Concentration Of Free Radicals Research Articles

Persistent Free Radicals in Petroleum

The persistent free radical content in petroleum is of the order 1018 spins/g (1 μmol/g), with higher and lower values found depending on origin and in different distillation fractions. The field of persistent free radicals in petroleum was reviewed with the aim of addressing and explaining apparent inconsistencies between free radical persistence and reactivity. The macroscopic average free radical concentration in petroleum is persistent over geological time, but individual free radical species in petroleum are short-lived and reactive. The persistent free radical concentration in petroleum can be explained in terms of a dynamic reaction equilibrium of free radical dissociation and association that causes a finite number of species at any given time to be present as free radicals. Evidence to support this description are observed changes in free radical concentration related to change in Gibbs free energy when the bulk liquid properties are changed and responsiveness of free radical concentration to dynamic changes in temperature. Cage effects, solvent effects, steric protection, and radical stabilization affect free radical reaction rate but do not explain the persistent free radical concentration in petroleum. The difference between persistent free radicals in straight-run petroleum and converted petroleum is that straight-run petroleum is an equilibrated mixture, but converted petroleum is not at equilibrium and the free radical concentration can change over time. Based on the limited data available, free radicals in straight-run petroleum appear to be part of the compositional continuum proposed by Altgelt and Boduszynski. Persistent free radical species are partitioned during solvent classification of whole oil, with the asphaltenes (n-alkane insoluble) fraction having a higher concentration of persistent free radicals than maltenes (n-alkane soluble) fraction. Attempts to relate persistent free radical concentration to petroleum composition were inconclusive.

Response characteristics of rhizosphere microbial community and metabolites of Iris tectorum to Cr stress

Chromium (Cr) is a toxic heavy element that interferes with plant metabolite biosynthesis and modifies the plant rhizosphere microenvironment, affecting plant growth. However, the interactions and response mechanisms between plants and rhizosphere bacteria under Cr stress still need to be fully understood. In this study, we used Iris tectorum as a research target and combined physiology, metabolomics, and microbiology to reveal the stress response mechanism of I. tectorum under heavy metal chromium stress. The results showed that Cr stress-induced oxidative stress inhibited plant growth and development and increased malondialdehyde and oxygen free radicals content. Also, it increased ascorbate peroxidase, peroxidase activity, and superoxide dismutase activity, as well as glutathione and soluble sugar content. Microbiome analysis showed that Cr stress changed the rhizosphere bacterial community diversity index by 33.56%. Proteobacteria, Actinobacteriota, and Chloroflexi together accounting for 71.21% of the total sequences. Meanwhile, the abundance of rhizosphere dominant and plant-promoting bacteria increased significantly with increasing time of Cr stress. The improvement of the soil microenvironment and the recruitment of bacteria by I. tectorum root secretions were significantly enhanced. By metabolomic analysis, five vital metabolic pathways were identified, involving 89 differentially expressed metabolites, divided into 15 major categories. In summary, a multi-omics approach was used in this study to reveal the interaction and stress response mechanisms between I. tectorum and rhizosphere bacterial communities under Cr stress, which provided theoretical basis for plant-microbial bioremediation of Cr-contaminated soils in constructed wetlands. This may provide more valuable information for wetland remediation of heavy metal pollution.

Measurement report: Atmospheric aging of combustion-derived particles – impact on stable free radical concentration and its ability to produce reactive oxygen species in aqueous media

Abstract. Environmentally persistent free radicals (EPFRs) are a pollutant found on fine atmospheric particulate matter (PM2.5), particularly on PM2.5 formed from combustion processes. EPFRs are organic radicals that can endure in the environment for days to years. Interest in the toxicity of EPFRs has increased significantly in recent years, as it has been shown to have substantial ability to form reactive oxygen species (ROS), but little is known about how its characteristics change as PM2.5 ages in the atmosphere. Here, we exposed newly produced hexane-generated soot to simulated sunlight for 24 h. Changes to the EPFR characteristics of the particles were measured by electron paramagnetic resonance (EPR) spectroscopy. The soot was then added to water, and a second exposure to light was used to measure hydroxyl radical (OH) formation from both photoaged and dark-aged soot. There were no changes to EPFR characteristics (spin concentration, g factor, peak width, or lineshape) due to the exposure to simulated sunlight; however, the soot's ability to form OH was greatly reduced by photoaging. Photoaged soot resulted in an almost 60 % reduction in OH formation over soot which had been aged in the dark for the same amount of time.

Characteristics and mechanism of Glutathione in inhibiting coal spontaneous combustion

Inhibitors play an important role in preventing and controlling coal spontaneous combustion (CSC). In this study, the inhibitory effects of antioxidant-reduced glutathione (G-SH) on CSC were examined. Thermogravimetric-differential scanning calorimetry (TG-DSC), cross-point temperature (CPT), and oxidation product tests were used to examine the effect of G-SH on the tendency of CSC and compare the discrepancy in the inhibition effect of G-SH and the halogen inhibitor. The changes in the free radical type, concentration, and surface functional groups in coal before and after the addition of G-SH were analyzed using electron spin resonance spectroscopy (ESR) and Fourier transform infrared spectroscopy (FT-IR). Six common active radical models were constructed, and the thermodynamic parameters of the reaction were calculated using density functional theory (DFT). The results revealed that G-SH inhibits the spontaneous combustion of coal. The inhibitory effect of G-SH was significantly stronger than that of the halogen salt inhibitors CaCl2 and MgCl2, and the higher the concentration of G-SH, the stronger is the inhibitory effect. The characteristic temperature points in the thermogravimetric experiment of coal samples with G-SH shifted to a higher temperature zone, and the CO concentration and oxygen consumption were lower than those of raw coal. After G-SH treatment, the type and relative concentration of free radicals in coal were lower than those in raw coal, the content of aliphatic hydrocarbon functional groups and oxygen-containing functional groups decreased, and the content of sulfur-containing functional groups increased. According to the calculation of Gibbs free energy and reaction enthalpy, G-SH can effectively neutralize the active free radicals in the process of coal oxidation, and the reaction activity with the free radicals in the process of coal oxidation is ·OOH > ·OH > ·CH3 > RO· > R· > ROO·. According to the experimental results, it is inferred that G-SH continuously supplies a large number of hydrogen donors (·H) for the reaction during the oxidation process and simultaneously neutralizes carbon free radicals and carbon oxygen free radicals, thereby reducing the concentration and reactivity of free radicals in the whole chain reaction process and blocking the occurrence of coal-oxygen composite reaction.

Iron reduction in composting environment synergized with quinone redox cycling drives humification and free radical production from humic substances

The aim of this paper was to investigate the influence of Fe (III) on humification and free radicals evolution. The experimental data showed that the experimental group (CT) with Fe2(SO4)3 had a better degree of humification than the control group (CK). The humic substances (HS) content was 10% higher in CT (23.94 mg·g−1) than in CK (21.54 mg·g−1) in the final. Fe (III) contributed significantly to the formation of free radicals in HS. The amount of H2O2 in CT increased to 74.8 mmol·kg−1, while CK was only 46.5 mmol·kg−1. The content of semiquinone free radical was 10.32 × 1011 spins/mm3 in CT, 5.11 × 1011 spins/mm3 in CK in the end. Several iron-reducing bacteria were detected in composting, among which Paenibacillus was dominant. The above findings suggested that the application of Fe2(SO4)3 enhanced the iron reduction synergistic quinone redox cycling and promoted the generation of free radicals during the humification of composting.

Outdoor Health Risk of Atmospheric Particulate Matter at Night in Xi'an, Northwestern China.

The deterioration of air quality via anthropogenic activities during the night period has been deemed a serious concern among the scientific community. Thereby, we explored the outdoor particulate matter (PM) concentration and the contributions from various sources during the day and night in winter and spring 2021 in a megacity, northwestern China. The results revealed that the changes in chemical compositions of PM and sources (motor vehicles, industrial emissions, coal combustion) at night lead to substantial PM toxicity, oxidative potential (OP), and OP/PM per unit mass, indicating high oxidative toxicity and exposure risk at nighttime. Furthermore, higher environmentally persistent free radical (EPFR) concentration and its significant correlation with OP were observed, suggesting that EPFRs cause reactive oxygen species (ROS) formation. Moreover, the noncarcinogenic and carcinogenic risks were systematically explained and spatialized to children and adults, highlighting intensified hotspots to epidemiological researchers. This better understanding of day-night-based PM formation pathways and their hazardous impact will assist to guide measures to diminish the toxicity of PM and reduce the disease led by air pollution.

Changes of lipid oxidation, volatile and taste-active compounds during pan-heating of pork belly

This study investigated the mechanisms underlying the evolution and formation of aroma and taste-active compounds of pork belly in representative traditional pork cuisines during pan-heating. The results revealed that as the temperature increased to 110 ℃, the unsaturation of fatty acids decreased from 60.25 % to 58.71 %, while the content of free radicals and secondary oxidation products increased. At the later heating stages, the addition of spices and increased heating temperature (150 ℃) led to continuous increments in the contents (from 958.20 μg/kg to 1511.88 μg/kg) and diversity of volatile compounds in pork belly, imparting the unique aroma. Additionally, the accumulation of low-molecular-weight peptides, free amino acids, and nucleotides not only provided the substrate for thermal reactions and their synergistic effects, but also contributed to the desired taste quality. These findings offered insights into the flavor formation mechanisms of traditional pork cuisines and provided direction for further research.

Oxygen vacancies-dominated reactive species generation from peroxymonosulfate activated by MoO3−x for pollutant degradation

Interface oxygen vacancies (OVs) are commonly used to improve the catalytic performance of activators in persulfate-based advanced oxidation processes, but the underlying mechanism was not fully explored. This work reports a facile heat treatment method to regulate OVs in MoO3−x to elucidate the mechanism of peroxymonosulfate (PMS) activated by OVs to degrade 2,4,4-Trichlorobiphenyl (PCB28). Electron spin resonance, free radical quenching, X-ray photoelectron spectroscopy, and Raman spectroscopy confirmed that both reducing Mo species and OVs of MoO3−x surface were responsible for PMS activation. Further experiments and Density Function Theory (DFT) calculation suggest that OVs in MoO3−x induced the formation of superoxide radical (O2•−), and then O2•− was transformed into singlet oxygen (1O2) or mediated PMS activation to generate radicals, which contritbued to 70.2% of PCB28 degradation. The steady-state concentrations of free radical calculated with the kinetics model show that OVs were more favorable to mediate PMS to generate hydroxyl radicals (•OH) under oxic conditions, while reducing Mo species would like to induce PMS to produce sulfate radicals (SO4•−). Overall, this study is dedicated to a new insight into the in-depth mechanism of PMS activation by OVs-rich catalysts and provides a novel strategy for reactive species regulation in PMS based oxidation process.

Random and block architectures of N-arylitaconimide monomers with methyl methacrylate

Abstract “Itaconimide” is the members of imide (–CO–NH–CO–) family with reactive exocyclic double bond and it is easily obtained from the renewable resource i.e. D-glucose. The polymerization of various N-arylitaconimide (NAI) monomers with methyl methacrylate (MMA) have been reported to improve the glass transition temperature (T g) and thermal stability of poly(methyl methacrylate) (PMMA). In literature, these studies have been done mostly using conventional free radical polymerization methods, which restricts the architecture of copolymers to “random” only. The block copolymers of NAI and MMA are an important due to the combination of glassy PMMA and thermally stable poly(NAI), which offers its applications for higher temperature service. The architectural control of polymers in provisions of its topology, composition, and various functionalities is possibly obtained using reversible-deactivation radical polymerizations (RDRPs). In RDRPs, the concentration of free radical is controlled in such a way that the termination reactions are minimized (normally in range of 1–10 mol%), and not allowed to obstruct with the desired architecture. However, this is possible by achieving (or by establishing) a rapid dynamic equilibrium between propagating radical and dormant species (i.e. R–X). Among all RDRPs, the atom transfer radical polymerization (ATRP) is very popular and adaptable method for the synthesis of polymers with specifically controlled architecture. Two different architectures of NAI and MMA copolymers are reported using ATRP process. The effect of various pedant groups on the rate constants of propagation (k p) and thermal properties NAI and MMA copolymers is studied. The poly(NAI-ran-MMA)-b-poly(MMA) are stable up to 200 °C and degraded in three steps. Whereas, the poly(NAI-ran-MMA)-b-poly(NAI) are stable up to 330 °C and degraded in two steps. The density functional theory methods are used for calculation of equilibrium constants (K ATRP) for the ATRP process for the series of laboratory synthesized alkyl halides. A good agreement was observed between the experimentally determined and theoretically calculated K ATRP values. The mechanistic studies are carried for poly(NAI-ran-MMA) copolymer system using statistical model discrimination method along with 1H decoupled 13C NMR spectroscopy. For studying the mechanism of copolymerization of NAI and MMA via ATRP methods, “trimer model or penultimate model” will be more accurate than “dimer model or terminal model”.

Effect of molecular structure change on the properties of persistent free radicals during coal oxidation

This study is aimed at exploring the effect of molecular structure changes on the properties of persistent free radicals in coal during the heating process of coal spontaneous combustion (CSC). Therefore, the persistent free radicals and main functional groups variation characteristics in the process of coal oxidation were analyzed by means of in situ electron spin resonance and in situ infrared spectroscopy, and the change relationship between the molecular structure of coal and the persistent free radicals in coal during the reaction was further discussed by correlation analysis. The results showed that the concentration of persistent free radicals showed a stage change of “first decreasing, then increasing and then decreasing”. The g-factor decreases gradually and the heteroatom free radicals are consumed continuously. Dehydrogenation oxidation reaction causes the weakening of the “electron-proton” interaction, which narrows the line-width (ΔH) of free radicals. The phenolic hydroxyl as the electron donating group is converted into -CO functional group through dehydrogenation and oxidation reaction, which promotes the formation and accumulation of persistent free radicals in coal. Under the influence of phenolic hydroxyl, the relationship between the stretching vibration strength of aromatic ring CH and the properties of persistent free radicals in coal shows a similar change law with phenolic hydroxyl. In addition, the chain structure represented by –CH2-, –CH3/–CH2- is continuously consumed in the oxidative dehydrogenation reaction, triggering a series of free radical reactions. The free radicals formed in this process are affected by the steric hindrance of polymer networks and the electron delocalization of aromatic group in coal, so the persistent free radicals can be formed and accumulated. The dehydrogenation and oxidation reaction of the active group led to the reduction of g-factor and ΔH. Persistent free radicals play an important role in the free radical chain reaction that triggers CSC, so preventing the dehydrogenation and oxidation reaction of hydroxyl (especially phenolic hydroxyl) and aliphatic hydrocarbons (especially –CH2- and –CH3/–CH2-) is the key to prevent CSC.

Sustainable exploitation and safe utilization of biochar: Multiphase characterization and potential hazard analysis

Pyrolysis temperature determines the multiphase (solid and dissolved) structure of biochar (BC). In this study, the temperature-dependent evolution of characteristics and potential hazards of three crop (cotton, alfalfa, and wheat) residue BC were systematically investigated. The results showed that pyrolysis temperature significantly affected the elemental composition and morphology of BC. A higher pyrolysis temperature led to a higher aromatization and graphitization degree of BC. A numerical relationship between pyrolysis temperature and BC surface properties (functional groups, carbonization degree) was established. Pyrolysis temperature controlled the content, composition, and functional group evolution of BC-derived dissolved organic matter. Although the amount of potentially toxic elements (PTEs) in BC was concentrated after pyrolysis, the potentially risk of PTEs significantly decreased. The spin concentration of persistent free radicals in BC prepared at 500 °C was the highest. These findings will hopefully offer comprehensive guidance for sustainable utilization of crop straw and fit-for-purpose exploitation of BC.

Transcription Factor VvDREB2A from Vitis vinifera Improves Cold Tolerance.

Low temperatures restrict the growth of the grapevine industry. The DREB transcription factors are involved in the abiotic stress response. Here, we isolated the VvDREB2A gene from Vitis vinifera cultivar 'Zuoyouhong' tissue culture seedlings. The full-length VvDREB2A cDNA was 1068 bp, encoding 355 amino acids, which contained an AP2 conserved domain belonging to the AP2 family. Using transient expression in leaves of tobacco, VvDREB2A was localized to the nucleus, and it potentiated transcriptional activity in yeasts. Expression analysis revealed that VvDREB2A was expressed in various grapevine tissues, with the highest expression in leaves. VvDREB2A was induced by cold and the stress-signaling molecules H2S, nitric oxide, and abscisic acid. Furthermore, VvDREB2A-overexpressing Arabidopsis was generated to analyze its function. Under cold stress, the Arabidopsis overexpressing lines exhibited better growth and higher survival rates than the wild type. The content of oxygen free radicals, hydrogen peroxide, and malondialdehyde decreased, and antioxidant enzyme activities were enhanced. The content of raffinose family oligosaccharides (RFO) also increased in the VvDREB2A-overexpressing lines. Moreover, the expression of cold stress-related genes (COR15A, COR27, COR6.6, and RD29A) was also enhanced. Taken together, as a transcription factor, VvDREB2A improves plants resistance to cold stress by scavenging reactive oxygen species, increasing the RFO amount, and inducing cold stress-related gene expression levels.

Study on the Effect of Oxygen on Free Radical Generation in Coal

ABSTRACT According to the theory of coal–oxygen combination, oxygen has an important effect on the spontaneous combustion of coal. In this study, Hailar lignite is taken as the research object to prepare and analyze the coal sample. The variation trends of the free radical concentration, g factor value, line width and line shape are measured by electron spin resonance (ESR) technology, and the influence of different oxidation times and oxygen concentrations on the free radical parameters in coal are studied. The results show that the relationship between the free radical reaction and the oxidation time is not linear. The critical point of the free radical reaction is the oxidation time of 5 h. With an increase in the oxygen concentration, the free radical concentration, g factor value and line width also increase. In a nitrogen environment, the free radical reaction still exists, but the new free radicals are hydrocarbon free radicals or alkyne free radicals, which will not lead to spontaneous combustion of coal. Oxygen molecules, meanwhile, make the free radical reaction more active. Oxygen atoms combine with carbon chains to form oxygen-containing free radicals and peroxide free radicals, which further decompose and oxidize to produce CO and CO2, eventually triggering the spontaneous combustion of coal.

Oxidative Stress and Neurodegeneration in Animal Models of Seizures and Epilepsy.

Free radicals are generated in the brain, as well as in other organs, and their production is proportional to the brain activity. Due to its low antioxidant capacity, the brain is particularly sensitive to free radical damage, which may affect lipids, nucleic acids, and proteins. The available evidence clearly points to a role for oxidative stress in neuronal death and pathophysiology of epileptogenesis and epilepsy. The present review is devoted to the generation of free radicals in some animal models of seizures and epilepsy and the consequences of oxidative stress, such as DNA or mitochondrial damage leading to neurodegeneration. Additionally, antioxidant properties of antiepileptic (antiseizure) drugs and a possible use of antioxidant drugs or compounds in patients with epilepsy are reviewed. In numerous seizure models, the brain concentration of free radicals was significantly elevated. Some antiepileptic drugs may inhibit these effects; for example, valproate reduced the increase in brain malondialdehyde (a marker of lipid peroxidation) concentration induced by electroconvulsions. In the pentylenetetrazol model, valproate prevented the reduced glutathione concentration and an increase in brain lipid peroxidation products. The scarce clinical data indicate that some antioxidants (melatonin, selenium, vitamin E) may be recommended as adjuvants for patients with drug-resistant epilepsy.

Endothelial dysfunction in COVID-19 with smoking

Endothelial dysfunction is one of the mechanisms that most likely to play a role in the occurrence of poor clinical outcomes in patients with COVID-19. The hyperinflammatory and pro-coagulation state in COVID-19 suggests an important role for the endothelium, both as an effector contributing to inflammation and thrombosis, as well as a target organ. This state of endothelial dysfunction is also believed to be exacerbated by a history of previous smoking. Tobacco can increase the severity of infectious diseases such as influenza, by increasing viral replication through suppression of antiviral mechanisms, and changes in cytokine patterns in cells also increase ACE2 expression. Smoking is associated with endothelial dysfunction because it can increase the concentration of free radicals and proinflammatory cytokines. So, it is very possible that SARS-CoV-2 will damage the endothelium of smokers who have previously been injured as a result of smoking habits. The literature that we used in this study was obtained through searching engines from the Google Scholar and PubMed databases, with the inclusion criteria being literature that used English. We managed to take 1,613 literature articles, then we selected 81 articles that were most relevant to the discussion of our study. In this study we conclude that endothelial dysfunction may play a role in the mechanism of clinical deterioration in COVID-19 and may be exacerbated by a history of previous smoking.

Numerical study of the effect of pressure on the combustion characteristics of ammonia/coal-derived syngas mixture under gas turbine operating conditions

This study investigates the influence of pressure variation on combustion properties, including laminar burning velocity and ignition delay time, as well as emissions in gas turbine conditions. Based on numerical simulations and using Matlab, the impact of pressure on the relationship between laminar burning velocity and free radicals, as well as the relationship between ignition delay time and laminar burning velocity, were analyzed. The results of Matlab curve fitting suggest that the decrease in free radical concentration due to increased pressure is the main cause of the reduction in laminar burning velocity. The presence of reactions such as H + O2 = O + OH and all ammonia-related reactions results in a linear relationship between the laminar combustion velocity and max(H) or max(NH2 + H), which varies with pressure in mixed ammonia combustion. Moreover, the linear correlation coefficient between the laminar combustion velocity and free radicals is a function of pressure. Using a one-dimensional laminar premixed model and a zero-dimensional closed reactor model, this study has identified a power function relationship between the laminar combustion velocity and ignition delay time in synthetic gas mixed with ammonia combustion, where the coefficients and exponents of the power function are functions of pressure. Moreover, these two fitting relationships are independent of equivalence ratio and fuel ratio. Finally, the analysis of NO emissions indicates that the NO produced by chemical pathways affects the chemical equilibrium of NO produced by thermal pathways. Additionally, the reaction CO + OH = CO2 + H initially produces some NO in the thermal pathway·NH3 participates in reactions after H2 and CO have reacted. Lastly, it was found that the increase in pressure promotes the reaction NH + NO = N2O + H, which leads to a decrease in the molar fraction of NO with increasing pressure.

Modification of the structure and function of myofibrillar protein by structurally relevant natural phenolic compounds

Protein gelation is an important functional characteristic of shrimp surimi products. The effects of structurally relevant natural phenolic compounds on the structure and functional properties of myofibrillar protein (MP) of the Penaeus vannamei were investigated. In the present study, phenolics improved the oxidative stability of MP, while leading to a decrease in the emulsification properties of MP. The carbonyl and free radical contents and fluorescence quantification of protein oxidation products showed that the addition of phenolic compounds could effectively prevent MP oxidation due to their antioxidant capacity derived from hydroxyl groups. In addition, phenolics could improve the rheological properties and gelling behavior of MP. Finally, the interactions between the substituents of MP and phenolic compounds were explored by molecular docking to elucidate the modification mechanism. Gallic acid (GA), quercetin (QT), and (−)-epigallocatechin-3-gallate (EGCG) interacted with MP mainly through hydrogen bonding to unfold the secondary structure of MP and reduce the surface hydrophobicity. Unlike GA and EGCG, QT interacted electrostatically with MP, maintaining the α-helical structure and leading to a slight increase in surface hydrophobicity. This study demonstrated the great potential of phenolic compounds as natural additives for the functional modification of shrimp surimi products.

Identification and structure-activity modeling of ACE inhibitory peptides demonstrating anti-inflammatory effects: Extracted from Antheraea assama and Philosomia ricnii pupae

Traditionally edible silkworm pupae abundantly available in North eastern region of India have a notable protein content and comprises vast scope of bioactive peptides with unrevealed possibilities. Therefore, in this study, peptides derived from Muga and Eri pupae with highest potential to inhibit ACE (Angiotensin converting enzyme) and scavenge free radicals have been characterized, followed by understanding molecular interaction mechanism behind inhibition action and anti-inflammatory potential in endothelial model. This study was proposed to generate most potent purified chromatography fractions comprising ACE-inhibitory peptides, identified to contain total 105 peptides in fraction F4 and 53 peptides in fraction F6, majorly acquired from haemolymph protein in pupae. 96 peptides with length 5–12 amino acids were selected and exposed to peptide-ACE interaction by molecular docking and simulation. Among top 15 peptides, LTSDRDFYVSK, VIELPYGVENR and IYVSDQY acted as effective competitive ACE inhibitor, peptide QTLVPFMK indicated its non-competitive inhibition. Fraction F4 and F6 remarkably alleviated COX-2, iNOS expression along with NO release, IL-6 (interleukin-6), IL-1β (interleukin-1 beta) and TNF-α (Tumor necrosis factor-alpha) generation. Additionally, peptide fractions showed significant potential to curb elevated free radical concentration and induced endogenous antioxidant enzymes expression. This conveyed that Muga and Eri pupae protein derived peptide fractions certainly carried an effective role in modulating the cross talk between ACE activity and inflammation mechanisms, supporting their therapeutic potency.

Biosafety Photooxidation Strategy of Levofloxacin Driven by Manganese-Doped Indium Zinc Sulfide.

Overuse of antibiotics has led to ecological hazards such as the emergence of resistance genes and super bacteria, necessitating the development of water pollution control technology. Indium zinc sulfide (ZnIn2 S4 , ZIS) is a promising material for environmental applications due to its narrow band gap and excellent light absorption ability. This study investigates Mn-doped ZIS photocatalysts to enhance their photocatalytic oxidation efficiency. Structural morphology, electrochemical testing, and active species testing confirm that Mn-doping optimizes the energy band structure of ZIS and increases the concentration of active free radicals, improving the efficiency of charge separation. Mn-doping also causes lattice distortion, leading to trapping centers to enhance charge separation efficiency. The optimal ZIS-4% oxidation degradation rate of levofloxacin was 2.5 times higher than that of pristine ZIS, with degradation rates reaching almost 100% in 30 minutes. This study provides a novel approach to designing Mn-doped photocatalysts for antibiotic pollution control.

Evolutions of Oxidation Products and Free Radicals for Coal-Gangue Samples with Various Gangue Contents

ABSTRACT To investigate the influence of gangue left in goafs on the low-temperature oxidation characteristics of coal, the variations of gas products and free radical parameters of coal-gangue mixed samples with different gangue contents were tested. The results show the concentration of gas products is directly proportional to temperature and inversely proportional to gangue content (except the sample with 20% gangue content (G(20))). In addition, the oxygen consumption rate and heat release intensity follow a variation trend similar to that of gas product. Pure gangue corresponds to the highest apparent activation energy, 57.6 kJ/mol, and G(20) has the lowest value, 48.8 kJ/mol. With the rise of temperature, the free radical concentration of the mixed samples decreased slowly when it was lower than 90°C and higher than 210°C, and increased between 90°C and 210°C. Compared with the theoretical calculation results, the mixed samples all possess higher gas product, oxygen consumption rates, heat release intensities, free radical concentrations and lower apparent activation energy in the experiments, which indicates that gangue can remarkably promote the reaction of coal during low-temperature oxidation. As a result, the gangue left in goafs may promote the risk of coal spontaneous combustion.