Sleep and Academic Performance in Undergraduates: A Multi-measure, Multi-predictor Approach

The present study examined the associations of sleep patterns with multiple measures of academic achievement of undergraduate university students and tested whether sleep variables emerged as significant predictors of subsequent academic performance when other potential predictors, such as class attendance, time devoted to study, and substance use are considered. A sample of 1654 (55% female) full-time undergraduates 17 to 25 yrs of age responded to a self-response questionnaire on sleep, academics, lifestyle, and well-being that was administered at the middle of the semester. In addition to self-reported measures of academic performance, a final grade for each student was collected at the end of the semester. Univariate analyses found that sleep phase, morningness/eveningness preference, sleep deprivation, sleep quality, and sleep irregularity were significantly associated with at least two academic performance measures. Among 15 potential predictors, stepwise multiple regression analysis identified 5 significant predictors of end-of-semester marks: previous academic achievement, class attendance, sufficient sleep, night outings, and sleep quality (R(2)=0.14 and adjusted R(2)=0.14, F(5, 1234)= 40.99, p < .0001). Associations between academic achievement and the remaining sleep variables as well as the academic, well-being, and lifestyle variables lost significance in stepwise regression. Together with class attendance, night outings, and previous academic achievement, self-reported sleep quality and self-reported frequency of sufficient sleep were among the main predictors of academic performance, adding an independent and significant contribution, regardless of academic variables and lifestyles of the students

Synthesis of bio-based Polyester from microbial lipidic residue intended for biomedical application

In the last decade, selectively tuned bio-based polyesters have been increasingly used for their clinical potential in several biomedical applications, such as tissue engineering, wound healing, and drug delivery. With a biomedical application in mind, a flexible polyester was produced by melt polycondensation using the microbial oil residue collected after the distillation of β-farnesene (FDR) produced industrially by genetically modified yeast, Saccharomyces cerevisiae. After characterization, the polyester exhibited elongation up to 150% and presented Tg of −51.2 °C and Tm of 169.8 °C. In vitro degradation revealed a mass loss of about 87% after storage in PBS solution for 11 weeks under accelerated conditions (40 °C, RH = 75%). The water contact angle revealed a hydrophilic character, and biocompatibility with skin cells was demonstrated. 3D and 2D scaffolds were produced by salt-leaching, and a controlled release study at 30 °C was performed with Rhodamine B base (RBB, 3D) and curcumin (CRC, 2D), showing a diffusion-controlled mechanism with about 29.3% of RBB released after 48 h and 50.4% of CRC after 7 h. This polymer offers a sustainable and eco-friendly alternative for the potential use of the controlled release of active principles for wound dressing applications.info:eu-repo/semantics/publishedVersio

Evaluating student behaviour on the MathE Platform - clustering algorithms approaches

The MathE platform is an online educational platform that aims to help students who struggle to learn college mathematics as well as students who wish to deepen their knowledge on subjects that rely on a strong mathematical background, at their own pace. The MathE platform is currently being used by a significant number of users, from all over the world, as a tool to support and engage students, ensuring new and creative ways to encourage them to improve their mathematical skills. This paper is addressed to evaluate the students’ performance on the Linear Algebra topic, which is a specific topic of the MathE platform. In order to achieve this goal, four clustering algorithms were considered; three of them based on different bio-inspired techniques and the k-means algorithm. The results showed that most students choose to answer only basic level questions, and even within that subset, they make a lot of mistakes. When students take the risk of answering advanced questions, they make even more mistakes, which causes them to return to the basic level questions. Considering these results, it is now necessary to carry out an in-depth study to reorganize the available questions according to other levels of difficulty, and not just between basic and advanced levels as it is.FCT - Fundação para a Ciência e a Tecnologia(2021-1-PT01-KA220-HED-000023288)This work has been supported by FCT Fundação para a Ciência e Tecnologia within the R&D Units Project Scope UIDB/00319/2020 and UIDB/05757/2020. Beatriz Flamia Azevedo is supported by FCT Grant Reference SFRH/BD/07427/202

Haemolytic anaemia secondary to arsenic poisoning: a case report

We report the case of a 56-year-old white man who presented at the Emergency Department for evaluation of dark-red urine. Rapid development of acute renal failure and haemolytic anaemia initially elicited the hypothesis of a haemolytic-uremic syndrome. A previous exposure to a gas mixture containing arsenic and copper was later recognized as the probable aetiology while other differential diagnoses were excluded. Chelating treatment was promptly initiated before laboratorial confirmation of arsenic and copper poisoning. Renal and haematological recovery was gradually observed and the patient survived with no sequelae

Data analysis techniques applied to the mathE database

MathE is an international online platform that aims to provide a resource for in-class support as well as an alternative instrument to teach and study mathematics. This work focuses on the investigations of the students’ behavior when answering the training questions available in the platform. In order to draw conclusions about the value of the platform, the ways in which the students use it and what are the most wanted mathematical topics, thus deepening the knowledge about the difficulties faced by the users and finding how to make the platform more efficient, the data collected since the it was launched (3 years ago) is analyzed through the use of data mining and machine learning techniques. In a first moment, a general analysis was performed in order to identify the students’ behavior as well as the topics that require reorganization; it was followed by a second iteration, according to the students’ country of origin, in order to identify the existence of differences in the behavior of students from distinct countries. The results point out that the advanced level of the platform’s questions is not adequate and that the questions should be reorganized in order to ensure a more consistent support for the students’ learning process. Besides, with this analysis it was possible to identify the topics that require more attention through the addition of more questions. Furthermore, it was not possible to identify significant disparities in the students behavior in what concerns the students’ country of origin.This work has been supported by FCT Fundação para a Ciência e Tecnologia within the R&D Units Project Scope UIDB/00319/2020, UIDB/05757/2020 and Erasmus Plus KA2 within the project 2021-1-PT01-KA220-HED-000023288. Beatriz Flamia Azevedo is supported by FCT Grant Reference SFRH/BD/07427/2021.info:eu-repo/semantics/publishedVersio

Peptide extract from spent yeast improves resistance of Saccharomyces cerevisiae to oxidative stress

Yeast cells face various stress factors during industrial fermentations, since they are exposed to harsh environmental conditions, which may impair biomolecules productivity and yield. In this work, the use of an antioxidant peptide extract obtained from industrial spent yeast was explored as supplement for Saccharomyces cerevisiae fermentation to prevent a common bottleneck: oxidative stress. For that, a recombinant yeast strain, producer of β-farnesene, was firstly incubated with 0.5 and 0.7 g/L peptide extract, in the presence and absence of hydrogen peroxide (an oxidative stress inducer), for 1–5 h, and then assayed for intracellular reactive oxygen species, and growth ability in agar spot assays. Results showed that under 2 mM H2O2, the peptide extract could improve cells growth and reduce reactive oxygen species production. Therefore, this antioxidant effect was further evaluated in shake-flasks and 2-L bioreactor batch fermentations. Peptide extract (0.7 g/L) was able to increase yeast resistance to the oxidative stress promoted by 2 mM H2O2, by reducing reactive oxygen species levels between 1.2- and 1.7-fold in bioreactor and between 1.2- and 3-fold in shake-flask fermentations. Moreover, improvements on yeast cell density of up to 1.5-fold and 2-fold, and on biomolecule concentration of up to 1.6-fold and 2.8-fold, in bioreactor and shake-flasks, respectively, were obtained. Thus, culture medium supplementation with antioxidant peptide extracted from industrial spent yeast is a promising strategy to improve fermentation performance while valuing biomass waste. This valorization can promote a sustainable and eco-friendly solution for the biotechnology industry by the implementation of a circular economy model.info:eu-repo/semantics/publishedVersio

Natural origin scaffolds with in situ pore forming capability for bone tissue engineering applications

This work describes the development of a biodegradable matrix, based on chitosan and starch, with the ability to form a porous structure in situ due to the attack by specific enzymes present in the human body (a-amylase and lysozyme). Scaffolds with three different compositions were developed: chitosan (C100) and chitosan/starch (CS80-20, CS60-40). Compressive test results showed that these materials exhibit very promising mechanical properties, namely a high modulus in both the dry and wet states. The compressive modulus in the dry state for C100 was 580 ± 33 MPa, CS80-20 (402 ± 62 MPa) and CS60-40 (337 ± 78 MPa). Degradation studies were performed using a-amylase and/or lysozyme at concentrations similar to those found in human serum, at 37 C for up to 90 days. Scanning electron micrographs showed that enzymatic degradation caused a porous structure to be formed, indicating the potential of this methodology to obtain in situ forming scaffolds. In order to evaluate the biocompatibility of the scaffolds, extracts and direct contact tests were performed. Results with the MTT test showed that the extracts of the materials were clearly non-toxic to L929 fibroblast cells. Analysis of cell adhesion and morphology of seeded osteoblastic-like cells in direct contact tests showed that at day 7 the number of cells on CS80-20 and CS60-40 was noticeably higher than that on C100, which suggests that starch containing materials may promote cell adhesion and proliferation. This combination of properties seems to be a very promising approach to obtain scaffolds with gradual in vivo pore forming capability for bone tissue engineering applications.This work was supported by the European NoE EXPERTISSUES (NMP3-CT-2004-500283), the European STREP HIPPOCRATES (NMP3-CT-2003-505758) and the Portuguese Foundation for Science and Technology (FCT) through POCTI and/or FEDER programmes

DNA repair genes polymorphisms and genetic susceptibility to Philadelphia-negative myeloproliferative neoplasms in a Portuguese population: the role of base excision repair genes polymorphisms

Sob uma licença CC-BY-NC-ND - http://creativecommons.org/licenses/by-nc-nd/4.0/The role of base excision repair (BER) genes in Philadelphia-negative (PN)-myeloproliferative neoplasms (MPNs) susceptibility was evaluated by genotyping eight polymorphisms [apurinic/apyrimidinic endodeoxyribonuclease 1, mutY DNA glycosylase, earlier mutY homolog (E. coli) (MUTYH), 8‑oxoguanine DNA glycosylase 1, poly (ADP‑ribose) polymerase (PARP) 1, PARP4 and X‑ray repair cross‑complementing 1 (XRCC1)] in a case‑control study involving 133 Caucasian Portuguese patients. The results did not reveal a correlation between individual BER polymorphisms and PN‑MPNs when considered as a whole. However, stratification for essential thrombocythaemia revealed i) borderline effect/tendency to increased risk when carrying at least one variant allele for XRCC1_399 single‑nucleotide polymorphism (SNP); ii) decreased risk for Janus kinase 2‑positive patients carrying at least one variant allele for XRCC1_399 SNP; and iii) decreased risk in females carrying at least one variant allele for MUTYH SNP. Combination of alleles demonstrated an increased risk to PN‑MPNs for one specific haplogroup. These findings may provide evidence for gene variants in susceptibility to MPNs. Indeed, common variants in DNA repair genes may hamper the capacity to repair DNA, thus increasing cancer susceptibility.info:eu-repo/semantics/publishedVersio

Identification of genetic determinants associated with susceptibility and therapeutic efficacy in Philadelphia-negative Myeloproliferative Neoplasms

Poster presented at the Scientific Toxomics Meeting, 28 September 2015, Lisbon, Portugal

Farmland abandonment decreases the fire regulation capacity and the fire protection ecosystem service in mountain landscapes

This study explored and applied the concepts of Fire Regulation Capacity (FRC) and Fire Protection Ecosystem Service (FPES) in the assessment of the effects of landscape change in a mountain fire-prone landscape in Portugal. We adopted a modeling and simulation approach using BFOLDS-FRM with landscape data for years 1990 and 2006 (observed) and with three landscape scenarios for 2020. Proxy indicators for FRC (burned area and fire intensity) and for economic damage by fire (loss of provisioning ES) were used to establish trends in the supply and value of FPES. We found decreased FRC to restrain simulated fires burning over 100 ha from 1990 on and to regulate Very High and Extreme fire intensity levels, particularly under our 2020 scenario of Forest expansion. FPES is also expected to decrease, as indicated by higher fire-related damages, particularly if fuel hazard increases in the landscape. However, there were differences among scenarios, suggesting potential tradeoffs between FPES and the supply of provisioning ES. Planning and management in this and similar areas experiencing farmland abandonment must consider fire trends and patterns, since landscape change is a major driver affecting FRC and FPES, which may further be decreased by future climatic conditions.Â. Sil received support from the Portuguese Foundation for Science and Technology (FCT) through Ph.D Grant SFRH/BD/132838/2017. This research was partially funded by the European Regional Development Fund (ERDF) through the Operational Programme for Competitiveness Factors–COMPETE and by Portuguese national funds through the Foundation for Science and Technology (FCT) under the projects PTDC/AAG-MAA/4539/2012/FCOMP-01-0124-FEDER- 027863 (IND_CHANGE) and UID/AGR/04033/2019. We thank two anonymous reviewers and the editor for extremely valuable comments and suggestions on the manuscript.info:eu-repo/semantics/publishedVersio