Comportamento acústico de blocos de terra compactada ativados alcalinamente

Dissertação de mestrado integrado em Engenharia CivilAo longo dos anos, a construção em terra, tem vindo destacar-se tanto na engenharia civil como a nível arquitetónico. As vantagens são muitas quando comparada com outras soluções construtivas convencionalmente utilizadas nos países desenvolvidos, que se baseiam na utilização de betão armado e alvenaria de tijolo cozido. Existem diferentes técnicas de construção em terra, contudo, o adobe é ainda a mais popular e a mais utilizada. Com a grande necessidade de se encontrar materiais e técnicas sustentáveis, o uso de bloco de terra compactada (BTC) está a tornar-se cada vez mais conhecido. É uma técnica relativamente recente e a produção consiste em compactar mecanicamente a terra num molde para que assim se diminua a porosidade e aumente a resistência. Contudo, é uma técnica com algumas limitações, como a diminuta adequabilidade dos solos disponíveis no local. Resultados obtidos por estudos anteriores com solos residuais graníticos da região Minho, ativados alcalinamente por cinzas volantes, são bastantes satisfatórios a nível de resistência dos blocos. Nesta dissertação pretende-se avaliar experimentalmente o comportamento acústico de blocos de terra, com solo residual granítico do Minho, compactada e estabilizada com recurso à ativação alcalina de cinzas volantes. A aplicação desta técnica (relativamente recente) ao desenvolvimento de BTCs é inovadora e espera-se que os resultados possam demonstrar o potencial de sustentabilidade da mesma e de adequação às exigências mínimas de isolamento acústico definidas nos Regulamentos e nas Normas de Desempenho Acústico dos Edifícios.Over the years, the earth construction, has a distinguished both in civil engineering, such as architectural level. There are many advantages when compared with other constructive solutions conventionally used in developed countries, which rely on the use of reinforced concrete and brickwork cooked. There are different construction techniques in earth, however, adobe is still the most popular and most used. With great need to find sustainable materials and techniques, the use of compressed earth block (BTC) are becoming increasingly well known. It is a relatively recent technique, and the production is to mechanically compact the soil into a mold to thereby decrease the porosity and increase strength. However, it is a technique with some limitations, such as reduced suitability of the soil on site. Results of previous studies with granitic residual soils of the Minho region, alkali-activated by fly ashes, are quite satisfactory to the blocks resistance level. This dissertation aims to experimentally evaluate the acoustic behavior of earth blocks, with granitic residual soil of Minho, compacted and stabilized using the alkaline activation of fly ashes. The application of this technique (relatively recent) at the developing of BTC’s is innovative and it is expected that the results can demonstrate the potential sustainability of the workstation and adaptation to the minimum requirements of sound insulation defined in the Regulations and in the buildings Acoustic Performance Standards

Peritoneal microbiome in end-stage renal disease patients and the impact of peritoneal dialysis therapy

The following are available online at http://www.mdpi.com/2076-2607/8/2/173/s1, Figure S1 (Rarefaction curves), Figure S2 (Relative proportion taxa for class, order, genus, and species), Figure S3 (Abundances of the genera and families between the ESRD-PD and ESRD-nonPD), Figure S4 (Alpha diversity of the peritoneum microbiome community at phylum, class, order, family, genus, species and OUT taxonomic levels calculated with Observed, Chao1, Shannon, Simpson, and Inverse Simpson indexes), Figure S5 (Beta-diversity of the peritoneum microbiome community at OTU level with Bray-Curtis, Jaccard, unweighted Unifrac, and Weighted Unifrac) and Figure S6 (Non-metric multidimensional scaling of blood and peritoneum microbiomes of non-PD and PD patients).Factors influencing the occurrence of peritoneal dialysis (PD)-related infections are still far from fully understood. Recent studies described the existence of specific microbiomes in body sites previously considered microbiome-free, unravelling new microbial pathways in the human body. In the present study, we analyzed the peritoneum of end-stage kidney disease (ESKD) patients to determine if they harbored a specific microbiome and if it is altered in patients on PD therapy. We conducted a cross-sectional study where the peritoneal microbiomes from ESKD patients with intact peritoneal cavities (ESKD non-PD, n = 11) and ESKD patients undergoing PD therapy (ESKD PD, n = 9) were analyzed with a 16S rRNA approach. Peritoneal tissue of ESKD patients contained characteristically low-abundance microbiomes dominated by Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. Patients undergoing PD therapy presented lower species richness, with dominance by the Pseudomonadaceae and Prevotelaceae families. This study provides the first characterization of the peritoneal microbiome in ESKD patients, bringing new insight to the human microbiome. Additionally, PD therapy may induce changes in this unique microbiome. The clinical relevance of these observations should be further explored to uncover the role of the peritoneal microbiome as a key element in the onset or aggravation of infection in ESKD patients, especially those undergoing PD.This research was funded by FEDER—Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020—Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by Portuguese funds through FCT/MCTES in the framework of the project MicroMOB “POCI-01-0145-FEDER-029777 / PTDC/MEC-MCI/29777/2017”; and by a Research Grant 2014 by the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) to I.S.-S. L.S.-S was supported by SFRH/BD/84837/2012 and I.S.-S was supported by SFRH/BPD/101016/2014 from FCT/QREN–POPH/FSE

Oral yeast colonization throughout pregnancy

Recent studies suggest that placenta may harbour a unique microbiome that may have origin in maternal oral microbiome. Although the major physiological and hormonal adjustments observed in pregnant women lead to biochemical and microbiological modifications of the oral environment, very few studies evaluated the changes suffered by the oral microbiota throughout pregnancy. So, the aim of our study was to evaluate oral yeast colonization throughout pregnancy and to compare it with non-pregnant women. The oral yeast colonization was assessed in saliva of 30 pregnant and non-pregnant women longitudinally over a 6-months period. Demographic information was collected, a non-invasive intra-oral examination was performed and saliva flow and pH were determined. Pregnant and non-pregnant groups were similar regarding age and level of education. Saliva flow rate did not differ, but saliva pH was lower in pregnant than in non-pregnant women. Oral yeast prevalence was higher in pregnant than in non-pregnant women, either in the first or in the third trimester, but did not attain statistical significance. In individuals colonized with yeast, the total yeast quantification (Log10CFU/mL) increase from the 1st to the 3rd trimester in pregnant women, but not in non-pregnant women. Pregnancy may favour oral yeast growth that may be associated with an acidic oral environment

The biochemistry of saliva throughout pregnancy

BACKGROUND & OBJECTIVE: Sialometric and sialochemical analyses during pregnancy are not consistent, and frequently contradictory in terms of salivary flow rate, pH, and concentration of calcium, phosphorous, sodium, potassium, chloride, glucose and α-amylase. We, therefore, measured the evolution of these parameters throughout pregnancy. METHOD: A cross-sectional study compared sialometric and sialochemical analyses of 30 pregnant women vs. 30 age-matched non-pregnant women, and a longitudinal study evaluated the pregnant women in the first and third trimester of pregnancy. RESULTS: Pregnant women presented acidic non-stimulated saliva, but neutral stimulated saliva pH, and no relevant changes in salivary flow rate. Scialochemical analysis showed decreased calcium levels, increased phosphate levels, and a progressive decrease in glucose levels throughout pregnancy. CONCLUSION: Pregnancy significantly changes the oral biochemical milieu, creating a favorable environment for the development of oral pathology, in particular, dental caries.OBJETIVO: Os achados relativos às análises sialométricas e sialoquímicas durante a gravidez não são consistentes, e por vezes são mesmo contraditórias. Assim, fizemos uma revisão da literatura e comparamos os níveis salivares de cálcio, fósforo, sódio, potássio, cloreto, glucose, α-amilase, pH e a taxa de fluxo salivar entre mulheres grávidas e não grávidas, bem como, avaliamos a evolução desses parâmetros ao longo da gravidez. MÉTODO: Realizamos um estudo transversal comparando a bioquímica salivar de um grupo inicial de 30 mulheres grávidas com um grupo inicial de 30 mulheres não gestantes da mesma idade seguido de um estudo longitudinal avaliando as mulheres grávidas no primeiro e terceiro trimestre de gravidez. RESULTADO: As mulheres grávidas apresentaram um pH da saliva não estimulada ácido, mas um pH da saliva estimulada neutro, assim como diminuição dos níveis salivares de cálcio, aumento dos níveis salivares de fosfato, e uma diminuição progressiva nos níveis de glicose na saliva ao longo da gravidez. CONCLUSÃO: A gravidez muda significativamente o ambiente bioquímico oral, criando condições favoráveis para o desenvolvimento de patologia oral, em particular da cárie dentária.info:eu-repo/semantics/publishedVersio

Antimicrobial activity of a bacterial nanocellulose film functionalized with Nisin Z for prospective burn wounds treatment

Burn wounds can lead to numerous severe complications including bacterial infections causing patient morbidity and mortality, mostly in low- and middle-income countries. The considerable increase of the microbial resistance against traditional antibiotics is leading towards alternative strategies to treat bacterial infections. Nisin Z is an antimicrobial peptide which exhibits a significant antibacterial activity against Gram-positive bacteria. Its efficacy against Gram-negative bacteria is limited, nonetheless it can be improved with the addition of surfactants, such as ethylenediaminetetraacetic acid (EDTA). The incorporation of peptide and other biomolecules within a biopolymer matrix provides protection maintaining their antimicrobial potential. Bacterial nanocellulose (BNC) has been widely used as wound dressings. Its impressive water retention capacity (> 99 %) and porosity are beneficial to manage wounds due to its potential to absorb exudates, providing a breathable and humid environment. In this work, the functionalization of BNC with Nisin Z (BNC-NZ) via vacuum filtration is reported. The entrapment of the peptide inside the BNC films was confirmed through morphological characterization using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectrometry. Typical absorbance peaks of Nisin Z are easily identifiable at 1647 cm-1 (amide group) and 1520 cm-1 (bending of primary amines). Thermal Gravimetric Analysis (TGA) suggested that Nisin Z did not interfere with the BNC matrix. The antimicrobial activity of Nisin Z against five of the most common bacteria found in burn wounds was verified by Minimum Bactericidal Concentration (MBC) ranging 8.0-256.0 µg/mL. Agar Diffusion and Shake Flask methods revealed the potential of BNC-NZ for prospective applications in burn wound dressings.This work is financed by FEDER funds through COMPETE and by national funds through FCT via the projects POCI-01-0145-FEDER-028074 and UID/CTM/00264/2020. L.M. and T.D.T also acknowledge FCT for their PhD scholarships with references 2020.04919.BD and 2020.06046.BD

Avaliação da simulação ou esforço insuficiente com o Rey 15-Item Memory Test (15-IMT): Estudos de validação em grupos de adultos idosos

A crescente evidência da possibilidade de desempenhos enganosos ou fraudulentos em contexto de exame neuropsicológico forense, incluindo casos envolvendo adultos idosos (por exemplo, determinação de incapacidade ou pedidos de reforma antecipada), torna imperativa a inclusão de medidas específicas de simulação e esforço insuficiente nos protocolos de avaliação. O Rey 15-Item Memory Test (15-IMT) é um dos testes mais utilizados neste âmbito. Contudo, apesar de se reconhecer que o efeito de tecto subjacente ao desenvolvimento dos testes de esforço insuficiente pode não resultar do mesmo modo em pessoas com doença mental ou demência, grupos de adultos idosos com determinadas condições clínicas, como as perturbações neurodegenerativas, são habitualmente excluídos dos estudos de validação. Pretendemos analisar o desempenho de diferentes grupos de adultos idosos (Saudáveis, com Problemas Cognitivos e com Depressão), contrapondo a um grupo de jovens adultos (Controlo), com o objectivo de examinar a validade dos resultados e necessidade de distintos pontos de corte nesta prova. Os resultados obtidos apontam para uma excelente especificidade do ponto de corte de <9 no Ensaio de Evocação Imediata e <20 no Resultado Combinado do Reconhecimento no grupo de jovens adultos. Contudo, estes mesmos pontos de corte não são aplicáveis em amostras de adultos idosos, sugerindo a sua inadequação para analisar os desempenhos de pessoas com défices verdadeiros ou mesmo de idosos sem problemas cognitivos

Decrease in APP and CP mRNA expression in Alzheimer’s disease patients suggests impairment of cellular iron export in this dementia

Recentemente tem-se assistido a um acumular de evidência sugerindo a implicação de uma desregulação do metabolismo do ferro (Fe) na fisiopatologia da doença de Alzheimer (DA). Neste trabalho, pretendemos esclarecer melhor os mecanismos moleculares subjacentes à homeostasia deste metal na DA, particularmente ao nível do efluxo celular. Assim, mediu-se em células mononucleares do sangue periférico de 73 doentes com DA e 74 controlos a expressão de genes diretamente envolvidos na regulação e exportação celular de Fe, utilizando a técnica de PCR quantitativo. Os resultados mostraram uma diminuição significativa na expressão dos genes aconitase (ACO1; P=0,007); ceruloplasmina (CP; P<0,001) e proteína precursora de beta amilóide (APP; P=0,006) em doentes com DA comparativamente com os voluntários saudáveis. Estas observações apontam para uma diminuição significativa da expressão dos genes associados com a exportação de Fe celular mediada pela ferroportina na DA. Assim, o presente estudo reforça resultados anteriores que mostram alterações no metabolismo do Fe e podem estar na origem da retenção intracelular deste metal e aumento de stress oxidativo caraterísticos desta patologia.A dysregulation of iron (Fe) metabolism in Alzheimer’s disease (AD) has been suggested previously. Herein, we intended to further clarify the molecular mechanisms underlying Fe homeostasis in AD particularly at the level of cellular iron efflux. Thus, the expression of specific Fe metabolism-related genes directly involved in Fe regulation and export was assessed by quantitative PCR in peripheral blood mononuclear cells (PBMCs) from 73 AD patients and 74 controls. A significant decrease in the expression of aconitase 1 (ACO1; P=0.007); ceruloplasmin (CP; P<0.001) and amyloid peptide precursor (APP; P=0.006) genes was fund in AD patients compared with healthy volunteers. These observations point out to a significant downregulation of the expression of genes associated with ferroportin-mediated cellular Fe export in PBMCs from AD patients. The present findings support previous studies suggesting impairment of Fe homeostasis in AD, which may lead to cellular Fe retention and oxidative stress, a typical feature of this disease