Vibration of the railway track-viaduct system under moving vehicles taking into account the interaction effect

Vibration of the railway track-viaduct system under moving vehicles taking into account the interaction effec

Experimental study of single span railway bridges

The main purpose of this paper is to present some results concerning the investigation that has been done by the authors regarding the dynamic response of small to médium span railway bridges using response acceleration data colleted during the measurements carried out on single span bridges on the railway track Linz-Wels, in Austria. Using output-only methods in this experimental program, it was possible to have an estimation of the igenfrequencies, mode shapes and the corresponding viscous damping. Due to the fact that the bridges were of the same type some generalizations concerning their structural behavior was possible and finite element models were calibrated in order to compute responses for real traffic. The numerical model of the bridges takes into account the track and the real boundary conditions of the decks. The measured and the computed acceleration responses of the track/bridge system are compared using two methods: the moving forces method and the interaction vehicle/track/bridge method

Influência das irregularidades da via na resposta dinâmica de pontes ferroviárias de médio vão

As irregularidades na via-férrea influenciam o comportamento dinâmico das pontes ferroviárias e aumentam os efeitos dinâmicos produzidos pela passagem dos eixos do comboio. Neste estudo é analisada a influência das irregularidades da via-férrea na resposta dinâmica de uma ponte, cuja primeira frequência natural de vibração se encontra sobre os limites definidos no Eurocódigo 1. São consideradas diferentes irregularidades, isolada a meio-vão e contínua de amplitude aleatória existente em toda a extensão do carril. As respostas máximas da ponte com as irregularidades são determinadas em termos de deslocamentos e acelerações, e comparadas com as obtidas sem as irregularidades. Recorre-se ao modelo dinâmico de via-férrea balastrada ERRI. São analisadas as acelerações na massa vibrante do balastro via-férrea bem como as forças de contacto entre a roda e o carril

Vibration measurements on small to medium single-span railway bridges

Due to the need for increasing train speeds several existing small to medium span bridges in the track Linz-Wels (Austria) were re-evaluated. In a preliminary numerical calculation, considering conservative values for the dynamic parameters, very high vertical accelerations were computed for some of those structures. An experimental program was thus carried out in order to get a better estimation for the dynamic behaviour of the bridges, concerning mainly the first vertical eigenfrequency and the corresponding viscous damping. The paper reports on the results of this experimental investigation and identifies some areas where further research is necessary

Correlation between hyperglycemia and glycated albumin with retinopathy of prematurity

Funding Information: The present publication was funded by Fundação Ciência e Tecnologia, IP national support through CHRC (UIDP/04923/2020).To determine the association between hyperglycemia, glycated albumin (GlyA) and retinopathy of prematurity (ROP). Prospective study of all infants under ROP screening from March 2017 to July 2019. All demographic, clinical and laboratory data were collected. Glucose was measured at birth and every 8 h for the first week and serum GlyA was evaluated at birth, 1st, 2nd and 4th weeks after birth. Reference range for GlyA was obtained. Univariate logistic regression was used to examine risk factors for ROP followed by multivariate regression. A total of 152 infants were included in the study. Median gestational age was 30 weeks and median birth weight 1240 g. Thirty-three infants (21.7%) had ROP. Hyperglycemia was present in 24 (72.7%) infants diagnosed with any ROP versus 6 (0.05%) in those without ROP. Median GlyA at birth, 1st, 2nd and 4th and respective reference ranges were 8.50% (6.00–12.65), 8.20% (5.32–11.67), 8.00% (5.32–10.00) and 7.90% (5.30–9.00) respectively. After multivariate logistic regression, hyperglycemia but not GlyA, remained a significant risk factor for ROP overpowering the other recognized risk factors (Exp (B) 28.062, 95% CI for Exp(B) 7.881–99.924 p < 0.001). In our cohort, hyperglycemia but not GlyA, remained a significant risk factor for ROP overpowering the other recognized risk factors.publishersversionpublishe

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

© 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

In Vitro and In Vivo Investigation of the Efficacy of Arylimidamide DB1831 and Its Mesylated Salt Form - DB1965 - against Trypanosoma cruzi Infection

Chagas disease is caused by infection with the intracellular protozoan parasite Trypanosoma cruzi. At present, nifurtimox and benznidazole, both compounds developed empirically over four decades ago, represent the chemotherapeutic arsenal for treating this highly neglected disease. However, both drugs present variable efficacy depending on the geographical area and the occurrence of natural resistance, and are poorly effective against the later chronic stage. As a part of a search for new therapeutic opportunities to treat chagasic patients, pre-clinical studies were performed to characterize the activity of a novel arylimidamide (AIA - DB1831 (hydrochloride salt) and DB1965 (mesylate salt)) against T.cruzi. These AIAs displayed a high trypanocidal effect in vitro against both relevant forms in mammalian hosts, exhibiting a high selectivity index and a very high efficacy (IC50 value/48 h of 5–40 nM) against intracellular parasites. DB1965 shows high activity in vivo in acute experimental models (mouse) of T.cruzi, showing a similar effect to benznidazole (Bz) when compared under a scheme of 10 daily consecutive doses with 12.5 mg/kg. Although no parasitological cure was observed after treating with 20 daily consecutive doses, a combined dosage of DB1965 (5 mg/kg) with Bz (50 mg/kg) resulted in parasitaemia clearance and 100% animal survival. In summary, our present data confirmed that aryimidamides represent promising new chemical entities against T.cruzi in therapeutic schemes using the AIA alone or in combination with other drugs, like benznidazole

Combined Treatment of Heterocyclic Analogues and Benznidazole upon Trypanosoma cruzi In Vivo

Chagas disease caused by Trypanosoma cruzi is an important cause of mortality and morbidity in Latin America but no vaccines or safe chemotherapeutic agents are available. Combined therapy is envisioned as an ideal approach since it may enhance efficacy by acting upon different cellular targets, may reduce toxicity and minimize the risk of drug resistance. Therefore, we investigated the activity of benznidazole (Bz) in combination with the diamidine prodrug DB289 and in combination with the arylimidamide DB766 upon T. cruzi infection in vivo. The oral treatment of T.cruzi-infected mice with DB289 and Benznidazole (Bz) alone reduced the number of circulating parasites compared with untreated mice by about 70% and 90%, respectively. However, the combination of these two compounds decreased the parasitemia by 99% and protected against animal mortality by 100%, but without providing a parasitological cure. When Bz (p.o) was combined with DB766 (via ip route), at least a 99.5% decrease in parasitemia levels was observed. DB766+Bz also provided 100% protection against mice mortality while Bz alone provided about 87% protection. This combined therapy also reduced the tissular lesions induced by T. cruzi infection: Bz alone reduced GPT and CK plasma levels by about 12% and 78% compared to untreated mice group, the combination of Bz with DB766 resulted in a reduction of GPT and CK plasma levels of 56% and 91%. Cure assessment through hemocultive and PCR approaches showed that Bz did not provide a parasitological cure, however, DB766 alone or associated with Bz cured ≥13% of surviving animals