Peroxide Compounds Research Articles

Selective grafting polymerization of nanochannels in track-etched pet membranes initiated by remnant peroxides

Track-etched PET membranes (TMs) are one of the first commercially available nanostructured materials. The number, size and shape of pores (or nanochannels) can be carefully tailored at industrial scale. Selective pore modification can be achieved using remnant radicals after the etching process; however, this technique has some limitations. In this work, a simple and straightforward procedure is described for selectively grafting glycidyl methacrylate (GMA) and acrylic acid into the nanochannel walls of track-etched PET membranes. Grafting polymerization was carried out at short and long post-etching time by thermal initiation. The ultra-low amounts of grafting modification were measured by fluorescence labelling and membrane hydrolysis. The presence/absence of polyGMA and polyacrylic acid was confirmed by FTIR spectroscopy and MS-ESI. Peroxide compounds were detected in track-etched membranes and attributed responsibility for the selective grafting polymerization in the nanochannel walls of TMs. This simple and quick procedure will enhance the development of novel functional materials based on this technology.

Hypergolic propellants based on hydrogen peroxide and organic compounds: historical aspect and current state

The research towards the development of new propellants aims to ensure not only their high performance, but also high environmental compatibility and low toxicity. Considerable attention is paid to the development of hypergolic propellant compositions, the use of which markedly simplifies the engine design and rocket system operation and provides the possibility of their repeated use. Hydrogen peroxide is a promising and nontoxic oxidant. The review summarizes the research and development data concerning the design and application of hypergolic rocket propellants involving hydrogen peroxide, starting from the 1930s and up to now. The data presented in the review could be useful for specialists engaged in the development of prospective high-performance green fuels.

Chronopotentiometric/chronoamperometric transient analysis of naproxen via electrochemically synthesized nano spinel ZnFe2O4 films

Nano spinel zinc ferrite films (ZFO) are synthesized by peroxide assisted electrochemical oxidation and used as functional anodic material to detect naproxen under chronopotemtiometric and chronoamperometric mode. Electrochemical characterization, texture, morphology and lattice structure of the films were explored. Electrochemical kinetics of oxy hydroxide deposition as well as anodic oxidation was evaluated and it follows quasi-reversible type. Formation of Zn2+ rich ferrite phase was impeded by mass-transfer rate, whereas Fe2+ oxy hydroxides formation was lowered in the initial stages by charge-transfer rate, with the diffusion coefficient of 6.44 × 10−8 cm2 s−1 and has an exchange current density of 0.83 A dm−2. In IR spectra, tetrahedral ZnO (463 cm−1) and octahedral FeO stretching (630 cm−1) vibrations are distinct. Based on X-ray diffraction data lattice parameters and d-spacing were explored with indigenously designed computer simulation program, ‘Crystalsim’. From electronic configurations and geometric correlations, it was observed that, tetrahedral sites are occupied by Zn2+ and octahedral sites are occupied by Fe3+ ions and thus forms normal cubic spinel and the O2– form fcc lattice. Anodic oxidation of naproxen involves predominantly one electron transfer through the formation of 2-methoxy-6-ethylnaphthalene carbanion by surface adsorptive decarboxylation followed by formation of peroxide compound. Thermodynamic parameters were estimated and the rate constant and free energy are 2.49 × 10−9 s−1 and −49.91 kJ mol−1 respectively. Surface coverage concentration of anions was about 3.45 × 10−10 mol cm−2 at 1.00 × 10−4 M and charge-transfer restriction lowers the coverage rate and 4.03 × 10−4 mM of anion was undergone for oxidative e- transfer under an applied potential of 0.55 V at 300 s. By ANOVA techniques, Limit of Detection and Limit of Quantitation were assessed and are about 1.30 × 10−5 M and 4.10 × 10−5 M respectively. Using non-linear interpolation models and from higher order polynomials, quantification of naproxenate ion can be achieved with better precision from the oxidation charge at the applied anodic potential. From electrochemical impedance studies, it can be shown that ZFO has substantial electrocatalytic activity towards the oxidation of naproxenate anion. The Nyquist charge-transfer resistance of the modified ZFO after adsorption and oxidation of the naproxenate anions is increased (2928 Ω) significantly when compared with unmodified ZFO (509 Ω). Since potentials are discrete in presence of interfering ions, such as ibuprofen, salicylate diion and Cl− and the respective selectivity coefficients were estimated by mixed two-solution method. It is about 1.9843 and 0.3509 at 1.0 × 10−4 M for ibuprofen and methyl salicylate respectively. As electrochemical synthesis of ZFO is relatively cost-effective and the fabricated films can be deployed as a viable functional anodic material for electrochemical detection of naproxen by chronopotentiometric/chronoamperometric techniques.

Biomonitoring airborne pollution: a case study of “Urginea maritima” species in Bentael natural reserve – Lebanon

ABSTRACTBiomonitoring airborne pollution has been a widespread practice. Its advantages make it an alternative to costly technological techniques. In this context, a rare species “Urginea maritima” was tested to measure the changes surrounding Bentael natural reserve in Lebanon, triggered by the inauguration of a new road on its south side, and revealed alarming results through two years study (2015–2016). Three environmental indicators were evaluated: Air Pollution Tolerance Index, Total Antioxidant Capacity and leaf Relative Water Content. These factors showed the escalated evolution of the air pollution during the studied months. In addition, six parameters, separated between pollution markers and scavengers, were studied: hydrogen peroxide, pheophytin, proline, ascorbic acid, carotenoids and total phenolic compounds showed a gradual and sharp increase. The passive biomonitoring with plants confirmed to be a reliable method to evaluate airborne pollution effects which will expose new extent to establish a routine monitoring program in Lebanon.

Steering reduction and decomposition of peroxide compounds by interface interactions between MgO thin film and transition-metal support

The detection, removal and reduction of hydrogen peroxide and organic peroxides is of significant importance for its increasing application in the areas of environment, food, electrochemistry and clinical laboratory. Herein the dissociative adsorption behavior of H2O2 and organic peroxides on ultrathin magnesia (0 0 1) films deposited on transition metal is uncovered for the first time by employing periodic density-functional theory calculations with van der Waals corrections. Splitting of H2O2 on bulk MgO(0 0 1) is highly endothermic process with activation barrier 1.85 eV, indicating it is extraordinarily difficult to dissociate H2O2 on pristine MgO(0 0 1). The H2O2 is dissociated smoothly and reduced to surface hydroxyls on MgO(0 0 1)/TM, and the dissociative adsorption energies of all the considered fragmentation configurations are substantially negative, demonstrating dissociation and reduction of H2O2 is thermodynamically favorable. The mechanism of reactivity enhancement for energetically and dynamically favorable decomposition of H2O2 on supported magnesia is elucidated by characterizing the geometric structures and electronic properties. The fragmentation and reduction of diethyl peroxide and peroxyacetone are also studied to reveal the catalytic activity of ultrathin magnesia toward splitting organic peroxides. The results are wished to provide useful clue for detecting and reducing hydrogen peroxide and organic peroxides by employing oxide-metal hybrid nanostructure.

Physicochemical Characterization and Antinociceptive Effect of β-cyclodextrin/Lippia pedunculosa Essential Oil in Mice.

Some research studies have shown that Lippia pedunculosa essential oil (EOLP) has interesting biological activities. However, its low water solubility is the main challenge to achieve its therapeutic potential. In this context, Cyclodextrins (CDs) have been widely used in order to overcome this problem due to your capability to improve the physicochemical properties of drugs. In this perspective, the main goal of this study was to investigate how the improvement of the physicochemical properties of inclusion complexes (EOLP and β-CD) enhance the antinociceptive effect in mice. To achieve that, we prepared samples by Physical Mixture (PM), Paste Complexation (PC) and Slurry Complexation (SC) methods, followed by their physicochemical characterization. In addition, it was evaluated if the use of β-CD enhances the antinociceptive effect of EOLP in mice. The analysis showed that rotundifolone (72.02%) was the major compound of EOLP and we found out based on DSC results that β-CD protected it from oxidation. In addition, TG techniques demonstrated that the best inclusion methods were PC and SC, due to their greater weight loss (10.8 and 11.6%, respectively) in the second stage (171-312°C), indicating that more complexed oil was released at the higher temperature than oil free. Other characteristics, such as changes in the typical crystalline form, and reduced particle size were observed by SEM and laser diffraction, respectively. The SC was the most effective complexation method, once the presence of rotundifolone was detected by FTIR. Based on that, SC method was used in all mice tests. In this regard, the number of paw licks was reduced for both compounds (all doses), but EOLP was more effective in reducing the nociceptive behavior. Therefore, CDs seem not to be a good tool to enhance the pharmacological properties of EOs rich in peroxide compounds such as rotundifolone.

Lignin and extractives degradation in poplar wood in the presence of hydrogen peroxide and molybdenum polyoxometalated compound

Lignin is an unwanted by-product in bioethanol production from a biomass. The treatment of poplar wood with hydrogen peroxide induces only a decreased amount of extractives and a small reduction in the amount of cellulose in the wood. When the reaction is performed in the presence of H3PMo12O40, besides the reduction of extractives, an effective decrease in the lignin amount (from 29 to 10%) was observed. A small reduction of the cellulose amount has been observed. When the reaction is performed in the presence of light, a reduction of the efficiency in lignin decomposition has been observed.

Abscisic acid cross-talking with hydrogen peroxide and osmolyte compounds may regulate the leaf rolling mechanism under drought

Leaf rolling observed in some crops such as maize, rice, wheat and sorghum is an indicator of decreased water status. Moderate leaf rolling not tightly or early increases the photosynthesis and grain yield of crop cultivars under environmental stresses. Moreover, the effects of exogenous abscisic acid (ABA) on stomatal conductance, water status and synthesis of osmotic compounds are a well-known issue in plants subjected to water deficit. However, it is not clear how the cross-talk of ABA with H2O2 and osmolyte compounds affects the leaf rolling mechanism. Regulation mechanism of leaf rolling by ABA has been first studied in maize seedlings under drought stress induced by polyethylene glycol 6000 (PEG 6000) in this study. ABA treatment under drought stress reduced hydrogen peroxide (H2O2) content and the degree of leaf rolling (%) while the treatment-induced ABA synthesis, osmolyte levels (proline, polyamine and total soluble sugars) and some antioxidant enzyme activities in comparison to the plants that were not treated with ABA. Furthermore, exogenous ABA up-regulated the expression levels of arginine decarboxylase (ADC) and pyrroline-5-carboxylate synthase (P5CS) genes and down-regulated polyamine oxidase (PAO), diamine oxidase (DAO) and proline dehydrogenase (ProDH) gene expressions. When endogenous ABA content was decreased by the treatment of fluoridone (FLU) that is an ABA inhibitor, leaf rolling degree (%), H2O2 content and antioxidant enzyme activities increased, but osmolyte levels, ADC and P5CS gene expressions decreased. Finally, the treatment of ABA to maize seedlings exposed to drought stress resulted in the stimulation of the antioxidant system, osmotic adjustment and reduction of leaf rolling. We concluded that ABA can be a signal compound cross-talking H2O2, proline and polyamines and thus involved in the leaf rolling mechanism by providing osmotic adjustment. The results of this study can be used to provide data for the molecular breeding of maize hybrids with high grain yield by means of moderately rolled leaves.

STUDY OF PURIFICATION PROCESS OF VEGETABLE OIL BY PINK CLAY

The phase composition of natural pink clay was studied and influence of sorption properties on purification of mustard oil was investigated. The clay was activated by treatment with oxalic acid and sodium carbonate before using. The acid-base activation of natural material was shown to promote the creation of the new centers on its surface. The new materials demonstrated a positive effect on the oil purification process from fatty acids, peroxide compounds and no effect on the concentrations of carotenoids.

Darkening, damage and oxidative protection are stimulated in tissues closer to the yam cut, attenuated or not by the environment.

This study investigated how the activities of the enzymes and metabolites of oxidative metabolism are affected in different regions of cut tissue, associating these changes with the evolution of browning in fresh-cut yam. Samples were collected from yam at 0-5 and 5-10 mm from the cut site. Fresh-cut yams were stored at 5 or 26 °C for days or hours respectively, simulating commercialization, with or without packaging. The results demonstrated that the injury to the yam was a physical inducer of changes in the levels of lipid peroxidation and phenolic compounds and in the activities of superoxide dismutase, catalase, ascorbate peroxidase, polyphenol oxidase and peroxidase. These responses were significant in the tissue closest to the wound but also observed, although less intense, in the more distant tissue. The combined effects of wounding and dehydration during storage intensified the above responses. Conversely, refrigeration attenuated the transmission of the wounding response through the adjacent tissue. The results of this work provide the first evidence in cut yam roots that the membrane degradation products, enzymes involved in oxidative protection and enzymes that modulate the oxidation of phenolic compounds are intertwined mechanisms that cause tissue darkening. © 2018 Society of Chemical Industry.

Plasma lipid peroxidation biomarkers for early and non-invasive Alzheimer Disease detection

IntroductionAlzheimer Disease (AD) standard diagnosis is based on evaluations and biomarkers that are non-specific, expensive, or requires invasive sampling. Therefore, an early, and non-invasive diagnosis is required. As regards molecular mechanisms, recent research has shown that lipid peroxidation plays an important role. MethodsWell-defined participants groups were recruited. Lipid peroxidation compounds were determined in plasma using a validated analytical method. Statistical studies consisted of an elastic-net-penalized logistic regression adjustment. ResultsThe regression model fitted to the data included six variables (lipid peroxidation biomarkers) as potential predictors of early AD. This model achieved an apparent area under the receiver operating characteristics (AUC-ROCs) of 0.883 and a bootstrap-validated AUC-ROC of 0.817. Calibration of the model showed very low deviations from real probabilities. ConclusionA satisfactory early diagnostic model has been obtained from plasma levels of 6 lipid peroxidation compounds, indicating the individual probability of suffering from early AD.

Antibacterial and antioxidant activity of different types of honey derived from Mount Olympus in Greece.

The aim of the present study was to examine the antioxidant and antibacterial activity of 21 types of honey derived from Mount Olympus (Mt. Olympus), a region with great plant biodiversity. The antibacterial activity was examined against the growth of Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) by the agar well diffusion assay and the determination of the minimum inhibitory concentration (MIC). The antioxidant activity was assessed by using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS•+) free radical scavenging assays. These activities were compared to Manuka honey which is used as an alternative medicine. The results revealed that all tested honey types exhibited antibacterial activity against S. aureus and P. aeruginosa. The MIC of the tested honey types against S. aureus ranged from 3.125 to 12.5% (v/v), while MIC of Manuka honey was determined to be 6.25% (v/v). The MIC values of the tested honey types against P. aeruginosa ranged from 6.25 to 12.5% (v/v) and the MIC of Manuka honey was determined at 12.5% (v/v). Moreover, the results suggested that the presence of hydrogen peroxide and proteinaceous compounds in the honey types accounted, at least in part, for the antibacterial activity. In addition, the total polyphenolic content (TPC) of the honey types seemed to contribute to the antibacterial activity against P. aeruginosa. Furthermore, some of the tested honey types exhibited potent free radical scavenging activity against DPPH and ABTS•+ radicals, which was greater than that of Manuka honey. The results indicated that not only the quantity, but also the quality of the polyphenols were responsible for the antioxidant activity. Moreover, four honey types exhibiting great antioxidant activity were converted to powder using a freeze drying method. The results indicated that following conversion to powder all honey types, apart from one, retained their antioxidant activity, although their TPC was reduced. On the whole, and at least to the best of our knowledge, the present study is the first that extensively examined the bioactivities of different types of honey derived from Mt. Olympus.

Production of High-Value-Added Chemicals on Oxide Semiconductor Photoanodes under Visible Light for Solar Chemical-Conversion Processes

This study reviews recent progress on the oxidative production of various high-value-added chemicals using simple and inexpensive oxide semiconductor photoanodes for technology associated with solar-to-chemical conversion processes. The photoelectrochemical production of oxidizing reagents can be highly economical and contribute to global warming by replacing the conventional processes. Various oxidizing reagents and useful chemicals, such as hydrogen peroxide (H2O2), hypochlorous acid (HClO), persulfates (H2S2O8), IO4–, Ce4+, and organic compounds, can be produced photoelectrochemically with excellent faradaic efficiencies. This process also allows H2O2 production via both photoanodic and cathodic reactions without external bias. These photoelectrochemical processes are key technologies enabling the expansion of solar energy utilization toward a sustainable and low-carbon society.

Key role of hydrogen peroxide in antimicrobial activity of spring, Honeydew maquis and chestnut grove Corsican honeys on Pseudomonas aeruginosa DNA.

We started to determine the antibacterial efficiency of Corsican chestnut grove and honeydew maquis honeys on Pseudomonas aeruginosa. No morphological alteration of the bacterial surface was observed. Antimicrobial action seems to be related to the synergy between hydrogen peroxide and phenolic compounds. The exerted pro-oxidant activity leads to a degradation of P. aeruginosa plasmidic DNA. This is the first study that investigate the primary antibacterial mechanism of Corsican honeys.

Novel Peroxides as Promising Anticancer Agents with Unexpected Depressed Antimalarial Activity.

Twenty six peroxides belonging to bridged 1,2,4,5-tetraoxanes, bridged 1,2,4-trioxolanes (ozonides), and tricyclic monoperoxides were evaluated for their in vitro antimalarial activity against Plasmodium falciparum (3D7) and for their cytotoxic activities against immortalized human normal fibroblast (CCD19Lu), liver (LO2 ), and lung (BEAS-2B) cell lines as well as human liver (HepG2) and lung (A549) cancer-cell lines. Synthetic ozonides were shown to have the highest cytotoxicity on HepG2 (IC50 =0.19-0.59 μm), and some of these compounds selectively targeted liver cancer (selectivity index values for compounds 13 a and 14 a are 20 and 28, respectively) at levels that, in some cases, were higher than those of paclitaxel, artemisinin, and artesunic acid. In contrast some ozonides showed only moderate antimalarial activity against the chloroquine-sensitive 3D7 strain of P. falciparum (IC50 from 2.76 to 24.2 μm; 12 b, IC50 =2.76 μm; 13 a, IC50 =20.14 μm; 14 a, IC50 =6.32 μm). These results suggest that these derivatives have divergent mechanisms of action against cancer cells and malaria-infected cells. A cyclic voltammetry study of the peroxides was performed, but most of the compounds did not show direct correlation in oxidative capacity-activity. Our findings offer a new source of antimalarial and anticancer agents through structural modification of peroxide compounds.

Reliable determination of new lipid peroxidation compounds as potential early Alzheimer Disease biomarkers

Lipid peroxidation plays an important role in Alzheimer Disease, so corresponding metabolites found in urine samples could be potential biomarkers. The aim of this work is to develop a reliable ultra-performance liquid chromatography-tandem mass spectrometry analytical method to determine a new set of lipid peroxidation compounds in urine samples.Excellent sensitivity was achieved with limits of detection between 0.08 and 17 nmol L−1, which renders this method suitable to monitor analytes concentrations in real samples. The method's precision was satisfactory with coefficients of variation around 5–17% (intra-day) and 8–19% (inter-day). The accuracy of the method was assessed by analysis of spiked urine samples obtaining recoveries between 70% and 120% for most of the analytes. The utility of the described method was tested by analyzing urine samples from patients early diagnosed with mild cognitive impairment or mild dementia Alzheimer Disease following the clinical standard criteria. As preliminary results, some analytes (17(RS)−10-epi-SC-Δ15−11-dihomo-IsoF, PGE2) and total parameters (Neuroprostanes, Isoprostanes, Isofurans) show differences between the control and the clinical groups. So, these analytes could be potential early Alzheimer Disease biomarkers assessing the patients’ pro-oxidant condition.

Metal-Organic Frameworks as Sorbents for Purification of Vegetable Oils

The ability of cobalt-, iron-, and zinc-containing framework compounds to take up impurities (free fatty acids and peroxide compounds) from linseed, false fl ax, and sunfl ower oil was studied. These framework structures improve the physicochemical properties and quality of the vegetable oils tested. The metal-organic frameworks surpass in performance the traditionally used industrial and natural sorbents. The sorbents tested preserve the performance for no less than five cycles.

Reactions of Initiation and Reinitiation in Polymerization Mediated by Organoborane–Oxygen Systems

The kinetics and mechanism of initiation and reinitiation reactions in the polymerization of methyl methacrylate mediated by the ammonia–tripropylborane–oxygen and 2-isopropyl-2-boraadamantane–oxygen systems are studied by ESR spectroscopy using C-phenyl-N-tert-butylnitrone and 2-methyl-2-nitrosopropane as spin traps. It is shown that alkyl and alkoxyl radicals are the main initiating radicals and the rate of initiation is directly proportional to the concentration of oxygen. Two mechanisms of radical formation are valid in the postpolymerization of methyl methacrylate at room temperature under vacuum. The first one (which is predominant) is the decomposition of poly(methyl methacrylate)–boroxyl macromolecules, i.e., the reinitiation of polymerization; the second one (additional during the first 30 min of the process) is the decomposition of borane peroxide compounds accumulated during the stage of oxidation.

Effect of trehalose- an impermeant cryoprotectant on cryopreservation of Black Bengal buck semen

The experiment was conducted to study the effect of trehalose an impermeant extra cellular cryoprotectant supplementation on cryopreservation of Black Bengal buck semen. Semen ejaculates (n = 24) were diluted in Tris- soybean lecithin - glycerol extender having trehalose @ 0, 50,100and 150 mM. Samples were equilibrated at 5°C for 3 hrs, frozen and stored in liquid nitrogen. Semen samples were evaluated for sperm motility,functional membrane integrityand concentration of lipid peroxide compound malondialdehyde at three stages such as 10 minsafter dilution with extender, after completion of equilibration period and after freeze thawing. It was found that the control group (0mM trehalose)had significantly better in vitro sperm characters when compared to extenders supplemented with trehalose (50 mM , 100 mM and 150 mM) during different stages of cryopreservation. It can be concluded that supplementation of trehaloseas a cryoprotectant did not improve the cryopreservability of Black Bengal buck semen.

Current state and urgent problems of production of hydrogen peroxide and peroxide compounds in Russia

Current state and urgent problems of production of hydrogen peroxide and peroxide compounds in Russia