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Basal cell carcinoma (BCC) is the most common type of skin cancer. Diagnosis and edge assessment of BCC lesions are based on clinical and dermoscopy evaluation, which are strongly dependent on the expertise and training of the physician. There is a high rate of underdiagnosis because BCC is frequently confused with certain common benign lesions and is often indistinguishable from the surrounding healthy tissue. In the present study, a multispectral fluorescence lifetime imaging (FLIm) dermoscopy system, designed for imaging and analyzing the autofluorescence emission of skin tissue, was used to image thirty-eight patients with diagnosed nodular BCC (nBCC) lesions, using clinically acceptable levels of excitation light exposure. With this system, skin autofluorescence was imaged simultaneously using three emission bands: 390 ± 20 nm, 452 ± 22 nm, and >496 nm, preferentially targeting collagen, NADH, and FAD autofluorescence, respectively. Statistical classifiers based on FLIm features developed to discriminate BCC from healthy tissue showed promising performance (ROC area-under-the-curve of 0.82). This study demonstrates the feasibility of clinically performing multispectral endogenous FLIm dermoscopy providing baseline results indicating the potential of this technology as an image-guided tool to improve the delineation of nBCC during surgical lesion resection.

Made available in DSpace on 2018-12-11T17:25:48Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-02-01 The analysis of soil texture is crucial for the proper management of agricultural systems and for environmental studies. Soil texture is important as it affects erosion potential, water retention capacity, organic matter complexation, and the retention of nutrients, among others. It is usually determined by pipette or hydrometer methods, but analysis requires a preparation with chemical reagents, which can take hours and hence is unfeasible for large number of samples. Here we propose the use of laser-induced breakdown spectroscopy (LIBS) to estimate the proportions of sand, silt, and clay in 60 Brazilian soil samples of varying composition. Two calibration models were developed with the partial least square regression method: one considering the spectral region from 188 to 980 nm and the other, emission lines of the elements Si, Na, Fe, Ti, Ca, K, Al, Co, Mg, V, Ba, and Be. The Pearson correlation coefficients for the estimated values were 0.89 and 0.90 on average for the first and second models, respectively. The uncertainties were 6% on average for both models. These results demonstrate the use of LIBS for rapid scanning of the texture of soil samples with distinct composition. The procedure presented here can be extended to other chemical and physical soil properties, which makes LIBS a universal tool for rapid soil analysis without preparation with chemical reagents. Embrapa Instrumentation, R. XV de Novembro 1452 Physics Institute of São Carlos University of São Paulo IFSC-USP, Av. Trabalhador Sancarlense, 400 Pq. Arnold Schimid Physics Department São Carlos Federal University, P.O. Box 676 São Paulo State University - UNESP Analytical Chemistry Department, P.O. Box 355, R. Prof. Francisco Degni, 55 São Paulo State University - UNESP Analytical Chemistry Department, P.O. Box 355, R. Prof. Francisco Degni, 55

International audience; The Amazon rainforest presents one of the greater biodiversity in the world and a huge and dynamic carbon reservoir, both in the vegetation and in the soil pools, so it is an attractive subject of study. In the present paper, humic acids from a toposequence of an Oxisol-Spodosol system associated with kaolin was studied using fluorescence emission-excitation matrix combined with parallel factor analysis. The combined techniques allowed to assess the intensities of the two different fluorophores associated with humic acid with core consistency diagnoses of 84.2%. The results for the Humiluvic Spodosol seem to corroborate the model of the supramolecular structure of humic acid, because the intensity ratio of fluorophores does not remain in the profile. Therefore, the use of these combined techniques can provide information about the transformation processes of humic substances in soils, becoming an interesting analytical tool for studying these substances of different soils.

Laser-induced fluorescence spectroscopy (LIFS) has shown advantages for analyses of whole soil, providing results about chemical structure of soil organic matter (SOM) without the need for a chemical fractionating process; thus, allowing direct analysis of soils. Moreover, another advantage is the potential for the development of portable systems, which could be usable in field analyses. The aim of this paper is to evaluate the performance of a portable LIFS system to assess the humification degree (HD) of SOM. A good correlation (R > 0.8) was obtained for results (HD) achieved using the proposed portable system and a conventional fluorescence spectrometric method for humic acid. In addition, the results obtained using the portable LIFS system statistically agreed with the ones achieved using a benchtop LIFS system already described in the literature for such application (R = 0.953). Thus, the portable LIFS system constitutes an affordable option for the in situ characterization of SOM.