3,221 research outputs found

    From the lab to the river: Determination of ecological hosts of Anodonta anatina

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    1. Coextinction is the simplest form of secondary extinction and freshwater mussels (Bivalvia, Unionida) may be particularly prone to this phenomenon as their life cycle includes an obligatory parasitic larval stage on fish hosts. 2. The main aims of this study were to determine the possible ecological fish hosts of Anodonta anatina (Linnaeus, 1758) in several rivers of the Douro basin in north ern Portugal and to assess possible spatial and temporal differences in glochidial (larval) loads. In order to achieve this, electrofishing was conducted from December to April, the fish fauna was characterized, and levels of infestation with A. anatina glochidia were determined. 3. Native cyprinid species, mainly Luciobarbus bocagei (Iberian barbel) and Squalius carolitertii (northern Iberian chub), together with the non-native Lepomis gibbosus (pumpkinseed sunfish) and Alburnus alburnus (common bleak), were found to have the highest glochidial loads. Clear differences in infestation between rivers and throughout time were detected, with an infestation period from January to March, and with the Tâmega River having the highest prevalence. 4. Anodonta anatina is able to infest a variety of fish species, and this together with earlier studies showed that the metamorphosis into juveniles occurs mainly in native cyprinid species, although non-native species like common bleak can also be considered suitable hosts. However, the larvae infesting other non-native spe cies, such as the pumpkinseed sunfish, do not metamorphose and can be consid ered ‘dead ends’. 5. Overall, the results reported here are important for the conservation of A. anatina (and other unionoid species) because several Iberian rivers (and worldwide) have been subjected to the extirpation of native fish species and the introduction of non-native fish species. Therefore, careful assessments of fish communities should be conducted to assess possible negative interactions with freshwater musselsFundação para a Ciência e a Tecnologia, Grant/Award Number: PTDC/AGRFOR/1627/201

    Numerical analysis of the Venda Nova II powerhouse complex

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    In the North of Portugal a hydroelectric scheme called Venda Nova II was recently built in order to optimize the resources of the reservoirs created by Venda Nova and Salamonde dams. The scheme, almost fully composed by underground structures and built in a predominantly granite rock mass, include several tunnels with a total length of about 7.5km, inclined and vertical shafts with a total length of 750m and two caverns which compose the powerhouse complex. The complex consists of two caverns interconnected by two galleries at a dept of about 350m. For this complex, 2D and 3D numerical models were developed considering the different construction stages. The geomechanical parameters of the granite formation for the numerical models were obtained using GEOPAT. This software is a knowledge based system which allows obtaining geomechanical parameters for underground structures modelling in granite formations. The 2D model was developed in the Phases2 software while the 3D model in FLAC3D. In this paper results of these models are analysed. Some comparisons are carried out between the models results and the monitored data. The numerical results show in general a good agreement with the monitored ones.Fundação para a Ciência e a Tecnologia (FCT) - projecto POCI/ECM/57495/2004 - Geotechnical Risk in Tunnels for High Speed Trains

    Numerical analysis of the venda nova II hydroelectrical complex main caverns and backanalysis of the geomechanical parameters

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    Neste trabalho é apresentado um modelo numérico 3D para as cavernas principais do complexo da Venda Nova II considerando as diferentes fases de escavação. Os parâmetros geomecânicos do maciço granítico, para os modelos, foram calculados utilizando o software GEOPAT. Este programa é um sistema baseado em conhecimento que permite obter os parâmetros geomecânicos para a modelação de obras subterrâneas em maciços graníticos. Os resultados do modelo são comparados com os deslocamentos observados por intermédio de extensómetros ao longo das várias fases construtivas. Nesta comparação são utilizadas diversas ferramentas estatísticas para a validação dos resultados obtidos. Finalmente, é realizada a retroanálise de parâmetros geomecânicos do maciço rochoso utilizando um algoritmo de optimização inovador. Os resultados obtidos permitiram concluir que a estimativa inicial dos parâmetros apresenta uma precisão bastante aceitável e que o algoritmo possui uma boa robustez e eficiência.In this work a 3D numerical model for the main caverns of the Venda Nova II complex which considers the different excavation stages is presented. The geomechanical parameters for the numerical models were computed using GEOPAT. This software is a knowledge based system which allows evaluating geomechanical parameters for the modelling of underground works built in granite rock masses. The results are compared with the observed displacements measured with extensometers along the different construction stages. In this comparison several statistical tools are used for the validation of the obtained results. Finally, the backanalysis of geomechanical parameters of the interested rock mass is performed using an innovative optimization algorithm. The results show that the initial evaluation of the parameters presents a very acceptable accuracy and that the algorithm posses good robustness and efficiency.Fundação para a Ciência e a Tecnologia (FCT) - Projecto POCI/ECM/57495/2004, intitulado Geotechnical Risk in Tunnels for High Speed Trains.Faculdade de Ciências e Tecnologia da Universidade de Coimbra (FCT-UC

    The association between cardiovascular risk factors and major cardiovascular diseases decreases with increasing frailty levels in geriatric outpatients

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    BACKGROUND: Frailty marks a process of increasing dysregulation of physiological systems which increases the risk of adverse health outcomes. This study examines the hypothesis that the association between multiple cardiovascular risk factors (CVRF) and cardiovascular diseases (CVD) becomes stronger with increasing frailty severity. METHODS: Cross-sectional analysis of 339 older adults (55.2% women; aged 75.2 ± 9.1 years) from an outpatient geriatric clinic from a middle-income country. The frailty index (FI) was calculated as the proportion of 30 possible health deficits. We assessed hypertension, diabetes, obesity, dyslipidemia, sedentarism and smoking as CVRF (determinants) and myocardial infarction, stroke, heart failure as CVD. Poisson regression models adjusted for age, sex, and education was applied to estimate the association between frailty as well as CVRF (independent variables) with CVD (dependent variable). RESULTS: Of the 339 patients, 18,3% were frail (FI ≥ 0.25) and 32.7% had at least one CVD. Both frailty and CVRF were significantly associated with CVD (PR = 1.03, 95% CI 1.01 to 1.05; p = 0.001, and PR = 1.46, 95% 1.24 to 1.71; p < 0.001, respectively) adjusted for covariates. The strength of the association between CVRF and CVD decreased with increasing frailty levels, as indicated by a significant interaction term of frailty and CVRF (p < 0.001). CONCLUSION: Frailty and CVRF are both associated with CVD, but the impact of CVRF decreases in the presence of frailty. When confirmed in longitudinal studies, randomized controlled trials or causal inference methods like Mendelian randomization should be applied to assess whether a shift from traditional CVRF to frailty would improve cardiovascular outcome in the oldest old

    Neuroprotective effects on microglia and insights into the structure–activity relationship of an antioxidant peptide isolated from Pelophylax perezi

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    © 2022 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly citedTryptophyllins constitute a heterogeneous group of peptides that are one of the first classes of peptides identified from amphibian's skin secretions. Here, we report the structural characterization and antioxidant properties of a novel tryptophyllin-like peptide, named PpT-2, isolated from the Iberian green frog Pelophylax perezi. The skin secretion of P. perezi was obtained by electrical stimulation and fractionated using RP-HPLC. De novo peptide sequencing was conducted using MALDI MS/MS. The primary structure of PpT-2 (FPWLLS-NH2 ) was confirmed by Edman degradation and subsequently investigated using in silico tools. PpT-2 shared physicochemical properties with other well-known antioxidants. To test PpT-2 for antioxidant activity in vitro, the peptide was synthesized by solid phase and assessed in the chemical-based ABTS and DPPH scavenging assays. Then, a flow cytometry experiment was conducted to assess PpT-2 antioxidant activity in oxidatively challenged murine microglial cells. As predicted by the in silico analyses, PpT-2 scavenged free radicals in vitro and suppressed the generation of reactive species in PMA-stimulated BV-2 microglia cells. We further explored possible bioactivities of PpT-2 against prostate cancer cells and bacteria, against which the peptide exerted a moderate antiproliferative effect and negligible antimicrobial activity. The biocompatibility of PpT-2 was evaluated in cytotoxicity assays and in vivo toxicity with Galleria mellonella. No toxicity was detected in cells treated with up to 512 µg/ml and in G. mellonella treated with up to 40 mg/kg PpT-2. This novel peptide, PpT-2, stands as a promising peptide with potential therapeutic and biotechnological applications, mainly for the treatment/prevention of neurodegenerative disorders.This work was financed by FEDER - Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 - Operacional Programme for Competitiveness and Internationalization (POCI), and by Portuguese funds through FCT - Fundação para a Ciência e a Tecnologia in the framework of the project POCI-01-0145-FEDER-031158 – PTDC/BII-BIO/31158/2017. The authors would like to thank the participation and scientific support of the Unit projects UIDB/50006/2020 | UIDP/50006/2020, and the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Universal Faixa ‘B’ (grant number 32103/2018-0). A.P. is a recipient of a post-doctoral grant from the project PTDC/BII-BIO/31158/2017. The authors would like to thank the researcher Roberto Resendes (CiBio, University of the Azores, Ponta Delgada, São Miguel, Azores, Portugal) for the logistical support in the collection of samples. C.P.A acknowledges FCT-MCTES fellowship PD/BD/136860/2018. A.B.-N. and F.C.D.A.L. acknowledge CNPq (grants 420449/2018-3 and 428211/2018-6) for financial support.info:eu-repo/semantics/publishedVersio

    Comparison of single- and multistage strategies during fenestrated-branched endovascular aortic repair of thoracoabdominal aortic aneurysms

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    Objective: The aim of this study was to compare outcomes of single or multistage approach during fenestrated-branched endovascular aortic repair (FB-EVAR) of extensive thoracoabdominal aortic aneurysms (TAAAs). Methods: We reviewed the clinical data of consecutive patients treated by FB-EVAR for extent I to III TAAAs in 24 centers (2006-2021). All patients received a single brand manufactured patient-specific or off-the-shelf fenestrated-branched stent grafts. Staging strategies included proximal thoracic aortic repair, minimally invasive segmental artery coil embolization, temporary aneurysm sac perfusion and combinations of these techniques. Endpoints were analyzed for elective repair in patients who had a single- or multistage approach before and after propensity score adjustment for baseline differences, including the composite 30-day/in-hospital mortality and/or permanent paraplegia, major adverse event, patient survival, and freedom from aortic-related mortality. Results: A total of 1947 patients (65% male; mean age, 71 ± 8 years) underwent FB-EVAR of 155 extent I (10%), 729 extent II (46%), and 713 extent III TAAAs (44%). A single-stage approach was used in 939 patients (48%) and a multistage approach in 1008 patients (52%). A multistage approach was more frequently used in patients undergoing elective compared with non-elective repair (55% vs 35%; P < .001). Staging strategies were proximal thoracic aortic repair in 743 patients (74%), temporary aneurysm sac perfusion in 128 (13%), minimally invasive segmental artery coil embolization in 10 (1%), and combinations in 127 (12%). Among patients undergoing elective repair (n = 1597), the composite endpoint of 30-day/in-hospital mortality and/or permanent paraplegia rate occurred in 14% of single-stage and 6% of multistage approach patients (P < .001). After adjustment with a propensity score, multistage approach was associated with lower rates of 30-day/in-hospital mortality and/or permanent paraplegia (odds ratio, 0.466; 95% confidence interval, 0.271-0.801; P = .006) and higher patient survival at 1 year (86.9±1.3% vs 79.6±1.7%) and 3 years (72.7±2.1% vs 64.2±2.3%; adjusted hazard ratio, 0.714; 95% confidence interval, 0.528-0.966; P = .029), compared with a single stage approach. Conclusions: Staging elective FB-EVAR of extent I to III TAAAs was associated with decreased risk of mortality and/or permanent paraplegia at 30 days or within hospital stay, and with higher patient survival at 1 and 3 years

    A presença de Microlobius foetidus causa alteraçõess na defesa antioxidante de Urochloa decumbens?

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    Urochloa decumbens (Stapf) R. D. Webster (Poaceae) is an exotic species with has spread rapidly through the Cerrado area of Pantanal, Mato Grosso do Sul, Brazil. It has covered the soil aggressively turning it into cultivated pastures. Thus, it has become a challenge to protect native areas due its capacity of exclusion of native species. It has been observed that Microlobius foetidus (Jacq.) M.Sousa & G.Andrade species (Fabaceae) shows a dominant pattern over the development of U. decumbens. This work shows that M. foetidus interfere on the natural growth of U. decumbens within 10 m ratio. Between 15 and 20 m, it was observed an increase of Importance Value index (IVI) and Relative cover (RC) values. It was also observed a variation on the antioxidant defense system of U. decumbens within 10m ratio from M. foetidus. The enzymes superoxide dismutase, catalase and peroxidase present higher levels of activity then those found for glutathione reductase. This data indicates that M. foetidus may have an effect on U. decumbens, increase the activity of antioxidant enzymes. This effect probably happens as means to neutralize the toxic effects of the oxygen generated due to the presence of allelochemicals, which increases oxidative stress. © 2015, Instituto Internacional de Ecologia. All Rights Reserved
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