The alignment of the polarization of HAe/Be stars with the interstellar magnetic field

We present a study of the correlation between the direction of the symmetry axis of the circumstellar material around intermediate mass young stellar objects and that of the interstellar magnetic field. We use CCD polarimetric data on 100 Herbig Ae/Be stars. A large number of them shows intrinsic polarization, which indicates that their circumstellar envelopes are not spherical. The interstellar magnetic field direction is estimated from the polarization of field stars. There is an alignment between the position angle of the Herbig Ae/Be star polarization and that of the field stars for the most polarized objects. This may be an evidence that the ambient interstellar magnetic field plays a role in shaping the circumstellar material around young stars of intermediate mass and/or in defining their angular momentum axis.Comment: ApJ accepte

Enhancing the longevity and functionality of Ti-Ag dry electrodes for remote biomedical applications: a comprehensive study

This study aims to evaluate the lifespan of Ti-Ag dry electrodes prepared using flexible polytetrafluoroethylene (PTFE) substrates. Following previous studies, the electrodes were designed to be integrated into wearables for remote electromyography (EMG) monitoring and electrical stimulation (FES) therapy. Four types of Ti-Ag electrodes were prepared by DC magnetron sputtering, using a pure-Ti target doped with a growing number of Ag pellets. After extensive characterization of their chemical composition and (micro)structural evolution, the Ti-Ag electrodes were immersed in an artificial sweat solution (standard ISO-3160-2) at 37 °C with constant stirring. Results revealed that all the Ti-Ag electrodes maintained their integrity and functionality for 24 h. Although there was a notable increase in electrical resistivity beyond this timeframe, the acquisition and transmission of (bio)signals remained viable for electrodes with Ag/Ti ratios below 0.23. However, electrodes with higher Ag content (Ag/Ti = 0.31) became insulators after 7 days of immersion due to excessive Ag release into the sweat solution. This study concludes that higher Ag/Ti atomic ratios result in heightened corrosion processes on the electrode’s surface, consequently diminishing their lifespan despite the advantages of incorporating Ag into their composition. This research highlights the critical importance of evaluating electrode longevity, especially in remote biomedical applications like smart wearables, where electrode performance over time is crucial for reliable and sustained monitoring and stimulation.This research was funded by the European Regional Development Fund (ERDF) through the Operational Programme for Competitiveness and Internationalization (COMPETE 2020) under Portugal 2020, in the framework of the NanoStim (POCI-01-0247-FEDER-045908) and NanoID (NORTE-01-0247-FEDER-046985) Projects

Maximal exercise test is a useful method for physical capacity and oxygen consumption determination in streptozotocin-diabetic rats

BACKGROUND: The aim of the present study was to investigate the relationship between speed during maximum exercise test (ET) and oxygen consumption (VO(2)) in control and STZ-diabetic rats, in order to provide a useful method to determine exercise capacity and prescription in researches involving STZ-diabetic rats. METHODS: Male Wistar rats were divided into two groups: control (CG, n = 10) and diabetic (DG, n = 8). The animals were submitted to ET on treadmill with simultaneous gas analysis through open respirometry system. ET and VO(2 )were assessed 60 days after diabetes induction (STZ, 50 mg/Kg). RESULTS: VO(2 )maximum was reduced in STZ-diabetic rats (72.5 ± 1 mL/Kg/min(-1)) compared to CG rats (81.1 ± 1 mL/Kg/min(-1)). There were positive correlations between ET speed and VO(2 )(r = 0.87 for CG and r = 0.8 for DG), as well as between ET speed and VO(2 )reserve (r = 0.77 for CG and r = 0.7 for DG). Positive correlations were also obtained between measured VO(2 )and VO(2 )predicted values (r = 0.81 for CG and r = 0.75 for DG) by linear regression equations to CG (VO(2 )= 1.54 * ET speed + 52.34) and DG (VO(2 )= 1.16 * ET speed + 51.99). Moreover, we observed that 60% of ET speed corresponded to 72 and 75% of VO(2 )reserve for CG and DG, respectively. The maximum ET speed was also correlated with VO(2 )maximum for both groups (CG: r = 0.7 and DG: r = 0.7). CONCLUSION: These results suggest that: a) VO(2 )and VO(2 )reserve can be estimated using linear regression equations obtained from correlations with ET speed for each studied group; b) exercise training can be prescribed based on ET in control and diabetic-STZ rats; c) physical capacity can be determined by ET. Therefore, ET, which involves a relatively simple methodology and low cost, can be used as an indicator of cardio-respiratory capacity in future studies that investigate the physiological effect of acute or chronic exercise in control and STZ-diabetic male rats

Characterization of levan produced by a Paenibacillus sp. isolated from Brazilian crude oil

A levan-type fructooligosaccharide was produced by a Paenibacillus strain isolated from Brazilian crude oil, the purity of which was 98.5% after precipitation with ethanol and dialysis. Characterization by FTIR, NMR spectroscopy, GC-FID and ESI-MS revealed that it is a mixture of linear (26) fructosyl polymers with average degree of polymerization (DP) of 18 and branching ratio of 20. Morphological structure and physicochemical properties were investigated to assess levan microstructure, degradation temperature and thermomechanical features. Thermal Gravimetric Analysis highlighted degradation temperature of 218°C, Differential Scanning Calorimetry (DSC) glass transition at 81.47°C, and Dynamic Mechanical Analysis three frequency-dependent transition peaks. These peaks, corresponding to a first thermomechanical transition event at 86.60°C related to the DSC endothermic event, a second at 170.9°C and a third at 185.2°C, were attributed to different glass transition temperatures of oligo and polyfructans with different DP. Levan showed high morphological versatility and technological potential for the food, nutraceutical, and pharmaceutical industries.São Paulo Research Foundation (FAPESP) within Grants 2020/13271-6 and 2018/25511-1. Additionally, the authors acknowledge the financial support by National Council for Scientific and Technological Development – CNPq and by Coordination for the Improvement of Higher Education Personnel (CAPES), Finance Code 001. In addition, this study was supported by the Portuguese Science Foundation (FCT) under the scope of the strategic funding of UID/BIO/04469/2020 unit and the Project FOSYNBIO (POCI-01-0145-FEDER-029549).info:eu-repo/semantics/publishedVersio

Práticas integradas de educação formal e não-formal de ciências nos cursos de formação inicial de professores

O estudo que se apresenta teve como principal finalidade identificar, caracterizar e partilhar, a nível de Instituições de Ensino Superior (lES), ações desenvolvidas nos cursos de formação de profissionais de educação, que potenciassem a promoção de competências de planificação, implementação e avaliação de práticas integradas de educação formal e não-formaL em ciências (PIEC). O estudo contemplou todas as lES públicas portuguesas que ofereciam cursos de formação de professores com componente de ciências: 25 lES e 75 cursos. Como técnica de recolha de dados optou-se pelo inquérito por entrevista, dirigida aos coordenadores/diretores de curso (CID). O retorno foi de 72%. Os dados foram analisados com recurso à técnica de análise de conteúdo através de um sistema categorial misto. Os C/D consideraram as PIEC muito importantes e afirmaram que os estudantes também lhe reconheciam importância para a sua formação, considerando contribuírem para o desenvolvimento dos seus conhecimentos, capacidades, atitudes e valores. Apesar disso, 11% dos inquiridos admite não se desenvolver PIEC em qualquer das Unidades Curriculares (UC) dos cursos dos quais são responsáveis. Em relação aos outros cursos, são identificadas as UC onde essas práticas predominam, assim como estratégias/atividades desenvolvidas. Relativamente à perceção dos C/D sobre a preparação dos estudantes para desenvolver PIEC, nas suas futuras práticas profissionais, 65% afirma ser insuficiente.info:eu-repo/semantics/publishedVersio

Microbiological quality of human milk from a Brazilian milk bank

OBJECTIVE: The objectives of the present study were to determine the prevalence of potentially pathogenic microorganisms that indicate the hygienic and sanitary conditions of human milk samples collected at a Human Milk Bank. METHODS: Three hundred and thirty eight (338) samples of human milk collected from a milk bank in a maternity in the municipality of Goiânia, in the state of Goias, Brazil were submitted to microbiological analysis. The latter were plated on McConkey agar according to the type of bacteria. Among the total number of samples collected, 194 consisted of raw milk and the remaining 144 were pasteurized milk. RESULTS: The presence of Staphylococcus spp., Streptococcus spp., yeasts and molds, and Enterobacteriaceae was verified in the raw milk samples. Staphylococcus aureus were isolated in 10 (5.2%) samples, Staphylococcus epidermidis in 28 (14.4%) samples, Streptococcus spp. in three (1.6%) samples, yeasts and molds in 43 (22.2%) and Enterobacteriaceae in 49 (25.3%) samples. In a hundred and forty four (144) samples which underwent thermal treatment Staphylococcus aureus was detected in five (3.5%) samples, Staphylococcus epidermidis in 15 (10.4%), Staphylococcus lugdenensis in two (1.4%), Streptococcus spp. in four (2.8%), yeasts and molds in 37 (25.7%), and Enterobacteriaceae in nine (6.3%). CONCLUSIONS: Analysis indicated a high degree of contamination in raw human milk, and as for the pasteurized milk, despite elimination of the great majority of potentially pathogenic microorganisms, the percentage of yeasts and molds was higher than in raw milk, demonstrating that a lower degree of initial contamination would be necessary for pasteurization to be an efficient means of microbiological control.OBJETIVO: Determinar a prevalência de microrganismos indicadores e potencialmente patogênicos que indicam as condições higiênico-sanitárias das amostras de leite humano ordenhado coletadas em banco de leite. MÉTODOS: Foram realizadas análises microbiológicas de 338 amostras de leite humano ordenhado, sendo 194 de leite cru e 144, pasteurizado, coletadas em banco de leite humano de um hospital materno infantil de Goiânia, GO. As análises microbiológicas foram realizadas com semeadura em ágar Mc Conkey, de acordo com o tipo de bactéria. RESULTADOS: No leite cru, verificou-se a presença de Staphylococcus spp. Streptococcus spp., bolores e leveduras e Enterobacteriaceae. Observou-se que Staphylococcus aureus esteve presente em 10 (5,2%) amostras, Staphylococcus epidermidis em 28 (14,4%), Streptococcus spp. em três (1,6%), bolores e leveduras em 43 (22,2%) e Enterobacteriaceae em 49 (25,3%). Das 144 amostras de leite humano ordenhado pasteurizado, detectaram-se Staphylococcus aureus em cinco (3,5%), Staphylococcus epidermidis em 15 (10,4%), Staphylococcus lugdenensis em duas (1,4%), Streptococcus spp. em quatro (2,8%), bolores e leveduras em 37 (25,7%) e Enterobacteriaceae em nove (6,3%). CONCLUSÕES: Os resultados mostraram um alto grau de contaminação no leite cru. No leite pasteurizado, apesar da eliminação da grande maioria de microrganismos potencialmente patogênicos, a percentagem de bolores e leveduras excedeu a de leite cru, mostrando a necessidade de obtenção de um leite com carga microbiana inicial mais baixa para que a pasteurização seja eficiente no controle microbiológico

Deforestation, degradation and violence in the “Gurupi Mosaic” – The most threatened region of Amazonia

O "Mosaico Gurupi" está localizado entre o oeste do Maranhão e o leste do Pará, na Área de Endemismo Belém, que embora seja a região mais desmatada do Bioma Amazônico no Brasil, preserva uma diversidade cultural e biológica superlativa. O mosaico engloba seis Terras Indígenas (Alto Turiaçu, Awá, Caru, Arariboia, Rio Pindaré e Alto Rio Guamá) e uma Unidade de Conservação (Reserva Biológica do Gurupi). Essas áreas protegidas conservam os principais remanescentes florestais da região e garantem a manutenção de serviços ecossistêmicos essenciais aos dois estados, principalmente de regulação hidrológica. No entanto, essa região vive sob ameaças constantes de desmatamento e de degradação pela extração ilegal de madeira, e por incêndios criminosos. Os povos indígenas e lideranças comunitárias da região são vitimados pela violência associada a tais crimes. Para promover a conservação e a restauração dessas áreas, uma rede formada por diversas instituições indígenas e não indígenas vem trabalhando em conjunto para o reconhecimento do "Mosaico Gurupi" pelo Ministério do Meio Ambiente. A proposta aqui apresentada inclui o mosaico em questão e o Corredor Ecológico da Amazônia Maranhense, que irá conectar os principais remanescentes florestais da região, por meio da restauração das matas ciliares ao longo dos rios Buriticupu, Pindaré e Zutiua. A conformação do mosaico visa integrar esforços para a proteção territorial, a restauração florestal e o fortalecimento da cultura e educação indígena; o que poderá converter a região mais ameaçada da Amazônia em um exemplo de conservação e sustentabilidade econômica e social por meio da promoção da restauração florestal.The "Gurupi Mosaic" is located between west Maranhão and east Pará states, in the Belém Endemism Area, which although being the most deforested region of the Amazonian biome in Brazil, preserves superlative biological and cultural diversity. The Mosaic includes six indigenous lands (Alto Turiaçu, Awá, Caru, Araribóia, Rio Pindaré, Alto Rio Guamá) and a conservation unit (Gurupi Biological Reserve). These protected areas conserve the region’s main forest remnants and guarantee the maintenance of essential ecosystem services. However, this region is under constant threats of deforestation and degradation by illegal logging and arson. Indigenous peoples living in the region are victims of the violence associated with such crimes. To promote the conservation and restoration of these areas, several indigenous and non-indigenous institutions have been working together to formalize the "Gurupi Mosaic" with the Ministry of the Environment. The proposal presented here includes the Mosaic and one ecological corridor in the state of Maranhão, which will connect the region’s last forest remnants through the restoration of the riparian forests along the main rivers. The conformation of the Mosaic aims to integrate efforts to protect territories, restore forests and strengthen indigenous culture and education. This could turn the most threatened region of Amazonia into an example of conservation and economic and social sustainability

Analytical protocols for separation and electron microscopy of nanoparticles interacting with bacterial cells

An important step toward understanding interactions between nanoparticles (NPs) and bacteria is the ability to directly observe NPs interacting with bacterial cells. NPbacteria mixtures typical in nanomedicine, however, are not yet amendable for direct imaging in solution. Instead, evidence of NPcell interactions must be preserved in derivative (usually dried) samples to be subsequently revealed in high-resolution images, e.g., via scanning electron microscopy (SEM). Here, this concept is realized for a mixed suspension of model NPs and Staphylococcus aureus bacteria. First, protocols for analyzing the relative colloidal stabilities of NPs and bacteria are developed and validated based on systematic centrifugation and comparison of colony forming unit (CFU) counting and optical density (OD) measurements. Rate-dependence of centrifugation efficiency for each component suggests differential sedimentation at a specific predicted rate as an effective method for removing free NPs after co-incubation; the remaining fraction comprises bacteria with any associated NPs and can be examined, e.g., by SEM, for evidence of NPbacteria interactions. These analytical protocols, validated by systematic control experiments and high-resolution SEM imaging, should be generally applicable for investigating NPbacteria interactions.financial support from the following sources: grant SFRH/BPD/47693/2008 from the Portuguese Foundation for Science and Technology (FCT); FCT Strategic Project PEst-OE/EQB/LA0023/2013; project “BioHealth Biotechnology and Bioengineering approaches to improve health quality”, Ref. NORTE-07-0124-FEDER-000027, cofunded by the Programa Operacional Regional do Norte (ON.2−O Novo Norte), QREN, FEDER; project “Consolidating Research Expertise and Resources on Cellular and Molecular Biotechnology at CEB/IBB”, ref. FCOMP-01-0124-FEDER- 027462