Peroxide Oxidation Research Articles

Peculiarities of the effect of zinc chelate on prooxidant-antioxidant homeosta-sis in the blood of sows and their relationship with the reproductive capacity

During the last decades, research has been actively conducted to increase the reproductive capacity of sows. It was determined that during puberty, the sow’s body actively assimilates nutrients that should provide for their own needs and embryos and creates a reserve for the lactation period. The study aimed to determine the influence of zinc in the form of chelate on the state of prooxidant-antioxidant homeostasis on the reproductive capacity of sows. In the experiment, 45 heads of the Large White breed sows were used, and they were selected and divided into groups (5 heads each) according to the principle of analogs. The norms fed barren and farrowing sows according to their physiological state. The diet of the control group of sows from sexual rest to the 28th day of farrowing remained unchanged; the 1st experimental group – MD+5 % Zinc in the form of zinc chelate, the II experimental group – MD+10 % Zinc in the form of Zinc chelate. Additional feeding of biologically active compounds was stopped one day before farrowing. During the phase of sexual rest, estrus, on the 90th and 104th days of farrowing, the day of farrowing, as well as on the 5th and 28th days of the suckling period, blood was taken from sows and their piglets to determine the state of PAH. It has been determined that in the blood of sows, the periods of the reproductive cycle determine the peculiarities of the formation of prooxidant-antioxidant homeostasis. In particular, during estrus, there is an intensification of peroxide oxidation processes – the content of diene conjugates increases by 56.9 %, TBC-active compounds by 12.3 %, and the level of low molecular weight antioxidants – reduced glutathione decreases (Р < 0.001). This is accompanied by a significant increase in the activities of antioxidant enzymes – superoxide dismutase (Р < 0.05) and catalase (Р < 0.05). It was found that the intensification of peroxide oxidation processes is intensified on the day of farrowing of sows – the content of diene conjugates increases by 26.6 % and TBC-active compounds by 31.8 % with a further decrease during lactation to the level of sexual rest. Animals that received zinc in the form of zinc chelate 5 % above the norm were characterized by a lower intensity of peroxide oxidation processes. Additional feeding of zinc in the form of zinc chelate to sows by 10 % more than the norm is accompanied by a decrease in fertility (Р < 0.05), the number of live piglets (Р < 0.05), litter weight at birth by 10.0 % and litter weight at weaning – 11.6 %. Sows that received this feed supplement of microelement 5 % above the norm are characterized by higher fertility by 4 % and litter weight at birth by 4.2 %.

Assessment of Microplastics in Hanumante River of Kathmandu Valley

Plastic debris is one of the most significant organic pollutants in the aquatic environment. Researchers are currently focusing on the impact of micro and nano-scale plastic waste on aquatic systems. In this study, we investigated the distribution of plastic pellets and fragments present in the freshwater ecosystem. The goal was to assess microplastic (MP) abundance in the Hanumante River, a tributary of the Bagmati River, and analyze their properties. Sample collection involved the bottle sampling method. Filtration, wet peroxide oxidation, density separation, gravimetric analysis, and microscopic examination were performed to study the characteristics of microplastics. The study was conducted by following the guidelines of the National Oceanic and Atmospheric Administration (NOAA) protocol. Gravimetric analysis was applied to calculate the reduced mass of the sample after total organic carbon reduction. Results showed that the maximum amount of reduced sample was obtained from the sample taken from sample taken from Madhyapur Thimi area (~3.593g) and the minimum amount of reduced sample was obtained from the sample taken from the Shiva temple Jagati area (~2.130g). Microscopic inspection showed that samples taken from different locations were composed of an average of 14–23 microplastics per liter of sample. FT-IR analysis was performed to analyze the characteristics of microplastics and the type of polymers present in the sample which showed the abundance of polymer materials like polyethylene, polypropylene, and polycarbonates. The findings imply that appropriate plastic waste management measures be implemented in the communities to safeguard the ecosystem benefits derived from the river.

Nitric oxide alleviates mercury toxicity by changing physiological and biochemical pathways in maize (Zea mays L.) seedlings

Like all life forms, plants suffer from high levels of mercury (Hg), known as one of the most harmful heavy metals in soil. The present study was performed to explore the effects of exogenous nitric oxide (NO) on Hg toxicity in maize (Zea mays L., cv. Arifiye-2) seedlings. Plants were grown in a hydroponic system containing 1/2 diluted Hoagland at 16 h day length, 25/20 °C (day/night) and 60% relative humidity. Eight day-old maize seedlings were first treated with NO (as 0.1 µM sodium nitroprusside) and then they were exposed to Hg toxicity (as 100 µM HgCl2) after 24 h. The toxic Hg decreased seedling growth, chlorophyll content, proline content, calcium and manganese contents, non-enzymatic antioxidant contents, cell membrane viscosity, and antioxidant enzyme activities (superoxide dismutase, catalase, peroxidases, and glutathione reductase) while it increased the generation of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) and super oxide anion (O2.-), and lipid peroxidation (as malondialdehyde, MDA) content and the amount of sodium ion (Na+) in the seedlings. However, NO treatment markedly enhanced the growth parameters (dry and fresh weight, and plant height) and manganese and potassium contents as well as contents of antioxidants and chlorophyll thus alleviating the negative effects caused by the Hg stress. Also, it decreased the generation of ROS and lipid peroxidation level by activating the antioxidant enzymes. These results show that NO in maize seedlings under Hg toxicity may improve stress response and mitigate oxidative stress by stimulating the antioxidant system and modulating ion homeostasis.

Effective photo-catalytic degradation of Malachite Green with water stable Cu based aliphatic di-carboxylate MOFs

Four different mesoporous Cu-MOFs named as Cu(Pima), Cu(Suba), Cu(Azla) and Cu(Seba) were prepared from aliphatic di-carboxylate linkers with the dimeric Cu paddle wheels as Secondary Building Units (SBUs). These as-synthesized aliphatic Cu-MOFs were applied as fresh heterogeneous catalysts for the catalytic wet peroxide oxidation of simulated Malachite Green waste-water and characterized using PXRD, FT-IR, Fe-SEM and BET. The results exhibited a better catalytic degradation efficiency of Cu(Seba) and Cu(Azla) (>90% in 200 mins) as compared to Cu(Pima) and Cu(Suba). It was established that degradation efficiency of Cu(seba) was approximately 9.8 times better than the rest of the synthesized Cu(MOFs). It was recognized that increasing the organic linker length can evidently boost the dye degradation process. Under optimum conditions, the degradation efficiency of 98% and 97% for Cu(Seba) and Cu(Azla) were achieved respectively. A optimal condition of 1.0 mL H2O2, 50 °C temperature and 3.5 pH was obtained. A recyclability experiment of four runs was performed for Cu(Seba) and Cu(Azla) which exhibited they maintained an effective degradation efficiency of ∼80% simulated MG solution. These analytical results of the degradation efficiency for Cu(Seba) and Cu(Azla) led us on a conclusion that, as synthesized Cu-MOFs outperformed several other reported MOFs, nanoparticles, adsorbents etc., as heterogeneous catalysts in the field of dye degradation for wastewater treatment.

Microplastics Trophic Transfer in Seafood Varieties Caught from the Coastal Waters off Negombo

Microplastics are a pervasive global pollutant that poses risks to marine organisms including commercially important species and poses threats even to humans. However, the trophic transfer of microplastics is yet to be understood. The present study was to study the occurrence of microplastics in five species used as seafood and in zooplankton, representing different trophic levels and feeding habits caught within coastal waters off Negombo. The Negombo coastal environs are known for high ecological diversity still subjected to massive anthropogenic activities as a major fishing and tourism hub in Sri Lanka. The same area was subjected to contaminating microplastics after the MV X-Press Pearl ship disaster which caught fire and spilled the largest point source of microplastic nurdles pollution in the world. Field sampling was carried out from October to-December 2021 in Negombo, Sri Lanka. The study included zooplankton, some fish (Sardinella gibbosa (n=10), Hemiramphus archipelagicus (n=10), and Ephipphus orbis (n=10)), crustaceans (Scylla serrata, (n=10)) and a bivalve (Perna perna, (n=10)). The samples were subjected to wet peroxide oxidation and acid digestion. Microplastic identification was conducted microscopically and confirmed with Fourier-Transform Infrared (FTIR) spectroscopy, Raman spectroscopy, and Nile red staining techniques. Microplastics were present in all the species studied except zooplankton samples. Four polymer types were identified and confirmed as Polyamide (PA), Polystyrene (PS), Polypropylene (PP), and Polycaprolactone (PCL). According to the literature, this is the first recorded PCL contamination in marine species in Sri Lanka. Fibers were the most abundant microplastic type recorded followed by fragments, films, spheres, and flakes. Red, green, blue, yellow, black, and transparent microplastics were recorded while blue colour was the most prominent. The mean number of microplastics recorded was 0.93±0.29 for S. gibbosa, 0.97±0.17 for H. archipelagicus, 0.53±0.09 for E. orbis, 0.36±0.16 for S. serrata and 1.13±0.29 items/g for P. perna. Investigation of microplastic concentrations at different trophic levels suggests that organisms at lower trophic levels are at greater risk of microplastics. 
 Keywords: Microplastics, Trophic transfer, Marine organisms, Seafood, Negombo

Biochemical and cellular characterization of the CISD3 protein: Molecular bases of cluster release and destabilizing effects of nitric oxide

The NEET proteins, an important family of iron-sulfur (Fe-S) proteins, have generated a strong interest due to their involvement in diverse diseases such as cancer, diabetes, and neurodegenerative disorders. Among the human NEET proteins, CISD3 has been the least studied, and its functional role is still largely unknown. We have investigated the biochemical features of CISD3 at the atomic and in cellulo levels upon challenge with different stress conditions i.e., iron deficiency, exposure to hydrogen peroxide, and nitric oxide. The redox and cellular stability properties of the protein agree on a predominance of reduced form of CISD3 in the cells. Upon the addition of iron chelators, CISD3 loses its Fe-S clusters and becomes unstructured, and its cellular level drastically decreases. Chemical shift perturbation measurements suggest that, upon cluster oxidation, the protein undergoes a conformational change at the C-terminal CDGSH domain, which determines the instability of the oxidized state. This redox-associated conformational change may be the source of cooperative electron transfer via the two [Fe2S2] clusters in CISD3, which displays a single sharp voltammetric signal at-31mV versus SHE. Oxidized CISD3 is particularly sensitive to the presence of hydrogen peroxide invitro, whereas only the reduced form is able to bind nitric oxide. Paramagnetic NMR provides clear evidence that, upon NO binding, the cluster is disassembled but iron ions are still bound to the protein. Accordingly, in cellulo CISD3 is unaffected by oxidative stress induced by hydrogen peroxide but it becomes highly unstable in response to nitric oxide treatment.

Determination of Trace Nickel(ΙΙ) Using a Kinetic Fluorescence Method with a Morin-Hydrogen Peroxide System

Nickel (Ni[Ⅱ]) was used to catalyze the hydrogen peroxide oxidation of morin to weaken its fluorescence. In Na2B4O7-NaOH buffer solution at pH 10.10, Ni(Ⅱ) has an obvious catalytic effect on the oxidation of morin by H2O2 solution. At the maximum excitation and emission wavelengths (λex = 440 nm and λem = 530 nm), the fluorescence intensity of the system is linearly correlated with the concentration of Ni(II) within a certain range. The linear equation is ΔF = 11463ρ (μg/mL) − 34.70, and the R2 = 0.9992. The linear range is 1.6 × 10-2 − 9.6 × 10-2 μg/mL, and the detection limit was 2.9 × 10-4 μg/mL. Finally, the samples of tap water, Yellow River water and tea were analyzed, with the recoveries being 99.6%, 107.3%, and 104.6%, respectively. This method is suitable for the determination of trace Ni(II) in water samples.

Can pharmaceutical care decrease the oxidative stress in type 2 diabetes mellitus?

Type 2 diabetes mellitus (T2D) is a chronic metabolic disorder characterized by an increase in oxidative stress, which is itself related to development of T2D’s main chronic complications. Oxidative stress caused by elevated production of reactive species of oxygen and decrease of antioxidant defense system level, leads to activation of lipid peroxidation (LPO) and oxidative lipoprotein modification with increasing atherogenicity. Therefore, the aim of this study was to evaluate whether pharmacotherapeutic follow-up in patients with T2D, users and non-users of insulin, interferes with the levels of oxidative stress, measuring lipid peroxidation and protein oxidation, nitric oxide and superoxide dismutase levels. After the follow-up, there was a decrease in nitric oxide levels and an increase in superoxide dismutase concentration for the group with insulin therapy. Accordingly, these results show that the proposed pharmaceutical care program reduced the oxidative stress levels, mainly in patients in insulin therapy, as a consequence, can impact in the surging of the main chronic complications in T2D.

Circular economy, turning decay into magic: heparin extraction from pig viscera

The transformation of industrial waste into valuable resources is an increasingly important concept. At Taiwanâ–™s National Cheng Kung University a multi-disciplinary team has been working towards the 17 Sustainable Development Goals (SDGs) adopted by the United Nations member states in 2015 and has developed a method of extracting a valuable medical drug called heparin from agricultural waste. The researchers have combined the advantages of chemical engineering and biotechnology to effectively improve the extraction efficiency and purity of heparin and protected it with technology patents. This exciting innovation could solve the problem of waste disposal from pork production while creating a high-medical value resource from that waste and the residue of the production process could be transformed into fertiliser and animal feed. As such, the researchers believe the application of this technology will help improve the economic productivity of pig farmers and promote environmentally sustainable farming. The value of Chiangâ–™s research are the anticoagulant benefits heparin offers to patients, and also providing new techniques that offer a sustainable and stable supply of the drug. He and the team have taken an innovative approach to extracting heparin sodium, which is the heparin precursor, from pig viscera waste by using dual hydrogen peroxide oxidation methodology and microbial monitoring to enhance the purity of the extracted heparin sodium, creating a higher-quality product for medical applications.

Nitrogen-doped carbon enhances Fe0 activation for efficient tetrabromobisphenol a decontamination and its removal mechanism

Biomass derived N-doped carbon-encapsulated nano zero-valent iron (NC@Fe0) was successfully used to activate hydrogen peroxide (H2O2) for efficient oxidation of tetrabromobisphenol A (TBBPA). The as-prepared NC@Fe0 exhibited high H2O2 activation performance, with a TBBPA removal efficiency of 95.9 % and an oxidation rate constant of 0.031 min−1. The quenching experiments and electrochemical tests showed that the overall contributions of nonradical pathways were over 83.0 %, via synergistic production of singlet oxygen (1O2) and an electron transfer process (ETP). Specifically, the N group on NC@Fe0 greatly enhanced 1O2 production, while formation of surface complexes (OVs-H2O2) was responsible for the ETP mechanism. High Performance Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometer (HPLC-Q-TOF MS/MS) and Toxicity Estimation Software Tool (T.E.S.T) clearly demonstrated that products were mainly generated via debromination and β-scission, where the products were less toxic than the parent. During practical wastewater, in both lake water and domestic wastewaters, NC@Fe0/H2O2 removed over 91.0 % of TBBPA. This study highlighted the considerable contribution of nonradicals in contaminant removal and enriched our understandings of a green activator for future environmental remediations.

Degradation of the cytostatic drug bicalutamide by photo-assisted catalytic wet peroxide oxidation

The presence of cytostatic drugs, such as bicalutamide (BICA), in aquatic compartments reveals the necessity of developing efficient processes for their elimination in wastewater treatment plants (WWTP). This work explores for the first time the use of natural magnetite as a low-cost catalyst in the photo assisted — catalytic wet peroxide oxidation (UV-CWPO) of BICA. For this purpose, real WWTP secondary effluents were spiked with 100 μg/L BICA and subjected to UV-CWPO. Preliminary runs comparing UV photolysis, UV/H2O2, CWPO and UV-CWPO confirmed the synergistic effect of UV radiation and the CWPO process employing magnetite. Afterwards, a parametric study was performed evaluating the influence of the pH, catalyst load, H2O2 dosage, temperature and water matrix. Under optimum operating conditions (pH 0: 6, [magnetite]: 375 mg/L and [H2O2]: 75 mg/L), 99.7 % BICA degradation and 60.7 % mineralization were reached after 30 min in WWTP effluent. UV-CWPO also proved to be effective in hospital wastewater. Catalyst activity was studied in 5 consecutive runs, showing great stability for both BICA removal and TOC elimination. Finally, phytotoxicity tests revealed a lower toxicity in the UV-CWPO effluent compared to the untreated stream. Hence, UV-CWPO proved to be a feasible to eliminate risky cytostatic drugs in relevant environmental matrices.

Optimasi Konsentrasi Fe(II) pada Metode Wet Peroxide Oxidation (WPO) untuk Identifikasi Mikroplastik Polypropylene (PP)

One of the global problem is plastic waste, if not handled properly it will cause waterpollution. Plastic will degrade into samall pasrticles called microplastic. Polyperopylene plastic will be cut very small size and soaked in water and left in an open room for one month, so that the microplastic degrade naturally and become contaminated by organic impurities. The method used is Wet Peroxide Oxidation (WPO) which was adapted from the National Oceanic and atsmospheric (NOAA). Optimization was carried out the concentration of the Fe(II) catalyst with variations (0.025, 0.05, 0.075, 0.1, 0.125) M. The research result showed that the optimum condition for the Fe(II) consentration was 0.1 M as evidenced by the microplastic mass obtained. Characterization tests were carried out using a stereo microscope, and microplastics were found in the form of fragments and filament.

High Power Density of a Hydrogen Peroxide Fuel Cell Using Cobalt Chlorin Complex Supported on Carbon Nanotubes as a Noncorrosive Anode.

Hydrogen peroxide fuel cells (HPFCs) have attracted much attention due to their simple one-compartment structures and high availability under harsh conditions such as an anaerobic environment; however, catalysis improvement is strongly demanded for both anodes and cathodes in terms of activity and durability. Herein, we report the high catalytic activity of CoII chlorin [CoII(Ch)] for hydrogen peroxide (H2O2) oxidation with a low overpotential (0.21 V) compared to that of the CoII phthalocyanine and CoII porphyrin complexes, which have previously been reported as active anode catalysts. Linear sweep voltammograms and differential pulse voltammograms of the CoII complexes (CoIIL) and the corresponding ligands clearly showed that the CoIIIL species are the active species for H2O2 oxidation. Then, one-compartment HPFCs were constructed with CoII(Ch) supported on multiwalled carbon nanotubes (CNTs) as the anode together with FeII3[CoIII(CN)6]2 supported on CNTs as the cathode. The maximum power density of the HPFCs reached 151 μW cm-2 with an open circuit potential of 0.33 V when the coverage of CNT surfaces with CoII(Ch) exceeded ∼60% at the anode.

Degradation of sodium butylxanthate in flotation wastewater by natural pyrite via visible light-assisted advanced oxidation processes: A comprehensive study

The advanced oxidation process (AOPs) based on natural pyrite (NP) as a catalyst is a promising strategy for flotation wastewater purification. However, the slow Fe(III)/Fe(II) cycle limits the number of active sites during oxidant activation. Therefore, this work attempts to accelerate Fe(III)/Fe(II) reduction on NP surface by introducing visible light irradiation. By comparing the degradation performance of sodium butylxanthate (SBX) via various oxidants (peroxydisulfate, periodate, hydrogen peroxide, and sulfite) activation under visible light, periodate was selected as the most suitable oxidant for SBX removal. Although peroxydisulfate exhibits optimal SBX degradation in acidic environments, its failure in alkaline environments and poor reusability caused by high surface oxidation limit its application. The investigation of active species suggests that O2[Formula: see text] are the dominant active species in hydrogen peroxide and sulfite activation systems, while the electron transfer process is the dominant active species in peroxydisulfate and periodate activation systems. Electrochemistry elucidates the interaction of different oxidants on the NP surface. XPS analysis revealed that the photogenerated electrons induced by visible light irradiation accelerate the Fe(III)/Fe(II) cycle on NP surface, thereby improving the continuous activation of NP towards the oxidants. In addition, the ecotoxicity of wastewater treated by the periodate activation system is greatly reduced. This work provides a new idea towards flotation wastewater purification.

Single-Particle Spectroelectrochemistry: Promoting the Electrocatalytic Activity of Gold Nanorods via Oxygen Plasma Treatment without Structural Deformation.

Understanding of the electrocatalytic activity enhancement in gold nanoparticles is still limited. Herein, we present the effect of the oxygen plasma treatment on the electrochemical activity of gold nanorods (AuNRs). Oxygen plasma treatment resulted in the blueshift and line width narrowing of the localized surface plasmon resonance (LSPR) spectra obtained from individual AuNRs immobilized on an indium tin oxide (ITO) surface. These changes can be attributed to increases in the surface charges of the AuNRs. The formation of a Au-ITO heterojunction provided structural stability to the immobilized AuNRs regardless of the duration of oxygen plasma exposure. The electrocatalytic oxidation of hydrogen peroxide (H2O2) was induced by increases in the free-electron densities on the surfaces of these AuNRs owing to oxygen plasma treatment, and Au did not dissolve under the experimental conditions. However, the potential-dependent LSPR spectra of the individual AuNRs showed similar patterns of LSPR behavior, irrespective of the duration of oxygen plasma treatment and the concentration of H2O2. Therefore, this study based on single-particle spectroelectrochemistry and cyclic voltammetry improves the understanding of the role of oxygen plasma treatment in promoting the catalytic activity of structurally stable AuNRs immobilized on an ITO surface.

Icariin ameliorates the cuprizone-induced demyelination associated with antioxidation and anti-inflammation.

The treatment of immunomodulation in multiple sclerosis (MS) can alleviate the severity and relapses. However, it cannot improve the neurological disability of patients due to a lack of myelin protection and regeneration. Therefore, remyelinating therapies may be one of the feasible strategies that can prevent axonal degeneration and restore neurological disability. Natural product icariin (ICA) is a flavonol compound extracted from epimedium flavonoids, which has neuroprotective effects in several models of neurological diseases. Here, we attempt to explore whether ICA has the potential to treat demyelination and its possible mechanisms of action using lipopolysaccharide-treated BV2 microglia, primary microglia, bone marrow-derived macrophages, and cuprizone-induced demyelination model. The indicators of oxidative stress and inflammatory response were evaluated using commercial kits. The results showed that ICA significantly reduced the levels of oxidative intermediates nitric oxide, hydrogen peroxide, malondialdehyde, and inflammatory cytokines TNF-α, IL-1β, and increased the levels of antioxidants superoxide dismutase, catalase, glutathione peroxidase, and anti-inflammatory cytokines IL-10 and TGF-β in vitro cell experiments. In vivo demyelination model, ICA significantly alleviated the behavioral abnormalities and enhanced the integrated optical density/mm2 of Black Gold II and myelin basic protein myelin staining, accompanied by the inhibition of oxidative stress/inflammatory response. Immunohistochemical staining showed that ICA significantly induced the expression of nuclear factor erythroid derived 2/heme oxygenase-1 (Nrf2/HO-1) and inhibited the expression of toll-like receptor 4/ nuclear factor kappa B (TLR4/NF-κB), which are two key signaling pathways in antioxidant and anti-inflammatory processes. Our results strongly suggest that ICA may be used as a potential agent to treat demyelination via regulating Nrf2/HO-1-mediated antioxidative stress and TLR4/NF-κB-mediated inflammatory responses.

Bis(1-methylimidazol-2-yl) diselenide and its evaluation as a chemical radio-protector: role of kinetic rate constants for ROS scavenging and glutathione peroxidase like activity

Bis(1-methylimidazol-2-yl) diselenide (MeImSe), a derivative of selenoneine, has been examined for bimolecular rate constants for scavenging of various radiolytically and non-radiolytically generated reactive oxygen species (ROS). Further, its potential to show glutathione peroxidase (GPx)-like activity and to protect in vitro models of DNA and lipid against radiation induced strand breakage and lipid peroxidation, respectively were studied. The results confirmed that MeImSe scavenged all major short-lived (hydroxyl radical) and long-lived (peroxyl radical, carbonate radical, nitrogen dioxide radical, hypochlorite and hydrogen peroxide) oxidants involved in the radiation toxicity either directly or through GPx-like catalytic mechanism. The rate constants of MeImSe for these oxidants were found to be comparable to analogous sulfur and selenium-based compounds. The enzyme kinetics study established that MeImSe took part in the GPx cycle through the reductive pathway. Further, MeImSe inhibited the radiation induced DNA strand cleavage and lipid peroxidation with half maximal inhibitory concentration (IC50) of ∼ 60 μM and ∼100 μM, respectively. Interestingly, MeImSe treatment in the above concentration range (>100 μM) did not show any significant toxicity in normal human lung fibroblast (WI26) cells. The balance between efficacy and toxicity of MeImSe as a chemical radioprotector was attributed to the formation of less reactive intermediates during its oxidation/reduction reactions as evidenced from NMR studies. Highlights MeImSe, a derivative of selenoneine protects DNA and lipid from radiation damage MeImSe scavenges all major short- and long-lived oxidants involved in radiation toxicity Rate constants of MeImSe for ROS scavenging determined by pulse radiolysis technique First organoselenium compound reported to scavenge nitrogen dioxide radical MeImSe exhibits GPx-like activity through reductive pathway

A novel concept and design for highly efficient photoelectrocatalytic materials with high performance, stability, and charge transport properties: development of an innovative next-generation green technology.

In semiconductors, generating charges via catalysis is a highly challenging task and characteristic of heterojunction photoanodes. A dithiophene-4,8-dione spin-coated film layer has a positive effect on the holes (positive charge carriers) for a long time in BHJ films in the solid state of materials. The photoexcited holes created in the BHJ film can persist for long periods of time, which is beneficial for catalytic reactions. In this study, a photoanode is electrically coupled to a hydrogen gas-evolving platinum cathode. When the photoanode is electrically coupled to a H2 gas evolving Pt cathode, curiously long-lived hole polaron states are observed on the timescale of seconds under operational conditions. These long-lived holes play a crucial role in enhancing the hydrogen peroxide oxidation performance of the film overlayer spin-coated onto the photoanode. The spin-coated film overlayer on the photoanode achieves the best oxidation performance for hydrogen peroxide of approximately 6.5 mA cm-2 at 1.23 VRHE without the need of a catalyst. This demonstrates the effectiveness of the overlayer in improving the catalytic performance of the photoanode with a better efficiency of 17.5% when using 851 nm excitation. This indicates that a relatively high percentage of incident photons at that specific wavelength is converted into photocurrent by the photoanode. This approach can lead to more efficient oxidation catalysis as demonstrated in the case of hydrogen peroxide oxidation.

The development of an analytical procedure for the determination of microplastics in freshwater ecosystems.

Microplastics raise growing concerns regarding their ubiquity and possible negative impact on human health; therefore, the need for comparable, standardized methods is urgent. Modern instrumental analytical techniques, such as IR and Raman spectroscopy, pyrolysis-gas chromatography-mass spectrometry and electron microscopy, are fundamental for the analysis of microplastics in environmental and biological objects. The quality of the samples prepared is a determining factor in the validity of the results obtained. Based on our research, currently approaches to preparing environmental samples are time-consuming and need some improvements. To overcome this problem, a new method for the preparation of freshwater samples was developed. In our research, peracetic acid and its combination with Fenton's reagent were employed for the first time to prepare natural water samples. Furthermore, we proposed the use of a heavy liquid based on sodium heteropolyoxotungstate with a density of 1.70 g cm-3, which allows the extraction of polymers with high density and is non-toxic. The new approach was compared with the most commonly used sample preparation method (peroxide oxidation (30% H2O2 + 0.05 M Fe(II) solution)) and showed higher recovery efficiency for microplastic particles in both test and freshwater samples collected from the rivers Ob (Novosibirsk, Russia) and Berd (Berdsk, Russia). The obtained results are promising; the time spent on this procedure is no more than 3 hours, which is 6 to 12 times faster than the most widely used methods. In addition, this approach makes it possible to obtain samples suitable for subsequent analysis by any analytical instrumental method.

Scanning electrochemical probe microscopy: towards the characterization of micro- and nanostructured photocatalytic materials.

Platinum-black (Pt-B) has been demonstrated to be an excellent electrocatalytic material for the electrochemical oxidation of hydrogen peroxide (H2O2). As Pt-B films can be deposited electrochemically, micro- and nano-sized conductive transducers can be modified with Pt-B. Here, we present the potential of Pt-B micro- and sub-micro-sized sensors for the detection and quantification of hydrogen (H2) in solution. Using these microsensors, no sampling step for H2 determination is required and e.g., in photocatalysis, the onset of H2 evolution can be monitored in situ. We present Pt-B-based H2 micro- and sub-micro-sized sensors based on different electrochemical transducers such as microelectrodes and atomic force microscopy (AFM)-scanning electrochemical microscopy (SECM) probes, which enable local measurements e.g., at heterogenized photocatalytically active samples. The microsensors are characterized in terms of limits of detection (LOD), which ranges from 4.0 μM to 30 μM depending on the size of the sensors and the experimental conditions such as type of electrolyte and pH. The sensors were tested for the in situ H2 evolution by light-driven water-splitting, i.e., using ascorbic acid or triethanolamine solutions, showing a wide linear concentration range, good reproducibility, and high sensitivity. Proof-of-principle experiments using Pt-B-modified cantilever-based sensors were performed using a model sample platinum substrate to map the electrochemical H2 evolution along with the topography using AFM-SECM.