2,284 research outputs found
A Finite ElementâBased Methodology for the Thermoâmechanical Analysis of Early Age Behavior in Concrete Structures
This paper presents a general procedure based on fracture mechanics models in order to analyze the level of cracking
and structural safety in reinforced concrete elements at early ages, depending on the stripping time. Our procedure
involves the development of a thermo-mechanical numerical model based on the finite element method that
accounts for the change in the mechanical properties of concrete with time. Moreover, fracture mechanisms are
analyzed by means of a material damage model, which is characterized via specific experimental results obtained for
standard specimens and notched beams under three-point bending testing. The loading conditions are both thermal
and mechanical, and are obtained from the hydration process for a given concrete dosage. The presented methodology
allows for the determination of the optimal stripping time, whereas it helps assessing the analysis of the cracking
and the stress states of the elements under consideration. A practical application, namely the analysis of a retaining
wall, is used to validate our methodology, showing its suitability in engineering practice.Ministerio de EconomĂa y Competitividad BIA2016-75431-
Evaluation of the inorganic content of six underused wild berries from Portugal: Potential new sources of essential minerals
The mineral content and levels of trace elements in six wild underused berries (Elaeagnus umbellata,
Myrica faya, Rubus grandifolius, Sambucus lanceolata, Vaccinium padifolium and Vaccinium cylindraceum)
have been determined by inductively coupled plasma-mass spectrometry after microwave digestion. The
inorganic content of these foodstuffs has not been previously described in scientific literature (except for
E. umbellata). Hence, this information is of high interest concerning the introduction of these noncommercial
berries in the mainstream market. The analytical method has been validated analyzing a
certified reference material and performing recovery experiments. The results obtained have been
discussed using the Recommended Daily Allowance for minerals provided by the Commission of the
European Community, and a comparison between the composition of the analyzed berries and different
commercialised berries has been carried out. Data obtained in this study support the consumption of
these less-known berries, in particular R. grandifolius and S. lanceolata, as potential novel sources of
essential minerals.The authors are grateful to Esmeralda Meneses, CĂąndida Dias
and to Funchal Ecological Park for the supply of plant material. E. J.
Llorent-MartĂnez acknowledges the financial support from the
UCLM Research Plan. CICT from University of Jaén is also
acknowledged.info:eu-repo/semantics/publishedVersio
Antioxidant polyphenols of Madeira sorrel (Rumex maderensis): How do they survive to in vitro simulated gastrointestinal digestion?
In this work, we report the phytochemical profile and antioxidant activity of different morphological parts of Rumex maderensis Lowe (Polygonaceae), a wild leafy-vegetable growing in Madeira Island (Portugal). Methanol extracts from leaves, flowers, and stems were submitted to high-performance liquid chromatography with mass spectrometry detection to obtain the phytochemical profile, which allowed the identification of 86 polyphenols (about 70% C- and O-flavonoids) and 9 non-phenolic compounds. In vitro antioxidant activities were measured against ABTS, DPPH, nitric oxide and superoxide free radicals. Then, the samples were subjected to an in vitro digestion, observing a decrease of about 50% in both the content of phenolics and the antioxidant activity. However, relevant antioxidant capacity was still observed after the simulated digestion. Therefore, this study supports the consumption of R. maderensis as an interesting foodstuff and a dietary source of antioxidant phytochemicals that survive the gastrointestinal digestion process.V. SpĂnola acknowledges Fundação para a CiĂȘncia e a Tecnologia (FCT, Portugal) for a
Ph.D. grant SFRH/BD/84672/2012. This research was supported by FCT with funds from
the Portuguese Government (Project PEst-OE/QUI/UI0674/2013) and the Portuguese
National Mass Spectrometry Network (Contract RNEMREDE/1508/REM/2005). Funding
through the project M1420-01-0145-FEDER-000005 - Centro de QuĂmica da Madeira -
CQM+ (Madeira 14-20) is also acknowledged.info:eu-repo/semantics/publishedVersio
Polyphenols of Myrica faya inhibit key enzymes linked to type II diabetes and obesity and formation of advanced glycation end-products (in vitro): Potential role in the prevention of diabetic complications
Myrica faya Aiton (fire tree, faya) is an underused species with a diverse flavonoid composition (anthocyanins, flavonols, ellagitannins) which can promote positive effects on human health. M. faya has been reported to possess high antioxidant activities, but its potential in the prevention of type II diabetes has not been evaluated so far. In the present study, eight M. faya samples from different areas of Madeira and Azores archipelagos (Portugal) were collected to determine their phytochemical profile and then tested for their in vitro anti-diabetic and antioxidant activities. The analyzed extracts showed strong inhibitory activities towards α -glucosidase, aldose reductase and glycation of bovine serum albumin (BSA) and moderate effects towards α-amylase and lipase (by comparison with reference compounds). Cyanidin-3-O-glucoside and ellagitannins were the main bioactive agents involved in the anti-diabetic effects of M. faya. Such results may provide important scientific evidence for further utilization of M. faya as dietary or nutraceutical products for the prevention and/or control of hyperglycaemia-associated complications.info:eu-repo/semantics/publishedVersio
Phenolic profiles of Lauraceae plant species endemic to Laurisilva forest: a chemotaxonomic survey
In this work, the phenolic composition of several trees endemic to Madeira archipelago (Portugal) was studied.
Specifically, the leaves of the most relevant species of the Lauraceae family (Laurus novocanariensis, Apollonias
barbujana, Ocotea foetens, and Persea indica) have been analyzed. The screening of the main phenolic compounds
in their methanol extracts has been performed by high-performance liquid chromatography with electrospray
ionization mass spectrometric detection (HPLC-ESIâMSn
), identifying or tentatively characterizing almost 100
compounds, including a high number of proanthocyanidins (A- and B-type), which have been reported to present
remarkable health benefits. Thirty-four compounds have been quantified, observing total individual phenolic
contents (TIPCs) between 18.43 and 88.99 mg gâ1 dry extract, with the lowest TIPC in O. foetens and the highest
in A. barbujana.E. J. Llorent-MartĂnez acknowledges the financial support from the
UCLM Research Plan. V. SpĂnola is grateful to Fundação para a CiĂȘncia
e a Tecnologia (FCT, Portugal) for a Ph.D. grant SFRH/BD/84672/
2012.info:eu-repo/semantics/publishedVersio
Estimation of slip rates and seismic hazard parameters using conventional techniques of structural geology in a slow-moving fault: Alhama de Murcia â Alcantarilla segment of the Alhama de Murcia Fault (Murcia, SE Spain)
The convergence between Nubian and Eurasian plates in the Western Mediterranean is being accommodated by the Eastern Betic Shear Zone, located in Southeastern Iberia. This is a low strain region whose faults show low slip rates and long recurrence periods of their maximum earthquakes, so they do not provide clear evidence of their seismogenic activity. The Alhama de Murcia - Alcantarilla segment, defined as the NE end of the Alhama de Murcia Fault, is one of the structures of the Eastern Betic Shear Zone and there are few in-depth studies about its seismic potential. In order to assess the seismogenic potential and slip-rate of this segment we have carried out a structural analysis. We have built a 3D geological model of the area where the fault is currently bounding the Neogene Fortuna basin. The structural model is based on seismic reflection profiles which have been later input in MOVE, structural modelling and analysis software. The analysis of the model has revealed several structural features related to positive inversion tectonics in Fortuna basin, specifically a typical "harpoon" structure whose deformation is estimated to have begun since Upper Miocene (Messinian). Geometric models and area balance methods (e.g. depth-to-detachment method) applied to the previously mentioned structure have allowed to estimate the heave of the fault, representing the amount of shortening observed in the fault section during its recent activity. The horizontal shortening rate estimated is between 0.09 and 0.26 mm/yr during the last 5.3 - 2.6 Ma. Projecting the obtained shortening onto the fault plane and considering the present regional tectonic shortening it has been possible to obtain a net slip rate between 0.13 and 0.37 mm/yr. Such parameters suggest that the Alhama de Murcia - Alcantarilla segment has less activity than other segments of the fault. The result obtained is consistent with the fact that the Carrascoy Fault, oriented parallel and located to the south of the Alhama de Murcia - Alcantarilla segment, seems to absorb part of the regional tectonic shortening. That is why the relief uplifted by the Alhama de Murcia - Alcantarilla segment during the Quaternary is significantly less prominent than the mountains fronts generated by the Carrascoy Fault. Even so, Alhama de Murcia - Alcantarilla segment should be considered as an active structure with implications for seismic hazard. The maximum size of earthquake is calculated to be Mw 6.3 - 6.6 according to magnitude-area and magnitude-length scaling relationships, with a mean recurrence interval lower than 10.000 years for the slip rate obtained. In the same way, Mw 5.0 earthquakes, such as those recorded in the historical seismic catalog, are estimated to have a recurrence interval lower than 50 years. These earthquakes could be very destructive in densely populated areas, as is the case of SE Spain, so they should be considered in seismic-hazard analysis
Multidrug Efflux Pumps at the Crossroad between Antibiotic Resistance and Bacterial Virulence
Multidrug efflux pumps can be involved in bacterial resistance to antibiotics at different levels. Some efflux pumps are constitutively expressed at low levels and contribute to intrinsic resistance. In addition, their overexpression may allow higher levels of resistance. This overexpression can be transient, in the presence of an effector (phenotypic resistance), or constitutive when mutants in the regulatory elements of the expression of efflux pumps are selected (acquired resistance). Efflux pumps are present in all cells, from human to bacteria and are highly conserved, which indicates that they are ancient elements in the evolution of different organisms. Consequently, it has been suggested that, besides antibiotic resistance, bacterial multidrug efflux pumps would likely contribute to other relevant processes of the microbial physiology. In the current article, we discuss some specific examples of the role that efflux pumps may have in the bacterial virulence of animalsâ and plantsâ pathogens, including the processes of intercellular communication. Based in these evidences, we propose that efflux pumps are at the crossroad between resistance and virulence of bacterial pathogens. Consequently, the comprehensive study of multidrug efflux pumps requires addressing these functions, which are of relevance for the bacterialâhost interactions during infection.Work in our laboratory is supported by grants from the Spanish Ministry of Economy and Competitiveness (BIO2014-54507-R and JPI Water StARE JPIW2013-089-C02-01); from Madrid Autonomous Community [S2010/BMD2414 (PROMPT)]; and from the Instituto de Salud Carlos III [Spanish Network for Research on Infectious Diseases (REIPI RD12/0015)]. MA-R and PB are recipients of FPI fellowships from MINECO.Peer reviewedPeer Reviewe
Changes in the phenolic compositions of Elaeagnus umbellata and Sambucus lanceolata after in vitro gastrointestinal digestion and evaluation of their potential anti-diabetic properties
In this work, the phenolic composition of E. umbellata leaves and berries is reported. Berries were rich in flavonols, whereas leaves presented abundant flavonols and ellagitannins. Then, the enzyme-inhibitory properties, anti-glycation and antioxidant activities of E. umbellata and Sambucus lanceolata (its phenolic profile has been already established in a previous work) were tested by several in vitro assays and compared. The simulated gastrointestinal digestion resulted in a decrease on their phenolic composition. Nevertheless, both species still had the ability to inhibit aldose reductase activity and protein glycation and scavenge free radicals at the end of the process. Thus, the potential beneficial effects of E. umbellata and S. lanceolata seems to be kept to some extent after passage throughout the digestive system. Altogether, this study provides further insight into investigation of these species as dietary sources of bioactive compounds to lower the risk of type-2 diabetes and obesity.The authors are grateful to Esmeralda Dias from âA Quintinha das
AromĂĄticasâ (Funchal, Portugal) for the supply of E. umbellata samples
and to Francisco Fernandes and José Carvalho from Madeira Botanical
Garden (Funchal) for the identification of plant material. V. SpĂnola
acknowledges Fundação para a CiĂȘncia e a Tecnologia (FCT, Portugal)
for a Ph.D. grant SFRH/BD/84672/2012. This work was also supported
by FCT (project PEst-OE/QUI/UI0674/2019, CQM, Portuguese
Government funds) and the Portuguese National Mass Spectrometry
Network (Contract RNEMREDE/1508/REM/2005), and through
Madeira 14-20 Program, project PROEQUIPRAM - Reforço do
Investimento em Equipamentos e Infraestruturas CientĂficas na RAM
(M1420-01-0145-FEDER-000008) and by ARDITI-AgĂȘncia Regional
para o Desenvolvimento da Investigação Tecnologia e Inovação,
through the project M1420-01-0145-FEDER-000005 - Centro de
QuĂmica da Madeira - CQM+ (Madeira 14-20).info:eu-repo/semantics/publishedVersio
Myrica faya: a new source of antioxidant phytochemicals
Myrica faya is a fruit tree endemic of the Macaronesia (Azores, Madeira, and Canary Island), and its edible fruits are known as "amorinhos" (little loves), bright red to purple berries, used fresh and in jams and liquors. The phenolic composition and antioxidant capacity of leaves and berries from M. faya are presented here for the first time. The screening of phytochemical compounds was carried out using high-performance liquid chromatography with online UV and electrospray ionization mass spectrometric detection (HPLC-DAD-ESI-MS(n)). There were 55 compounds characterized, mostly galloyl esters of flavonoids and phenolic acids; 26 of the identified compounds (anthocyanins, isoflavonoids, lignans, terpenes, fatty acids, and phenylethanoids) have not been reported in Myrica genus so far. From the data presented here, it can be concluded that faya berries represent a rich source of cyanidin-3-glucoside, flavonoids, and vitamin C. In fact, higher antioxidant activity than that of the well-known Myrica rubra berries (Chinese bayberry) has been observed.info:eu-repo/semantics/publishedVersio
HPLC-ESI-MSn characterization of phenolic compounds, terpenoid saponins, and other minor compounds in Bituminaria bituminosa
Bituminaria bituminosa is a wild legume that can endure drastic conditions, including contaminated and
degraded soils. It has been traditionally used as feeding for livestock, and different uses in folk medicine
are known. The chemical composition of leaves and flowers from B. bituminosa is presented for the
first time. The screening of phytochemical compounds was carried out using high-performance liquid
chromatography with electrospray ionization mass spectrometric detection (HPLC-ESI-MSn). More than
40 compounds were identified or tentatively characterized. A high percentage of the detected compounds
corresponded to glycosylated flavonoids, especially from apigenin, although phenolic acids, lignans, and
saponins were also identified.info:eu-repo/semantics/publishedVersio
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