Influence of the measurement configuration on the results of Raman microspectroscopy of human hair

Increasing interest in spectroscopic studies of human hair raises the question about the accuracy of measurement of their spectra and requires optimisation of experimental facilities. An original method of obtaining transverse hair sections without using a microtome and chemical influence is proposed. The results obtained by confocal Raman microspectroscopy of human hair differently oriented with respect to the optical axis of the measuring setup are compared. It is shown that, in addition to expected changes in the spectra measured at different distances from the hair periphery in the direction to its centre, the spectra measured in the case of hair excitation perpendicular and parallel to its axis are also considerably different.

Physical-Chemical Effects of Nanoparticles on Electropolymerized Polyaniline

The incorporation of nanoparticles on polymer films is possible to obtain materials with desired properties. In the present work, we address the physical-chemical influence of nanoparticles in polymer films by producing and characterizing polyaniline hybrids with SiO2 and Au nanoparticles and comparing them with films with TiO2 nanoparticles. The hybrid films were characterized by SEM, EDS, UV-Vis, AFM, Raman, and cyclic voltammetry. Unlike TiO2 nanoparticles, SiO2 and Au nanoparticles do not promote any noticeable change in polyaniline oxidation state in less acid environments (pH 5.9 and 6.15). However, in those environments, the presence of nanoparticles significantly increases the film's conductivity. At a pH of 1.5 and 3.9, all three kinds of nanoparticles are screened by ions from the solution diminishing their physical-chemical effects on polyaniline. Thus, our results suggest that, in general, nanoparticles don't have any physical-chemical effects on polyaniline films when deposited in acid enough environments but can change their physical and chemical properties when deposited in less acid environments.

OBTENÇÃO E CARACTERIZAÇÃO DE EXTRATO BRUTO DE CAVALINHA PARA FINS MEDICINAIS

O uso de plantas medicinais para o tratamento de doenças está associado à medicina popular de diferentes partes do mundo. A cavalinha, pertencente à família Equisetaceae, é amplamente distribuída na região sul do Brasil. Possui propriedades medicinais, tais como diurética, hemostática, anti-inflamatória, cicatrizante, dentre outros princípios ativos intrínsecos. O presente trabalho teve por objetivo a obtenção de extratos brutos da planta Equisetum hyemale por uso de dois métodos extrativos diferentes, a caracterização dos extratos por meio de suas propriedades e potencialidades medicinais e avaliação do efeito da temperatura em ambos os extratos. Os resultados permitiram a comparação de ambos os métodos extrativos, por influência térmica (Soxhlet) e influência química (Maceração), utilizando técnicas como espectroscopia no Uv-visível e na região do Infravermelho, que permitiram a quantificação de clorofila e da atividade antioxidante. O cultivo celular em monocamadas como modelo biológico permitiu avaliar a citotoxicidade dos extratos brutos. Tendo em vista a carência de pesquisas científicas sobre o mecanismo de extração de ativos de origem vegetal, este trabalho contribui para a área de produtos naturais, os quais são utilizados para a melhoria da qualidade de vida.Palavras-chave: Extração. Caracterização. Cavalinha.ABSTRACTThe use of medicinal plants for the treatment of diseases is associated with folk medicine from different parts of the world. The “cavalinha”, belonging to the family Equisetaceae, is widely distributed in southern Brazil. It has medicinal properties such as diuretic, hemostatic, anti-inflammatory, healing, among other intrinsic active ingredients. The objective of the present work was to obtain crude extracts from the Equisetum hyemale plant by using two different extractive methods, the characterization of the extracts by their medicinal properties and potentialities and the evaluation of the temperature effect on both extracts. The results allowed the comparison of both extractive methods, by thermal influence (Soxhlet) and chemical influence (Maceration), using techniques such as UV-visible and Infrared spectroscopy, which allowed the quantification of chlorophyll and antioxidant activity. Cell culture in monolayers as a biological model allowed to evaluate the cytotoxicity of crude extracts. Given the lack of scientific research on the mechanism of extraction of plant-based assets, this work contributes to the area of natural products, which are used to improve the quality of life.Keywords: Extraction. Characterization. Cavalinha.