Hydrogen Peroxide

The world rapidly growing demand for manganese has made it increasingly important to develop processes for economical recovery of manganese from low grade manganese ores and other secondary sources. Part I of this review outlines metallurgical processes for manganese production from various resources, particularly focusing on recent developments in direct hydrometallurgical leaching and recovery processes to identify potential sources of manganese and products which can be economically produced.

Glucose oxidase (β-D-glucose:oxygen 1-oxidoreductase; EC 1.1.2.3.4) catalyzes the oxidation of β-D-glucose to gluconic acid, by utilizing molecular oxygen as an electron acceptor with simultaneous production of hydrogen peroxide. Microbial glucose oxidase is currently receiving much attention due to its wide applications in chemical, pharmaceutical, food, beverage, clinical chemistry, biotechnology and other industries. Novel applications of glucose oxidase in biosensors have increased the demand in recent years. Present review discusses the production, recovery, characterization, immobilization and applications of glucose oxidase. Production of glucose oxidase by fermentation is detailed, along with recombinant methods. Various purification techniques for higher recovery of glucose oxidase are described here. Issues of enzyme kinetics, stability studies and characterization are addressed. Immobilized preparations of glucose oxidase are also discussed. Applications of glucose oxidase in various industries and as analytical enzymes are having an increasing impact on bioprocessing.

Over the past 10-20 years the amount of the natural organic matter (NOM) has been increased in raw water supplies on several areas. The presence of NOM causes many problems in drinking water treatment processes, including: (i) negative effect on water quality by colour, taste and odor problems, (ii) increased coagulant and disinfectant dose requirements (which in turn results increased sludge and potential harmful disinfection by-product formation), (iii) promoted biological growth in distribution system, and (iv) increased levels of complexed heavy metals and adsorbed organic pollutants. Thus, more efficient methods for the removal of NOM have emerged. Among these are advanced oxidation processes (AOPs). These include O 3 /H 2 O 2 , O 3 /UV, UV/H 2 O 2 , TiO 2 /UV, H 2 O 2 /catalyst, Fenton and photo-Fenton prosesses as well as ultrasound. In the present work, an overview of the recent research studies dealing with AOP methods for the removal of NOM and related compounds from drinking water is presented.

Radiation hazards in outer space present an enormous challenge for the biological safety of astronauts. A deleterious effect of radiation is the production of reactive oxygen species, which result in damage to biomolecules (e.g., lipid, protein, amino acids, and DNA). Understanding free radical biology is necessary for designing an optimal nutritional countermeasure against space radiation–induced cytotoxicity. Free radicals (e.g., superoxide, nitric oxide, and hydroxyl radicals) and other reactive species (e.g., hydrogen peroxide, peroxynitrite, and hypochlorous acid) are produced in the body, primarily as a result of aerobic metabolism. Antioxidants (e.g., glutathione, arginine, citrulline, taurine, creatine, selenium, zinc, vitamin E, vitamin C, vitamin A, and tea polyphenols) and antioxidant enzymes (e.g., superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidases) exert synergistic actions in scavenging free radicals. There has been growing evidence over the past three decades showing that malnutrition (e.g., dietary deficiencies of protein, selenium, and zinc) or excess of certain nutrients (e.g., iron and vitamin C) gives rise to the oxidation of biomolecules and cell injury. A large body of the literature supports the notion that dietary antioxidants are useful radioprotectors and play an important role in preventing many human diseases (e.g., cancer, atherosclerosis, stroke, rheumatoid arthritis, neurodegeneration, and diabetes). The knowledge of enzymatic and non-enzymatic oxidative defense mechanisms will serve as a guiding principle for establishing the most effective nutrition support to ensure the biological safety of manned space missions.

The antioxidant properties of plants have been investigated, in the light of recent scientific developments, throughout the world due to their potent pharmacological activities and food viability. Basil (Ocimum basilicum L. Family Lamiaceae) is used as a kitchen herb and as an ornamental plant in house gardens. In the present study, the possible radical scavenging and antioxidant activity of the water (WEB) and ethanol extracts (EEB) of basil was investigated using different antioxidant methodologies: 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging, scavenging of superoxide anion radical-generated non-enzymatic system, ferric thiocyanate method, reducing power, hydrogen peroxide scavenging and metal chelating activities. Experiments revealed that WEB and EEB have an antioxidant effects which are concentration-dependent. The total antioxidant activity was performed according to the ferric thiocyanate method. At the 50 µ µ µ µ µg/mL concentration, the inhibition effects of WEB and EEB on peroxidation of linoleic acid emulsion were found to be 94.8% and 97.5%, respectively. On the other hand, the percentage inhibition of a 50 µ µ µ µ µg/mL concentration of BHA, BHT and α α α α α-tocopherol was found to be 97.1%, 98.5% and 70.4% inhibition of peroxidation of linoleic acid emulsion, respectively. In addition, WEB and EEB had effective DPPH radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, reducing power and metal chelating activities. Additionally, these various antioxidant activities were compared with BHA, BHT and α α α α α-tocopherol as reference antioxidants. The additional total phenolic content of these basil extracts was determined as the gallic acid equivalent and were found to be equivalent.

Fenton Process, a type of Advanced Oxidation Processes is an efficient method for treating textile
wastewaters. However, excessive use of hydrogen peroxide and catalyst has made this process
economically non-feasible. Besides, industrial grade hydrogen peroxide costs $390 e500 per ton. One of
the means to overcome this problem is the in-situ production of hydrogen peroxide. In this paper, a
detailed review was conducted on the generation methods, degradation potential and optimum operating parameters for in-situ production of hydrogen peroxide/hydroxyl radicals. Additionally the scavenging aspect for hydroxyl radicals was also investigated. From this review, it can be concluded that
hydroxyl radical is highly oxidative and non selective in nature and its in-situ production can be performed through application of catalyst, ozonation, photocatalysis, electro and microbial fuel cells.
Furthermore, optimization of operating parameters can result in an increase in the yield of hydroxyl
radicals/hydrogen peroxide. Sonolysis as an auxiliary tool has potential to induce synergetic effects in
combination with Advanced Oxidation Processes to increase in-situ hydrogen peroxide production.
However, the problem of the scavenging effect is an aspect that needs to be dealt with, as hydroxyl
radicals are prone to deactivation by scavengers. Therefore based on the review, it is concluded that insitu production of hydrogen peroxide/hydroxyl radical for treating textile wastewater is economically
viable and practically feasible if careful selection of process is conducted through selective research

Treatment of wastewater effluent from the secondary wastewater treatment plant of a dyeing and finishing mill is investigated for possible reuse. The treatment system employed in the present study consists of an electrochemical method, chemical coagulation and ion exchange. The electrochemical method and chemical coagulation are intended primarily to remove color, turbidity (NTU) and COD concentration of the wastewater effluent while ion exchange is employed to further lower the COD concentration and reduce Fe ion concentration, conductivity and total hardness of the wastewater. To enhance the efficiency of electrochemical method, addition of a small amount of hydrogen peroxide is found to be highly beneficial. Experimental results throughout the present study have indicated that the combined chemical treatment methods are very effective and are capable of elevating the water quality of the treated waste effluent to the reuse standard of the textile industry.

Arundo donax L. (or giant reed), a plant with annual harvesting period and high biomass productivity, is a promising non-wood fibre crop for pulp and paper production. The presented data of chemical, anatomical and morphological studies of Arundo donax, given from the viewpoint of raw material characterization, allow prediction of the potential of this crop for fibre production. The correlation between biometric data of fibres of Arundo donax and papermaking properties of pulps produced is discussed.

Glucose oxidase (GOX) from Aspergillus niger is a well-characterised glycoprotein consisting of two identical 80-kDa subunits with two FAD co-enzymes bound. Both the DNA sequence and protein structure at 1.9 Ǻ have been determined and reported previously. GOX catalyses the oxidation of d-glucose (C6H12O6) to d-gluconolactone (C6H10O6) and hydrogen peroxide. GOX is produced naturally in some fungi and insects where its catalytic product, hydrogen peroxide, acts as an anti-bacterial and anti-fungal agent. GOX is Generally Regarded As Safe, and GOX from A. niger is the basis of many industrial applications. GOX-catalysed reaction removes oxygen and generates hydrogen peroxide, a trait utilised in food preservation. GOX has also been used in baking, dry egg powder production, wine production, gluconic acid production, etc. Its electrochemical activity makes it an important component in glucose sensors and potentially in fuel cell applications. This paper will give a brief background on the natural occurrence, functions as well as the properties of glucose oxidase. A good coverage on the diverse uses of glucose oxidase in the industry is presented with a brief outline on the working principles in the various settings. Furthermore, food grade GOX preparations are relatively affordable and widely available; the readers may be encouraged to explore other potential uses of GOX. One example is that GOX-catalysed reaction generates significant amount of heat (∼200 kJ/mol), and this property has been mostly neglected in the various applications described so far.

The gastrointestinal tract is a complex ecosystem that associates a resident microbiota and cells of various phenotypes lining the epithelial wall expressing complex metabolic activities. The resident microbiota in the digestive tract is a heterogeneous microbial ecosystem containing up to 1 Â 10 14 colony-forming units (CFUs) of bacteria. The intestinal microbiota plays an important role in normal gut function and maintaining host health. The host is protected from attack by potentially harmful microbial microorganisms by the physical and chemical barriers created by the gastrointestinal epithelium. The cells lining the gastrointestinal epithelium and the resident microbiota are two partners that properly and/or synergistically function to promote an efficient host system of defence. The gastrointestinal cells that make up the epithelium, provide a physical barrier that protects the host against the unwanted intrusion of microorganisms into the gastrointestinal microbiota, and against the penetration of harmful microorganisms which usurp the cellular molecules and signalling pathways of the host to become pathogenic. One of the basic physiological functions of the resident microbiota is that it functions as a microbial barrier against microbial pathogens. The mechanisms by which the species of the microbiota exert this barrier effect remain largely to be determined. There is increasing evidence that lactobacilli and bifidobacteria, which inhabit the gastrointestinal microbiota, develop antimicrobial activities that participate in the host's gastrointestinal system of defence. The objective of this review is to analyze the in vitro and in vivo experimental and clinical studies in which the antimicrobial activities of selected lactobacilli and bifidobacteria strains have been documented.

The purity of wafer surfaces is an essential requisite for the successful fabrication of VLSI and ULSI silicon circuits. Wafer cleaning chemistry has remained essentially unchanged in the past 25 years and is based on hot alkaline and acidic hydrogen peroxide solutions, a process known as "RCA Standard Clean." This is still the primary method used in the industry. What has changed is its implementation with optimized equipment: from simple immersion to centrifugal spraying, megasonic techniques, and enclosed system processing that allow simultaneous removal of both contaminant films and particles. Improvements in wafer drying by use of isopropanol vapor or by "slow-pull" out of hot deionized water are being investigated. Several alternative cleaning methods are also being tested, including choline solutions, chemical vapor etching, and UV/ozone treatments. The evolution of silicon wafer cleaning processes and technology is traced and reviewed from the 1950s to August 1989.

License Plate detection and recognition is a key technique in most of the traffic related applications such as searching of stolen vehicles, road traffic monitoring, airport gate monitoring, speed monitoring and Automatic parking access control. It is simply the ability to automatically extract and recognition of the vehicle license number plate's character from a captured image. The License plate recognition systems have established a lot of interest from the research community because there is a certain limitation in particular territory, city or countries and lack of equivalence among different license plates. In This paper, we try to give an enhance and comprehensive view of the research work made in the area of LP detection and recognition and the techniques employed in developing a License Plate Recognition (LPR) system. In this analysis we not only study and also compare the License Plate Recognition Techniques based on different criteria like plate region extraction, character segmentation and character recognition rate using ANN, RBFNN and Template Matching along with its pros and cons.

Small satellites have historically been forced to use low cost propulsion, or to do without in order to maintain low cost. Since 1999 an increasing number of SSTL's customers have demanded the capability to precisely position and subsequently manoeuvre their satellites, driven largely by the current attraction of small satellite constellations such as Disaster Monitoring (DMC), which require propulsion for launcher injection error correction, drag compensation, constellation phasing and proximity manoeuvring and rendezvous. SSTL has successfully flight qualified a simple, low cost propulsion system based on a low power (15-100 W) resistojet employing green propellants such as butane and xenon, and demonstrated key constellation manoeuvres. The system is capable of up to 60 m/s deltaV and will be described here. The SSTL low power resistojet is however limited by a low Isp (∼ 50 s for Xenon in the present design, and ∼ 100 s with nitrogen and butane) and a slow reaction time (10 min warm-up required). An increasing desire to apply small satellite technology to high deltaV missions while retaining the low cost aspect demands new solutions. 'Industry standard' solutions based on cryogenic propulsion, or toxic, carcinogenic storable propellants such as hydrazine/nitrogen oxides combination are not favourable for small satellite missions developed within SSTL's low cost engineering environment. This paper describes a number of strawman missions with high deltaV and/or precision manoeuvring requirements and some low cost propulsion solutions which have been explored at the Surrey Space Centre to meet future needs:

Tooth discoloration varies in etiology, appearance, localization, severity, and adhesion to tooth structure. It can be defined as being extrinsic or intrinsic on the basis of localization and etiology. In this review of the literature, various causes of tooth discoloration, different bleaching materials, and their applications to endodontically treated teeth have been described. In the walking bleach technique the root filling should be completed first, and a cervical seal must be established. The bleaching agent should be changed every 3-7 days. The thermocatalytic technique involves placement of a bleaching agent in the pulp chamber followed by heat application. At the end of each visit the bleaching agent is left in the tooth so that it can function as a walking bleach until the next visit. External bleaching of endodontically treated teeth with an in-office technique requires a high concentration gel. It might be a supplement to the walking bleach technique, if the results are not satisfactory after 3-4 visits. These treatments require a bonded temporary filling or a bonded resin composite to seal the access cavity. There is a deficiency of evidence-based science in the literature that addresses the prognosis of bleached nonvital teeth. Therefore, it is important to always be aware of the possible complications and risks that are associated with the different bleaching techniques. (J Endod 2008; 34:394 -407)

Glucose oxidase, producing gluconic acid and hydrogen peroxide from glucose, is demonstrated in honey. Its activity increases markedly on dilution of the honey. Inhibine, the antibacterial material previously reported in honey, is shown to be hydrogen peroxide produced in the inhibine assay by the natural glucose oxidase in honey. A direct relationship is shown between inhibine number and hydrogen peroxide production.

During the past two decades, coral reefs have experienced extensive degradation worldwide. One etiology for this global degradation is a syndrome known as coral bleaching. Mass coral bleaching events are correlated with increased sea-surface temperatures, however, the cellular mechanism underlying this phenomenon is uncertain. To determine if oxidative stress plays a mechanistic role in the process of sea-surface temperature-related coral bleaching, we examined corals along a depth transect in the Florida Keys over a single season that was characterized by unusually high sea-surface temperatures. We observed strong positive correlations between accumulation of oxidative damage products and bleaching in corals over a year of sampling. High levels of antioxidant enzymes and small heat-shock proteins were negatively correlated with levels of oxidative damage products. Corals that experienced oxidative stress had higher chaperonin levels and protein turnover activity. Our results indicate that coral bleaching is tightly coupled to the antioxidant and cellular stress capacity of the symbiotic coral, supporting the mechanistic model that coral bleaching (zooxanthellae loss) may be a final strategy to defend corals from oxidative stress.

In this paper, a comparison of various advanced oxidation processes (O 3 , O 3 /UV, H 2 O 2 /UV, O 3 /H 2 O 2 /UV, Fe 2þ / H 2 O 2 ) and chemical treatment methods using Al 2 (SO 4 ) 3 AE 18H 2 O, FeCl 3 and FeSO 4 for the chemical oxygen demand (COD) and color removal from a polyester and acetate fiber dyeing effluent is undertaken. Advanced oxidation processes (AOPs) showed a superior performance compared to conventional chemical treatment, which maximum achievable color and COD removal for the textile effluent used in this study was 50% and 60%, respectively. Although O 3 /H 2 O 2 /UV combination among other AOPs methods studied in this paper was found to give the best result (99% removal for COD and 96% removal for color), use of Fe 2þ /H 2 O 2 seems to show a satisfactory COD and color removal performance and to be economically more viable choice for the acetate and polyester fiber dyeing effluent on the basis of 90% removal.

Viability of yoghurt and probiotic bacteria was assessed during manufacture and 35 d storage in yoghurt made from four commercial starter cultures. The titratable acidity, pH and dissolved oxygen content showed similar patterns of increase or decrease during manufacture and storage of yoghurt, whereas concentration of hydrogen peroxide increased in the product prepared with cultures that contained L. delbrueckii ssp. bulgaricus. The increase in numbers of probiotic organisms during manufacture and the viability of these organisms during storage were dependent on the species and strain of associative yoghurt organisms. The viability of L. acidophilus was affected by the presence of L. delbrueckii ssp. bulgaricus, whereas bifidobacteria exhibited better stability in the yoghurt prepared from cultures that contained L. delbrueckii ssp. bulgaricus. The viability of both probiotic organisms was improved when the dissolved oxygen concentration was low in the product. The storage temperature of yoghurt affected the viability of bifidobacteria, but not L. acidophilus. The variations in titratable acidity, pH, dissolved oxygen and hydrogen peroxide were almost identical at storage temperatures of 4 and 10 °C. In one of the commercial cultures, 3 log cycles inhibition of bifidobacteria was observed from initial counts of >106 mL−1.

To gain a better insight into long-term salt-induced oxidative stress, some physiological parameters in marigold (Calendula offıcinalis L.) under 0, 50 and 100 mM NaCl were investigated. Salinity affected most of the considered parameters. High salinity caused reduction in growth parameters, lipid peroxidation and hydrogen peroxide accumulation. Under high salinity stress, a decrease in total glutathione and an increase in total ascorbate (AsA + DHA), accompanied with enhanced glutathione reductase (GR, EC 1.6.4.2) and ascorbate peroxidase (APX, EC 1.11.1.11) activities, were observed in leaves. In addition, salinity induced a decrease in superoxide dismutase (SOD, EC 1.15.1.1) and peroxidase (POX, EC 1.11.1.7) activities. The decrease in dehydroascorbate reductase (DHAR, EC 1.8.5.1) and monodehydroascorbate reductase (MDHAR, EC 1.6.5.4) activities suggests that other mechanisms play a major role in the regeneration of reduced ascorbate. The changes in catalase (CAT, EC 1.11.1.6) activities, both in roots and in leaves, may be important in H 2 O 2 homeostasis.

During normal cellular activities, various processes inside of cells produce reactive oxygen species (ROS). Some of the most common ROS are hydrogen peroxide (H 2 O 2 ), superoxide ion (O 2 À ), and hydroxide radical (OH À ). These compounds, when present in a high enough concentration, can damage cellular proteins and lipids or form DNA adducts that may promote carcinogenic activity. The purpose of antioxidants in a physiological setting is to prevent ROS concentrations from reaching a high-enough level within a cell that damage may occur. Cellular antioxidants may be enzymatic (catalase, glutathione peroxidase, superoxide dismutase) or nonenzymatic (glutathione, thiols, some vitamins and metals, or phytochemicals such as isoflavones, polyphenols, and flavanoids).

The objective of this study is the kinetic interpretation of hydrogen peroxide decomposition on manganese oxide (pyrolusite) and the explanation of the reaction mechanism including the hydroperoxide/ superoxide anion. The decomposition of hydrogen peroxide on manganese oxide at pH 7 was represented by a pseudo first-order model. The maximum value of the observed first-order rates constants (k obs ) was 0.741 min À1 at 11.8 of [H 2 O 2 ]/["MnO 2 ] when [H 2 O 2 ]/["MnO 2 ] were ranged from 58.8 to 3.92. The pseudo first-order rate constants (k MnO 2 ) approximated as the average value of 0.025 (min mM) À1 with a standard deviation of 0.003 at [H 2 O 2 ]/["MnO 2 ] ranged from 39.2 to 11.8. When [H 2 O 2 ]/["MnO 2 ]

Reactive oxygen species (ROS) play a multitude of signaling roles in different organisms from bacteria to mammalian cells. They were initially thought to be toxic byproducts of aerobic metabolism, but have now been acknowledged as central players in the complex signaling network of cells. In this review, we will attempt to address several key questions related to the use of ROS as signaling molecules in cells, including the dynamics and specificity of ROS signaling, networking of ROS with other signaling pathways, ROS signaling within and across different cells, ROS waves and the evolution of the ROS gene network.

Pure (MnO x ), mixed (A y Mn 1Ày O x ) and composite ((A,B) y Mn 1Ày O x ) manganese oxide based catalysts were prepared, where A is either Ni II , Cu II , Bi III or Ce IV , A and B are various combinations of them, and y0.4. Subsequently, they were characterized for the crystalline bulk structure by X-ray powder diffractometry, the electron availability by magnetic susceptibility measurements, the surface area by BET-analysis of nitrogen adsorption isotherms, and the surface chemical composition and oxidation state by X-ray photoelectron spectroscopy. The H 2 O 2 decomposition activity was determined by oxygen-gasometry of the reaction kinetics at 20±358C. Results thus obtained have helped to conclude that (i) the mixed and composite catalysts are generally more active than the pure catalyst, and (ii) of the mixed and composite catalysts, those assuming mixed bulk phases with the host oxide are relatively more active. The optimal catalytic surface has been found to be that exposing ionic sites of different oxidation states and residing on a crystalline bulk of ca. 50% electron availability. These properties were found to be accomplished by surfaces of NiMnO x , on which the H 2 O 2 decomposition required a much lower activation energy (11.6 kJ mol À1 ) as compared to that (77.1 kJ mol À1 ) necessary for the reaction on the pure catalyst (MnO x ). #

To evaluate, using conventional in vitro procedures, the abrasivity, enamel polishing properties, and stain removal effectiveness of various commercial dentifrices that have a variety of compositions and are marketed for cleaning, whitening, and/or polishing capabilities, and to examine their relationships between stain removal and abrasivity. The Relative Dentin Abrasivity (RDA) method was used to measure abrasivity, and the Pellicle Cleaning Ratio (PCR) procedure was used to evaluate stain removal performance. A Cleaning Efficiency Index (CEI) was calculated using the RDA and PCR values. Enamel polish was determined on bovine enamel specimens using a reflectometer. All treatments were performed on a V-8 cross-brushing machine using aqueous dentifrice slurries and standard nylon-bristle toothbrushes. A total of 26 dentifrices, purchased at retail, were tested against the American Dental Association (ADA) calcium pyrophosphate reference standard. All dentifrices removed extrinsic st...

The chloroform and aqueous fractions of Carissa opaca fruit, a traditional medicinal fruit in Pakistan possessed a high amount of total phenolic and flavonoid contents as compare to other solvent fractions with potent antioxidant activities in scavenging DPPH, superoxides, hydroxyl, hydrogen peroxide, ABTS radicals, and had strong iron chelating activity. On the other hand, the ethyl acetate fraction showed the highest inhibition of b-carotene linoleic acid peroxidation and phosphomolybdate assay. A high correlation coefficient existed between EC 50 values of DPPH, superoxides, hydroxyl, hydrogen peroxide, ABTS radicals, total phenolics and flavonoids, but a non significant correlation was found in the case of iron chelaters, b-carotene and phosphomolybdate assay. This study verified that the chloroform and aqueous fractions have strong antioxidant activities which were correlated with its high level of phenolics and flavonoids. These fractions can be used as a source of potential antioxidant or functional food material.

This study describes a preclinical investigation with laser-activated bleaching agent for discolored teeth. Bleaching techniques involve a broad-spectrum approach utilizing hydrogen peroxide (3-38%) with or without heat or laser, carbamide peroxide (10-30%), or a mixture of sodium perborate and hydrogen peroxide. Extracted human maxillary central incisors were selected. In the bleaching experiment, 38% hydrogen peroxide was used. Two different laser

sh h p pe er ro ox xi id da as se e f fo or r r re em mo ov va al l a an nd d d de et to ox xi if fi ic ca at ti io on n o of f a az zo o d dy ye e f fr ro om m a aq qu ue eo ou us s s so ol lu ut ti io on n Abstract The development and application of an immobilized horseradish peroxidase (HRP) on calcium alginate gel beads are reported for the successful and effective decolorization textile industrial effluent. The optimal condition for the immobilization of HRP on calcium alginate gel beads which leads to a specific activity of 15 U/g calcium alginate was identified. Upon immobilization, considering enzyme encapsulation efficiency, retention activity and enzyme leakage of the capsules, the best gelation condition was found to be 2 % w/v of sodium alginate solution and 2 % w/v of calcium chloride hexahydrate. Upon immobilization, pH profile of enzyme activity changes as it shows higher value at basic and acidic solution. The capsules were reusable up to ten cycles but decreased in their efficiency. The ratio of hydrogen peroxide/dye at which highest dye removal occurs is 1.25. Optimum conditions for removal of AO-7 and AB-25 were: 90 min, reaction time; 0.8 units/g, enzyme concentration for 500 ADMI colore, ratio of H 2 O 2 /dye, 1.25/1; temperature, 25-50°C that cause 75% and 84% removal in AO-7 and AB-25 solution respectively. There was a significant reduction in toxicity of dye solution after the enzymatic treatment.

The study examined degradation of the antibiotics amoxicillin, ampicillin and cloxacillin in aqueous solution by the photo-Fenton process. The optimum operating conditions for treatment of an aqueous solution containing 104, 105 and 103 mg/L amoxicillin, ampicillin, and cloxacillin, respectively was observed to be H 2 O 2 /COD molar ratio 1.5, H 2 O 2 /Fe 2+ molar ratio 20 and pH 3. Under optimum operating conditions, complete degradation of amoxicillin, ampicillin and cloxacillin occurred in 2 min. Biodegradability (BOD 5 /COD ratio) improved from ∼ 0 to 0.4, and COD and DOC degradation were 80.8 and 58.4%, respectively in 50 min. Photo-Fenton treatment resulted in the release and mineralization of organic carbon and nitrogen in the antibiotic molecule. Increase in ammonia and nitrate concentration, and DOC degradation were observed as a result of organic carbon and nitrogen mineralization. DOC degradation increased to 58.4% and ammonia increased from 8 to 13.5 mg/L, and nitrate increased from 0.3 to 14.2 mg/L in 50 min.

An attempt was made to prepare CuO/ZnO nanophotocatalyst for visible light assisted degradation of a textile dye (Acid Red 88) in aqueous solutions by wet impregnation method. The CuO/ZnO samples annealed at 550°C for 5h were changed from purple to grey, indicating that CuO clusters on ZnO may not be metallic Cu but it may be CuO-ZnO. Characterization using Transmission

The electrochemical production of hydrogen peroxide (H2O2) by 2-electron oxygen reduction reaction (ORR) is an attractive alternative to the present complex anthraquinone process. The objective of this paper is to provide a state-of-the-arts review of the most important aspects of this process. First, recent advances in H2O2 production are reviewed and the advantages of H2O2 electrogeneration via 2-electron ORR are highlighted. Second, the selectivity of the ORR pathway towards H2O2 formation as well as the development process of H2O2 production are presented. The cathode characteristics are the decisive factors of H2O2 production. Thus the focus is shifted to the introduction of commonly used carbon cathodes and their modification methods, including the introduction of other active carbon materials, hetero-atoms doping (i.e., O, N, F, B, and P) and decoration with metal oxides. Cathode stability is evaluated due to its significance for long-term application. Effects of various operational parameters, such as electrode potential/current density, supporting electrolyte, electrolyte pH, temperature, dissolved oxygen, and current mode on H2O2 production are then discussed. Additionally, the environmental application of electrogenerated H2O2 on aqueous and gaseous contaminants removal, including dyes, pesticides, herbicides, phenolic compounds, drugs, VOCs, SO2, NO, and Hg0, are described. Finally, a brief conclusion about the recent progress achieved in H2O2 electrogeneration via 2-electron ORR and an outlook on future research challenges are proposed.

This paper gives an overview of the Amelia small rocket program, developed to build low cost, reusable CanSat launchers and enable the construction of sounding rockets in Poland in the near future. The CanSat payload standard requires experiments to be containable in soda cans of 350 ml volume with a launch mass of up to 500 g. The paper covers early flown rocket designs as well as the recently tested two-stage Amelia 2 vehicle. A single stage, larger CanSat launcher is also presented. All of the vehicles are propelled by reusable composite solid rocket motors that will make it possible for small scientific experiments to be sent to altitudes of up to 10 km. One of the main goals is to develop rockets that are fully recoverable and reusable, thereby reducing operational costs. The sounding rocket that is viewed as a possible outcome of the presented research is also discussed. The work on the first rotating detonating engine flying demonstrator is also covered. This paper contains descriptions of the main subsystems of the rocket. Key technical facts and the vehicle visualizations are presented. The design methodology and calculation methods are also given. The paper contains a description of the technical equipment and background developed during the program, including propellant and motor production facilities and the launch pad. The results of the program, focused on using innovative propulsion technologies, are presented. This work is based on results of the  joint project of the Space Technology Department of the Institute of Aviation and the Division of Aircraft Engines of the Institute of Heat Engineering of Warsaw University of Technology (WUT) with a key role played by members of the Students' Rocketry Group of the WUT Students' Space Association.

The complex of Fe III 2[2-(hydroxy-benzeylidine)-amino]benzoic acid has been encapsulated in pores of NaA zeolite by two different synthesis procedures, namely a zeolite synthesis method in the presence of preformed iron complex (Fe III L/A en ) and a solid-solid-type reaction (Fe III L/A ss ). The preparations were characterized by using powder XRD, mid-FTIR, Mössbauer spectroscopy, TGA/DTGA, sorption and surface texture measurements. These results have been compared with those obtained for neat complex. The carbon and iron percentages obtained by elemental analysis indicate a mononuclear structure of the complex with 1Fe:1L proportion. Analysis by Mössbauer confirmed that Fe III acquires distorted octahedral structure of the encapsulated complex, with a number of iron ions being formed as ␣-Fe 2 O 3 in Fe III L/A ss . The compatible physicochemical data of solids have indicated a better complex encapsulation for sample prepared by the zeolite synthesis method. The complex in Fe III L/A en serves to impart structural order to the inorganic NaA network where the integrity of the matrix was confirmed by FTIR, XRD and texture studies. The resulting host/guest compound including H 2 O 2 /UV is active system for the oxidative color removal of direct blue-1 in aqueous heterogeneous suspensions with very low catalyst/substrate ratio. The heterogenized complex especially Fe III L/A en is significantly more stable than the corresponding homogeneous complex over prolonged reaction time, and therefore a better catalyst than the homogeneous one.

Strawberries (Fragaria × ananassa Duch., cv. Selva) were heat-treated in an air oven (45 • C, 3 h). After treatment, the fruit were stored at 0 • C for 0, 7 or 14 d, and then held for 2 d at 20 • C. Respiration rate, hydrogen peroxide level, potassium leakage, antioxidant capacity, ascorbic acid, superoxide dismutase (SOD), ascorbate peroxidase (APX) and pyrogallol peroxidase (POD) activities were measured. Heat-treated fruit showed lower decay and less tissue damage than control fruit as judged by changes in ion leakage, respiration rate and pyrogallol peroxidase (POD). Heat-treated fruit also presented lower levels of H 2 O 2 than control fruit during storage. In addition, antioxidant capacity was higher in heat-treated fruit both after 1 d at 20 • C or 7 d at 0 • C. Ascorbate peroxidase (APX) and superoxide dismutase (SOD) activity were not affected immediately after the treatment. However, higher activity was found in heat-treated fruit during storage, indicating that the heat treatment produced changes in the oxidative metabolism of the fruit. Interestingly, the main differences were not observed immediately after the treatment but during the storage. The differential responses observed in the case of heat-treated fruit during storage could protect the fruit against reactive oxygen species generated during senescence or pathogen attack.

It has been reported that salicylic acid (SA) induces both immediate spike and long lasting phases of oxidative burst represented by the generation of reactive oxygen species (ROS) such as superoxide anion radical (O2
-). In general, in the earlier phase of oxidative burst, apoplastic peroxidase are likely involved and in the late phase of the oxidative burst, NADPH oxidase is likely involved. Key signaling events connecting the 2 phases of oxidative burst are calcium channel activation and protein phosphorylation events. To date, the known earliest signaling event in response to exogenously added SA is the cell wall peroxidase-catalyzed generation of O2
- in a hydrogen peroxide (H2O2)-dependent manner. However, this model is incomplete since the source of the initially required H2O2 could not be explained. Based on the recently proposed role for H2O2-independent mechanism for ROS production catalyzed by plant peroxidases (Kimura et al., 2014, Frontiers in Plant Science), we hereby propose a novel model for plant peroxidase-catalyzed oxidative burst fueled by SA.

A comparison is presented of six methods involving nitric acid in conjunction with other reagents to digest three certified marine biological samples (DOLT-3, DORM-3, IAEA-407) and a fish bone homogenate (prepared from Merluccius australis). An inductively coupled plasma-mass spectrometer with an octopole collision cell was used to determine up to 40 elements (Li, U) in the digests. These results were assessed in terms of their accuracy and precision, and a flow chart was developed to aid the selection of the optimal digestion method. Although none of the methods was found to give accurate determinations for all elements in the different reference materials, a relatively simple method involving nitric acid and hydrogen peroxide heated in a domestic microwave oven gave the most acceptable results. (B.M. Peake).

Background: Pretreatment is a critical step in the conversion of lignocellulose to fermentable sugars. Although many pretreatment processes are currently under investigation, none of them are entirely satisfactory in regard to effectiveness, cost, or environmental impact. The use of hydrogen peroxide at pH 11.5 (alkaline hydrogen peroxide (AHP)) was shown by Gould and coworkers to be an effective pretreatment of grass stovers and other plant materials in the context of animal nutrition and ethanol production. Our earlier experiments indicated that AHP performed well when compared against two other alkaline pretreatments. Here, we explored several key parameters to test the potential of AHP for further improvement relevant to lignocellulosic ethanol production.

After a long initial stage obscured by empirism and misconceptions, oxygen-ozonetherapy has now become a scientific discipline where the reactions between ozone and human blood are within the realm of orthodox biochemistry, physiology and pharmacology. Most of the basic mechanisms of action have been clarified and ozone can be considered a pro-drug, which almost instantaneously reacts with antioxidants and unsaturated fatty acids. These reactions generate the actual ozone messengers represented by either hydrogen peroxide as a fast acting compound or a variety of lipid oxidation products as late effectors. While ozone is totally consumed, micromolar amounts of these messengers are able to enhance the delivery of oxygen via erythrocyte activation, the immune system by a bland leukocyte stimulation and most of the remaining body cells by up-regulating the antioxidant system. The hazard of ozone toxicity has been dispelled by using the gas only within a dose range perfectly calibrated against the potent blood antioxidant capability. Ozonetherapy can be very useful in patients with chronic vascular disorders and ischemic problems and should be extensively used by official medicine. An extraordinary facet of ozone is its medical application versatility, as represented by several administration routes, and the minimal cost of this drug.