Femtosecond laser ablation of dentin

The surface morphology, structure and composition of human dentin treated with a femtosecond infrared laser (pulse duration 500 fs, wavelength 1030 nm, fluences ranging from 1 to 3 J cm(-2)) was studied by scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The average dentin ablation threshold under these conditions was 0.6 +/- 0.2 J cm(-2) and the ablation rate achieved in the range 1 to 2 mu m/pulse for an average fluence of 3 J cm(-2). The ablation surfaces present an irregular and rugged appearance, with no significant traces of melting, deformation, cracking or carbonization. The smear layer was entirely removed by the laser treatment. For fluences only slightly higher than the ablation threshold the morphology of the laser-treated surfaces was very similar to the dentin fracture surfaces and the dentinal tubules remained open. For higher fluences, the surface was more porous and the dentin structure was partially concealed by ablation debris and a few resolidified droplets. Independently on the laser processing parameters and laser processing method used no sub-superficial cracking was observed. The dentin constitution and chemical composition was not significantly modified by the laser treatment in the processing parameter range used. In particular, the organic matter is not preferentially removed from the surface and no traces of high temperature phosphates, such as the beta-tricalcium phosphate, were observed. The achieved results are compatible with an electrostatic ablation mechanism. In conclusion, the high beam quality and short pulse duration of the ultrafast laser used should allow the accurate preparation of cavities, with negligible damage of the underlying material

Investigations on the Wear Performance of Coated Tools in Machining UNS S32101 Duplex Stainless Steel

Due to their high mechanical property values and corrosion resistance, duplex stainless steels (DSSs) are used for a wide variety of industrial applications. DSSs are also selected for applications that require, especially, high corrosion resistance and overall good mechanical properties, such as in the naval and oil-gas exploration industries. The obtention of components made from these materials is quite problematic, as DSSs are considered difficult-to-machine alloys. In this work, the developed wear during milling of the UNS S32101 DSS alloy is presented, employing four types of milling tools with different geometries and coatings. The influence of feed rate and cutting length variations on the tools’ wear and their performance was evaluated. The used tools had two and four flutes with different coatings: TiAlN, TiAlSiN and AlCrN. The cutting behavior of these tools was analyzed by collecting data regarding the cutting forces developed during machining and evaluating the machined surface quality for each tool. After testing, the tools were submitted to SEM analysis, enabling the identification of the wear mechanisms and quantification of flank wear, as well as identifying the early stages of the development of these mechanisms. A comparison of all the tested tools was made, determining that the TiAlSiN-coated tools produced highly satisfactory results, especially in terms of sustained flank wear.The present work was conducted and funded under the scope of the project ON-SURF (ANI|P2020|POCI-01-0247-FEDER-024521, co-funded by Portugal 2020 and FEDER, through the COMPETE 2020-Operational Programme for Competitiveness and Internationalisation. F.J.G. Silva thanks INEGI—Instituto de Ciência e Inovação em Engenharia Mecânica e Engenharia Indústria for its support. The authors would like to thank Rui Rocha from CEMUP (Porto, Portugal), due to his active collaboration in getting the best SEM pictures and helping with his critical analysis of some phenomena. The authors also would like to thank Ing. Ricardo Alexandre for his extremely important role in providing all the coatings through the TEandM company, and Eng. Nuno André for providing the substrate material and uncoated tools through the Inovatools company.info:eu-repo/semantics/publishedVersio

A potential signature for muscle-invasive tumors

Funding: This work was supported by the Astellas European Foundation Uro-Oncology Grant 2014; JABA RECORDATI Urology 2011 - Portuguese Society of Urology; Portuguese Foundation for Science and Technology (Strategic Project: PEst-C/SAU/UI3282/2013 and UID/NEU/04539/2013); GAI/FMUC and Santander Totta (Ref. FreitasGomes04.01.13) and Center of Investigation in Environment, Genetics and Oncobiology (CIMAGO), Portugal (Ref. 14/12). Margarida FerreiraTeixeira benefits from a PhD scholarship from the Portuguese Foundation for Science and Technology (Reference SFRH/BD/77314/2011).Striking evidence associates cancer stem cells (CSCs) to the high recurrence rates and poor survival of patients with muscle-invasive bladder cancer (BC). However, the prognostic implication of those cells in risk stratification is not firmly established, mainly due to the functional and phenotypic heterogeneity of CSCs populations, as well as, to the conflicting data regarding their identification based on a single specific marker. This emphasizes the need to exploit putative CSC-related molecular markers with potential prognostic significance in BC patients. This study aimed to isolate and characterize bladder CSCs making use of different functional and molecular approaches. The data obtained provide strong evidence that muscle-invasive BC is enriched with a heterogeneous stem-like population characterized by enhanced chemoresistance and tumor initiating properties, able to recapitulate the heterogeneity of the original tumor. Additionally, a logistic regression analysis identified a 2-gene stem-like signature (SOX2 and ALDH2) that allows a 93% accurate discrimination between non-muscle-invasive and invasive tumors. Our findings suggest that a stemness-related gene signature, combined with a cluster of markers to more narrowly refine the CSC phenotype, could better identify BC patients that would benefit from a more aggressive therapeutic intervention targeting CSCs population.publishersversionpublishe

Explanation-by-Example Based on Item Response Theory

Intelligent systems that use Machine Learning classification algorithms are increasingly common in everyday society. However, many systems use black-box models that do not have characteristics that allow for self-explanation of their predictions. This situation leads researchers in the field and society to the following question: How can I trust the prediction of a model I cannot understand? In this sense, XAI emerges as a field of AI that aims to create techniques capable of explaining the decisions of the classifier to the end-user. As a result, several techniques have emerged, such as Explanation-by-Example, which has a few initiatives consolidated by the community currently working with XAI. This research explores the Item Response Theory (IRT) as a tool to explaining the models and measuring the level of reliability of the Explanation-by-Example approach. To this end, four datasets with different levels of complexity were used, and the Random Forest model was used as a hypothesis test. From the test set, 83.8% of the errors are from instances in which the IRT points out the model as unreliable.Comment: 15 pages, 5 figures, 3 tables, submitted for the BRACIS'22 conferenc

Optimization of ultrasound-assisted extraction of bioactive compounds from Pelvetia canaliculata to sunflower oil

In this study, Pelvetia canaliculata L. macroalga, collected from the Atlantic Portuguese coast, was used as a source of bioactive compounds, mostly antioxidants, to incorporate them in sunflower oil with the aim of increasing its biological value and oxidative stability. The lyophilized alga was added to the oil, and ultrasound-assisted extraction (UAE) was performed. Algae concentration and UAE time varied following a central composite rotatable design (CCRD) to optimize extraction conditions. The following parameters were analyzed in the oils: oxidation products, acidity, color, chlorophyll pigments, carotenoids, flavonoids, total phenolic content, antioxidant activity by DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (ferric reducing antioxidant power) assays, and sensory analysis. Extraction conditions did not affect the acidity and the amount of oxidation products in the oil. Chlorophylls and carotenoid contents increased with algae concentration, while flavonoid extraction did not depend on algae content or UAE time. Total phenolics in the oil were highly related only to FRAP antioxidant activity. Storage experiments of supplemented oil (12.5% algae; 20 min UAE) were carried out under accelerated oxidation conditions at 60 C/12 days. Antioxidant activity (FRAP) of supplemented oil was 6-fold higher than the value of non-supplemented oil. Final samples retained 40% of their initial antioxidant activity. The presence of algae extracts contributed to the increased oxidative stability of sunflower oilinfo:eu-repo/semantics/publishedVersio

Absolutely continuous invariant measures for random non-uniformly expanding maps

We prove existence of (at most denumerable many) absolutely continuous invariant probability measures for random one-dimensional dynamical systems with asymptotic expansion. If the rate of expansion (Lyapunov exponents) is bounded away from zero, we obtain finitely many ergodic absolutely continuous invariant probability measures, describing the asymptotics of almost every point. We also prove a similar result for higher-dimensional random non-uniformly expanding dynamical systems. The results are consequences of the construction of such measures for skew-products with essentially arbitrary base dynamics and asymptotic expansion along the fibers. In both cases our method deals with either critical or singular points for the random maps.Comment: 30 pages; 2 figures. Keywords: non-uniform expansion, random dynamics, slow recurrence, singular and critical set, absolutely continuous invariant measures, skew-product. To appear in Math Z, 201

Metabolic syndrome in elderly from a northeastern brazilian city

Introduction: Population aging is a global reality. In Brazil, it is so expressive and in 2050 is estimated that the number of men and women over 80 years old can overcome the 20-24 years old population and also children under 14 years old. Metabolic syndrome is defined as a set of cardiovascular risk factors, detection and intervention in this age group may decrease cardiovascular mortality. We aimed to estimate the prevalence of metabolic syndrome (MS) in elderly patients in a northeastern Brazilian city. Method: This is a quantitative, observational, cross-sectional and population-based study. The population consisted of non-institutionalized individuals aged> 60 years old, attended in the Family Health Strategy (FHS) and residents in Cajazeiras, PB, Brazil. For the diagnosis of metabolic syndrome we considered the criteria recommended by the International Federation of Diabetes. Results: We studied 351 elderly patients with 72.4+8.7 years old and 66.1% were female. The prevalence of MS was 69.8% and the most frequent criterion was increased waist circumference (82.6%), followed by high triglycerides (81.5%) and low HDL-cholesterol (80.6%). We observed a statistically significant positive association between MS and women [OR: 1.38 (95% CI: 1.18 to 1.63)] and housing in urban areas [OR: 1.23 (1.02 to 1.48)]. Conclusion: There is a high prevalence of MS among the elderly mainly in women and those living in urban areas

Geo-environmental management of watersheds : the geological systems as the initial decision to land use.

Ap?s a cartografia da bacia do Rio Paracatu (Noroeste de Minas Gerais) ser atualizada em escala de 1:250.000, foi poss?vel elaborar a l?gica para a metodologia de gest?o geoambiental/geossistemas, como parte de uma ampla metodologia de gest?o, em elabora??o desde 1998. Apresenta-se como primeira etapa a verifica??o das rela??es entre rochas, geoformas e solos com as quais se exploram possibilidades e potencialidades de usos da terra para produ??o agr?cola, florestal, industrial, rural, energ?tica e de obras civis. Com o quadro de potencialidades fundamentado sobre os geossistemas, foi poss?vel ent?o realizar uma an?lise avaliativa das condi??es de acerto ou inconveni?ncia dos usos atuais da terra, as possibilidades de expans?o de usos e as necessidades de mitiga??o sob o ponto de vista da estabilidade do substrato. Com a cartografia na escala de 1:250.000 pode-se estabelecer uma vis?o regional e fornecer indicativos para estudos em escala local e a tomada de decis?o que envolve ainda um conjunto de outras ci?ncias, engenharias e modelos econom?tricos. Este artigo apresenta os procedimentos dessa primeira etapa de aux?lio ? elabora??o de decis?es, passo a passo.After the mapping of the Paracatu River basin (Northwestern Minas Gerais, Brazil) was updated on a scale of 1:250,000, it was possible to elaborate the rationale for the methodology of geo-environmental/geosystems management as part of a broad management methodology, under development since 1998. It presents as the first step to verify the relationship between rocks, landforms, and soils with which one can explore possibilities and potential land use for agricultural production, forestry, rural industrial, energy production, and civil works. With the framework of potentials based on geosystems, it was possible to make an evaluation analysis about the terms of settlement or inconvenience of the land current uses, the possibilities for expansion of uses, and the requirements for mitigation under the terms of the substrate stability. With the mapping at the 1:250,000 scale, it was possible to establish a regional vision provide the indicative scale studies and local decision-making that still involves a number of other sciences, engineering as well as the econometric models. This article presented the procedures of the first stage of the aid business decision making, step-by-step