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1.
Acta Odontol Latinoam ; 33(2): 59-68, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920607

RESUMO

The aim of this in vitro study was to evaluate the effect of bleaching protocols on the surface roughness (Ra), color change and surface micromorphology of a low-viscosity bulk-fill composite (Filtek Bulk Fill Flow, 3M ESPE), a highviscosity bulk-fill composite (Filtek Bulk Fill, 3M ESPE) and a conventional nanoparticulate composite resin (control) (Filtek Z350 XT, 3M ESPE). Forty samples of each composite (disks 5 mm in diameter and 2 mm thick) were randomly divided into four groups (n=10), according to bleaching protocol: a) 10% carbamide peroxide gel (Opalescence, Ultradent Products) (2 h/ day, for 14 days); b) 40% hydrogen peroxide gel (Opalescence Boost, Ultradent Products) (three bleaching sessions, once a week, 45 min/session); c) whitening rinse (Listerine Whitening Extreme, Johnson & Johnson) (2 min/day, for 14 days); and d) distilled water (control). The samples were submitted to triplicate readings (Ra and color [CIELAB parameters]) before and after contact with bleaching protocols. Micromorphology was analyzed in a scanning electron microscope (SEM). Ra and color parameters (ΔL, Δa, Δb and ΔE) were analyzed by generalized linear models (α=0.05). The Ra of the high-viscosity bulk-fill was significantly higher than that of the other composites (p<0.05). Ra increased significantly (p<0.05) and surface became more irregular (SEM analysis) in all the composite resins, regardless of the bleaching protocol (p<0.05). The high-viscosity bulk-fill composite resin group had significantly lower ΔE (p<0.05) than the nanoparticulate composite resin group immersed in distilled water. It was concluded that the characteristics of each resin significantly influenced the Ra more than the bleaching protocol. The high-viscosity bulk-fill resin presented minor color change.


Assuntos
Resinas Compostas/química , Peróxido de Hidrogênio/química , Clareadores Dentários/química , Clareamento Dental/métodos , Descoloração de Dente/tratamento farmacológico , Viscosidade/efeitos dos fármacos , Cor , Humanos , Teste de Materiais
2.
Chemosphere ; 254: 126916, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957301

RESUMO

4-Nonylphenol (4-NP), a phenolic endocrine disruptor chemical (EDC), is known to have high toxicity to aquatic organisms and humans. The remediation of 4-NP-contaminated marine sediments was studied using red algae-based biochar (RAB) thermochemically synthesized from Agardhiella subulata with simple pyrolysis process under different temperatures of 300-900 °C in CO2 atmosphere. The RAB was characterized by XRD, Raman, FTIR spectroscopy, and zeta potential measurements. The calcium in RAB efficiently activated sodium percarbonate (SPC) to generate reactive radicals for the catalytic degradation of 4-NP at pH 9.0. The oxygen-containing functional groups reacted with H2O2, which increased the generation of reactive radicals under alkaline pH condition. Ca2+ ion was the active species responsible for 4-NP degradation. CaO/CaCO3 on RAB surface enhanced direct electron transfer, increased HO production, and 4-NP degradation in marine sediments. Langmuir‒Hinshelwood type kinetics well described the 4-NP degradation process. Remediation of contaminated sediments using RAB could be a sustainable approach toward closed-loop biomass cycling in the degradation of 4-NP contaminants.


Assuntos
Carvão Vegetal/química , Disruptores Endócrinos/análise , Recuperação e Remediação Ambiental/métodos , Sedimentos Geológicos/química , Fenóis/análise , Rodófitas/química , Poluentes Químicos da Água/análise , Biomassa , Carbonatos/química , Catálise , Humanos , Peróxido de Hidrogênio/química , Cinética
3.
Ecotoxicol Environ Saf ; 202: 110939, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800222

RESUMO

Pulp and paper mill wastewater (PPMWW) contains high concentrations of recalcitrant compounds that cause toxicity to organisms. Advanced oxidation processes (AOPs) have the ability to degrade these compounds and reduce overall toxicity. Physicochemical characterization and Lactuca sativa toxicity test were conducted to compare the effectiveness of two post-treatments: UV/H2O2 and photo-Fenton. A comparison of four phytotoxicity indexes was carried out. PPMWW from a Brazilian treatment plant was characterized by high values of phenols, color, integrated spectral area (ISA), and chemical oxygen demand (COD), and caused significant inhibition to seedling development. The use of both post-treatments allowed the removal of over 75% of phenols, color, ISA, and COD. Although UV/H2O2 was more effective in removing phenols and ISA, photo-Fenton better reduced phytotoxicity. The most sensitive phytotoxicity indexes were RGIC0.8 and GIC80%, whereas SGC0, REC-0.25 and REC-0.50 better showed the effectiveness of the post-treatments. We suggest the combined use of two phytotoxicity indexes: one that evaluates the effects on seed germination and, another, on root elongation, e.g., SGC0 and RGIC0.8. Additionally, we recommend the use of ISA for monitoring programs of wastewater treatments because it is a cost-effective approach that allows narrowing down the search and identification of compounds present in complex mixtures.


Assuntos
Papel , Fenóis/toxicidade , Eliminação de Resíduos Líquidos/métodos , Análise da Demanda Biológica de Oxigênio , Brasil , Cor , Corantes/toxicidade , Peróxido de Hidrogênio/química , Resíduos Industriais/análise , Oxirredução , Fenóis/análise , Plantas/efeitos dos fármacos , Águas Residuárias/química
4.
Ecotoxicol Environ Saf ; 204: 110977, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32739673

RESUMO

Indirect oxidation induced by reactive free radicals, such as hydroxyl radical (HO), sulfate radical (SO4-) and carbonate radical (CO3-), plays an important or even crucial role in the degradation of micropollutants. Thus, the coadjutant degradation of phenacetin (PNT) by HO, SO4- and CO3-, as well as the synergistic effect of O2 on HO and HO2 were studied through mechanism, kinetics and toxicity evaluation. The results showed that the degradation of PNT was mainly caused by radical adduct formation (RAF) reaction (69% for Г, the same as below) and H atom transfer (HAT) reaction (31%) of HO. For the two inorganic anionic radicals, SO4- initiated PNT degradation by sequential radical addition-elimination (SRAE; 55%), HAT (28%) and single electron transfer (SET; 17%) reactions, while only by HAT reaction for CO3-. The total initial reaction rate constants of PNT by three radicals were in the order: SO4- > HO > CO3-. The kinetics of PNT degradation simulated by Kintecus program showed that UV/persulfate could degrade target compound more effectively than UV/H2O2 in ultrapure water. In the subsequent reaction of PNT with O2, HO and HO2, the formation of mono/di/tri-hydroxyl substitutions and unsaturated aldehydes/ketones/alcohols were confirmed. The results of toxicity assessment showed that the acute and chronic toxicity of most products to fish increased and to daphnia decreased, and acute toxicity to green algae decreased while chronic toxicity increased.


Assuntos
Carbonatos/toxicidade , Peróxido de Hidrogênio/toxicidade , Fenacetina/toxicidade , Sulfatos/toxicidade , Testes de Toxicidade Aguda , Testes de Toxicidade Crônica , Animais , Carbonatos/química , Clorófitas/efeitos dos fármacos , Daphnia/efeitos dos fármacos , Peixes , Peróxido de Hidrogênio/química , Íons/química , Íons/toxicidade , Cinética , Modelos Químicos , Oxigênio/química , Fenacetina/química , Sulfatos/química , Água/química
5.
Food Chem ; 332: 127396, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32615386

RESUMO

The effects of oxidation degree on the isoelectric point (pI), aggregation, and structural characteristics for pork myofibrillar protein (MP) were studied by employing extracted MP, which was incubated by using a hydroxyl radical oxidation system. The concentrations of hydrogen peroxide (H2O2) were 0, 0.5, 1, 3, 5, 10, and 20 mM. With the increased oxidation degree, the contents of α-helix, ionic bonds, and hydrogen bonds decreased significantly (P < 0.05). Moreover, the pI value and total amino acids showed a declining trend, and the ß-sheet as well as solubility rised firstly and then declined. On the contrary, random curl, ß-turn, and turbidity increased significantly (P < 0.05). Therefore, amino acid side chain groups were modified, and the opposite effect, caused by oxidation that leads to protein cross-linking and aggregation, was greater than the promotion effect, such as net negative charge, these are the main factors that leads to the instability of protein solution systems.


Assuntos
Proteínas Musculares/química , Agregados Proteicos , Animais , Peróxido de Hidrogênio/química , Radical Hidroxila/química , Ponto Isoelétrico , Oxirredução , Solubilidade , Suínos
6.
Ecotoxicol Environ Saf ; 203: 110945, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32684517

RESUMO

The high-concentration wastewater produced in the industrial reverse osmosis (RO) process contains a large amount of refractory organic matters, which will have serious impacts on the natural environment and human health. Among them, contaminants can be transformed by humus-reducing bacteria based on humus. In this study, O3- assisted UV-Fenton method was applied as pretreatment. Biological activated carbon (BAC) technology in which humus-reducing bacteria were the dominant bacteria, enhanced by electron donor and Fe3+, was used to dispose of RO concentrate (ROC). The results showed that water treatment process combining oxidation with biological filtration had a positive effect on the removal of stubborn contaminants in ROC. The system was strengthened by adding electron donor and Fe3+, and the chemical oxygen demand (COD) removal efficiency was up to 80.1%. However, when the removal efficiency of UV254 absorbing pollutants reached optimal value (87.3%), that means only Fe3+ was added.


Assuntos
Carvão Vegetal/análise , Compostos Férricos/química , Substâncias Húmicas , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Análise da Demanda Biológica de Oxigênio , Filtração/métodos , Substâncias Húmicas/análise , Substâncias Húmicas/microbiologia , Hidrocarbonetos Halogenados/análise , Peróxido de Hidrogênio/química , Ferro/química , Osmose , Oxirredução , Ozônio/química , Raios Ultravioleta , Águas Residuárias/análise , Águas Residuárias/microbiologia
7.
Chemosphere ; 259: 127466, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32615456

RESUMO

This work addresses the mineralization of the widely used Methyl Orange (MO) azo dye by technologies based on H2O2 electrogeneration at a 3D-like air-diffusion cathode. These include two Fe2+-catalyzed processes such as electro-Fenton (EF) and photoelectro-Fenton (PEF). Bulk electrolyses were performed in a recirculation flow plant, in which the Eco-Cell filter-press electrochemical reactor was connected in series with a UVA photoreactor. The former reactor was equipped with a Ti|Ir-Sn-Sb oxide plate anode alongside a 3D-like air-diffusion cathode made from graphite felt and hydrophobized carbon cloth, aimed at electrogenerating H2O2 on site. The influence of current density (j), volumetric flow rate (Q) and initial MO concentration was examined. The greatest oxidation power corresponded to PEF process. The best operation conditions to treat 30 mg L-1 of total organic carbon of MO in a 50 mM Na2SO4 solution by PEF were found at 0.50 mM Fe2+, pH 3.0, j = 20 mA cm-2 and Q = 2.0 L min-1, obtaining 100% and 94% of color and TOC removals at 30 and 240-300 min, respectively. This accounted for 35% of mineralization current efficiency and 0.12 kWh (g TOC)-1 of energy consumption at the end of the electrolysis. The oxidation power of EF and PEF was compared with that of anodic oxidation (AO), and the sequence obtained was: PEF > EF > AO. The dye was gradually degraded, yielding non-toxic short carboxylic acids, like maleic, fumaric, formic, oxalic and oxamic, whose Fe(III) complexes were rapidly photolyzed.


Assuntos
Compostos Azo/química , Poluentes Químicos da Água/química , Carbono , Ácidos Carboxílicos , Difusão , Eletrodos , Eletrólise , Compostos Ferrosos , Peróxido de Hidrogênio/química , Ferro/química , Oxirredução , Fotólise
8.
Chemosphere ; 260: 127570, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32668364

RESUMO

Plastics profoundly threatens ecological balance in marine ecosystems across the globe in the current era of industrialization. Microplastics (MP), in particular, can pose risks reaching humans through the food web via various marine organisms. Among these organisms, since they are consumed as a whole, mussels are vital vectors of MP transfer during human consumption. Hence, here we analyzed MP pollution in Mediterranean mussel (Mytilus galloprovincialis) sampled from 23 different locations all along the Turkish coasts of the Black Sea, Sea of Marmara, and the Aegean Sea. After digestion of the mussels with H2O2, the micro-particles were determined under a stereomicroscope and characterized by confirming with FTIR analyses. 48% of the sampled mussels were found to have MPs. The average MP abundance was 0.69 item/mussel and 0.23 item/g fresh weight (fw) of soft tissue. Morphology was ordered as follows: fragments (67.6%)> fibers (28.4%)> films (4.05%). The dominant size of MPs was detected less than 0.5 mm (26.58%). 12 different polymers have been identified by FTIR and PET (32.9%), PP (28.4%), and PE (19.4%) were found to constitute 80% of the total MPs. The annual average exposure amount for mussel consumers in Turkey was estimated as 1918 MPs item/per year. Even though international organizations such as FAO, JECFA, or EU have not declared permissible limits, our data may inform human health uptake of MP ingestion via mussels. This data might also serve as a reference data-set for further MP monitoring research in Turkish and European Seas.


Assuntos
Microplásticos/análise , Mytilus/química , Poluentes Químicos da Água/análise , Animais , Mar Negro , Ecossistema , Monitoramento Ambiental/métodos , Contaminação de Alimentos/análise , Peróxido de Hidrogênio/química , Frutos do Mar/análise , Turquia
9.
Food Chem ; 333: 127510, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32673958

RESUMO

Aqueous coenzyme Q10 (CoQ10) dispersions were prepared using sugary maize dendrimer-like glucan (SMDG) with solid-dispersion treatment. After measuring solubility, recovery rate and loading rate, the initial weight ratio of CoQ10:SMDG was optimized to be 1:27, with the solubility markedly increasing up 188.8-folds compared to pure CoQ10 solution. The structural characterizations of CoQ10-SMDG formulation showed crystal CoQ10 was entrapped in SMDG matrix for amorphous state, associated with the strong interactions with glucan chains. The antioxidant activity of CoQ10-SMDG was assessed via DPPH and FRAP assay. DPPH scavenging activity and FRAP value of it were as high as 95.1% and 0.87 mM, respectively. The cellular uptake of CoQ10 in CoQ10-SMDG group was significantly higher than that of natural CoQ10. CoQ10-SMDG also exhibited significant protective effects against cellular damage in H2O2-induced HaCaT cell model. The results indicated that dendrimer-like glucan is an excellent platform to encapsulate and improve biological activity of hydropholic compounds.


Assuntos
Antioxidantes/química , Glucanos/química , Nanopartículas/química , Ubiquinona/análogos & derivados , Antioxidantes/farmacologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Dendrímeros/química , Humanos , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/toxicidade , Queratinócitos/citologia , Queratinócitos/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Tamanho da Partícula , Solubilidade , Ubiquinona/química , Ubiquinona/metabolismo
10.
Chemosphere ; 260: 127496, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32659541

RESUMO

Activated carbons have been reported to be useful for adsorptive removal of the volatile anaesthetic sevoflurane from a vapour stream. The surface functionalities on activated carbons could be modified through aqueous oxidation using oxidising solutions to enhance the sevoflurane adsorption. In this study, an attempt to oxidise the surface of a commercial activated carbon to improve its adsorption capacity for sevoflurane was conducted using 6 mol/L nitric acid, 2 mol/L ammonium persulfate, and 30 wt per cent (wt%) of hydrogen peroxide (H2O2). The adsorption tests at fixed conditions (bed depth: 10 cm, inlet concentration: 528 mg/L, and flow rate: 3 L/min) revealed that H2O2 oxidation gave desirable sevoflurane adsorption (0.510 ± 0.005 mg/m2). A parametric study was conducted with H2O2 to investigate the effect of oxidation conditions to the changes in surface oxygen functionalities by varying the concentration, oxidation duration, and temperature, and the Conductor-like Screening Model for Real Solvents (COSMO-RS) was applied to predict the interactions between oxygen functionalities and sevoflurane. The H2O2 oxidation incorporated varying degrees of both surface oxygen functionalities with hydrogen bond (HB) acceptor and HB donor characters under the studied conditions. Oxidised samples with enriched oxygen functionalities with HB acceptor character and fewer HB donor character exhibited better adsorption capacity for sevoflurane. The presence of a high amount of oxygen functional groups with HB donor character adversely affected the sevoflurane adsorption despite the enrichment of oxygen functional groups with HB acceptor character that have a higher tendency to adsorb sevoflurane.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/prevenção & controle , Anestésicos Inalatórios/análise , Carvão Vegetal/química , Oxigênio/química , Sevoflurano/análise , Adsorção , Ligação de Hidrogênio , Peróxido de Hidrogênio/química , Modelos Teóricos , Ácido Nítrico/química , Oxirredução , Porosidade , Propriedades de Superfície , Temperatura
11.
Chemosphere ; 260: 127461, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32673865

RESUMO

Tris (1-chloro-2-propyl) phosphate (TCPP) is a chlorinated organic phosphate used in various applications as a flame retardant and plasticizer. TCPP is a known suspected carcinogen and is not effectively removed by traditional water treatments such as biological, chlorination, and UV irradiation. In this study, the UV/H2O2 reaction was employed to degrade TCPP in water. TCPP was effectively degraded in the UV/H2O2 reaction by pseudofirst-order kinetics. The second-order rate constant of the reaction between the TCPP and OH radical was determined to be 4.35 (±0.13) × 108 M-1 s-1 using the competition kinetics with nitrobenzene as a reference compound. The degradation of TCPP was affected by the amount of H2O2, pH, and coexisting water components such as HCO3-, NO3-, and humic acid. Approximately 64.2% of total organic carbon (TOC) in TCPP was mineralized in 12 h during the UV/H2O2 reaction, whereas chloride (Cl-) and phosphate (PO43-) ions were identified as ionic byproducts with the recoveries of 96% chlorine (Cl) and 50% phosphorus (P). Five organic transformation products (TPs) of TCPP were also identified using LC-qTOF/MS. Considering the identified TPs, the main degradation pathway of TCPP during the UV/H2O2 reaction was found to be OH-radical-induced hydroxylation. Finally, a 70% decrease in bioluminescence inhibition in Vibrio fischeri was observed during the UV/H2O2 reaction, and the time-toxicity profile was similar to the time-peak area profile of TPs. The result of this study implies that TCPP can be efficiently removed with significant mineralization and toxicity reduction by the UV/H2O2 process.


Assuntos
Compostos Organofosforados/química , Cloretos , Cloro , Retardadores de Chama/análise , Substâncias Húmicas , Peróxido de Hidrogênio/química , Cinética , Organofosfatos/química , Oxirredução , Fosfatos/química , Plastificantes/química , Raios Ultravioleta , Água , Poluentes Químicos da Água/análise , Purificação da Água
12.
Chemosphere ; 260: 127460, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32673866

RESUMO

Advanced oxidation processes (AOPs), such as photolysis, photocatalysis, ozonation, Fenton process, anodic oxidation, sonolysis, and wet air oxidation, have been investigated extensively for the removal of a wide range of trace organic contaminants (TrOCs). A standalone AOP may not achieve complete removal of a broad group of TrOCs. When combined, AOPs produce more hydroxyl radicals, thus performing better degradation of the TrOCs. A number of studies have reported significant improvement in TrOC degradation efficiency by using a combination of AOPs. This review briefly discusses the individual AOPs and their limitations towards the degradation of TrOCs containing different functional groups. It also classifies integrated AOPs and comprehensively explains their effectiveness for the degradation of a wide range of TrOCs. Integrated AOPs are categorized as UV irradiation based AOPs, ozonation/Fenton process-based AOPs, and electrochemical AOPs. Under appropriate conditions, combined AOPs not only initiate degradation but may also lead to complete mineralization. Various factors can affect the efficiency of integrated processes including water chemistry, the molecular structure of TrCOs, and ions co-occurring in water. For example, the presence of organic ions (e.g., humic acid and fulvic acid) and inorganic ions (e.g., halide, carbonate, and nitrate ions) in water can have a significant impact. In general, these ions either convert to high redox potential radicals upon collision with other reactive species and increase the reaction rates, or may act as radical scavengers and decrease the process efficiency.


Assuntos
Poluentes Químicos da Água/análise , Purificação da Água , Benzopiranos , Carbonatos/química , Substâncias Húmicas , Peróxido de Hidrogênio/química , Radical Hidroxila/química , Oxirredução , Fotólise , Raios Ultravioleta
13.
Arch Biochem Biophys ; 690: 108432, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32663474

RESUMO

Oxidative stress is proposed to be one of the major causes of neurodegenerative diseases. Cellular prion protein (PrP) oxidation has been widely studied using chemical reagents such as hydrogen peroxide. However, the experimental conditions used do not faithfully reflect the physiological environment of the cell. With the goal to explore the conformational landscape of PrP under oxidative stress, we conducted a set of experiments combining the careful control of the nature and the amount of ROS produced by a60Co γ-irradiation source. Characterization of the resulting protein species was achieved using a set of analytical techniques. Under our experimental condition hydroxyl radical are the main reactive species produced. The most important findings are i) the formation of molecular assemblies under oxidative stress, ii) the detection of a majority of unmodified monomer mixed with oxidized monomers in these molecular assemblies at low hydroxyl radical concentration, iii) the absence of significant oxidation on the monomer fraction after irradiation. Molecular assemblies are produced in small amounts and were shown to be an octamer. These results suggest either i) an active recruitment of intact monomers by molecular assemblies' oxidized monomers then inducing a structural change of their intact counterparts or ii) an intrinsic capability of intact monomer conformers to spontaneously associate to form stable molecular assemblies when oxidized monomers are present. Finally, abundances of the intact monomer conformers after irradiation were modified. This suggests that monomers of the molecular assemblies exchange structural information with intact irradiated monomer. All these results shed a new light on structural exchange information between PrP monomers under oxidative stress.


Assuntos
Proteínas Priônicas/química , Sequência de Aminoácidos , Escherichia coli/genética , Humanos , Peróxido de Hidrogênio/química , Radical Hidroxila/química , Espectrometria de Massas , Concentração Osmolar , Oxirredução , Estresse Oxidativo , Proteínas Priônicas/genética , Conformação Proteica , Multimerização Proteica , Espécies Reativas de Oxigênio/química
15.
PLoS Negl Trop Dis ; 14(7): e0008500, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32730339

RESUMO

Schistosomiasis remains a serious public health problem in tropical regions, affecting more than 250 million people. Sensitive diagnostic methods represent key tools for disease elimination, in particular in areas with low endemicity. Advances in the use of luminol-based chemiluminescent techniques have enabled greater sensitivity and speed in obtaining results in different diagnostic settings. In this study, we developed a luminol-H2O2 chemiluminescence (CL) method to detect Schistosoma mansoni eggs in human fecal sediments processed by the Helmintex (HTX) method. After S. mansoni eggs were incubated with a solution of luminol-H2O2 the light emission was detected and measured by spectrophotometry at 431 nm for 5 min, using detection and counts of eggs by bright field optical microscopy as a reference. CL intensity was found to correlate with different sources and numbers of eggs. Furthermore, our results showed that the CL method can distinguish positive from negative samples with 100% sensitivity and 71% specificity. To our knowledge, this is the first study to report the use of CL for the diagnosis of helminths from fecal samples. The combination of the HTX method with CL represents an important advance in providing a reference method with the highest standards of sensitivity.


Assuntos
Fezes/parasitologia , Peróxido de Hidrogênio/química , Luminol/química , Óvulo , Schistosoma mansoni/isolamento & purificação , Esquistossomose mansoni/diagnóstico , Animais , Humanos , Medições Luminescentes , Camundongos , Esquistossomose mansoni/parasitologia
16.
Food Chem ; 330: 127173, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32569930

RESUMO

Pleurotus ostreatus is an edible mushroom with pharmacological potential, due to its metabolites, mainly polysaccharides. On here, the development of a new methodology for the recovery of extract rich in antioxidant polysaccharide was reported. The extracts were characterized, evaluated for antioxidant activity in vitro and in cell models and cytotoxicity. The best defined extraction condition was 25 MPa, 433.15 K, and 20% H2O, with 30.69% of the total yield and 0.921 mg of CHO3. The anomeric bonds, identified in the FTIR and NMR spectrum, indicate that the extracts are a mixture of heteropolysaccharides, ß-glucans, α-glucans, and oligosaccharides. The best extraction condition has 80.83% of antioxidant activity, without cytotoxic effect in vitro. In addition to antioxidant activity in cell model, increasing protection against oxidative damage induced by H2O2. Finally, H2O + CO2-SFE technology can be used to obtain extracts rich in antioxidant polysaccharides with pharmacological and food potential.


Assuntos
Antioxidantes/química , Pleurotus/química , Polissacarídeos/química , Dióxido de Carbono/química , Glucanos/química , Temperatura Alta , Peróxido de Hidrogênio/química , Oxirredução , Água/química
17.
Chemosphere ; 258: 127266, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32535443

RESUMO

Copper oxide nanoparticles (CuO-NPs) have been suggested as effective catalysts to degrade many persistent organic contaminants. In parallel, CuO-NPs are considered toxic to soil microorganisms, plants and human cells, possibly because they induce oxidative stress and generation of reactive oxygen species (ROS). However, the mechanism of the catalytic process and the generated ROS are poorly understood. Here we discuss the reaction mechanism of CuO-NPs during the catalytic degradation of enrofloxacin - an antibiotic pharmaceutical used in this study as a representative persistent organic compound. The degradation of an aqueous solution of the enrofloxacin exposed to CuO-NPs and hydrogen peroxide was studied showing fast removal of the enrofloxacin at ambient conditionsns. ROS production was identified by electron spin resonance and a spin trapping technique. The distribution of the free radical species indicated production of a high percentage of superoxide (O2-.) radicals as well as hydroxyl radicals; this production is similar to the "radical production" activity of the superoxide dismutase (SOD) enzyme in the presence of hydrogen peroxide. This activity was also tested in the opposite direction, to examine if CuO-NPs show reactivity that potentially mimics the classical SOD enzymatic activity. The CuO-NPs were found to catalyze the dismutation of superoxide to hydrogen peroxide and oxygen in a set of laboratory experiments.


Assuntos
Cobre/química , Enrofloxacina/análise , Nanopartículas/química , Espécies Reativas de Oxigênio/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Catálise , Enrofloxacina/química , Humanos , Peróxido de Hidrogênio/química , Modelos Teóricos , Oxirredução , Superóxido Dismutase/química , Poluentes Químicos da Água/química
18.
Chemosphere ; 258: 127268, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32569955

RESUMO

In this work, UVA radiation that is part of solar light is taken as the irradiation source and radicals (HO, SO4- and HO2/O2-) are generated through activation of hydrogen peroxide (H2O2), sodium persulfate (Na2S2O8) and Bismuth catalyst (BiOCl), respectively. The distinguished performance in removing acetaminophen (ACTP), a model pharmaceutical pollutant, by these three radicals was compared for the first time. Effect of pH, halide ions concentration and interfacial mechanism have been investigated in detail. Interestingly, results show that heterogeneous UVA/BiOCl process has higher degradation efficiency than homogeneous UVA/H2O2 and UVA/Na2S2O8 systems whatever the solution's pH. To explain these results, second order reaction rate constant (kradical, ACTP) have been determined with laser flash photolysis (LFP) or radical scavenging experiments. The strongly interfacial-depended HO2/O2- radicals have the lowest second order rate constant with ACTP but highest steady state concentration. BiOCl is much easier activated by UVA, and outstanding ACTP mineralization can be achieved. Combination of BiOCl and Na2S2O8 exhibits synergistic effects rather than antagonism effects with H2O2. This study highlights the relative effective utilization of solar light through interfacial directed BiOCl photocatalysis and its synergistic effects with traditional oxidants.


Assuntos
Acetaminofen/análise , Peróxido de Hidrogênio/química , Oxidantes/química , Compostos de Sódio/química , Sulfatos/química , Raios Ultravioleta , Poluentes Químicos da Água/análise , Bismuto/química , Catálise , Radical Hidroxila/química , Modelos Teóricos , Oxirredução
19.
J Appl Oral Sci ; 28: e20190384, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32520077

RESUMO

OBJECTIVES: This study evaluated if the use of a bioactive glass-ceramic-based gel, named Biosilicate (BS), before, after or mixed with bleaching gel, could influence the inflammation of the dental pulp tissue of rats' molars undergoing dental bleaching with hydrogen peroxide (H2O2). METHODOLOGY: The upper molars of Wistar rats (Rattus norvegicus, albinus) were divided into Ble: bleached (35% H2O2, 30-min); Ble-BS: bleached and followed by BS-based gel application (20 min); BS-Ble: BS-based gel application and then bleaching; BS/7d-Ble: BS-based gel applications for 7 days and then bleaching; Ble+BS: blend of H2O2 with BS-based gel (1:1, 30-min); and control: placebo gel. After 2 and 30 days (n=10), the rats were euthanized for histological evaluation. The Kruskal-Wallis and Dunn statistical tests were performed (P<0.05). RESULTS: At 2 days, the Ble and Ble-BS groups had significant alterations in the pulp tissue, with an area of necrosis. The groups with the application of BS-based gel before H2O2 had moderate inflammation and partial disorganization in the occlusal third of the coronary pulp and were significantly different from the Ble in the middle and cervical thirds (P<0.05). The most favorable results were observed in the Ble+BS, which was similar to the control in all thirds of the coronary pulp (P>0.05). At 30 days, the pulp tissue was organized and the bleached groups presented tertiary dentin deposition. The Ble group had the highest deposition of tertiary dentin, followed by the Ble-BS, and both were different from control (P<0.05). CONCLUSION: A single BS-based gel application beforehand or BS-based gel blended with a bleaching gel minimize the pulp damage induced by dental bleaching.


Assuntos
Polpa Dentária/efeitos dos fármacos , Vidro/química , Peróxido de Hidrogênio/química , Pulpite/prevenção & controle , Clareadores Dentários/química , Clareamento Dental/métodos , Animais , Polpa Dentária/patologia , Peróxido de Hidrogênio/efeitos adversos , Masculino , Dente Molar , Pulpite/induzido quimicamente , Pulpite/patologia , Distribuição Aleatória , Ratos Wistar , Reprodutibilidade dos Testes , Fatores de Tempo , Clareamento Dental/efeitos adversos , Clareadores Dentários/efeitos adversos , Resultado do Tratamento
20.
Food Chem ; 328: 127099, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32474238

RESUMO

In this study, we developed a competitive colorimetric immunoassay for qualitative detection of DAN based on oxidation of iron (Ⅱ) (Fe2+) in the presence of glucose oxidase (GOx) and color change induced by Fe2+-phenanthroline (Phen) chromogenic system. Streptavidin (SA) acted as a linker between biotinylated anti-DAN-monoantibody (bio-mAb) and biotinylated GOx (bio-GOx) to form the immunocomplexes bio-mAb-SA-bio-GOx. In the absence of DAN, the immunocomplexes bio-mAb-SA-bio-GOx combining with coated DAN-ovalbumin (DAN-OVA) will be immobilized and catalyze glucose to produce H2O2. Fe2+ is oxidized to Fe3+ by H2O2, giving rise to a colorless result. In the presence of DAN, Fe2+ produces a chelation reaction with Phen, leading to orange-red color. Under optimal conditions, the detection limit (LOD) by naked eyes was 2.5 ng mL-1 in milk, chicken, beef, and pork samples. Low LOD, no matrix effect, and no signal reader requirement make it possibly applied to quickly screen DAN on site.


Assuntos
Técnicas Biossensoriais/métodos , Colorimetria/métodos , Fluoroquinolonas/análise , Glucose Oxidase/metabolismo , Imunoensaio/métodos , Quelantes de Ferro/química , Fenantrolinas/química , Biocatálise , Catálise , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Fluoroquinolonas/química , Glucose/química , Glucose Oxidase/química , Peróxido de Hidrogênio/química , Limite de Detecção
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