Oxidizer Concentration Research Articles

Synthesis and formation mechanism of PANI nanotubes prepared via facile aqueous solution polymerization

Polyaniline nanotubes were fabricated using itaconic acid as dopant and soft template via facile aqueous solution polymerization. On basis of scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR), the influence of polymerization conditions such as oxidizer/aniline molar ratio and oxidizer concentration on the morphology and chemical structure of PANI was studied. Polyaniline nanotubes with 3D porous network structure were successfully prepared under the optimal conditions. The formation mechanism of PANI nanotubes was thoroughly analyzed by the measurements such as transmission electron microscopy (TEM), 1H nuclear magnetic resonance (NMR), the diffusion ordered spectroscopy (DOSY) and relaxation time (T1 H) measurements. Itaconic acid micelles were used as "soft template" to form self-assembled polyaniline nanostructures. Meanwhile, in the micelles composed of aniline and itaconic acid, the aniline cations initiated by oxidizer free radicals were polymerized into polyaniline with the structure of nanotubes. Furthermore, the formation of polyaniline nanotubes was guaranteed by the double electric layer structure.

Enhanced visible light photo-Fenton catalysis by lanthanum-doping BiFeO3 for norfloxacin degradation

Efficient photo-Fenton removal of antibiotic effluent is a widely followed and significant attempt to deal with the growing environmental pollution. In this study, BiFeO3 and lanthanum doped BiFeO3 catalysts were synthesized via one-step hydrothermal method as hydrogen peroxide activator for mineralization of norfloxacin (NOR). Various characterization measurements were used to verify La was successfully doped into the lattice of perovskite and investigated the effect of La doping molar ratio on BiFeO3 through the characterization of the morphology and physicochemical properties. The degradation experiment and reaction rate constants showed that the La-doped BiFeO3 particle exhibited superior photo-Fenton catalytic performance to undoped BiFeO3. Especially, the degradation efficiency of 15% La-doped BiFeO3 could reach up to 84.94%. And the first order kinetic constant of optimized conditions was 0.01638 min−1, which was about 6.9 times than that of undoped BiFeO3.The influence of pH, oxidizer content and catalyst dosage in photo-Fenton reaction were investigated detailedly. Besides, the synthetic catalyst possessed favorable stability and reusability with little metal leaching after many cycles of use. Radical scavenger experiments and electron spin resonance tests were carried out to conclude that the ·OH and holes were regarded as the dominate active species in the catalytic process. The narrow band gap and excellent electron transfer efficiency were the key factors for La-doped BiFeO3 to have high catalytic efficiency in the photo-Fenton system. Current works demonstrated the great promise of La-doped BiFeO3 in the elimination of antibiotic organics.

Radical chemistry in the Pearl River Delta: observations and modeling of OH and HO2 radicals in Shenzhen in 2018

Abstract. The ambient radical concentrations were measured continuously by laser-induced fluorescence during the STORM (STudy of the Ozone foRmation Mechanism) campaign at the Shenzhen site, located in the Pearl River Delta in China, in the autumn of 2018. The diurnal maxima were 4.5×106 cm−3 for OH radicals and 4.2×108 cm−3 for HO2 radicals (including an estimated interference of 23 %–28 % from RO2 radicals during the daytime), respectively. The state-of-the-art chemical mechanism underestimated the observed OH concentration, similar to the other warm-season campaigns in China. The OH underestimation was attributable to the missing OH sources, which can be explained by the X mechanism. Good agreement between the observed and modeled OH concentrations was achieved when an additional numerical X equivalent to 0.1 ppb NO concentrations was added into the base model. The isomerization mechanism of RO2 derived from isoprene contributed approximately 7 % to the missing OH production rate, and the oxidation of isoprene oxidation products (MACR and MVK) had no significant impact on the missing OH sources, demonstrating further exploration of unknown OH sources is necessary. A significant HO2 heterogeneous uptake was found in this study, with an effective uptake coefficient of 0.3. The model with the HO2 heterogeneous uptake can simultaneously reproduce the OH and HO2 concentrations when the amount of X changed from 0.1 to 0.25 ppb. The ROx primary production rate was dominated by photolysis reactions, in which the HONO, O3, HCHO, and carbonyls photolysis accounted for 29 %, 16 %, 16 %, and 11 % during the daytime, respectively. The ROx termination rate was dominated by the reaction of OH+NO2 in the morning, and thereafter the radical self-combination gradually became the major sink of ROx in the afternoon. As the sum of the respective oxidation rates of the pollutants via reactions with oxidants, the atmospheric oxidation capacity was evaluated, with a peak of 11.8 ppb h−1 around noontime. The ratio of P(O3)net to AOCVOCs, which indicates the yield of net ozone production from VOC oxidation, trended to increase and then decrease as the NO concentration increased. The median ratios ranged within 1.0–4.5, with the maximum existing when the NO concentration was approximately 1 ppb. The nonlinear relationship between the yield of net ozone production from VOC oxidation and NO concentrations demonstrated that optimizing the NOx and VOC control strategies is critical to controlling ozone pollution effectively in the future.

Preparation of mesoporous carbon containing Polyurethane/Clay nanocomposite membrane based sensors for sensitive and selective determination of vitamin D2 in urine samples

Mesoporous carbon containing polyurethane/clay membrane based sensors were produced for the rapid and sensitive electroanalytical determination of fat-soluble vitamin D2. Mesoporous carbon structures were prepared by the carbonization of bee pollens which were easily available in nature. These structures were combined with clay and polyurethane structures. The determination of vitamin D2 with modified electrodes was carried out by using square wave voltammetry in acetonitrile containing 0.1 M LiClO4. According to the response of modified electrode, a linear relationship was obtained between the anodic oxidation peak currents and concentrations of vitamin D2 in the linear concentration range (23 µM − 844 µM) with a low detection limit (0.73 µM) was obtained. The sensitivity (4.65 μA cm−2 μM−1) and reproducibility (RSD%, 1.87 %) of the prepared novel sensor were found to be quite satisfactory. The proposed method and applicability of the electrode were tested in urine samples, achieving dramatic recovery values (99.99 %).

PSXI-6 Effects of a Saccharomyces Cerevisiae Fermentation Product-Supplemented Diet on Circulating Immune Cells and Oxidative Stress Markers of Dogs

Abstract Feeding Saccharomyces cerevisiae fermentation product (SCFP) has previously altered fecal microbiota, fecal metabolites, and immune cell function of adult dogs. The objective of this study was to further measure circulating immune cell numbers and activity, antioxidant status, and oxidative stress marker concentrations of adult dogs fed SCFP in an extruded diet. Sixteen adult pointer dogs (8M, 8F; mean age = 8.35 y; mean BW = 27.13 kg) were used in a randomized crossover design study. All dogs were fed a control diet for 4 wk, then randomly assigned to the control or SCFP-supplemented diet and fed to maintain BW for 10 wk. A 6-wk washout preceded the second 10-wk experimental period with dogs receiving opposite treatments. After baseline/washout and treatment phases, pre- and post-prandial blood samples were collected. Oxidative stress and immune cell function were measured using commercial ELISA kits, circulating immune cell numbers were analyzed using flow cytometry, and mRNA expression of oxidative stress genes were analyzed using RT-PCR. Change from baseline data were analyzed using the Mixed Models procedure of SAS 9.4, with P< 0.05 being significant and P< 0.10 being trends. Changes in unstimulated lymphocytes and stimulated IFN-g secreting T-cells were lower (P< 0.05) in SCFP-fed dogs, while change in stimulated T cells were lower (P< 0.05) in control-fed dogs. The stimulated cytotoxic T cells delta trended lower (P< 0.10) in SCFP-fed dogs. Change in serum superoxide dismutase (SOD) concentrations were higher (P< 0.05) and change in catalase mRNA expression was lower (P< 0.05) in SCFP-fed dogs. All other immune cells, oxidative stress markers, and gene expression were unaffected by treatment. In conclusion, SCFP-fed dogs have increased SOD, which supports lower acute-inflammatory responses and aligns with some immune stimulation data.

Associations between Maternal Dietary Patterns, Biomarkers and Delivery Outcomes in Healthy Singleton Pregnancies: Multicenter Italian GIFt Study.

Background: Maternal nutrition represents a critical risk factor for adverse health outcomes in both mother and offspring. We aimed to investigate associations between maternal nutritional habits, biomarker status, and pregnancy outcome among Italian healthy normal-weight pregnancies. Methods: Multicenter prospective cohort study recruiting Italian healthy normal-weight women with singleton spontaneous pregnancies at 20 ± 2 weeks (T1) in Milan and Naples. All patients underwent nutritional evaluations by our collecting a 7-day weighed dietary record at 25 ± 1 weeks (T2) and a Food Frequency Questionnaire at 29 ± 2 weeks (T3). Maternal venous blood samples were collected at T3 to assess nutritional, inflammatory and oxidative biomarker concentrations (RBCs folate, vitamin D, hepcidin, total antioxidant capacity). Pregnancy outcomes were collected at delivery (T4). General linear models adjusted for confounding factors were estimated to investigate associations between maternal dietary pattern adherence, nutrient intakes, biomarker concentrations and delivery outcomes. Results: 219 healthy normal-weight pregnant women were enrolled. Vitamin D and RBCs folate concentrations, as well as micronutrient intakes, were consistently below the recommended range. In a multi-adjusted model, maternal adherence to the most prevalent ‘high meat, animal fats, grains’ dietary pattern was positively associated with hepcidin concentrations and negatively associated with gestational age at delivery in pregnancies carrying female fetuses. Hepcidin plasma levels were further negatively associated to placental weight, whereas vitamin D concentrations were positively associated to neonatal weight. Conclusions: A high adherence to an unbalanced ‘high meat, animal fats, grains’ pattern was detected among Italian normal-weight low-risk pregnancies, further associated with maternal pro-inflammatory status and gestational age at delivery. This evidence underlines the need for a dedicated nutritional counseling even among low-risk pregnancies.

Effects of a Saccharomyces cerevisiae fermentation product-supplemented diet on circulating immune cells and oxidative stress markers of dogs.

Feeding Saccharomyces cerevisiae fermentation product (SCFP) has previously altered fecal microbiota, fecal metabolites, and immune function of adult dogs. The objective of this study was to investigate measures of skin and coat health, changes in circulating immune cell numbers and activity, antioxidant status, and oxidative stress marker concentrations of healthy adult dogs fed a SCFP-supplemented extruded diet. Sixteen adult English Pointer dogs (8 M, 8 F; mean age = 6.7 ± 2.1 yr; mean BW = 25.9 ± 4.5 kg) were used in a randomized crossover design study. All dogs were fed a control diet for 4 wk, then randomly assigned to either the control or SCFP-supplemented diet (0.13% of active SCFP) and fed to maintain BW for 10 wk. A 6-wk washout preceded the second 10-wk experimental period with dogs receiving opposite treatments. After baseline/washout and treatment phases, skin and coat were scored, and pre and postprandial blood samples were collected. Transepidermal water loss (TEWL), hydration status, and sebum concentrations were measured (back, inguinal, ear) using external probes. Oxidative stress and immune cell function were measured by ELISA, circulating immune cell percentages were analyzed by flow cytometry, and mRNA expression of oxidative stress genes was analyzed by RT-PCR. Change from baseline data was analyzed using the Mixed Models procedure of SAS 9.4. Sebum concentration changes tended to be higher (P < 0.10; inguinal, ear) in SCFP-fed dogs than in controls. TEWL change was lower (P < 0.05) on the back of controls, but lower (P = 0.054) on the ear of SCFP-fed dogs. Delayed-type hypersensitivity response was affected by diet and time post-inoculation. Other skin and coat measures and scores were not affected by diet. Changes in unstimulated lymphocytes and stimulated IFN-γ secreting T cells were lower (P < 0.05) in SCFP-fed dogs, while changes in stimulated T cells were lower (P < 0.05) in control-fed dogs. Upon stimulation, the percentage of cytotoxic T cells delta trended lower (P < 0.10) in SCFP-fed dogs. Change in serum superoxide dismutase concentrations was higher (P < 0.05) and change in catalase mRNA expression was lower (P < 0.05) in SCFP-fed dogs. All other measurements of immune cell populations, oxidative stress markers, and gene expression were unaffected by treatment. In conclusion, our data suggest that SCFP positively impacts indicators of skin and coat health of dogs, modulates immune responses, and enhances some antioxidant defense markers.

The outcome of ketogenic diets on the liver and the protecting role of atorvastatin: A histological, immunohistochemical and ultrastructural study

The current study investigated structural and functional modifications of the liver following long-term ketogenic diet (KD) and every-otherday ketogenic diet (EODKD) usage. The probable role of atorvastatin (ATO) in the adjustment process was also investigated. It was carried out on 24 Sprague-Dawley rats, which were divided into four groups: control, KD, EODKD, and ATO. Various biochemical, histological, and immunohistochemical analysis were performed on the liver. The blood was tested for aspartate aminotransferase (AST), alanine aminotransferase (ALT), triglycerides, cholesterol, inflammatory markers, Bax, BCL2, NLRP3 inflammasome, and oxidative stress markers. KDs induced damages to the liver mainly due to oxidative stress (increase TBARS, MDA/decrease SOD/GSH) and inflammation. In addition, the hepatic triglycerides and cholesterol levels are decreased. The KD group was worse off than the EODKD group. ATO administered concurrently with KD preserved liver architecture, reduced oxidative stress, normalized NLRP3, and further reduced intrahepatic triglycerides and cholesterol levels. Both KD and EODKD cause structural liver damage that is accompanied by an elevation of hepatic markers (AST and ALT) and a decrease in hepatic triglycerides, hepatic cholesterol, and serum cholesterol. KD has a more destructive effect. Oxidative stress, inflammation, and high fat concentrations are contributing factors to hepatic injury in these diets. ATO with KD is beneficial.

Ultrasonic-assisted stewing enhances the aroma intensity of chicken broth: A perspective of the aroma-binding behavior of fat

This experiment investigated the underlying mechanism of ultrasonic-assisted stewing to enhance the aroma intensity of chicken broth by measuring fat content, oil droplet sizes, zeta potential, viscosity, surface protein loading, lipid oxidation, and aroma compound concentrations. As the thermo-ultrasound time increased, the fat content increased from 0.3 % to 1.2 %, resulting in a milky white appearance. After 1 h of thermo-ultrasound, the broth had the smallest particle size and the highest surface protein load, viscosity, and emulsion stability, as well as the highest total amount of aroma-active compounds of 314.70 ng/mg. With the further extension of thermo-ultrasound time, lipid oxidation increased, but the stability of chicken broth decreased, lowering the content of aroma-active compounds. These outcomes suggested that thermo-ultrasound could enhance the aroma intensity of chicken broth by increasing the fat content and the emulsion stability of the broth.

Activation of periodate using ultrasonic waves and UV radiation for landfill leachate treatment.

In the present work, saline leachate of the Bushehr coastal city (Iran) was purified using the ultraviolet/ultrasonication wave/periodate process. The initial TDS and TOC values of the leachate studied were 7390mg/L and 975mg/L, respectively. During the effect of various parameters on leachate purification, the experiments were optimized at pH 3, oxidizer concentration of 4mM, and treatment time of 120min. The initial BOD5/COD ratio of 0.66 was reduced to 0.42 at the end of the purification time (120min). After leachate treatment under optimal conditions, the amount of BOD5, COD, and UV254 were 451.5mg/L, 1072mg/L, and 12.69cm-1, respectively. Concentrations of heavy metals in crude leachate by ICP-OES were checked. Also, the concentration of organic compounds before and after purification was determined using GC-Mass. The leachate purification kinetics followed the first-order model using the designed method. Based on the COD factor, the system energy consumption for leachate treatment was calculated to be 11.4 kWh/m3. The results showed that the system explored (UV/US/IO4-) can effectively purify high salinity waste leachate.

Comparative Studies of Photochemical and Electrochemical Methods on Mineralization of Picric Acid

The effluents generated from synthesis and processing plant of Picric acid is reported to be carcinogenic and hence needs to be treated to reduce its concentration below safe discharge limit. Present paper deals with studies on mineralization of Picric acid by adopting photochemical and electrochemical processes and the efficacy of the both processes have been explored in details. Crucial process parameters viz. pH, concentration of oxidizer and catalyst for mineralization of Picric acid are optimized. In photochemical method, It is observed that Picric acid is treated to bring down its concentration from 100 ppm to ≤ 1 ppm under Photo-Fenton process in 2 hrs whereas same treatment carried out under Photo- catalytic process takes only 1 hr. It is also observed that TiO2 xerogel and beads of nano-TiO2 are more efficient compared to that of commercially available TiO2. The TiO2–Polysulfone (PS) beads show less efficiency than TiO2 xerogel. However, the Picric acid oxidation efficiency for TiO2–PS beads is comparable and advantage of TiO2–PS beads is that it can easily be recovered from the treated solution and can be reused in the next experiments. Electrochemical process is user’s friendly and economical. In case of electrochemical treatments at optimized process parameters under Electro-Fenton reaction picric acid is completely mineralized below its drain discharge limit where as under Electro-peroxide reaction picric acid is mineralized upto 3 ppm within 3 hrs. The treated solution has been characterized by using UV-Visible spectrophotometer, High performance Liquid Chromatography (HPLC) and Total Organic Carbon (TOC) Analyzer. The observed results have been interpreted and reported in the present paper.

Oxidative Stress in the Oral Cavity before and After Prosthetic Treatment

BACKGROUND: Metal ions emitted from dental alloys may induce oxidative stress leading to numerous pathological changes. Lipid peroxidation may cause disturbance of structure and function of cell membranes, apoptosis, autophagy, and formation of potentially mutagenic compounds. Products of interaction between reactive oxygen species and biomolecules may be used for evaluation of oxidative stress level. AIM: The aim of this study was to evaluate the influence of the prosthetic dental treatment with metal ceramic restorations on the level of oxidative stress in the oral cavity. MATERIALS AND METHODS: Metal ceramic crowns with copings fabricated by direct metal laser sintering were produced for 35 patients. CoCr dental alloy EOS CobaltChrome SP2 (EOS) was used. Non-stimulated and stimulated saliva samples were collected from the patients before and after the prosthetic treatment. For evaluation of oxidative stress concentration of 8-isoPGF2-alpha was measured by liquid chromatography tandem mass spectrometry. For statistical processing, non-parametric Wilcoxon signed-rank test and Mann–Whitney test were applied. RESULTS: The concentration of isoprostane 8-isoPGF2-alpha in non-stimulated saliva was lower 2 h after fixing the crowns compared to the initial level and statistically significant difference was observed. On the 7th day the concentration of isoprostanes remained significantly lower than the initial one. No significant differences were found in isoprostane concentration in stimulated saliva before and after prosthetic treatment. CONCLUSION: Prosthetic dental treatment leads to decrease in oral oxidative stress.

Dicarboxylated hyaluronate: Synthesis of a new, highly functionalized and biocompatible derivative

Sequential periodate-chlorite oxidation of sodium hyaluronate to 2,3-dicarboxylated hyaluronate (DCH), a novel biocompatible and highly functionalized derivative bearing additional pair of COOH groups at C2 and C3 carbons of oxidized ᴅ-glucuronic acid units, is investigated. The impact of various reaction parameters (time, oxidizer concentration, and molar amount) on DCH's composition, molecular weight, degree of oxidation, and cytotoxicity are investigated to guide the synthesis of DCH derivatives of desired properties. Subsequently, fully (99%) and partially (70%) oxidized DCH derivatives were compared to untreated sodium hyaluronate in terms of anticancer drug cisplatin loading efficacy, carrier capacity, drug release rates, and cytotoxicity towards healthy and cancerous cell lines. DCH derivatives were found to be superior in every aspect, having nearly twice the carrier capacity, significantly slower release rates, and higher efficacy. DCH is thus a highly interesting hyaluronate derivative with an adjustable degree of oxidation, molecular weight, and great potential for further modifications.

Computational Study on Parametric Variation with Solar Heat Induction of an Entrained Flow Gasifier

Gasification has played an important role in the sustainable use of waste biomass, providing useful combustible gases in the process. Gasification has an important role in waste management and promotes energy independence for many oil-deficit countries. The gasification process has been studied by various researchers, and improvements have been achieved in its sub-processes such as devolatilization, feed input methods, and so on. We examined the influence of gasifier operation parameters, such as oxidizer content, moisture content in the feedstock, and solar flux input inside the gasifier, on the temperature distribution, velocity distribution, and product gas yields of the gasifier. The results indicate that inducing solar energy at different stages of the gasifier leads to different yields of product gas composition (CO and H2).

Understanding the Dynamics of the Transient and Permanent Opening Events of the Mitochondrial Permeability Transition Pore with a Novel Stochastic Model.

The mitochondrial permeability transition pore (mPTP) is a non-selective pore in the inner mitochondrial membrane (IMM) which causes depolarization when it opens under conditions of oxidative stress and high concentrations of Ca2+. In this study, a stochastic computational model was developed to better understand the dynamics of mPTP opening and closing associated with elevated reactive oxygen species (ROS) in cardiomyocytes. The data modeled are from “photon stress” experiments in which the fluorescent dye TMRM (tetramethylrhodamine methyl ester) is both the source of ROS (induced by laser light) and sensor of the electrical potential difference across the IMM. Monte Carlo methods were applied to describe opening and closing of the pore along with the Hill Equation to account for the effect of ROS levels on the transition probabilities. The amplitude distribution of transient mPTP opening events, the number of transient mPTP opening events per minute in a cell, the time it takes for recovery after transient depolarizations in the mitochondria, and the change in TMRM fluorescence during the transition from transient to permanent mPTP opening events were analyzed. The model suggests that mPTP transient open times have an exponential distribution that are reflected in TMRM fluorescence. A second multiple pore model in which individual channels have no permanent open state suggests that 5–10 mPTP per mitochondria would be needed for sustained mitochondrial depolarization at elevated ROS with at least 1 mPTP in the transient open state.

Gold Adsorption from Pregnant Thiocyanate Solution Using Activated Carbon

Gold adsorption from dissolution of gold ore concentrate at Tanggamus mine using activated carbon from thiocyanate leached solution was investigated in this research. As the pollution of the environment has been raising accordingly with the increasing of cyanidation, thiocyanate is becoming current alternative and less toxic reagent in terms of gold dissolution. However, the research was still limited. The development and implementation of thiocyanate in gold extraction is the core of this research. Solvent and oxidizer concentrations (KSCN and FeCl3) were used in this study with 0.3 M and 0.1 M of concentration, respectively. Adsorption process was carried out for 4 hours using 100 ml of filtrate with activated carbon addition. Adsorption of thiocyanate complex gold compounds was studied by varying the size of activated carbon, the concentration of activated carbon, and the rotary speed of bottle roll. At-10+20# of activated carbon size, the %-adsorption obtained was 93.65%. Meanwhile, 94.31% of gold adsorption was achieved with the concentration of activated carbon at 1500 mg/l and 93.37% of gold adsorption was reached with the rotary speed of 150 rpm. Pseudo second order was applied to calculate the kinetics of gold adsorption with the R2 value obtained was 0.9999.

Is the Energy Cost of Rowing a Determinant Factor of Performance in Elite Oarsmen?

In elite oarsmen, the rowing ergometer is a valuable tool for both training and studying rowing performance determinants. However, the energy cost of rowing, often reported as a determinant of performance, has never been described for ergometer rowing. Therefore, this study aimed to characterize the energy cost of ergometer rowing (ECR) in elite oarsmen, its contribution to 2,000 m performance, and its determinants. This study was conducted on 21 elite oarsmen from the French national team. It included an incremental exercise test up to exhaustion and an all-out performance test over 2,000 m, both conducted on a rowing ergometer. Gas exchange analysis was performed to calculate oxygen uptake and substrate utilization rate. Whole blood lactate concentrations during the incremental test were obtained from the earlobe. During the incremental test, ECR displayed a significant linear increase up to a plateau that reached a mean rowing speed of 5.23 ± 0.02 m⋅s–1. The ECR values at 300, 350, and 400 W were positively correlated with performance expressed as the time required to perform the 2,000 m distance on the rowing ergometer. The same ECR values were found to be significantly related to fat oxidation (expressed in percentage of total energy supply) and blood lactate concentrations. This study provides the first description of ECR and of its relationship to exercise intensity on the rowing ergometer in elite oarsmen. ECR appeared to be a factor of performance and interestingly was related to energy supply from fat and blood lactate concentrations.

Combustion characteristics of aluminum particle jet flames in a hot co-flow

Aluminum(Al) powder has been proposed as a promising dense energy carrier to store and transport abundant renewable power for a future carbon-neutral society. In this work, a detailed model for simulating Al particle cloud combustion with multiple oxidizers in the context of large eddy simulation is developed. The Al particles are tracked in the lagrangian framework with various sub-models including phase change, heterogeneous surface reaction, evaporation and radiation. The model is then employed to simulate turbulent jet flames with Al particles(d32=25μm) in a hot co-flow. Tunable diode laser absorption spectroscopy(TDLAS) is used to measure the temperature and H2O distribution. The present model is first validated by comparing the predicted condensed Al2O3 distribution with the measured Mie scattering signals. The results indicate that the simulation results are in good agreement with the experimental measurements. Further comparisons of the temperature and H2O profile are then conducted. The numerical simulation predicts weaker mass and heat transport in the upstream and middle of the flame along the centerline of the burner, compared with the reconstructed TDLAS results, but the downstream scalar profiles of the jet flame agree well with the measurements. Discrete characteristics are observed in the simulated instantaneous temperature and condensed Al2O3 snapshots, which are due to the nature of heterogeneous combustion of metal fuel particles under fuel-lean conditions. Finally, the influence of the oxidizer mole fraction and the initial temperature of the primary jet on the ignition distance is analyzed. The results demonstrate that the ignition distance can be decreased effectively by increasing the oxidizer concentration of the hot co-flow or the initial temperature of the Al particles and carrier gas.

Oxidative stress biomarkers and free amino acid concentrations in the blood plasma of moderately exercised horses indicate adaptive response to prolonged exercise training.

Oxidative stress caused by routine physical stressors may negatively impact the performance of equine athletes; thus, the present study identifies oxidative biomarkers in the blood plasma of exercising horses. Stock-type horses were subject to a standardized moderate-intensity exercise protocol 3 times per week for 8wk. Exercise protocol followed NRC guidelines consisting of 30% walk, 55% trot, and 15% canter, with a target heart rate (HR) of 90 BPM. Blood plasma was collected in wk 1, 2, 7, and 8 immediately before and 0, 30, 60, and 90min after exercise and analyzed for total antioxidant capacity (TAC), thiobarbituric acid reactive substance (TBARS), glutathione peroxidase activity (GPx), and superoxide dismutase activity (SOD). Data were analyzed as repeated measures with wk, d, time, and their interactions as fixed effects. The TAC on day 2 (0.40mM Trolox) was 7.5% greater than on day 3 (P = 0.013). There were wk × d × time interactions for SOD, TBARS, and GPx (P < 0.001). The TBARS remained at pre-exercise baseline (d-1 wk-1; 2.7 µM malondialdehyde) for most collection times within weeks 1, 7, and 8 (P ≥ 0.058); however, TBARS increased by 0.24 to 0.41 µM on day 2 of week 2 post-exercise (P < 0.001) and remained similarly elevated on day 3 pre- and immediately post-exercise (P < 0.001). The GPx similarly remained at baseline (172.6 µM/min; P ≥ 0.621) but increased by 48.18 to 83.4 µM/min at most collection times on days 1 and 2 of week 2 (P ≤ 0.023). The SOD remained at baseline (167.2 U/ mL; P ≥ 0.055) until increasing by 11.28 to 15.61 U/mL at 30min post-exercise on day 1, week 1 and at most collection times on day 3, week 8 (P ≤ 0.043). Amino acids with antioxidant properties such as Met, Tyr, and Trp drastically decreased from weeks 2 to 8 (P < 0.001). Met and Tyr also decreased from -60 to 90min (P < 0.047), whereas there was no time effect on Trp concentration (P = 0.841). The current study indicates the time-dependent nature of oxidative stress concerning persistent stressors such as exercise.

The association between urinary glyphosate and aminomethyl phosphonic acid with biomarkers of oxidative stress among pregnant women in the PROTECT birth cohort study

BackgroundGlyphosate is a widely used herbicide in global agriculture. Glyphosate and its primary environmental degradate, aminomethyl phosphonic acid (AMPA), have been shown to disrupt endocrine function and induce oxidative stress in in vitro and animal studies. To our knowledge, these relationships have not been previously characterized in epidemiological settings. Elevated urinary levels of glyphosate and AMPA may be indicative of health effects caused by previous exposure via multiple mechanisms including oxidative stress. MethodsGlyphosate and AMPA were measured in 347 urine samples collected between 16 and 20 weeks gestation and 24–28 weeks gestation from pregnant women in the PROTECT birth cohort. Urinary biomarkers of oxidative stress, comprising 8-isoprostane-prostaglandin-F2α (8-iso-PGF2α), its metabolite 2,3-dinor-5,6-dihydro-15-F2 t-isoprostane (8-isoprostane metabolite) and prostaglandin-F2α (PGF2α), were also measured. Linear mixed effect models assessed the association between exposures and oxidative stress adjusting for maternal age, smoking status, alcohol consumption, household income and specific gravity. Potential nonlinear trends were also assessed using tertiles of glyphosate and AMPA exposure levels. ResultsNo significant differences in exposure or oxidative stress biomarker concentrations were observed between study visits. An interquartile range (IQR) increase in AMPA was associated with 9.5% (95% CI: 0.5–19.3%) higher 8-iso-PGF2α metabolite concentrations. Significant linear trends were also identified when examining tertiles of exposure variables. Compared to the lowest exposure group, the second and third tertiles of AMPA were significantly associated with 12.8% (0.6–26.5%) and 15.2% (1.8–30.3%) higher 8-isoprostane metabolite, respectively. An IQR increase in glyphosate was suggestively associated with 4.7% (−0.9 to 10.7%) higher 8-iso-PGF2α. ConclusionsUrinary concentrations of the main environmental degradate of glyphosate, AMPA, were associated with higher levels of certain oxidative stress biomarkers. Associations with glyphosate reflected similar trends, although findings were not as strong. Additional research is required to better characterize the association between glyphosate exposure and biomarkers of oxidative stress, as well as potential downstream health consequences.