Does Eumelanin Oxidation Play a Role on the Photostability of Ethyl Glucuronide in Hair Exposed to Simulated Solar Radiation?

2020 ◽  
Author(s):  
Giorgia Miolo ◽  
Benedetta Vicario ◽  
Giulia Stocchero ◽  
Valerio Causin ◽  
Susanna Vogliardi ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Sun Exposure ◽  
Tricarboxylic Acid ◽  
Sem Analysis ◽  
Ethyl Glucuronide ◽  
Brown Hair ◽  
Hair Samples ◽  
Before And After ◽  
Simulated Solar Radiation ◽  
Scanning Electron

Abstract The action of solar radiation on the concentration of the ethanol metabolite ethyl glucuronide (EtG) in 40 hair samples of nonabstinent subjects was investigated. Hair samples of different colors were analyzed before and after irradiation with artificial sunlight under a light dose corresponding to 3 months of sun exposure. After irradiation, an increase of EtG concentration was detected in 55% of the samples ranging from 5% to 141%. In 16 cases, a concentration reduction ranging from −2% to −74% was observed. The measure of the level of pyrrole-2,3,5-tricarboxylic acid (PTCA), a marker of eumelanin oxidation, demonstrated the largest increase in oxidation in light brown hair where the greatest degradation of EtG was observed after irradiation. However, the rise of PTCA in all hair tested was accompanied by increase in EtG concentration in 8/10 samples and by decrease in 2/10, suggesting no correlation between the two markers. To verify if hair structure was modified by light, scanning electron microscopy (SEM) analysis was performed on irradiated hair of different colors and compared with the dark samples. SEM revealed modification of hair structure in all samples showing partial shaft exfoliation and reduction of hair thickness under the treatment with solar radiation.

scholarly journals The significance of scanning electron microscopy (SEM) analysis on the microstructure of improved clay: An overview

2021 ◽  
Vol 13 (1) ◽  
pp. 197-218
Author(s):  
Nazile Ural
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Physical And Mechanical Properties ◽  
Sem Analysis ◽  
Clay Particles ◽  
Soil Microstructure ◽  
Before And After ◽  
Problematic Soils ◽  
High Level ◽  
Scanning Electron

Abstract This study aims to emphasize the importance of scanning electron microscopy (SEM) in explaining the differences in the physical and mechanical behaviors of the improved clays before and after improvement. Generally, clays appear as problematic soils in the construction area. The reasons for this can be low strength, high compressibility, high level of volumetric changes, and swelling potential. The behavior of clays may not always be interpreted according to their physical and mechanical properties. In such cases, analyses are carried out according to the microstructure of the clay. Among several microstructural analyzes, SEM is very important, because the soil microstructure formed by clay particles and additives can be observed. This work discusses the studies based on the microstructural properties of the improved clay with SEM analysis. As a result of the studies carried out, it has been seen that unexplained physical or mechanical behavior can be explained by the microstructural behaviors of clay particles and additives.

scholarly journals Effects of erosive challenge on the morphology and surface properties of luting cements

2016 ◽  
Vol 45 (2) ◽  
pp. 103-109
Author(s):  
Brenna Louise Cavalcanti GONDIM ◽  
Isabella Cavalcante MEDEIROS ◽  
Bruna Palmeira COSTA ◽  
Hugo Lemes CARLO ◽  
Rogério Lacerda dos SANTOS ◽  
...  
Keyword(s):  
Surface Properties ◽  
Zinc Phosphate ◽  
Artificial Saliva ◽  
Sem Analysis ◽  
Resin Matrix ◽  
Luting Cements ◽  
Porous Surfaces ◽  
Before And After ◽  
And Control ◽  
Scanning Electron

Abstract Introduction Few studies investigated the surface properties of luting cements after erosive challenge. Objective To evaluate the surface roughness (Ra), Vickers hardness (VHN) and morphology of 4 luting cements after erosive challenge. Material and method Twenty specimens of each cement were prepared (4×2mm) and divided into experimental (erosive challenge) and control (artificial saliva) groups (n=10): Rely X U200 (U200); Rely X ARC (ARC); Ketac Cem Easy Mix (Ketac) and Zinc phosphate (ZnP). The erosive challenge was performed by four daily erosive cycles (90s) in a cola drink and 2 h in artificial saliva over 7 days. Ra and VHN readings were performed before and after erosion. The percentage of hardness loss (%VHN) was obtained after erosion. The surface morphology was analyzed by scanning electron microscopy (SEM). ANOVA, Tukey and Student-T tests were used (α=0.05). Result After erosion, all luting cements had increase in Ra values and U200 and ZnP groups had the highest %VHN. After saliva immersion, only U200 and ZnP groups had significant increases in Ra values and there were no significant differences among the groups in %VHN. SEM analysis showed that Ketac and ZnP groups had rough and porous surfaces, and U200 group had higher resin matrix degradation than ARC group. Conclusion Erosive challenge with a cola drink affected the surface properties of all luting cements.

scholarly journals Flexabrasion Applied to the Evaluation of the Photodegradation of Hair Fibers

Cosmetics ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Nathália F. de Oliveira ◽  
Rima Rakshit ◽  
Anthony Galliano ◽  
Daiane Garcia Mercurio ◽  
Elcio Cruz de Oliveira ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Initial Conditions ◽  
Natural Fibers ◽  
Sun Exposure ◽  
Mechanical Resistance ◽  
Hair Samples ◽  
Lamp Source ◽  
Hair Properties ◽  
The Impact

Solar radiation is a significant source of damage to hair fibers. However, the instrumental measurement of the consequences of its interaction with hair fibers’ constituents remains a challenge. In this work, the flexabrasion methodology was investigated as a potential tool to quantify the damage to mechanical hair properties caused by solar rays. The in vitro experiment developed for this study simulated four initial conditions of human hair samples, which subsequently underwent different periods of exposure to the radiation emitted by a Xenon arc lamp source. The statistical analysis of the results characterized the methodology’s ability to evaluate the impact of solar radiation on the hair’s mechanical resistance. More evident effects were observed on natural fibers subjected to exposures of up to 60 h and over, corresponding to about 1.5 h per day of sun exposure in Rio de Janeiro over five months. The results point to flexabrasion as an option to evaluate the photoprotection efficacy offered by hair-care products.

PTCA (1-H-Pyrrole-2,3,5-Tricarboxylic Acid) as a Marker for Oxidative Hair Treatment: Distribution, Gender Aspects, Correlation with EtG and Self-Reports

2020 ◽  
Author(s):  
Sara Casati ◽  
Alessandro Ravelli ◽  
Ilaria Angeli ◽  
Roberta F Bergamaschi ◽  
Giorgio Binelli ◽  
...  
Keyword(s):  
High Performance ◽  
Hair Analysis ◽  
False Negative ◽  
Tricarboxylic Acid ◽  
Single Step ◽  
Ethyl Glucuronide ◽  
Hair Samples

Abstract Hair analysis is an important and reliable resource for the assessment of alcohol or drug abstinence in both clinical and forensic toxicology. Recently, it has been demonstrated that hair oxidative cosmetic treatments lead to the reduction in incorporated xenobiotics in hair, such as ethyl glucuronide (EtG), a marker of alcohol abuse, and the formation of 1-H-pyrrole-2,3,5-tricarboxylic acid (PTCA), a degradation product of melanin. The aim of the present study was to investigate PTCA trends in a large number of samples in order to evaluate the reliability of this biomarker in recognizing previous cosmetic treatment in forensic analyses. Therefore, a single-step extraction followed by an high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) method was established and validated for the simultaneous determination of EtG and PTCA. This method was applied to 1,219 scalp hair samples from two groups, namely self-reported untreated and in vivo treated hair, exhibiting a concentration range of 6.7 to 440.0 pg/mg for EtG (mean 26.8 pg/mg, median 14.6 pg/mg) and 0.009 to 49.8 ng/mg for PTCA (mean 0.66 ng/mg, median 0.02 ng/mg). The PTCA content was significantly different among the two experimental groups, with the in vivo treated group showing significantly higher levels of PTCA than the untreated group. Finally, an in vitro bleaching was performed and the results confirmed that a strong hair oxidative treatment may negatively affect EtG test results (false negative), whereas the mean PTCA content increased showing statistically significant differences between untreated and in vitro oxidative treated samples. The present study suggests that the determination of PTCA in routine hair analysis procedure could be useful in order to discover previous cosmetic treatment including oxidation.

SEM analysis of fish scale cross sections: A technique study

1992 ◽  
Vol 50 (1) ◽  
pp. 744-745
Author(s):  
M.E. Lee ◽  
A. Moller ◽  
P.S.O. Fouche ◽  
I.G Gaigher
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cross Sections ◽  
Soft Tissues ◽  
Close Association ◽  
Sem Analysis ◽  
Fish Scale ◽  
Fish Scales ◽  
Micro Structures ◽  
Scanning Electron

Scanning electron microscopy of fish scales has facilitated the application of micro-structures to systematics. Electron microscopy studies have added more information on the structure of the scale and the associated cells, many problems still remain unsolved, because of our incomplete knowledge of the process of calcification. One of the main purposes of these studies has been to study the histology, histochemistry, and ultrastructure of both calcified and decalcified scales, and associated cells, and to obtain more information on the mechanism of calcification in the scales. The study of a calcified scale with the electron microscope is complicated by the difficulty in sectioning this material because of the close association of very hard tissue with very soft tissues. Sections often shatter and blemishes are difficult to avoid. Therefore the aim of this study is firstly to develop techniques for the preparation of cross sections of fish scales for scanning electron microscopy and secondly the application of these techniques for the determination of the structures and calcification of fish scales.

Human-hair analysis

1992 ◽  
Vol 50 (1) ◽  
pp. 886-887
Author(s):  
Brenda E. Lambert ◽  
Ernest C. Hammond
Keyword(s):  
Human Hair ◽  
Hair Analysis ◽  
Hair Shaft ◽  
White Female ◽  
Chemical Processing ◽  
X Ray ◽  
Hair Samples ◽  
Wave Technique ◽  
Permanent Wave ◽  
Scanning Electron

The purpose of this study was to examine the external structure of four human hair shaft samples with the scanning Electron Microscope (SEM) and to obtain information regarding the chemical composition of hair by using the attached x ray microanalysis unit.The hair samples were obtained from two female subjects. Sample A was taken from a black female and had not undergone any type of chemical processing. Sample B, C, D were taken from a white female, and were natural, processed, and unpigmented, i.e. “gray”, respectively. Sample C had been bleached, tinted, and chemically altered using a permanent wave technique.

Novas Considerações sobre a Fotoproteção no Brasil: Revisão de Literatura/New Considerations on the Photoprotection in Brazil: Literature Review

1970 ◽  
Vol 5 (3) ◽  
pp. 80-96
Author(s):  
Mayara Motta Melo ◽  
Clarissa Santos de Carvalho Ribeiro
Keyword(s):  
Skin Cancer ◽  
Solar Radiation ◽  
Literature Review ◽  
Sun Exposure ◽  
International Consensus ◽  
De Se ◽  
Literature Reviews ◽  
Relationship Of ◽  
The Relationship ◽  
Harmful Effects

RESUMOA incidência do câncer de pele vem aumentando a cada ano. Sabe-se que entre outros fatores, a radiação solar é a principal responsável pelo desenvolvimento dessa patologia. A prevenção, feita através da fotoproteção, teria grande impacto nesse cenário. No entanto, as orientações sobre como se proteger dos malefícios do sol devem ser coerentes com a incidência solar da região, os hábitos da população e o fototipo da pele. Os conceitos sobre fotoproteção foram definidos por entidades européias e norte americanas e não devem ser reproduzidos para o Brasil de forma aleatória, pois a incidência solar no Brasil é muito maior, a população tem fototipos diferentes e o hábito de se expor ao sol é muito mais frequente. Portanto, faz-se necessário elaborar conceitos próprios para o Brasil e conscientizar a população sobre os perigos da radiação solar para que a incidência do câncer de pele reduza definitivamente. Essa revisão visa mostrar a relação da radiação solar no Brasil com a pele dos brasileiros e evidenciar a importância da fotoproteção para essa população. Para isso foi feito um levantamento de artigos originais, revisões de literatura, consensos brasileiros e internacionais e livros de dermatologia.Palavras-chave: Fotoproteção, Câncer de pele, Exposição solar, Radiação ultravioleta, Vitamina D. ABSTRACTThe incidence of skin cancer is increasing every year. It is known that among other factors, solar radiation is the main responsible for the development of this pathology. Prevention, made by photoprotection, would have great impact in this scenario. However, the guidelines on how to protect themselves from the sun's harmful effects should be consistent with the sunlight of the region, the habits of the population and the phototype skin. The concepts of photoprotection were defined by European and North American entities and should not be played for Brazil at random, as the solar incidence in Brazil is much higher, people have different skin types and the habit of sun exposure is much more frequent. Therefore, it is necessary to draw up own concepts for Brazil and raise awareness about the dangers of solar radiation, so that the incidence of skin cancer can be definitely reduced. This review aims to show the relationship of solar radiation in Brazil with the skin of Brazilian and to highlight the importance of sun protection for this population. With this purpose, it was  made a survey of original articles, literature reviews , Brazilian and international consensus and dermatology books.Keywords: Photoprotection, Skin cancer, Sun exposure, Ultraviolet radiation, D vitamin.

scholarly journals Photocatalytic-Fenton Process under Simulated Solar Radiation Promoted by a Suitable Catalyst Selection

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 885
Author(s):  
Aida M. Díez ◽  
Helen E. Valencia ◽  
Maria Meledina ◽  
Joachim Mayer ◽  
Yury V. Kolen'ko
Keyword(s):  
Methylene Blue ◽  
Solar Radiation ◽  
Water Scarcity ◽  
Published Data ◽  
Fenton Process ◽  
Optimal Conditions ◽  
Operational Conditions ◽  
The Future ◽  
Simulated Solar Radiation ◽  
Catalyst Selection

Considering water scarcity, photo-based processes have been presented as a depollution technique, which should be optimized in order to be applied in the future. For that, the addition of an active photocatalyst and the usage of solar radiation are mandatory steps. Thus, Fe3O4–SiO2–TiO2 was synthesized, and its performance was evaluated using simulated solar radiation and methylene blue as a model pollutant. Under optimal conditions, 86% degradation was attained in 1 h. These results were compared to recent published data, and the better performance can be attributed to both the operational conditions selection and the higher photocatalyst activity. Indeed, Fe3O4–SiO2–TiO2 was physico-chemically characterized with techniques such as XRD, N2 isotherms, spectrophotometry, FTIR, electrochemical assays and TEM.

scholarly journals Redox Mechanism of Azathioprine and Its Interaction with DNA

2021 ◽  
Vol 22 (13) ◽  
pp. 6805
Author(s):  
Mihaela-Cristina Bunea ◽  
Victor-Constantin Diculescu ◽  
Monica Enculescu ◽  
Horia Iovu ◽  
Teodor Adrian Enache
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Scanning Electron Microscopy ◽  
Structural Changes ◽  
Differential Pulse ◽  
Immunosuppressive Drug ◽  
Redox Mechanism ◽  
Before And After ◽  
Dna Film ◽  
Scanning Electron

The electrochemical behavior and the interaction of the immunosuppressive drug azathioprine (AZA) with deoxyribonucleic acid (DNA) were investigated using voltammetric techniques, mass spectrometry (MS), and scanning electron microscopy (SEM). The redox mechanism of AZA on glassy carbon (GC) was investigated using cyclic and differential pulse (DP) voltammetry. It was proven that the electroactive center of AZA is the nitro group and its reduction mechanism is a diffusion-controlled process, which occurs in consecutive steps with formation of electroactive products and involves the transfer of electrons and protons. A redox mechanism was proposed and the interaction of AZA with DNA was also investigated. Morphological characterization of the DNA film on the electrode surface before and after interaction with AZA was performed using scanning electron microscopy. An electrochemical DNA biosensor was employed to study the interactions between AZA and DNA with different concentrations, incubation times, and applied potential values. It was shown that the reduction of AZA molecules bound to the DNA layer induces structural changes of the DNA double strands and oxidative damage, which were recognized through the occurrence of the 8-oxo-deoxyguanosine oxidation peak. Mass spectrometry investigation of the DNA film before and after interaction with AZA also demonstrated the formation of AZA adducts with purine bases.

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