: The indicators of induced blood oxidation do not depend on the method of revascularization during coronary bypass grafting (artificial circulation or a working heart). The changes in the parameters indicating activation of the oxidative and antioxidant blood systems may be transient by their nature and occur in the early postoperative period.

Chronic carbohydrate restriction improves endurance capacity and body composition in men and women

This study was designed to test whether adaptation to a CHO-restricted diet affects physical capacity during prolonged exercise. It is hypothesised that chronically reducing an individual’s dietary carbohydrate intake during training will increase their maximal rate of fatty acid oxidation during subsequent exercise compared to a chronic high carbohydrate diet. Thirteen highly trained endurance athletes (eight males, VO2max 66.0 ± 9.5 ml/kg/min, five females VO2max 50.6 ± 8.4 ml/kg/min) consumed a high (>5 g CHO/kg/day) or low (<2 g CHO/kg/day) carbohydrate training diet for four weeks in a randomized cross-over design. Performance was measured after a 24 h high carbohydrate “loading” regime, through a self-paced time trial to complete a fixed workload equivalent to five hours at a workload calculated to elicit 55% VO2max. Although time to completion was not significantly different between diets, the average absolute (watts) and relative (W/kg) power outputs were significantly better on the carbohydrate restricted diet (p = 0.03 and 0.02 respectively). Both sexes responded similarly in terms of performance whilst only women significantly improved body composition when carbohydrate was restricted (p = 0.02). Results from this study highlight that when carbohydrate is restricted during training, trained endurance athletes show improved ultra-endurance performance relative to their body mass.

Enhanced Microbial Oxidation-Neutralization Treatment of Acid Mine Drainage Rich in Ferrous Ions (Fe2+).

In this work, a method of enhanced packed-bed microbial oxidation–neutralization has been employed to treat Fe2+-rich acid mine drainage. The method features the use of a large number of immobile Acidithiobacillus ferrooxidans (A. ferrooxidans) in a bioreactor to promote the oxidation of Fe2+ to Fe3+. Results show that when the influent Fe2+ concentration is about 900 mg/L and the Fe2+ oxidation efficiency tends to 100%, the maximum oxidation rate of Fe2+ in the bio-ceramsite, bio-volcanic stone, and bio-activated carbon packed columns are 301 mg/(L·h), 234 mg/(L·h), and 139 mg/(L·h), respectively. Compared with the direct neutralization method, the enhanced microbial oxidation–neutralization method has several advantages. Firstly, it oxidizes Fe2+ to Fe3+, directly neutralizing the acid mine drainage at low pH and reducing the consumption of neutralizer. Secondly, more economical CaCO3 can be used as neutralizer. Thirdly, it produces precipitates with high solid content (5.50%), good settling performance (SV30 = 4%), and small volume, and the capillary suction time (CST) is 8.9 s, which is easy to dehydrate.