664 research outputs found

    Synthesis of sub-5 nm Co-doped SnO2_2 nanoparticles and their structural, microstructural, optical and photocatalytic properties

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    A swift chemical route to synthesize Co-doped SnO2_2 nanopowders is described. Pure and highly stable Sn1x_{1-x}Cox_xO2δ_{2-\delta} (0 \le x \le 0.15) crystalline nanoparticles were synthesized, with mean grain sizes < 5 nm and the dopant element homogeneously distributed in substitutional sites of the SnO2_2 matrix. The UV-visible diffuse reflectance spectra of the Sn1x_{1-x}Cox_xO2δ_{2-\delta} samples reveal red shifts, the optical bandgap energies decreasing with increasing Co concentration. The Urbach energies of the samples were calculated and correlated with their bandgap energies. The photocatalytic activity of the Sn1x_{1-x}Cox_xO2δ_{2-\delta} samples was investigated for the 4-hydroxylbenzoic acid (4-HBA) degradation process. A complete photodegradation of a 10 ppm 4-HBA solution was achieved using 0.02% (w/w) of Sn0.95_{0.95}Co0.05_{0.05}O2δ_{2-\delta} nanoparticles in 60 min of irradiation.Comment: 29 pages, 2 tables, 10 figure

    O inquérito à Arquitectura Regional Portuguesa e a antropologia: Um caso de transversalidade metodológica

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    A presente comunicação expõe os resultados de uma investigação em curso conduzida pelas autoras desta comunicação, cujas primeiras abordagens permitiram identificar no Inquérito da Arquitectura Regional Portuguesa uma importante fonte de informação para o aprofundamento do estudo da morfologia urbana em Portugal (MaratMendes e Cabrita, 2015). Assim, partindo dos primeiros resultados dessa investigação, que permitiram identificar a realização de uma sistematização de carácter tipo-morfológico em Portugal, nos finais da primeira metade do século XX, conduzida por Arquitectos Portugueses que participaram na realização do Inquérito atrás referido, através de um confronto com as abordagens morfológicas em uso pelos geógrafos portugueses à época, e identificadas pelas autoras desta comunicação, torna-se agora oportuno aferir que metodologias foram utilizadas pelos Arquitectos, bem como quais as suas eventuais partilhas com métodos conduzidos por outras áreas disciplinares, nomeadamente a Antropologia. No sentido de responder ao objetivo atrás exposto, esta comunicação expõe os resultados de um estudo comparativo das abordagens metodológicas conduzidas por Arquitectos e Antropólogos nas suas análises a um território específico, cujo interesse partilharam durante um mesmo período temporal. O território em apreço refere-se à aldeia de Rio de Onor e aldeias circundantes, que se localiza no noroeste de Portugal. Especificamente, na região identificada como Zona 2 do Inquérito da Arquitectura Regional Portuguesa. O confronto da abordagem metodológica identificada para os Arquitectos e Antropólogos, contemporâneos à realização do Inquérito, leva-nos a concluir pela existência de uma partilha de metodologias que nos propomos aqui a identificar, e que incluem alguns denominadores comuns, nomeadamente a observação directa, a utilização de dados de outras disciplinas, a reflexão e sistematização e a incidência na obra colectiva. Julgamos igualmente importante reflectir sobre o facto de a abordagem metodológica atrás identificada, para os Arquitectos da Zona 2 do Inquérito ter sido central na preparação das soluções propositivas apresentadas por alguns desses arquitectos ao 10º Congresso dos CIAM, em 1956. Configura-se assim a existência de uma transversalidade metodológica, praticada pelos Arquitectos, comum às abordagens dos Antropólogos, contudo vocacionada para aspectos propositivos do projecto; procurando responder por um lado à contemporaneidade dos problemas colocados e com conhecimento das condições locais, nas vertentes do ambiente físico e humano, que também hoje constituem questões prementes na prática profissional de todos os agentes da intervenção na cidade e no território, nomeadamente os arquitectos.info:eu-repo/semantics/publishedVersio

    Fgf-23 and vascular calcification in a peritoneal dialysis population with residual renal function

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    Introduction and Aims: Fibroblast growth factor 23 (FGF-23) induces phosphaturia. Its clinical impact is beyond mineral bone disease in chronic kidney disease (CKD), being coupled with vascular calcification and mortality. Residual renal function (RRF) is associated with significant capacity to excrete phosphate in peri- toneal dialysis (PD). Besides testing whether FGF-23 is still related with glomerular filtration rate (GFR) and phosphate excretion in this late stage of CKD (5d), we aimed to explore its link with vascular calcification.Subjects and Methods: FGF-23 (C terminal) was measured in forty prevalent PD patients with RRF, aged 61.5 (51.0-67.0) years old, in renal replacement therapy (RRT) for 43.5 (23-80.0) months; 36.6% were female, 19.5% had diabetes mellitus and 37.5% were under automated PD regimen; 80% were on PD first, and only 20% had previous RRT. Relevant variables including dietary phosphate (P) intake, CKD-bone laboratory parameters, serum 25-hydroxyvitamin D, magnesium (Mg) levels, GFR, urinary phosphate, fractional excretion of phosphorus (FEP), albumin, proBNP and Adragão vascular calcification score were explored. Results: Median levels (25-75% range) of serum variables were: FGF-23 1997 (1623-2149) RU/mL, Mg 0.94 (0.8-1.0) mmol/L, 25-hydroxyvitamin D 30 (18-47) nmol/L, calcium 2.2 (2.0-2.37) mmol/L, phosphorus 1.69 (1.30-1.90) mmol/L, PTH 429 (309-626) pg/mL. FGF-23 correlated positively with serum phosphate (r = 0.39, p = 0.013) and negatively with urine volume (r = -0.48, p = 0.001), phosphaturia (r = -0.594, p < 0.0001) and GFR (r =-0.61,p < 0.0001). However, FGF-23 was not significantly correlated with age, total time of RRT, dietary P, FEP, Mg, nor 25-hydroxyvitamin D. High FGF-23 group had higher FEP. GFR was the single inde- pendent predictor of increased FGF-23. On the other hand, neither FGF-23 nor low FEP/FGF-23 ratio were significantly associated with the vascular calcification score. Only albumin (lower), magnesium (lower) and proBNP (higher) levels significantly differed in calcified versus non-calcified patients (all with p < 0.05). Conclusions: In our population, FGF-23 was not associated with vascular calcification. GFR was the single independent predictor of increased FGF-23 in patients with diuresis. Increment of FGF-23 in PD patients signalizes an active endocrine phosphaturic process compensating renal function loss, as expressed by higher fractional excretion of phosphorus. It alerts for dietetic and therapy optimization. However, its link with vascular calcification still lacks validation

    Common sequence motifs of nascent chains engage the ribosome surface and trigger factor

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    In the cell, the conformations of nascent polypeptide chains during translation are modulated by both the ribosome and its associated molecular chaperone, trigger factor. The specific interactions that underlie these modulations, however, are still not known in detail. Here, we combine protein engineering, in-cell and in vitro NMR spectroscopy, and molecular dynamics simulations to explore how proteins interact with the ribosome during their biosynthesis before folding occurs. Our observations of α-synuclein nascent chains in living Escherichia coli cells reveal that ribosome surface interactions dictate the dynamics of emerging disordered polypeptides in the crowded cytosol. We show that specific basic and aromatic motifs drive such interactions and directly compete with trigger factor binding while biasing the direction of the nascent chain during its exit out of the tunnel. These results reveal a structural basis for the functional role of the ribosome as a scaffold with holdase characteristics and explain how handover of the nascent chain to specific auxiliary proteins occurs among a host of other factors in the cytosol

    Two isoforms of vasa maternal factor in Senegalese sole: Biotechnological applications

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    Primordial Germ Cells (PGCs) identification and manipulation present considerable potential for hatchery practice and surrogate broodstocks. To carry out the PGCs characterization a specific molecular marker is required. The vasa gene is a good candidate to identify PGCs and others germinal cells (Nagasawa et al., 2009). The aim of this study was the cloning of the Solea senegalensis vasa cDNA and its expression pattern during early development and adulthood

    Dectin-1-Mediated Production of Pro-Inflammatory Cytokines Induced by Yeast β-Glucans in Bovine Monocytes

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    Yeast-derived products containing β-glucans have long been used as feed supplements in domesticated animals in an attempt to increase immunity. β-glucans are mainly recognized by the cell surface receptor CLEC7A, also designated Dectin-1. Although the immune mechanisms elicited through Dectin-1 activation have been studied in detail in mice and humans, they are poorly understood in other species. Here, we evaluated the response of bovine monocytes to soluble and particulate purified β-glucans, and also to Zymosan. Our results show that particulate, but not soluble β-glucans, can upregulate the surface expression of costimulatory molecules CD80 and CD86 on bovine monocytes. In addition, stimulated cells increased production of IL-8 and of TNF, IL1B, and IL6 mRNA expression, in a dose-dependent manner, which correlated positively with CLEC7A gene expression. Production of IL-8 and TNF expression decreased significantly after CLEC7A knockdown using two different pairs of siRNAs. Overall, we demonstrated here that bovine monocytes respond to particulate β-glucans, through Dectin-1, by increasing the expression of pro-inflammatory cytokines. Our data support further studies in cattle on the induction of trained immunity using dietary β-glucans.This work received financial support from PT national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through the project UIDB/info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDB/50006/2020/PT. AP was supported by FCT phD grant PD/BDE/135540/2018. AC was supported by FCT Individual CEEC 2017 Assistant Researcher Grant CEECIND/01514/2017. MM was supported by FCT through program DL 57/2016 – Norma transitória (SFRH/BPD/70716/2010)

    Análisis sensorial y detección electrónica de aromas para comparar aceites obtenidos por diferentes métodos de extracción

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    A sensorial analysis and an aroma analysis by electronic sensory devices were used to compare olive oils produced according to two different extraction methods. The extraction methods compared were the press system and two phase decanter. Samples were taken from the harvests of 2002-2004 and the olives were all from the same variety. The variety used was the Portuguese Galega sp. Olives were picked and technologically handled under predetermined and supervised conditions. Olive oils produced were better classified when the sensory analysis by a panel was applied than when an electronic sensory analysis was performed, even after sensor optimization. This observation is in accordance with the fact that olive oil has a low volatility matrix and “flavor”, rather than aroma, can give a clearer characterization than electronic sensory analysis alone, where aroma is the main characteristic evaluated.El análisis sensorial y el análisis de aromas por medio de sistemas sensoriales electrónicos han sido utilizado para comparar aceites de oliva producidos a través de dos sistemas de extracción diferentes. Los métodos de extracción comparados han sido el sistema de prensas y el decantador de dos fases. Las muestras fueron producidas durante las cosechas del periodo 2002- 2004, y las aceitunas eran todas de la misma variedad portuguesa Gallega sp. Las aceitunas fueron seleccionadas y tratadas tecnológicamente bajo condiciones predeterminadas y supervisadas. Los aceites producidos resultaron mejor clasificados cuando fue aplicado el análisis sensorial por panel que cuando se utilizó el análisis con detección electrónica de aromas, incluso después de la optimización de los sensores. Esta observación está de acuerdo con el hecho de que los aceites son una matriz poco volátil y que es el “flavour”, más que el aroma, el que junto con el gusto puede proporcionar una caracterización mejor que la detección electrónica, en la que el aroma es la principal característica evaluada

    Tacrolimus, a forgotten agent in kidney transplant leukopenia

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    Leukopenia in kidney transplant patients is frequent, it causes potentially life-threatening complications, but it is often poorly characterized. Opportunistic infections, immunologic disturbances and drug-related toxicity are principal causes of single or multilineage cytopenias. Tacrolimus-induced leukopenia is a less recognized but frequent complication. We describe one patient with leukopenia developing within seven months after renal transplant. After excluding other potential causes, tacrolimus was switched to cyclosporine, with recovery of white blood cell count. Based on the clinical report, the authors reviewed causes of post-transplant leukopenia, focusing on the diagnostic investigation. Early diagnosis and interventions are fundamental to improve prognosis
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