Towards an insight on photodamage in hair fibre by UV-light: An experimental and theoretical study

Synopsis: Objectives: In this research, an experimental and theoretical study was conducted to design a photodegradation mechanism of the amino acid tryptophan (Trp) in hair fibres. Methods: For the experimental research, Caucasian hair fibres were exposed to several different solar radiation simulation periods. Then, Trp and its photoproducts (N-formylkynurenine and kynurenine) were assayed by excitation and emission spectroscopic analysis. Results: For the theoretical study, reactions involved in the photodegradation of Trp were evaluated by high-level quantum mechanical calculations in a density functional theory (DFT) framework which indicate a probable Trp degradation mechanism with a minimum expended energy pathway. Conclusion: The biochemistry concerning these reactions is essentially important for a biological system where the degradation of Trp occurs. © 2013 John Wiley & Sons Ltd.

Photoelectrocatalytic oxidation of hair dye basic red 51 at W/WO 3/TiO2 bicomposite photoanode activated by ultraviolet and visible radiation

We prepared a W/WO3/TiO2 bicomposite photoanode by simple electrochemical anodization of W foil, followed by cathodic electrodeposition of TiO2 and annealing at 450 C for 30 min. This photoanode shows good photoactivity under irradiation with UV and visible light. In optimized conditions, it promotes complete photoelectrocatalytic oxidation of 3.33 × 10-5 mol L-1 basic red 51 solution (which is used in hair dye) at 0.1 mol L-1 Na2SO4, pH 2.0, under a current density of 1.25 mA cm-2 and ultraviolet and visible radiation-total organic carbon removal is 94 and 88%, respectively. This effect paves the way for the sustainable solar-assisted remediation of water bodies contaminated with organic components of hair dyes. © 2013 Elsevier Ltd. All rights reserved.

Estimativa das radiações ultravioleta (UV), fotossintéticamente ativa (PAR) e infravermelha (IV) em função da razão de insolação

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Radiciações e frações solares UV, PAR, IV em estufa de polietileno: evolução anual média mensal diária e equações de estimativa

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Radiação gama, ultravioleta (UV-C) e atmosfera controlada na conservação da qualidade de tomate ‘Débora Plus’ e ‘Pitenza’

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Tratamento térmico, radiação ultravioleta (UV-C), quitosana e cera na prevenção de injúrias pelo frio em mangas ‘Tommy Atkins’ e ‘Palmer’

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito da radiação UV -B na interação Botrytis cinerea – clonostachys rosea em morangueiro e do ácido 4 - aminobenzóico no controle do patógeno em tabaco

Pós-graduação em Agronomia (Proteção de Plantas) - FCA

Utilização de luz ultravioleta contínua (UV-C) e luz pulsada para conservação de mangas CV. Tommy Atkins minimamente processadas

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Filtros UV na água de abastecimento público na região da bacia hidrográfica tietê-jacaré: desenvolvimento de método, estudo de ocorrência e concentrações ambientais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Complexos heterobilantanídicos luminescentes sob excitação UV e raios X

Pós-graduação em Química - IQ

Sensitivity of yellow passion fruit plants to ultraviolet-B radiation

The objective of this work was to evaluate the effects of UV-B radiation on the vegetative growth and on the gas exchange characteristics of passion fruit plants (Passiflora edulis) grown in greenhouse. The average unweighted UV-B radiation near the apex of the plants was 8 W m-2 for the UV-B treatment (high UV-B), and 0.8 W m-2 for the control plants (low UV-B). Plants were irradiated with UV-B for 7 hours per day, centered on solar noon, during 16 days. High UV-B radiation resulted in lower shoot dry matter accumulation per plant. The content of UV-B absorbing compounds and anthocyanins was increased in the plants exposed to high UV-B radiation, when compared with the control. UV-B radiation did not affect stomatal conductance or transpiration rate, but reduced photosynthesis and instantaneous water‑use efficiency, and increased intercellular CO2 concentration. The accumulation of UV-B-absorbing compounds and anthocyanins did not effectively shield plants from supplementary UV-B radiation, since the growth and photosynthetic processes were significantly reduced.

Qualidade do tomate 'Pitenza' com utilização da radiação ultravioleta (UV-C)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Qualidade do tomate ‘pitenza’ com utilização da radiação ultravioleta (UV-C)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

MEH-PPV Thin Films for Radiation Sensor Applications

This work deals with MEH-PPV thin films to be used as gamma radiation sensors. The polymer thin films with two different thicknesses (30 and 100 nm) were irradiated at room temperature with different gamma radiation doses (up to 25 kGy). Optical properties of the material were investigated with FTIR and UV-Vis absorption spectroscopy. Results show that gamma radiation does not degrade substantially the thin-film material, suggesting that a crosslink effect may be occurring. The characteristic absorption peak of MEH-PPV, around 500 nm is shifted to shorter wavelengths with the increase of gamma radiation doses for both thicknesses samples. The 30-nm-thick samples showed a larger variation absorbance at a specific wavelength and a larger peak shift. These results indicate their potential for use in monitoring the radiation doses used on the sterilization of health care products.

Synthesis and characterization of silver/alanine nanocomposites for radiation detection in medical applications: the influence of particle size on the detection properties

Silver/alanine nanocomposites with varying mass percentage of silver have been produced. The size of the silver nanoparticles seems to drive the formation of the nanocomposite, yielding a homogeneous dispersion of the silver nanoparticles in the alanine matrix or flocs of silver nanoparticles segregated from the alanine crystals. The alanine crystalline orientation is modified according to the particle size of the silver nanoparticles. Concerning a mass percentage of silver below 0.1%, the nanocomposites are homogeneous, and there is no particle aggregation. As the mass percentage of silver is increased, the system becomes unstable, and there is particle flocculation with subsequent segregation of the alanine crystals. The nanocomposites have been analyzed by transmission electron microscopy (TEM), UV-Vis absorption spectroscopy, X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy and they have been tested as radiation detectors by means of electron spin resonance (ESR) spectroscopy in order to detect the paramagnetic centers created by the radiation. In fact, the sensitivity of the radiation detectors is optimized in the case of systems containing small particles (30 nm) that are well dispersed in the alanine matrix. As the agglomeration increases, particle growth (up to 1.5 mu m) and segregation diminish the sensitivity. In conclusion, nanostructured materials can be used for optimization of alanine sensitivity, by taking into account the influence of the particles size of the silver nanoparticles on the detection properties of the alanine radiation detectors, thus contributing to the construction of small-sized detectors.