1,178 research outputs found
Ensaios virtuais à rotura em estruturas de betão armado com base em modelos BIM
Com a finalidade de otimizar o controlo e reduzir os erros do projeto de estruturas, o presente
trabalho descreve uma metodologia baseada na utilização de informação detalhada,
providenciada pelo modelo BIM de estruturas de betão armado, nomeadamente a representação
tridimensional de geometria do betão e de todas as armaduras, bem como as suas propriedades
mecânicas. Essa mesma informação é diretamente utilizada por programa de análise não-linear
estrutural, baseado no método dos elementos finitos, para avaliação do comportamento da
estrutura num ensaio virtual à rotura. O principal objetivo é desenvolver uma ferramenta
expedita, mediante um modelo de cálculo automático, baseado em modelos constitutivos
simplificados e cujos parâmetros de entrada são os necessários em contexto de
preparação/submissão do projeto de estruturas em BIM, para verificação de erros/omissões no
projeto de estruturas através da informação da carga última e do respetivo modo de rotura.
A metodologia foi implementada em Autodesk Revit (para modelação BIM), Dynamo (para
desenvolvimento da ferramenta de interoperabilidade) e DIANA (para análise não-linear
estática). A implementação, o teste e a validação foram efetuados, recorrendo, inicialmente, a
uma viga em betão armado, sujeita a diferentes simulações de configuração de rotura e,
posteriormente, a uma estrutura tridimensional porticada, na qual foram estudadas simulações
de erros de modelação/projeto
Evaluating simulated annealing algorithms in the optimization of bacterial strains
In this work, a Simulated Annealing (SA) algorithm is proposed
for a Metabolic Engineering task: the optimization of the set of
gene deletions to apply to a microbial strain to achieve a desired production
goal. Each mutant strain is evaluated by simulating its phenotype
using the Flux-Balance Analysis approach, under the premise that microorganisms
have maximized their growth along natural evolution. A
set based representation is used in the SA to encode variable sized solutions,
enabling the automatic discovery of the ideal number of gene
deletions. The approach was compared to the use of Evolutionary Algorithms
(EAs) to solve the same task. Two case studies are presented
considering the production of succinic and lactic acid as the target, with
the bacterium E. coli. The variable sized SA seems to be the best alternative,
outperforming the EAs, showing a fast convergence and low
variability among the several runs and also enabing the automatic discovery
of the ideal number of knockouts.FEDER.Portuguese Foundation for Science and Technology (FCT) - POSC/EIA/59899/2004
PT-CRIS: Um miradouro sobre o universo científico nacional
Reconhecida a importância da ciência, tecnologia, inovação e do conhecimento gerado pela investigação científica, são inúmeros os sistemas de informação criados para dar resposta a necessidades de gestão e disseminação de informação em diferentes domínios.
Contudo, a dispersão de informação em vários sistemas, a não adoção de normas/práticas de referência e consequentemente a replicação de informação criam dificuldades às várias entidades que gerem ou consultam informação sobre ciência e respetivos indicadores na capacidade de gestão, execução, avaliação e tomada de decisão relativa a processos de investigação.
Surge assim a necessidade de criar um sistema que ofereça uma visão global do universo de ciência e tecnologia, agregando e relacionando informação de suporte à atividade científica desenvolvida em Portugal, i.e., informação sobre investigadores, organizações, programas de financiamento, projetos, resultados de investigação, instalações, equipamentos e serviços.
O sistema, ao relacionar e contextualizar a informação científica atualmente dispersa em vários sistemas, permitirá transformar informação em conhecimento, aumentar a visibilidade e difusão da ciência e simplificar processos na gestão da produção científica nacional.Comunicação patrocinada pela KEEP SOLUTION
Assessment of perioperative mortality risk in patients with infective endocarditis undergoing cardiac surgery: performance of the EuroSCORE I and II logistic models
OBJECTIVES: The European System for Cardiac Operative Risk Evaluation (EuroSCORE) has been established as a tool for assisting decision- making in surgical patients and as a benchmark for quality assessment. Infective endocarditis often equires surgical treatment and is associated with high mortality. This study was undertaken to (i) validate both versions of the EuroSCORE, the older logistic EuroSCORE I and the recently developed EuroSCORE II and to compare their performances; (ii) identify predictors other than those included in the EuroSCORE models that might further improve their performance.
METHODS: We retrospectively studied 128 patients from a single-centre registry who underwent heart surgery for active infective endocarditis between January 2007 and November 2014. Binary logistic regression was used to find independent predictors of mortality and to create a new prediction model. Discrimination and calibration of models were assessed by receiver-operating characteristic curve analysis, calibration curves and the Hosmer–Lemeshow test. RESULTS: The observed perioperative mortality was 16.4% (n = 21). The median EuroSCORE I and EuroSCORE II were 13.9% interquartile
range (IQ) (7.0–35.0) and 6.6% IQ (3.5–18.2), respectively. Discriminative power was numerically higher for EuroSCORE II {area under the curve (AUC) of 0.83 [95% confidence interval (CI), 0.75–0.91]} than for EuroSCORE I [0.75 (95% CI, 0.66–0.85), P = 0.09]. The Hosmer– Lemeshow test showed good calibration for EuroSCORE II (P = 0.08) but not for EuroSCORE I (P = 0.04). EuroSCORE I tended to overpredict and EuroSCORE II to under-predict mortality. Among the variables known to be associated with greater infective endocarditis severity, only prosthetic valve infective endocarditis remained an independent predictor of mortality [odds ratio (OR) 6.6; 95% CI, 1.1–39.5;
P = 0.04]. The new model including the EuroSCORE II variables and variables known to be associated with greater infective endocarditis severity showed an AUC of 0.87 (95% CI, 0.79–0.94) and differed significantly from EuroSCORE I (P = 0.03) but not from EuroSCORE II (P = 0.4).
CONCLUSIONS: Both EuroSCORE I and II satisfactorily stratify risk in active infective endocarditis; however, EuroSCORE II performed better in the overall comparison. Specific endocarditis features will increase model complexity without an unequivocal improvement in predictive ability.info:eu-repo/semantics/publishedVersio
Inorganic Hg toxicity in plants: a comparison of different genotoxic parameters
Inorganic Mercury (Hg) contamination persists an environmental problem, but its cyto- and genotoxicity in plants remains yet unquantified. To determine the extent of Hg-induced cyto- and genotoxicity, and assess most sensitive endpoints in plants, Pisum sativum L. seedlings were exposed for 14 days to different HgCl2 concentrations up to 100 μM. Shoots and roots from hydroponic exposure presented growth impairment and/or morphological disorders for doses >1 μM, being the roots more sensitive. Plant growth, ploidy changes, clastogenicity (HPCV), cell cycle dynamics (G1-S-G2), Comet-tail moment (TM), Comet-TD, Mitotic-index (MI) and cell proliferation index (CPI) were used to evaluate Hg-induced cyto/genotoxicity. Both leaf and root DNA-ploidy levels, assessed by flow cytometry (FCM), remained unaltered after exposure. Root cell cycle impairment occurred at lower doses (≥1 μM) than structural DNA damages (≥10 μM). Cytostatic effects depended on the Hg concentration, with delays during S-phase at lower doses, and arrests at G1 at higher ones. This arrest was paralleled with decreases of both mitotic index (MI) and cell proliferation index (CPI). DNA fragmentation, assessed by the Comet assay parameters of TD and TM, could be visualized for conditions ≥10 μM, while FCM-clastogenic parameter (FPCV) and micronuclei (MNC) were only altered in roots exposed to 100 μM. We demonstrate that inorganic-Hg induced cytostaticity is detectable even at 1 μM (a value found in contaminated sites), while structural DNA breaks/damage are only visualized in plants at concentrations ≥10 μM. We also demonstrate that among the different techniques tested for cyto- and genotoxicity, TD and TM Comet endpoints were more sensitive than FPCV or MNC. Regarding cytostatic effects, cell cycle analysis by FCM, including the difference in % cell cycle phases and CPI were more sensitive than MI or MNC frequency. Our data contribute to better understand Hg cyto- and genotoxicity in plants and to understand the information and sensitivity provided by each of the genotoxic techniques used.publishe
Skeletal muscle–adipose tissue–tumor axis : molecular mechanisms linking exercise training in prostate cancer
© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).Increased visceral adiposity may influence the development of prostate cancer (PCa) aggressive tumors and cancer mortality. White adipose tissue (WAT), usually referred to as periprostatic adipose tissue (PPAT), surrounds the prostatic gland and has emerged as a potential mediator of the tumor microenvironment. Exercise training (ET) induces several adaptations in both skeletal muscle and WAT. Some of these effects are mediated by ET-induced synthesis and secretion of several proteins, known as myo- and adipokines. Together, myokines and adipokines may act in an endocrine-like manner to favor communication between skeletal muscle and WAT, as they may work together to improve whole-body metabolic health. This crosstalk may constitute a potential mechanism by which ET exerts its beneficial role in the prevention and treatment of PCa-related disorders; however, this has not yet been explored. Therefore, we reviewed the current evidence on the effects of skeletal muscle–WAT–tumor crosstalk in PCa, and the potential mediators of this process to provide a better understanding of underlying ET-related mechanisms in cancer.info:eu-repo/semantics/publishedVersio
Large scale repository auditing to ISO 16363
This paper describes an audit process carried out on 26 digital repositories according to
the recently approved standard ISO16363 (Audit and Certification of Trustworthy Digital
Repositories). The 26 repositories share a common infrastructure hosted by RCAAP
(Open Access Scientific Repository from Portugal), a free hosting service provided to
research institutions in Portugal. It addresses the process and the strategic alignment with
the project objectives integrated with other developments related to digital preservation of
institutional repositories. This work presents the first results of the analysis of the three
topics: Organizational Infrastructure, Digital Object Management and Infrastructure and
Security Risk Management
mais uma limitação na avaliação pré‐competitiva
Publisher Copyright: © 2017 Sociedade Portuguesa de CardiologiaIntroduction Assessment of the electrocardiogram (ECG) in athletes remains controversial, with lack of standardization and difficulty in applying specific criteria in its interpretation. The purpose of this study was to assess variability in the interpretation of the ECG in athletes. Methods Twenty ECGs of competitive athletes were assessed by cardiologists and cardiology residents, 11 of them normal or with isolated physiological changes and nine pathological. Each ECG was classified as normal/physiological or pathological, with or without the use of specific interpretation criteria. Results The study presents responses from 58 physicians, 42 (72.4%) of them cardiologists. Sixteen (27.6%) physicians reported that they regularly assessed athletes and 32 (55.2%) did not use specific ECG interpretation criteria, of which the Seattle criteria were the most commonly used (n=13). Each physician interpreted 15±2 ECGs correctly, corresponding to 74% of the total number of ECGs (variation: 45%‐100%). Interpretation of pathological ECGs was correct in 68% (variation: 22%‐100%) and of normal/physiological in 79% (variation: 55%‐100%). There was no significant difference in interpretation between cardiologists and residents (74±10% vs. 75±10%; p=0.724) or between those who regularly assessed athletes and those who did not (77±12% vs. 73±9%; p=0.286), but there was a trend for a higher rate of correct interpretation using specific criteria (77±10% vs. 72±10%; p=0.092). The reproducibility of the study was excellent (intraclass correlation coefficient=0.972; p<0.001). Conclusions A quarter of the ECGs were not correctly assessed and variability in interpretation was high. The use of specific criteria can improve the accuracy of interpretation of athletes’ ECGs, which is an important part of pre‐competitive screening, but one that is underused.publishersversionpublishe
Apple Flour in a Sweet Gluten-Free Bread Formulation: Impact on Nutritional Value, Glycemic Index, Structure and Sensory Profile
Baking bread without gluten presents many challenges generally related with poor sensorial
and nutritional characteristics, and strategies to overcome this issue are needed. Despite many glutenfree
(GF) bread studies, to the best of our knowledge, few are dedicated to sweet GF bread. Sweet
breads have traditionally been an important type of food and are still frequently consumed worldwide.
Apple flour is naturally GF, and is obtained from apples which do not accomplish market quality
requirements and are being wasted. Apple flour was, therefore, characterized in terms of nutritional
profile, bioactive compounds, and antioxidant capacity. The aim of this work was to develop a GF
bread with incorporation of apple flour, in order to study its effect on nutritional, technological, and
sensory characteristics of sweet GF bread. Additionally, in vitro starch hydrolysis and glycemic index
(GI) were also analyzed. Results demonstrated the influence of apple flour in dough’s viscoelastic
behavior, increasing G’ and G”. Regarding bread characteristics, apple flour led to better acceptance
by the consumer, with firmness increasing (21.01; 26.34; 23.88 N), and consequently specific volume
decreasing (1.38; 1.18; 1.13 cm3/g). In addition, an increase of bioactive compounds content and
antioxidant capacity of the breads were revealed. As expected, the starch hydrolysis index increased,
as well as GI. Nevertheless the values were really close to low eGI (56), which is a relevant result for a
sweet bread. Apple flour showed good technological and sensory properties as a sustainable and
healthy food ingredient for GF breadinfo:eu-repo/semantics/publishedVersio
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