New U-Pb zircon age constraints for the emplacement of the Reguengos de Monsaraz Massif (Ossa Morena Zone)

The Reguengos de Monsaraz massif is located in the Portuguese sector of the Ossa Morena Zone (ZOM), one of the major geotectonic units of the Iberian Variscan Belt. It intruded Lower Paleozoic metasediments, strongly affected by deformation and metamorphism during the Varis-can orogeny. Pluton emplacement was responsible for the development of a contact metamor-phism aureole in the surrounding country rocks. Based on regional constraints, the intrusion was included in the group of the late-post-tectonic granitoids. The pluton shows an inversely zoned pattern and consists of tonalitic to granodioritic rocks with abundant mafic microgranular enclaves, occupying most of the presently exposed intrusion area and minor bodies of gabbro-diorites in the east and centre. Field, petrographical and geo-chemical data reveal that mixing / mingling between mantle- and crustally-derived magmas and fractional crystallization played a major role in the genesis and evolution of these granitoids 1. Early attempts to date the Reguengos de Monsaraz intrusion, using Rb-Sr isotopic data for a feldspar-amphibole pair from one granodiorite sample, yielded an age of 297.5 ± 2.9 Ma. This age was interpreted as a cooling age and provided a minimum estimate for the timing of mag-matic crystallization. In order to better constrain the age and emplacement sequence of the mas-sif, five samples representing the different magmatic units (gabbro diorites, tonalites and mafic microgranular enclaves) were selected for determination of U-Pb zircon ages by isotope dilution techniques. The zircon populations from two samples of the gabbro diorites (one from the central sector and the other from the easternmost body) yielded overlapping 206Pb/238U average ages of 337.4 1.1 Ma and 338.6 ± 0.7 Ma, respectively. Similar ages were obtained in two samples from the main tonalite-granodiorite facies (337.3 ± 2.3 Ma; 337.8 ± 0.7 Ma). Finally, the zircons from the microgranular enclave yielded a 206Pb/238U average age of 336.5 ± 0.5 Ma. A slightly younger age was obtained in two fractions of titanite from the enclave (333.6 ± 2.5 Ma), suggesting either resetting of their original magmatic ages or late stage crystallization. The new U-Pb age data support a coeval emplacement for all the members of this suite, at ap-proximately 337-338 Ma. Such a close space-time association between mafic and felsic grani-toids is consistent with the proposed mixing model. According to recent studies, this sector of the OMZ was affected by three Variscan deforma-tion events 2. The earlier deformation phases (D1 and D2) occurred in Late Devonian ( 380-360 Ma) and Early Carboniferous times ( 360-345 Ma), whilst the latter (D3) has a Pennsylva-nian age (305-295 Ma). Based on the available geochronological information, the emplacement of the Reguengos de Monsaraz magmas took place at a time of tectonic quiescence between D2 and D3. The relatively young Rb-Sr age recorded in the feldspar-amphibole pair may therefore reflect the effects of the last tectonothermal event, also documented by the replacement of horn-blende crystals by actinolite

Geochronology and Isotope Geochemistry of Felsic Marginal Facies of the Reguengos de Monsaraz Pluton (OMZ)

No sector sueste do maciço de Reguengos de Monsaraz (Zona de Ossa-Morena), ocorrem rochas félsicas quer em continuidade espacial com as litologias principais do plutonito quer em pequenos corpos aparentemente separados. Neste trabalho, estudou-se o granito marginal da zona de Arraieiras, bem como o tonalito da zona do ribeiro dos Gagos. Datações U-Pb (em zircão e monazite) revelam que estas litologias são, no essencial, contemporâneas entre si, bem como relativamente às fácies mais comuns do maciço de Reguengos, e que os processos de instalação magmática deverão ter decorrido há 337-338 Ma. Do ponto de vista geoquímico, o granito de Arraieiras parece ter uma relação genética forte com o resto do plutonito, através de processos de mistura de líquidos (de origens mantélica e de anatexia de metassedimentos) e diferenciação magmática, a que se terão seguido fenómenos locais de assimilação do encaixante no nível de instalação final. O paradoxo de haver rochas mais máficas do que o granito com assinaturas isotópicas mais “crustais” poderá ser explicado pela intervenção final destes processos de assimilação. Quanto ao tonalito de Gagos, as suas características geoquímicas, e em particular as razões isotópicas de Sr e Nd, requerem uma origem distinta, com contribuição de fonte infracrustal.Felsic rocks occur in the SE sector of the Reguengos de Monsaraz massif either as a border zone of the pluton or as small satellite bodies. In this work, the Arraieiras granite (from the border zone) and the Gagos tonalite (from a satellite body) were studied for geochronology and geochemistry. The obtained zircon and monazite U-Pb ages show that the two felsic lithologies and the main units of the Reguengos pluton are essentially contemporaneous to each other and that magma emplacement took place at 337-338 Ma. Geochemical features of the Arraieiras granite suggest that it has a strong genetic link with the other lithologies of the pluton, through magma mixing (from mantle and metasedimentary sources) and differentiation processes; in a late evolutionary stage, at the final emplacement level, assimilation of country rock material also took place. The paradox of some more mafic rocks displaying isotope signatures more “crustal” than those revealed by the Arraieiras granite is probably a consequence of late assimilation events. In contrast, the Gagos tonalite, according to the Sr and Nd isotope fingerprints, seems to be related to a different sequence of processes and, in particular, it requires the contribution of an infracrustal source

Colorectal Endoscopic Submucosal Dissection in a Western Center: Analysis of Outcomes and Safety Profile

Introduction: Endoscopic submucosal dissection (ESD) is a well-established endoscopic technique for the treatment of gastrointestinal lesions. Colorectal ESD outcomes are less reported in the Western literature, and Portuguese data are still very scarce. Our aim was to describe our experience on colorectal ESD regarding its outcomes and safety profile. Methods: We conducted a retrospective evaluation of recorded data on ESDs performed between 2015 and 2020. Only ESDs performed on epithelial neoplastic lesions were selected for further analysis. Results: Of a total of 167 colorectal ESDs, 153 were included. Technical success was achieved in 147 procedures (96%). The lesions were located in the colon (n = 24) and rectum (n = 123). The en bloc resection rate was 92% and 97%, the R0 resection rate was 83% and 82%, and the curative resection rate was 79% and 78% for the colon and the rectum, respectively. The need for a hybrid technique was the only risk factor for piecemeal or R1 resection. We report a perforation rate of 3.4% and a 4.1% rate of delayed bleeding; all the adverse events were manageable endoscopically, without the need of blood transfusions or surgery. Most of the lesions were laterally spreading tumours of the granular mixed type (70%), and 20% of the lesions were malignant (12% submucosal and 8% intramucosal cancer). Conclusion: Our series on colorectal ESD reports a very good efficacy and safety profile. This technique can be applied by endoscopists experienced in ESD

Learning scorecard: Monitor and foster student learning through gamification

This paper presents the Learning Scorecard (LS), a platform that enables students to monitor their learning progress in a Higher Education course during the semester, generating the data that will also support the ongoing supervision of the class performance by the course coordinator. The LS uses gamification techniques to increase student engagement with the course. Business Intelligence best practices are also applied to provide an analytical environment for student and faculty to monitor course performance. This paper describes the initial design of the LS, based on a Balanced Scorecard approach, and the prototype version of the platform, currently in use by graduate and undergraduate students in the fall semester of 2016-2017.info:eu-repo/semantics/publishedVersio

Assessment of stiffness and fatigue tests in Portugal

In the last decade, quality control of asphalt mixtures for pavement construction on the main Portuguese national road network used, most of the time, four-point bending beam tests (4pb) results as a reference. Stiffness modulus and fatigue laws established with samples prepared in the laboratory are usually used as a reference for behaviour/quality control analysis of the samples coming from the construction site. There is however, with this procedure, not only a problem of real world representation but also a question of the compatibility of results coming, again most of the time, from different laboratories using different equipments. Trying to address the second problem, this paper presents the results obtained from four-point bending tests carried out in three different laboratories in Portugal, owning three different 4pb equip-ments, concerning the performance characterization of a typical Portuguese base course asphalt mixture. The paper finally discusses the variability of the results obtained and underlines the main inferences that could be extracted

From sugarcane to skin: lignin as a multifunctional ingredient for cosmetic application

Lignin has been suggested as a promising candidate for cosmetic applications due to its remarkable potential to absorb ultraviolet rays and distinctive antioxidant activity. This study aims at evaluating the performance of lignin from sugarcane bagasse (SCB) as natural UV blocker, antioxidant, and pigment. Lignin was extracted from SCB, characterized and incorporated into a blemish balm (BB) cream. The biological potential, concretely, in vitro and in vivo sun protection factor (SPF) and in vitro UVA-PF, and safety were assessed. A high-purity SCB lignin (>92 %) was obtained by a mild alkaline extraction process. The results of cytotoxicity, mutagenicity, skin sensitization and in vivo acute cutaneous irritation demonstrated that SCB lignin is safe for topical applications. Lignin showed capacity to scavenge both ABTS and DPPH radicals, which were preserved after its incorporation into the cosmetic formulation. Notable results were achieved in terms of in vitro and in vivo SPF of 9.5 ± 2.9 and 9.6 ± 0.8, respectively. Furthermore, the tested lignin-based BB cream revealed a broad-spectrum UV protection (critical wavelength of 378 ± 0.5 nm). These results suggest SCB lignin as multifunctional and safe ingredient for use in cosmetic products.info:eu-repo/semantics/publishedVersio

A review on the valorization of lignin from sugarcane by-products: from extraction to application

The sugarcane industry generates several by-products including the harvest residue (straw) and the fibrous fraction following juice extraction (bagasse). The conversion of sugarcane industry by-products into value-added products is of paramount importance from a sustainable circular economy perspective. Also, the increase of second-generation bioethanol production has triggered the development of approaches to convert residues into functional bioproducts thus increasing the overall sustainability of the process. Lignin is the major biopolymer in nature, and one of the three main components of sugarcane bagasse (SCB) and straw (SCS) biomasses. Due to the potential of lignin as natural antioxidant, antimicrobial, and ultraviolet protector, lignin-based research and new product development have significantly increased. Therefore, this review aims at updating the progress on the valorization of SCS and SCB, and emphasizing their main potential bioactivities and applications, thus serving as a valuable reference material for the academy and industry. A brief introduction of the sugarcane and sugar industry in terms of by-products generation and current end-uses is presented. Recent research studies on SCB and SCS delignification techniques, lignin purification/separation and the main physical-chemical differences between SCS and SCB are covered. The most reported biological activities for sugarcane lignin and their potential applications in the cosmetic and materials fields are also detailed in this review.info:eu-repo/semantics/publishedVersio

Sugarcane bagasse as source of bioactive lignin: influence of pretreatment on the antioxidant and antibacterial activities

Sugarcane industry generates several by-products of particular interest in the context of a circular economy, due to their potential as a source of value-added ingredients. Bagasse is one of the main by-products, consisting of a fibrous fraction obtained after juice extraction. Sugarcane bagasse is composed of cellulose, hemicellulose, and lignin, with lower amounts of extractives and ash (del Río et al., 2015). Lignin is one of the most abundant renewable resources on earth and recognized as a profitable source of high value compounds. The main functions attributed to lignin in the plant are elasticity and mechanical strength. It is a complex aromatic macromolecule formed by the dehydrogenative polymerization of three phenylpropanoid monomers coniferyl, synapyl, and p-coumaryl alcohols. The antimicrobial activity of lignin is related to plant sources and attributed to the phenolic components, particularly the side-chain structure and its functional groups (Chauhan, 2020). The antioxidant activity of lignin is mainly attributed to the scavenging action of their phenolic structures on oxygen-containing reactive free radicals. For the antioxidant activity of the lignin, free phenolic hydroxyl groups and ortho-methoxy substitution in aromatic rings are essential. The structural characteristics of lignin depend on several factors including the botanical origin, and environmental growth and extraction conditions. The main objective of this work was to study the potential of lignin from sugarcane bagasse as antimicrobial and antioxidant agent and assess the influence of two different pretreatments - deep eutectic solvents and organosolv – on the biological potential.info:eu-repo/semantics/publishedVersio