Valley polarization effects on the localization in graphene Landau levels

Effects of disorder and valley polarization in graphene are investigated in the quantum Hall regime. We find anomalous localization properties for the lowest Landau level (LL), where disorder can induce wavefunction delocalization (instead of localization), both for white-noise and gaussian-correlated disorder. We quantitatively identify the contribution of each sublattice to wavefunction amplitudes. Following the valley (sublattice) polarization of states within LLs for increasing disorder we show: (i) valley mixing in the lowest LL is the main effect behind the observed anomalous localization properties, (ii) the polarization suppression with increasing disorder depends on the localization for the white-noise model, while, (iii) the disorder induces a partial polarization in the higher Landau levels for both disorder models.Comment: 5 pages, 6 figures, extended version, with 2 new figures adde

Resonant tunneling through protected quantum dots at phosphorene edges

We theoretically investigate phosphorene zigzag nanorribons as a platform for constriction engineering. In the presence of a constriction at the upper edge, quantum confinement of edge protected states reveals resonant tunnelling Breit-Wigner transmission peaks, if the upper edge is uncoupled to the lower edge. Coupling between edges in thin constrictions gives rise to Fano-like and anti-resonances in the transmission spectrum of the system.Comment: 8 pages,7 figure

Amino acids and biogenic amines evolution during the estufagem of fortified wines

The current study was focused on the impact of accelerated ageing (heating step) on the amino acid and biogenic amine profiles of fortified wines. In this sense, three Madeira wines from two commonly used grape varieties (one red and the other white) were analysed during the heating, at standard (45∘ C, 3 months) and overheating (70∘ C, 1 month) conditions, following a precolumn derivatization procedure using iodoacetic acid, o-phthaldialdehyde, and 2-mercaptoethanol, carried out in the injection loop prior to RP-HPLC-FLD detection. Eighteen amino acids were identified, with arginine being the most abundant. An important decrease of the amino acid levels was detected during the standard heating (up to 30%), enhanced up to 61% by the temperature increase. Cysteine, histidine, and asparagine revealed the greatest decreases at 45∘ C. Conversely, some amino acids, such as asparagine, slightly increased. Four biogenic amines were identified but always in trace amounts. Finally, it was observed that the accelerated ageing did not favour the biogenic amine development. The results also indicate that the heating process promotes the amino acid transformation into new ageing products.info:eu-repo/semantics/publishedVersio

Fasting Glucose Metabolism in Pregnancy

The HAPO study found a continuous association between hyperglycemia at 24-32 weeks of gestation, below the diagnostic levels of gestational diabetes mellitus (GDM), and adverse pregnancy outcomes, suggesting the need to reconsider the diagnostic criteria for GDM. Recently, a consensus for diagnosis of diabetes in pregnancy was published, based on the results of the HAPO study. Diagnosing for diabetes is considered already in the first trimester with fasting plasma glucose (FPG), but oral glucose tolerance test is recommended to be performed only at 24-28 weeks of gestation. Identifying all pregnant women at risk for GDM in the first trimester would allow an individualization of obstetric care and establishment of a dietetic and exercise plan since earlier stages of pregnancy with potential benefits for both mother and fetus. The glycemic metabolism varies throughout pregnancy, as insulin resistance increases during pregnancy. However the cut-off values for blood glucose tests in screening and diagnosing GDM are independent of gestational age. The objectives of this study are to verify if the pregnant women with and without GDM diagnosed in the second/third trimester are already different from each other in the first trimester regarding FPG levels and to study the evolution of the FPG throughout pregnancy

Ciprofloxacin removal catalysed by conductive carbon materials

Current wastewater treatment technologies are not effective in the removal of pharmaceuticals. In anaerobic bioreactors, the electrons produced during the oxidation of organic matter can potentially be used for the biological reduction of pharmaceuticals. However, these reactions occur generally at a slow rate, due to electron transfer limitations, and might be accelerated through redox mediators (RM). Carbon nanomaterials (CM) have been effective RM in the biological reduction of other pollutants. For instance, CNT@2%Fe were found to increase 76-fold the biological reduction of Acid Orange 10. The magnetic properties of those composites allow their easier recover after the process by using a magnetic field. In this study, CNT and CNT@2%Fe were studied in the anaerobic removal of Ciprofloxacin (CIP). Furthermore, the potential contribution of adsorption and biodegradation processes for CIP removal was assessed. Toxicity assessment is highly important as it is desired that the products formed after the process are not more toxic than the initial compound. Moreover, the evaluation of the possible contribution of nanomaterials used in the process for the final toxic effect of threated solution, is crucial. In this sense, the detoxification of the treated solutions was evaluated towards Vibrio fischeri.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2019 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Development of PVD-deposited Pd-Ag functional thin films membranes on ceramic supports for hydrogen purification/separation

Palladium (Pd)-based membranes have been studied for many years, regarding applications in production and purifi-cation of hydrogen. The reaction of water gas shift (CO+ H2O ↔ CO2 + H2), for example, can advantageously be conducted in a Pd-based membrane reactor, where hydrogen produced selectively permeates the membrane [1]. When hydrogen permeates with an infinite selectivity, its passage is governed by sorption-diffusion mechanism through the atomic struc-ture. Among all metals, palladium is the material that exhibits the highest atomic hydrogen permeability, resulting from the high capability in the catalytic dissociation of H2 molecules it in its metallic structure [2]. However, the use of pure palladi-um membranes has some limitations [3]. When palladium alloys such as Pd-Ag are used, the result is a homogeneous solid solution with a fcc structure [4,5]. This alloy prevents the formation of hybrid phases, allowing higher hydrogen permeation along with chemical and mechanical stability, reducing also the overall cost of raw material [2].Patricia Pérez is grateful to Fundação para a Ciência e a Tecnologia (FCT) for the doctoral grant (reference: SFRH/BD/73673/2010). The authors also acknowledge fi-nancing from FCT through the project PTDC/EQU-ERQ/098730/2008 and COMPETE scientific program. The authors show appreciation for the collaboration of Sandra Rodrigues on the permeation experiments

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

New Quantum-Dot-Based Fluorescent Immunosensor for Cancer Biomarker Detection

Cancer antigen 15-3 (CA 15-3) is a biomarker for breast cancer used to monitor response to treatments and disease recurrence. The present work demonstrates the preparation and application of a fluorescent biosensor for ultrasensitive detection of the cancer antigen CA 15-3 protein tumor marker using mercaptopropionic-acid-functionalized cadmium telluride (CdTe@MPA) quantum dots (QDs) conjugated with CA 15-3 antibodies. First, the QDs were synthesized by the hydrothermal route, resulting in spherical nanoparticles up to 3.50 nm in diameter. Subsequently, the QD conjugates were characterized by Fourier transform infrared spectroscopy (FTIR), UV absorption, and fluorescence. The interaction between the conjugates and the protein was studied by fluorescence spectroscopy in buffer and in 10-fold diluted commercial human serum. Calibration in spiked serum samples gave a detection limit of 0.027 U/mL, 1000-fold lower than the clinical limit for CA 15-3 (25 U/mL to 30 U/mL), indicating that this is an ultrasensitive technique. In addition, a rapid response was obtained within 10 min. The biosensor was selective in the presence of the interfering serum proteins BSA, CEA, and CA-125, with a maximum interference of 2% for BSA. The percent recovery was close to 100% with maximum relative standard deviation (RSD%) values of 1.56. Overall, the developed CA 15-3 biosensor provides a simple and sensitive method for ultrasensitive monitoring of breast cancer, as well as the ability to detect other molecules of interest in human serum matrices.This research was funded by Fundação para a Ciência e Tecnologia, I.P, grant number 2022.09032.PTDCinfo:eu-repo/semantics/publishedVersio

Avaliação do efeito da associação do Rituximab ao protocolo de quimioterapia ciclofosfamida, doxorrubicina, vincristina e prednisolona (CHOP) no tratamento de linfomas Não-Hodgkin

O protocolo de quimioterapia ciclofosfamida, doxorrubicina, vincristina e prednisolona (CHOP) e, posteriormente, rituximab, ciclofosfamida, doxorrubicina, vincristina e prednisolona (RCHOP) têm sido utilizados como terapêutica em Linfomas não-Hodgkin (LNH) como o Linfoma Difuso de Grandes Células B (LDGCB) e o Linfoma Folicular (LF). O LDGCB constitui o tipo de LNH mais frequente, com uma incidência de 40% e o LF representa cerca de 25% de todos os LNH-B. O anticorpo monoclonal rituximab foi associado ao protocolo de quimioterapia CHOP, pois este apresenta actividade sobre a maioria das células CD20+, sendo este um marcador expresso pela maioria das células B de linfomas. Actualmente, em oncologia, além dos ganhos clínicos que possam advir de novas opções terapêuticas, têm também vindo a ser analisadas as suas consequências a nível económico, devido ao aumento significativo das despesas com a Saúde. Assim, nos últimos anos, têm vindo a realizar-se estudos que avaliam parâmetros clínicos e de custo efectividade decorrentes da associação do rituximab ao CHOP, relativamente a este protocolo de quimioterapia isolado. Este trabalho teve como objectivo comparar os ganhos terapêuticos da associação do rituximab ao CHOP face a este protocolo de quimioterapia isolado, através da avaliação de indicadores clínicos (probabilidade de sobrevivência, probabilidade de sobrevivência sem sintomas, taxa de resposta, toxicidade, risco de infecção) e de custo efectividade descritos na literatura publicada nos últimos 5 anos