Fast estimation of the spectral optical properties of rabbit pancreas and pigment content analysis

The pancreas is a highly important organ, since it produces insulin and prevents the occurrence of diabetes. Although rare, pancreatic cancer is highly lethal, with a small life expectancy after being diagnosed. The pancreas is one of the organs less studied in the field of biophotonics. With the objective of acquiring information that can be used in the development of future applications to diagnose and treat pancreas diseases, the spectral optical properties of the rabbit pancreas were evaluated in a broad-spectral range, between 200 and 1000 nm. The method used to obtain such optical properties is simple, based almost on direct calculations from spectral measurements. The optical properties obtained show similar wavelength dependencies to the ones obtained for other tissues, but a further analysis on the spectral absorption coefficient showed that the pancreas tissues contain pigments, namely melanin, and lipofuscin. Using a simple calculation, it was possible to retrieve similar contents of these pigments from the absorption spectrum of the pancreas, which indicates that they accumulate in the same proportion as a result of the aging process. Such pigment accumulation was camouflaging the real contents of DNA, hemoglobin, and water, which were precisely evaluated after subtracting the pigment absorption

Fast Estimation of the Spectral Optical Properties of Rabbit Pancreas and Pigment Content Analysis

The pancreas is a highly important organ, since it produces insulin and prevents the occurrence of diabetes. Although rare, pancreatic cancer is highly lethal, with a small life expectancy after being diagnosed. The pancreas is one of the organs less studied in the field of biophotonics. With the objective of acquiring information that can be used in the development of future applications to diagnose and treat pancreas diseases, the spectral optical properties of the rabbit pancreas were evaluated in a broad-spectral range, between 200 and 1000 nm. The method used to obtain such optical properties is simple, based almost on direct calculations from spectral measurements. The optical properties obtained show similar wavelength dependencies to the ones obtained for other tissues, but a further analysis on the spectral absorption coefficient showed that the pancreas tissues contain pigments, namely melanin, and lipofuscin. Using a simple calculation, it was possible to retrieve similar contents of these pigments from the absorption spectrum of the pancreas, which indicates that they accumulate in the same proportion as a result of the aging process. Such pigment accumulation was camouflaging the real contents of DNA, hemoglobin, and water, which were precisely evaluated after subtracting the pigment absorption.The work of I.S.M. was supported by the Portuguese Science Foundation, grant no. FCTUIDB/ 151528/2021. The work of H.F.S and L.M.O. was supported by the Portuguese Science Foundation, grant No. FCT-UIDB/04730/2020. The work of V.V.T. was supported by a grant under the Decree of the Government of the Russian Federation No. 220 of 09 April 2010 (Agreement No. 075-15-2021-615 of 4 June 2021).info:eu-repo/semantics/publishedVersio

Mechanical analysis of asphalt mixtures produced with waste plastic modified binders

This work compares the viscoelastic properties of an asphalt binder (70/100 pen) modified with different waste plastics and the mechanical properties of the resultant asphalt mixtures. Two different plastic wastes were used, namely recycled HDPE and EVA. Three different polymer modified binders were produced with these plastic wastes: i) 5% HDPE modified binder (P5); ii) 5% EVA modified binder (E5) and; iii) a modified binder with 4% of EVA and 2% HDPE (E4P2). Asphalt mixtures were produced with these modified binders, and their mechanical properties were analysed and compared with a conventional mixture produced with a 30/50 pen bitumen. It was possible to conclude that these recycled polymers are able to improve the mechanical performance of the asphalt mixtures used in road paving.FEDER funds through the Operational Programme for Competitiveness Factors & COMPETE and National Fund s through FCT & Foundation for Science and Technology under the project PLASTIROADS (PTDC/ECM/119179/2010) and Symposium_22 Recycling and Reuse of Wastes into New Composite Materials -2062-of the strategic project UI 4047- 2011-2012 Centre of Territory, Environment and Construction

Colloidal lithography for photovoltaics: An attractive route for light management

DFA/BD/7882/2020The pursuit of ever‐more efficient, reliable, and affordable solar cells has pushed the development of nano/micro‐technological solutions capable of boosting photovoltaic (PV) performance without significantly increasing costs. One of the most relevant solutions is based on light management via photonic wavelength‐sized structures, as these enable pronounced efficiency improvements by reducing reflection and by trapping the light inside the devices. Furthermore, optimized microstructured coatings allow self‐cleaning functionality via effective water repulsion, which reduces the accumulation of dust and particles that cause shading. Nevertheless, when it comes to market deployment, nano/micro‐patterning strategies can only find application in the PV industry if their integration does not require high additional costs or delays in high‐throughput solar cell manufacturing. As such, colloidal lithography (CL) is considered the preferential structuring method for PV, as it is an inexpensive and highly scalable soft‐patterning technique allowing nanoscopic precision over indefinitely large areas. Tuning specific parameters, such as the size of colloids, shape, monodispersity, and final arrangement, CL enables the production of various templates/masks for different purposes and applications. This review intends to compile several recent high‐profile works on this subject and how they can influence the future of solar electricity.publishersversionpublishe

Measurement of tissue optical properties in a wide spectral range: a review

A distinctive feature of this review is a critical analysis of methods and results of measurements of the optical properties of tissues in a wide spectral range from deep UV to terahertz waves. Much attention is paid to measurements of the refractive index of biological tissues and liquids, the knowledge of which is necessary for the effective application of many methods of optical imaging and diagnostics. The optical parameters of healthy and pathological tissues are presented, and the reasons for their differences are discussed, which is important for the discrimination of pathologies and the demarcation of their boundaries. When considering the interaction of terahertz radiation with tissues, the concept of an effective medium is discussed, and relaxation models of the effective optical properties of tissues are presented. Attention is drawn to the manifestation of the scattering properties of tissues in the THz range and the problems of measuring the optical properties of tissues in this range are discussed. In conclusion, a method for the dynamic analysis of the optical properties of tissues under optical clearing using an application of immersion agents is presented. The main mechanisms and technologies of optical clearing, as well as examples of the successful application for differentiation of healthy and pathological tissues, are analyzed

Conceptual maps : representations of History teachers’ knowledge

Este texto pretende discutir o papel dos mapas de conceitos como representações gráficas do conhecimento do professor de história, aquando o desenho de um trajecto didáctico específico. Identificar-se-ão as dificuldades inerentes à sua construção assim como possíveis modos de utilização na sala de aula de História do Ensino Básico.This text intends to discuss the role of conceptual maps as graphic representations of History teachers’ knowledge, when they draw a didactic plan. We aim also to identify the problems teachers faced during the maps construction, and as well to point out possible ways to use them in 2nd and 3rd cycle history classrooms

LocalEnergy: Local Resources for Multifunctional Tetrahedrite-based Energy: Harvesting Applications

info:eu-repo/semantics/publishedVersio

Conhecimento profissional do jovem professor de Matemática sobre os alunos

Este artigo procura estudar o conhecimento profissional sobre os alunos de professores de Matemática e de professores do 1.º ciclo do ensino básico em início de carreira. Na sua base está um trabalho colectivo realizado por formadores de instituições de ensino superior em Portugal, preocupados em melhorar a qualidade da formação inicial dos professores em especial no que se refere à Didáctica da Matemática. A metodologia, de natureza qualitativa e interpretativa, envolveu a realização de 13 estudos de caso. Entre os principais resultados obtidos destacamos a tendência dos jovens professores para apreciar de forma positiva os seus alunos, transmitindo elevadas expectativas sobre o seu desempenho. A concretização dessas expectativas parece estar relacionada com a importância que dão ao seu papel. Apontam dificuldades de aprendizagem essencialmente de natureza transversal, situando-se sobretudo na linguagem matemática, no raciocínio e na resolução de problemas. As concepções que os alunos têm sobre a Matemática estão ausentes no discurso dos professores. Reconhecem que as características do ambiente de sala de aula são um factor importante para a aprendizagem. A diversidade entre turmas e entre os alunos, embora referenciada, constitui em diversos casos uma dificuldade para o processo de ensino e aprendizagem.This article aims to study the professional knowledge that young mathematic teachers and elementary education teachers have about students. In its basis there is a collective work done by educators from high education institutions, in Portugal, concerned with the improvement of the quality of teachers training, specially, in regard to the domain of the Didactics of Mathematics. The methodology has a qualitative and interpretative nature, and involved 13 case studies. Among the main results we highlight the trend, among young teachers, to appreciate positively their students, showing high expectations about their performance. The concretization of these expectations seems to be related with the importance that teachers give to their own role. They mention students learning difficulties, mainly concerning mathematics’ communication, reasoning and problem solving. The conceptions that students have on Mathematics are absent from teachers’ discourse. They recognize that classroom environment characteristics are an important factor for learning. The diversity among classes and students constitutes, in several situations, a difficulty to the teaching and learning process

Nightside condensation of iron in an ultra-hot giant exoplanet

Ultra-hot giant exoplanets receive thousands of times Earth's insolation. Their high-temperature atmospheres (>2,000 K) are ideal laboratories for studying extreme planetary climates and chemistry. Daysides are predicted to be cloud-free, dominated by atomic species and substantially hotter than nightsides. Atoms are expected to recombine into molecules over the nightside, resulting in different day-night chemistry. While metallic elements and a large temperature contrast have been observed, no chemical gradient has been measured across the surface of such an exoplanet. Different atmospheric chemistry between the day-to-night ("evening") and night-to-day ("morning") terminators could, however, be revealed as an asymmetric absorption signature during transit. Here, we report the detection of an asymmetric atmospheric signature in the ultra-hot exoplanet WASP-76b. We spectrally and temporally resolve this signature thanks to the combination of high-dispersion spectroscopy with a large photon-collecting area. The absorption signal, attributed to neutral iron, is blueshifted by -11+/-0.7 km s-1 on the trailing limb, which can be explained by a combination of planetary rotation and wind blowing from the hot dayside. In contrast, no signal arises from the nightside close to the morning terminator, showing that atomic iron is not absorbing starlight there. Iron must thus condense during its journey across the nightside.Comment: Published in Nature (Accepted on 24 January 2020.) 33 pages, 11 figures, 3 table