Concentration Of Free Radicals Research Articles

Heating of consumer cannabis oils can lead to free radical initiated degradation, causing CBD and THC depletion

Commercial cannabis oil products are widely available in Canada even though there is a significant gap in scientific information regarding them. Oils, such as vegetable oils, are known to undergo oxidative changes through free radical mechanisms when they are heated or aged, but the cannabis oils used in this study did not have expiry dates or best-before usage dates. This led to the question of how these products would be affected with time. We hypothesized that cannabis oils would produce increased concentrations of free radicals in aging-simulated conditions, which would be related to a decrease in cannabidiol (CBD) or Δ9-tetrahydrocannabinol (THC) content.Cannabis oils and their respective vehicles (oils) were heated using two protocols: One (moderate aging method) used a 2-day heating protocol at 50 °C, and the other (enhanced aging method) used a 14-day heating protocol at 70 °C. We used electron paramagnetic resonance (EPR) spectroscopy for free radical analysis using the spin trapping technique using 200 mM PBN and 0.02 mM CuCl2 (for peroxide breakdown to free radicals). For active ingredient analysis (CBD, THC), we used LC/MS.Cannabis oils that contained unsaturated oils as their vehicles, such as olive or sunflower oil, all showed varying degrees of free radical formation. In both aged and unaged oils containing CBD or THC, less free radical formation was detected compared to the vehicle controls. Cannabis oils using medium-chain triglycerides (MCT) showed little or no free radical formation. The most significant decrease in CBD or THC was observed in the products using sunflower oil, to a lesser extent in MCT oil, and THC also decreased in olive oil.These findings are important for consumers and policymakers considering using such products in hot beverages or cooking and highlighting the importance of appropriate storage conditions.

Study on the mechanism of free radical scavenger TEMPO blocking in coal oxidation chain reaction

The inhibitory effect of free radical scavenger 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) on the spontaneous combustion process of coal has been experimentally confirmed. However, the mechanism of free radical trapping in coal by TEMPO is not clear. This paper revealed the mechanism of free radical capture in coal by TEMPO from three perspectives by quantum chemistry method, including capture radicals directly, regenerative cycle chain and hydrogen transfer. It was regarded as a beginning that the formation of free radicals (R-CH2∙, CH3∙) by breaking alkane groups in the side chain of the coal molecule. The oxidation process of these free radicals was analyzed and the capturing models of radicals were described. The thermodynamic data for reactions (R2 ∼ R5) are calculated to reveal the initial reaction process of coal. The adsorption energy and thermodynamic data for reactions (Process1 ∼ 4, R6 ∼ R10, R12 ∼ R13) are computed to illustrate spontaneity and difficulty of traps free radicals by TEMPO. The results indicate that the initial reaction (R2, R4) of free radicals with oxygen in coal is exothermic and some other reactions (R3, R5) need to overcome large reaction energy barriers. TEMPO can capture free radicals in coal directly, reducing the concentration of free radicals, and is most effective in capturing ∙OH and alkyl radicals. At the same time, TEMPO can capture peroxide radicals and alkyl radicals in coal through regenerative cycle chains and keep reborn to maintain the efficiency of its capture. For coals under acidic conditions, TEMPO can bind to H+ first, then transfers hydrogen with oxygen-containing radicals in the coal. This process is prone to occur due to the presence of hydrogen bonds. In future applications, the pH value of TEMPO can be appropriately reduced to enhance the effect of capturing free radicals in coal.

Degradation of Chloroquine Phosphate by UV-activated Persulfate

The degradation of chloroquine phosphate (CQP), an anti-COVID-19 drug, was investigated in a UV-activated persulfate system (UV/PS). The second-order rate constants of CQP with hydroxyl radicals (HO·) and sulfate radicals (SO4-·) were determined using a competition kinetics experiment, and the effects of persulfate concentration, pH, and inorganic anions on the degradation of CQP were also systematically studied. Furthermore, a kinetic model was established to predict the concentration of CQP and major free radicals to explore its mechanism of influence. The results showed that the degradation efficiency of CQP could reach 91.3% after 10 min under UV/PS, which was significantly higher than that under UV, sunlight, or PS alone. At pH=6.9, the second-order rate reaction constants of CQP with HO· and SO4-· were 8.9×109 L·(mol·s)-1and 1.4×1010 L·(mol·s)-1, respectively, and the main active species was SO4-·. The degradation rate of CQP increased with increasing concentrations of PS and decreased with the addition of HCO3- and Cl-. The removal efficiency of CQP was inhibited under stronger alkaline conditions. N-de-ethylation, cleavage of the C-N bond, and hydrogen abstraction were proposed as the principal pathways of CQP degradation based on LC-MS analysis. The mineralization rate of CQP could be improved by increasing PS concentration and pH values. This study could be helpful for the treatment of anti-COVID-19 pharmaceutical wastewater.

Experimental study on inhibition of spontaneous combustion of different-rank coals by high-performance m-Cresol water-based inhibitor solutions

A kind of simple and efficient m-Cresol water-based inhibitor was proposed. The inhibitory effects of its solutions on the spontaneous combustion of different-rank coals were discussed. Furthermore, the micromorphology and wetting characteristics of different-rank coals were analyzed through a scanning electron microscope and a contact angle meter, respectively. Besides, the weight loss rates, oxidation characteristics, pore structure characteristics and free radical changes of different coal samples were investigated by a thermogravimetric analyzer, temperature-programmed experiments, a surface area analyzer and an electron spin resonance spectrometer, respectively. The results indicate that the prepared inhibitor solution at the 0.3 wt% sodium dodecyl sulfate (SDS) not only boasts good emulsification and wetting performance, but also plays a role in permeability enhancement. The m-Cresol/SDS solution can wet the coal surface and permeate the inner pore surface, forming a uniform inhibitor layer on both the coal surface and the inner pore surface to isolate oxygen, retain water and inhibit free radical generation. Moreover, it can not only effectively reduce the weight loss rate, CO production, specific surface areas and free radical concentration in the oxidation process of CoalXLH, CoalBLT and CoalYQ, but also improve the inhibition rate (to 79.1%, 67.4% and 54.3% at 170 °C respectively).

The influence of methane on the development of free radical during low-temperature oxidation of coal in gob

Methane dilutes the oxidation environment of coal in the gob, thus affecting the free radical reaction in low-temperature oxidation of coal. To investigate methane’s effects in this process, three coal samples (i.e., anthracite, coking coal, gas-fat coal) were non-isothermally oxidized to different temperatures in methane-containing environments and then analyzed in an electron paramagnetic resonance (EPR) spectrometer. The experimental results demonstrate that the g-factor and free radical concentration were not only related to oxygen but also associated with methane in the oxidation environment. The g-factor grew with the rising methane and the oxidation temperature. With the rising methane, the free radicals of the anthracite changed from carbon-centred radicals to carbon-centred radicals with an adjacent oxygen atom. Besides, the free radical concentration was found to decrease with methane and increase with oxidation temperature. The rising methane restrains the increase of free racial concentration during coal spontaneous combustion. It is inferred that the influence of methane is related to the competitive adsorption of coal on different gases. The results of this study added to our understanding of the role that methane plays in the low-temperature oxidation of coal and can serve as a reference in coal spontaneous combustion prevention in working face gobs with methane emissions.

Degradation Efficiency Analysis of Sulfadiazine in Water by Ozone/Persulfate Advanced Oxidation Process

Antibiotics are a new class of organic compounds that have antibacterial and anti-inflammatory effects in the clinic, but their widespread use has serious adverse effects on the natural water environment. Sulfadiazine (SDZ) is a typical kind of antibiotic, and the treatment effect of the traditional biochemical degradation process has not been ideal. Thus, in order to find a more efficient and clean degradation method, we investigated the degradation effect of ozone/persulfate (O3/PMS) advanced oxidation process (AOPs) on SDZ in prepared water and natural water for the first time and compared it with the experimental results of ozone (O3) and ozone/ultraviolet (O3/UV) methods. The experimental results showed that when the initial mass concentration of O3 was 3 mg/L, the initial mass concentration of SDZ was 10 mg/L, the temperature was 25 °C, the pH was 6.8 ± 0.1, the Kobs of O3/PMS was 0.2497 min−1, and the Kobs values of O3 and O3/UV were 0.1242 and 0.1328 min−1, respectively. The time required for O3/PMS to degrade SDZ below the detection limit (0.01 mg/L) was about 7 min shorter than that of O3 and O3/UV. It was found that in O3/PMS, the increase in the initial mass concentration of SDZ inhibited its degradation, and the increase in the initial mass concentration of ozone increased the degradation rate of sulfadiazine. The degradation process conformed to the pseudo-first-order reaction kinetic equation. O3/PMS was suitable for weak alkaline environments. When pH was 9, the concentration of free radicals was the highest. Excessive alkalinity led to mutual quenching of free radicals and reduced the degradation rate. The mineralization effect of O3/PMS was slightly worse than that of the O3/UV process, but O3/PMS effectively degraded SDZ and fluorescent substances dissolved in water, with good prospects in practical engineering applications.

Comparing Direct Numerical Modeling Predictions With Field Evidence for Methane Vertical Microseepage in Two Geological Settings

The footprints of petroleum microseepage can be associated with chemical and microbial processes in initially homogeneous strata and/or with the fluid transport properties of the rocks through which oil and gas migrate. This work examines the role of such driving factors in two contrasting geological settings by comparing numerical modeling predictions for upward methane microseepage with some field evidence for hydrocarbons transport and accumulation. The two case studies are a monitoring borehole (BH8) from a landfill in southern Ontario, Canada, and an oil well (Saltarin 1A) from the Eastern Llanos Basin in Colombia. Profiles of relative methane concentrations versus depth were generated using a time-dependent, one-dimensional, simulation of the advection-diffusion equation applied to multiple strata of soils, and sediments. The model employs the layered sequences of these two geological settings. The results obtained hinge on the standard permeability values for the rock types involved and their corresponding flow velocities and diffusion coefficients. Resistivity logs were utilized as direct proxies of hydrocarbon concentrations. As additional evidence for petroleum microseepage, experiments of electron paramagnetic resonance (EPR) were carried out in drilling cuts of Saltarin 1A to measure traces of organic matter free radicals concentrations (OMFRC). Extractable organic matter (EOM) and magnetic susceptibility data were also considered in interpreting the EPR results. Qualitative comparisons between modeled methane profiles and their corresponding resistivity logs suggest that microseepage and hydrocarbon accumulations are conditioned by the fluid transport properties of the rocks contained by BH8 and Saltarin 1A. Moreover, in most of the Saltarin 1A sequence, the OMFRC profiles follow the trends displayed by the resistivity and modeled methane logs. Thus, the EPR data also indicates that hydrocarbon microseepage and accumulation are largely controlled by lithology. Conversely, EOM and magnetic susceptibility appear to be evidence for hydrocarbon-mediated near-surface chemical processes.

Melatonin confers fenugreek tolerance to salinity stress by stimulating the biosynthesis processes of enzymatic, non-enzymatic antioxidants, and diosgenin content.

Salinity-induced stress is widely considered a main plant-growth-limiting factor. The positive effects of melatonin in modulating abiotic stresses have led this hormone to be referred to as a growth regulator in plants. This study aims to show how melatonin protects fenugreek against the negative effects of salt stress. Different amounts of melatonin (30, 60, and 90 ppm), salinity stress (150 mM and 300 mM), and the use of both salinity and melatonin were used as treatments. The results showed that applying different melatonin levels to salinity-treated fenugreek plants effectively prevented the degradation of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid contents compared with salinity treatment without melatonin application. Besides, melatonin increases the biosynthesis of enzymatic and non-enzymatic antioxidants, thereby adjusting the content of reactive oxygen species, free radicals, electrolyte leakage, and malondialdehyde content. It was observed that applying melatonin increased the activity of potassium-carrying channels leading to the maintenance of ionic homeostasis and increased intracellular water content under salinity stress. The results revealed that melatonin activates the defense signaling pathways in fenugreek through the nitric oxide, auxin, and abscisic acid-dependent pathways. Melatonin, in a similar vein, increased the expression of genes involved in the biosynthesis pathway of diosgenin, a highly important steroidal sapogenin in medical and food industries, and hence the diosgenin content. When 150 mM salinity stress and 60 ppm melatonin were coupled, the diosgenin concentration rose by more than 5.5 times compared to the control condition. In conclusion, our findings demonstrate the potential of melatonin to enhance the plant tolerance to salinity stress by stimulating biochemical and physiological changes.

Enhancing bioactive compounds accumulation in red beet (Beta Vulgaris L.) plants by managing N nutrition. The identification of the ‘critical’ zone as a cultivation technique

The increasing interest in natural health-promoting compounds, which are mostly plant secondary metabolites, inspired attempts to stimulate mechanisms strengthening their bioaccumulation in crop plants via abiotic stress while maintaining the yield potential. This study investigates the long-term effects of limiting nitrogen (N) supply on the concentration of total phenolics, free radical activity of natural antioxidants, betacyanin content, biomass production, net photosynthetic rate, total chlorophyll content, and plant water relations in red beetroot plants (Beta vulgaris L.) grown hydroponically. Depending on fertilization, the range of N supply for evaporative demand comprises two contrasted nutrient zones, in which N is limiting (zone-1) or non-limiting (zone-2). Based on the carbon-nutrient-balance hypothesis, at the transition from 1st-zone to 2nd-zone, there is a narrow transition zone in which the plant nutrient status is considered ‘critical’. Herein, to determine the ‘critical’ zone, a modified Michaelis-Menten (M-M) model was used using a piecewise linear regression on two indexes: net photosynthetic rates and free radical-scavenging capacity of phenolic antioxidants. The model showed that the ‘critical’ transition points of net photosynthetic rate and phenolic free radical content are located in a narrow zone ranging between 196.70 ± 8.75 and 271.54 ± 75.50 ppm NO3−, while the cropping season appears to affect slightly the range of ‘critical’ (transition) zone. Thus, supplying N to red beetroot plants to levels ranging within this ‘critical’ zone may be an efficient, profitable and sustainable way to increase the accumulation of health-promoting plant bioactive compounds (total phenolic compounds with radical activity and betacyanins) in hydroponically cultivated reed beetroot plants.

Effect of phytic acid combined with lactic acid on color and texture deterioration of ready-to-eat shrimps during storage

To retard the deterioration of texture and color of ready-to-eat (RTE) shrimps during storage, phytic acid (PA) and lactic acid (LA) were used to soak the shrimp prior to cooking. The factors affecting texture (water holding capacity, protein oxidation and degradation, and microstructure) and color (Maillard reaction and lipid oxidation) were determined separately. The free radical and copper ion content were also determined in order to investigate the regulation mechanism of phytic acid and lactic acid on the texture and color of RTE shrimps. It was found that the inhibitor-treated RTE shrimps showed better texture and color properties than the control group, and the compound inhibitor (PA + LA) showed a better inhibition effect than single inhibitor. In addition, PA and LA prevented the oxidation of RTE shrimps by scavenging free radicals and chelating copper ions, which in turn enabled the regulation of color and texture deterioration.

A Novel multi-fruit acids formula design on molecular basis for skin brightening via a system biology approach.

Fruit acids have long been recognized as highly effective actives with world-wide popularity, covering skin peeling, anti-acne, anti-wrinkle applications, and skin depigmentation. There are complicated interconnections between the fruit acid formula and skin pigmentation behaviors. However, the lack of systematic researches on multi-ingredient formula restricted our understanding on its mechanism. Therefore, it is of great necessity to study the interactions and cascades among components, potential gene targets, signaling pathways, and biological processes via a system biology approach. We used system biology, molecular fingerprint, and structural biology to calculate and collect target information of the functional formula. Gene Ontology (GO) enrichment analysis was further applied to study the biological processes and pathways of the formula, and a multi-level network model of "component - molecular target - signaling pathway - skin disease" was established. Besides, the zebrafish model was utilized to verify the formula. We obtained 69 hub targets by constructing a protein-protein interaction (PPI) network based on the intersection between multi-fruit acids formula (mandelic acid, lactobionic acid, niacinamide, and hydroxytyrosol) and skin indications targets (whitening-sebum balance). In vitro zebrafish models, including pigmentation, antioxidant, and radiation protection models, showed that the current formula significantly alleviated pigmentation intensity and intracellular free radical content, thus proving the efficacy of skin brightening and UV irradiation protection. This research uncovered the underlying mechanism of multi-fruit acids formula and predicted its function in skin brightening and UV irradiation prevention.

Mechanistic insight into the inhibitory effect of artemisinin sustained-release inhibitors with different particle sizes on Microcystis aeruginosa.

Environment-friendly algaecides based on allelopathy have been widely used to control harmful algal blooms. In this research, micro and nano scale artemisinin sustained-release algal inhibitor was prepared, the optimal preparation conditions were explored, and the inhibitory mechanism of artemisinin algaecides was turned perfect. The results showed that when the particle size of artemisinin sustained-release microspheres (ASMs) was 2/10,000 of artemisinin sustained-release granules (ASGs), the inhibitory effect was more remarkable. The optimal concentration of ASMs was 0.2gL-1, and the inhibitory effect reached 99% on the 10th day. The algal density and chlorophyll a both showed a downward trend, indicating that ASGs and ASMs could promote the degradation of chlorophyll a. The inhibition rate of ASGs was faster than that of ASMs on the 4th day, and the inhibitory effect of ASMs was more significant after the 5th day. The activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) increased rapidly at first and then decreased, which indicated that ASGs and ASMs caused oxidative damage to Microcystis aeruginosa and inhibited the activity of antioxidant enzymes. Furthermore, the content of the oxygen free radical (O2-) and malondialdehyde (MDA) continued to rise after the 5th day, and the protein, nucleic acid, and conductivity in the culture medium increased. These results showed that lipid peroxidation occurred in the algal cell membrane, and the permeability of the membrane increased. In summary, the ASMs had a significant sustained inhibitory effect while the ASGs had a better short-term effect. The main inhibitory mechanism of artemisinin algaecides is the irreversible damage of cell membrane.

Interactions between H2O2 and dissolved organic matter during granular activated carbon-based residual H2O2 quenching from the upstream UV/H2O2 process

Granular activated carbon (GAC) filtration can be employed to synchronously quench residual H2O2 from the upstream UV/H2O2 process and further degrade dissolved organic matter (DOM). In this study, rapid small-scale column tests (RSSCTs) were performed to clarify the mechanisms underlying the interactions between H2O2 and DOM during the GAC-based H2O2 quenching process. It was observed that GAC can catalytically decompose H2O2, with a long-lasting high efficiency (>80% for approximately 50,000 empty-bed volumes). DOM inhibited GAC-based H2O2 quenching via a pore-blocking effect, especially at high concentrations (10 mg/L), with the adsorbed DOM molecules being oxidized by the continuously generated ·OH; this further deteriorated the H2O2 quenching efficiency. In batch experiments, H2O2 could enhance DOM adsorption by GAC; however, in RSSCTs, it deteriorated DOM removal. This observation could be attributed to the different ·OH exposure in these two systems. It was also observed that aging with H2O2 and DOM altered the morphology, specific surface area, pore volume, and the surface functional groups of GAC, owing to the oxidation effect of H2O2 and ·OH on the GAC surface as well as the effect of DOM. Additionally, the changes in the content of persistent free radicals in the GAC samples were insignificant following different aging processes. This work contributes to enhancing understanding regarding the UV/H2O2-GAC filtration scheme, and promoting the application in drinking water treatment.

Influence of CO on Explosion Limits and Characteristics of the CH4/Air Mixture.

The study of gas explosion under the influence of CO generated by spontaneous combustion of coal has practical value for preventing and controlling such accidents. The explosion limit and the explosion characteristic parameters of the CO/CH4/air mixture were measured with a 20 L explosion tank. The changes in free radical concentration and temperature sensitivity in the process of mixture explosion reaction were analyzed using the GRI-mech 3.0 mechanism. The test results show that with the increase of the CO concentration in the mixture, both the lower explosion limit and the upper explosion limit of CH4 explosion decreased, the explosion limit range became wider, and the maximum explosion pressure of the mixture decreased. The time for the H•, O•, and •OH radical molar fractions to reach the peak value was found to be prolonged with the increase of the CO ratio in the mixture. Under oxygen-enriched conditions, the •OH and O• mole fractions were larger than those under oxygen-lean conditions, while the H• concentration was reversed. The higher the proportion of CO in the premixed gas, the higher the value of the temperature sensitivity coefficient. The reaction processes R155 CH3 + O2 ⇌ O• + CH3O and R158 2•CH3 (+M) ⇌ C2H6 (+M) had the greatest influence on the temperature of the reaction process. Explosion suppression techniques can be developed for similar explosive environments based on this study.

Role of persistent free radicals and lewis acid sites in visible-light-driven wet peroxide activation by solid acid biochar catalysts – A mechanistic study

We report the synthesis of H2SO4-modified biochars (SBCs) as solid-acid catalysts to activate H2O2 at circumneutral pH under visible light radiation. Spent coffee grinds were pyrolyzed with TiO2 at 300, 500 and 600 °C followed by steeping in 5 M H2SO4 and were used for the Fenton-like degradation of methyl orange (MO). The catalytic activity of SBC depended on the pyrolysis temperature and correlated well with the surface acidity and persistent free radical (PFR) concentration. Results showed that a complete MO removal and a TOC reduction of 70.2% can be achieved with SBC500 under photo-Fenton conditions. However, poisoning of the Lewis acid sites on SBC by PO43- led to a dramatic decrease in the removal of MO with inhibition effects more pronounced than with radical scavengers, suggesting the key role played by acid-sites on the activation of H2O2. Finally, electron paramagnetic resonance (EPR) studies identified •OH as the key transient in the degradation followed by •O2- and 1O2. These findings suggest that H2O2 was likely adsorbed on the surface oxygenated functional groups before being decomposed by accepting electrons from the PFRs on the SBC surface.

P-226 Efficiency of different antioxidants in reducing the supra-physiological Oxidation Reduction Potential Levels in human embryo culture media

Abstract Study question Does every antioxidant compounds perform similarly in reducing the excessive levels of Oxidation Reduction Potential (ORP) in IVF culture media? Summary answer Not all antioxidant compounds perform similarly in maintaining physiological ORP levels in IVF culture media. What is known already During assisted reproduction technologies (ART), several external factors are responsible for disturbing the ORP equilibrium in gametes and embryos. Therefore, antioxidant supplementation of culture media has been evaluated and reported. However, there is lack of consensus on the efficiency of antioxidant action in embryo culture media. Antioxidants are known to lower the levels of free radical concentration to physiological levels, preventing cellular damage caused by oxidative stress. Therefore, it is important to determine which antioxidant compound are the most effective in reducing ORP levels in embryo culture media. Study design, size, duration In this prospective study was performed at CITMER Reproductive Medicine, Mexico city. ORP levels were measured by MiOXSYS System (UAB Caerus Biotechnologies, Vilnius, Lithuania) in embryo-free culture medium (Global® Total®, LifeGlobal®, Connecticut, US). Embryo-free culture medium was supplemented with cumene hydroperoxide and seven different antioxidants were tested each day for 5 continuous days (n = 40). Follicular fluid ORP levels from dominant follicles of 40 oocyte donors were used as control and considered as a physiological target. Participants/materials, setting, methods Cumene hydroperoxide (CH) 1mM, was utilized to increase ORP values in culture media from 224 mV to 415 mV. The following compounds considered as antioxidants according to literature were supplemented at 2 mM to the CH culture media: Ascorbic acid (ASC), L-Carnitine (CAR), L-Cysteine (CYS), Glutathione (GLT), Curcumin (CU), Resveratrol (RSV) and b-Mercaptoethanol (BME). ORP levels were quickly evaluated each time. Main results and the role of chance In this study, CH was used as a culture media oxidant to measure the antioxidants capacity in lowering the excessive ORP values of CH culture media. ORP in CH solution was 415 mV ± 4.3. All antioxidants showed a statistically different capacity (p < 0.05) to lower the ORP values when added to CH solution: RSV decreased the ORP to 348.3 mV ± 3.6 p = 0.0449, CAR to 316.32 mV ± 4.7 (p < 0.0001), CU to 315.7 mV ± 4.4 (p < 0.0001) and GLT to 258.4 mV ± 15.1 (p = 0.00002). The compounds that showed higher antioxidant capacity were CYS 158.4 mV ± 4.7 (p < 0.00001), ASC 154.1 mV ± 3.1 (p < 0.00001) and BME 136.1 mV ± 9.6 (p < 0.00001). CYS, ASC and BME ORP values reached the physiological ORP values found in follicular fluid from donors, which are 89 mV±23.6 mV. Limitations, reasons for caution Further studies should focus on the comparison between physiological dynamics of antioxidant supplementation on culture media and molecular and biochemical effect of antioxidants on embryos and gametes. Wider implications of the findings According to our results, CYS, ASC and BME were significantly more potent antioxidants in lowering the ORP in culture medium to physiological levels. The measurement of antioxidant capacity in lowering excess of ROS in culture media may assist in developing the most effective antioxidant supplements, thus improving ART outcomes. Trial registration number none

Cell-type-specific H+-ATPase activity and antioxidant enzymes improve the Echinacea purpurea L. Moench tolerance to salinity stress at different NO3-/NH4+ ratios

While the importance of biochemical processes in plant adaptive responses is widely accepted, only a limited number of studies have addressed cell-type specific and enzymatic activities in E. purpurea under salt stress conditions. So, various antioxidant enzymatic activities, H+ transport activity, and non-invasive ion flux mechanisms in the root apex and mature zones of E. purpurea grown at different NO3-/NH4+ ratios (90:10, 80:20, and 70:30) were studied in salinity stress condition (0, 15, 30, and 60 mM NaCl). Various parameters, photosynthetic and transpiration rates, gas exchange, ion accumulation, electrolyte leakage (EL) in addition to antioxidant enzyme activities and cell-specific mechanisms were measured according to the standard methods. Based on the results, 60 mM NaCl salinity stress significantly decomposed the cell membrane, causing to increase in the electrolyte leakage and malondialdehyde (MDA) content (89.4% compared with control) and a decrease in the photosynthetic rate (84% compared with control). The activity of antioxidant enzymes such as superoxide dismutase (SOD) and ascorbate peroxidase (APX), catalase (CAT), and glutathione peroxidase (GP) significantly increased up to 30 mM NaCl to diminish the free radicals content by increasing the hydrogen peroxide (H2O2) concentration (89.4% compared with control). High Na+ and Cl- content and their accumulation in the leaves caused to inhibit the antioxidants enzymes activities at 60 mM NaCl salinity stress. Based on the nitrogen (N) supply form, more antioxidant activities and physiological properties were found at the 90:10 NO3-/NH4+ ratio. Salinity stress is caused to limit the root apex growth in a high tissue- and treatment-specific manner. The differential sensitivity between the two zones originates from a 10-fold difference in K+ efflux and H+-ATPase activity between the mature zone and the apical region.

Discussion of Orientation and Performance of Crosslinked Ultrahigh-Molecular-Weight Polyethylene Used for Artificial Joints.

Previously, the orientation structure of ultrahigh-molecular-weight polyethylene (UHMWPE) for artificial joints was considered to be unchanged after irradiation crosslinking. Therefore, much of the research related to the long-term failure of artificial joints has focused on material improvements. In this study, ultrasmall-angle X-ray scattering (USAXS) and the small/wide-angle X-ray scattering (SAXS-WAXS) combined technique reveal that the orientation structures of UHMWPE materials at all scales (nanoscale to microscale) are responsible for the long-term failure of artificial joints. To further illustrate the formation of these hierarchical oriented structures, a simple model is presented. In this model, first, the migration of free radicals plays a vital role, and the different steric hindrances in different directions directly lead to uneven migration behavior of free radicals. Second, the uneven migration of free radicals contributes to an inhomogeneous concentration of free radicals, thus resulting in observable crosslinking nonuniformities. Finally, all the hierarchical structural nonuniformities promote long-term failure of artificial joints after long-term wear.

Cadmium-induced splenic lymphocytes anoikis is not mitigated by activating Nrf2-mediated antioxidative defense response

Cadmium (Cd) is a widely used heavy metal which is reported to exert extensive harm to the environment and human health. Owing to Cd being an element it is continuously enriched in the environment. The mechanism of splenic toxicity by Cd, however, is not yet clear. In order to explore the toxic mechanism of Cd exposure to the spleen, we added 0, 35, 70 and 140 mg/kg of Cd to the diet of chicken and fed them this diet for 90 days. Analysis of histopathological sections showed that Cd exposure damaged the spleen structure, the spleen red pulp, the white pulp boundary disappeared and the number of lymphocytes decreased significantly, suggesting that Cd exposure leads to organ injury to the spleen. Particularly, Cd-induced anoikis - a special form of programmed cell death caused by the loss of contact between cells and extracellular matrix and other cells - is associated with integrin-related cell detachment and activation of apoptotic signaling pathways. Moreover, Cd exposure leads to an increase in free radicals content and affects the activity of antioxidant enzymes resulting in oxidative stress. Simultaneously, Cd activated the body's antioxidant defense system mediated by the Nuclear factor related factor 2 (Nrf2) signaling pathway. Based on our results Cd-induced splenic lymphocytes anoikis is not mitigated by Nrf2-mediated antioxidative defense response.

Thiophene and Its Analogs as Prospective Antioxidant Agents: A Retrospective Study.

The field of Free Radical Chemistry has gained considerable interest in the current scenario. The formation of free radicals is attributable to different physiochemical factors, radiation exposure, pathological conditions, environmental contaminants, and as by-products of metabolized drugs. The concentration of free radicals is regulated strongly under normal conditions by physiological antioxidants. Free radicals may cause oxidative damage to proteins, lipids, sugars, and DNA when abundantly produced or when antioxidants are depleted. This imbalance of reduction-oxidation, referred to as oxidative stress, can change the body's physiological conditions and ultimately lead to tissue injury, further contributing to various disease pathologies. A proper balance between free radicals and antioxidants is required for an effective physiological process. The oxidation mechanism is chemically hindered by antioxidants; these are often called free radical scavengers. The application of an external antioxidant source is crucial in addressing the issue of oxidative stress. Plenty of naturally occurring, semi-synthetic, and synthetic antioxidants are used, and the search for an efficient, non-toxic, and safe antioxidant is stepped up over time. As an influential scaffold, thiophene and its derivatives have become a significant source of interest for researchers due to its substantial variety of biological activities. The versatility of thiophene moiety has been identified by an affluent unveiling of its derivatives with anti-inflammatory, antioxidant, anti-cancer, and antimicrobial behaviors. Thiophene activity has been influenced greatly by the nature and orientation of the substitutions. The current study aims at addressing various synthetic compounds with thiophene or condensed thiophene as a fundamental moiety or substituent as radical scavengers.