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The hair-dyeing ingredient, p-phenylenediamine (PPD), was previously reported to be mutagenic, possibly by inducing oxidative stress. However, the exact mechanism of PPD in inducing ...oxidative stress upon skin exposure during hair-dyeing in human keratinocytes remains unknown. The aim of our studies was therefore to investigate the toxicity of PPD and its by-products in human immortalized keratinocytes (HaCaT) after auto-oxidation and after reaction with hydrogen peroxide (H2O2). We found that the PPD half maximal effective cytotoxic concentration (EC50) to HaCaT is 39.37 and 35.63μg/mL after 24 and 48h, respectively, without addition of H2O2 to induce oxidation. When PPD (10 or 100μg/mL) is combined with 10.5μg/mL of H2O2, intracellular ROS production by HaCaT after 1h was significantly increased and enhanced levels of DNA damage were observed after 4h of exposure. After 24h incubations, 20μg/mL of PPD increased the level of DNA oxidation in HaCaT. Also, we found that the in vitro reaction between PPD and H2O2, even below the maximum allowance by cosmetic industries, released hydroxyl radicals which can damage DNA. Taken together, we conclude that PPD alone and when combined with H2O2 increases the formation of reactive oxygen species in human keratinocytes, leading to oxidative stress and subsequent DNA damage. These alterations suggest that the mechanism by which PPD exposure, alone or combined with H2O2, damages keratinocytes by the formation of the high reactive HO radicals.
High performance liquid chromatography coupled to a diode array detector method was developed to detect disperse dyes in water samples over the range 0.50–35
ng, with detection limits of 0.09
ng, ...0.84
ng and 0.08
ng, respectively, with good repeatability and accuracy. This study identifies the disperse azo dyes C.I. Disperse Blue 373, C.I. Disperse Orange 37 and Disperse Violet 93 as components of a commercial dye formulation assigned as Dispersol Black Dye (CVS) used in the textile industry for dyeing synthetic fibers that are contributing to the mutagenicity found in the Cristais River, São Paulo, Brazil. High performance liquid chromatography coupled to a diode array detector was applied to monitor the occurrence of these dyes in: (1) the treated industrial effluent, (2) raw river water, (3) treated river water, and (4) the sludge produced by a Drinking Water Treatment Plant (DWTP) which is located 6
km downstream from the textile industrial discharge, where dyes’ concentrations changed from 1.65
ng
L
−1 to 316
μ
L
−1.
Extra virgin olive oil has been increasingly investigated in scientific research for its hedonic and nutritional value. A synoptic approach on applicability of copious data available for process ...control appears to be a necessary, useful tool. Based on literature data, transformation pathways of the main components of olive oil (i.e tryglicerides, phenolic compounds, volatile compounds) were described in detail in the paper. They were also attributed to olive oil chain processing, which was expressed by operating modules. A process control plan of extra virgin olive oil chain was proposed. PUBLICATION ABSTRACT
► IC exhibits genotoxic effects on HepG2 cells and is no harmful after treatment. ► Nanostrucutured Ti/TiO2/WO3 electrode are easily prepared by template. ► Cytotoxicity is negligible after treatment ...with visible light and potential of 1V.
New assays with HepG2 cells indicate that Indigo Carmine (IC), a dye that is widely used as additive in many food and pharmaceutical industries exhibited cytotoxic effects. This work describes the development of a bicomponent nanostructured Ti/TiO2/WO3 electrode prepared by “template” method and investigates its efficiency in a photoelectrocatalytic method by using visible light irradiation and applied potential of 1V. After 2h of treatment there are reduction of 97% discoloration, 62% of mineralization and formation of three byproducts assigned as: 2-amine-5-sulfo-benzoic acid, 2,3-dioxo-14-indole-5-sulfonic acid, and 2-amino-α-oxo-5-sulfo-benzeneacetic acid were identified by HPLC-MS/MS. But, cytotoxicity was completely removed after 120min of treatment.
•We evaluated peer tutoring as a way to help children learn programming languages.•Children taught by a peer had the same overall performance as those taught by an adult.•Peer-taught children ...responded more quickly and with less accuracy than adult-taught children.•Although we found no learning benefits of teaching a peer, we found no impairments either.
There is growing interest in teaching computer science and programming skills in schools. Here we investigated the efficacy of peer tutoring, which is known to be a useful educational resource in other domains but never before has been examined in such a core aspect of applied logical thinking in children. We compared (a) how children (N = 42, age range = 7 years 1 month to 8 years 4 months) learn computer programming from an adult versus learning from a peer and (b) the effect of teaching a peer versus simply revising what has been learned. Our results indicate that children taught by a peer showed comparable overall performance—a combination of accuracy and response times—to their classmates taught by an adult. However, there was a speed–accuracy trade-off, and peer-taught children showed more exploratory behavior, with shorter response times at the expense of lower accuracy. In contrast, no tutor effects (i.e., resulting from teaching a peer) were found. Thus, our results provide empirical evidence in support of peer tutoring as a way to help teach computer programming to children. This could contribute to the promotion of a widespread understanding of how computers operate and how to shape them, which is essential to our values of democracy, plurality, and freedom.
The feasibility of the photobleaching of a leather acid dye, acid red 151, simultaneously to degradation of anionic surfactant, Tamol
®, and reduction of Cr(VI) to the less toxic Cr(III) was ...investigated by photoelectrocatalytic oxidation. The best experimental conditions were found to be pH 2.0 and 0.1
mol
L
−1 sodium sulfate when the nanoporous Ti/TiO
2 photo anode was biased at +1.0
V and submitted to UV-irradiation. The photoelectrocatalytic oxidation promotes 100% discoloration, reducing around 98–100% of Cr(VI) and achieving an abatement of 95% of the original total organic carbon. The effect of pH, the applied potential, the Cr(VI) concentration and the complexation reaction between Cr(VI) and acid red dye were evaluated as to their effect on the kinetics of the reaction.
The oxidation of a reactive dye, Reactive Blue 4, RB4, (C.I. 61205), widely used in the textile industries to color natural fibers, was studied by electrochemical techniques. The oxidation on glassy ...carbon electrode and reticulated vitreous carbon electrode occurs in only one step at 2.0
<
pH
<
12 involving a two-electron transfer to the amine group leading to the imide derivative. Dye solution was not decolorized effectively in this electrolysis process. Nevertheless, the oxidation of this dye on Ti/SnO
2/SbO
x
(3% mol)/RuO
2 (1% mol) electrode showed 100% of decolorization and 60% of total organic carbon removal in Na
2SO
4 0.2
M at pH 2.2 and potential of +2.4
V. Experiments on degradation photoelectrocatalytic were also carried out for RB4 degradation in Na
2SO
4 0.1
M, pH 12, using a Ti/TiO
2 photoanode biased at +1.0
V and UV light. After 1
h of electrolysis the results indicated total color removal and 37% of mineralization.
An original computer program was set up to predict and control olive paste malaxation in the range of temperature between 22 and 37 °C under exposure to air. The program consisted of four sections to ...solve the our previous literature time-temperature kinetics. It was able to predict both the apparent oil extraction yield and the relative variation of 3,4 DHPEA-EDA and sum of verbascoside diastereoisomers contents in steady and unsteady-conditions; it was also able to determine optimal malaxation time-temperature conditions to maximize the oil extraction yield and minimize the oxidative degradation of phenolic compounds. Simulation examples were carried out to test prediction potentiality. The malaxation treatments at low temperatures appeared preferable, since they seemed to be unaffected by time-temperature profiles under unsteady-state conditions. However, it seemed more difficult to identify optimal time-temperature conditions at a low temperature than at a high temperature in some operating states.
•An original computer program was written to optimize olive paste malaxation under exposure to air.•Simulation examples were carried out to predict oil yield and damage to phenols.•Malaxation at low temperature and intermediate time appeared preferable.•Some operating states appeared critical to identify optimal conditions.
Phenols from olive mill waste water (OMWW) represent valuable functional ingredients. The negative impact on sensory quality limits their use in functional food formulations. Chemical interactions ...phenols/biopolymers and their consequences on bioactivity in plant-base foods have been widely investigated, but no studies to date have explored the variation of bitterness, astringency and pungency induced by OMWW phenols as a function of the food composition.
The aim of the paper was to profile the sensory and chemical properties of phenols from OMWW in plant-base foods varied in their macro-composition.
Four phenol concentrations were selected (0.44, 1.00, 2.25, 5.06 g/kg) to induce significant variations of bitterness, sourness, astringency and pungency in three plant-base food: proteins/neutral pH – bean purée (BP), starch/neutral pH – potato purée (PP), fiber/low pH – tomato juice (TJ). The macro-composition affected the amount of the phenols recovered from functionalized food. The highest recovery was from TJ and the lowest from BP. Two groups of 29 and 27 subjects, trained to general Labelled Magnitude Scale and target sensations, participated in the evaluation of psychophysical curves of OMWW phenols and of functionalized plant-base foods, respectively. Target sensations were affected by the food macro-composition. Bitterness increased with phenol concentration in all foods. Astringency and sourness slightly increased with concentration, reaching the weak-moderate intensity at the highest phenol concentration in PP and TJ only. Pungency was suppressed in BP and perceived at weak-moderate intensity in PP and TJ sample at the highest phenol concentration.
Proteins/neutral pH plant-food (BP) resulted more appropriate to counteract the impact of added phenol on negative sensory properties thus allowing to optimize the balance between health and sensory properties.
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•Food macro-composition affects the amount of recovered phenols.•The lowest recovery was from proteins/neutral pH plant-food.•Intensities of sensations depend by phenol concentration and food macro-composition.•Proteins/neutral pH food counteracted phenol induced “warning” sensations.
An original kinetic study of the transformation phenomena of phenolic compounds in olive paste was carried out at different malaxation time-temperature conditions under exposure to air, using Abencor ...lab equipment to process olives (Frantoio cv) of a known degree of ripeness.
Empirical kinetic models and the relevant apparent kinetic constants were determined for the following significant indices: total phenolic compound content in waste water samples using the Folin-Ciocalteu method; verbascoside and β-OH-verbascoside contents in olive paste samples using HPLC; and 3,4-DHPEA-EDA contents in olive oil samples using HPLC. Two opposite phenolic compound transformation phenomena were proposed to explain the kinetic models: (i) enzymatic oxidative damage of phenolic compounds; (ii) physical and enzymatic release of phenolic compounds from cellular tissues. It was possible to propose a reference optimization chart to predict “selective” time-temperature conditions to maximize the apparent EVOO extraction yield while minimizing the degradation phenomena of phenolic compounds during malaxation.
•An original experimental approach was used to study olive paste malaxation.•A time-temperature kinetic study was applied to predict malaxation phenomena.•Indices were selected to monitor oxidative damage to phenolic compounds.•A reference synoptic chart was proposed to optimize malaxation.
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