2,532 research outputs found
Implementation of robust multi-objective optimization in the build orientation problem
Additive manufacturing (AM) is an emerging technology to create 3D objects layer-by-layer directly from a 3D CAD model. The build orientation is a critical issue in AM and its optimization will significantly reduce the building costs and improve object accuracy. This paper aims to optimize the build orientation problem of a 3D CAD model using a robust multi-objective approach, taking into account the staircase effect and the support area characteristics. Thus, themain objective is to obtain a robust Pareto optimal front, composed of solutions that are not quite sensitive to perturbations in the variables. In this manner, a set of robust solutions is presented as alternatives and the decision-maker can identify the compromise solutions and choose according to his/her preferences.This work has been developed under the FIBR3D project - Hybrid processes based on additive manufacturing of composites with long or short fibers reinforced thermoplastic matrix (POCI-01-0145-FEDER-016414), supported by the Lisbon Regional Operational Programme 2020, under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). This work has been supported by FCT - Fundacao para a Ciencia e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020
Build orientation optimization of car hoodvent with additive manufacturing
Additive manufacturing is a widely used process consisting in the
building of a three-dimensional (3D) object from a model projected on a computer, adding the material layer-by-layer. This technology allows the printing of
complex shape objects and is being increasingly adopted by the aircraft industry,
medical implants, jewelry, footwear, automotive, fashion products, among others.
The build orientation optimization of 3D models has a great influence on costs
and surface quality when printing three-dimensional objects.
In this work, three build orientation optimization problems are studied: single objective problem, bi-objective problem and many-objective problem. To this
end, three quality measures are applied: the support area, the build time and the
surface roughness, for the Car Hoodvent model. First, a single-objective optimization problem is presented and solved by the genetic algorithm, obtaining
optimal solutions for each objective function. Then, the study of the bi-objective
optimization problem is carried out for each pair of two objectives and some
representative trade-off solutions are identified. Finally, the study of the many objective optimization problem, considering the three measures optimized simultaneously, is presented with some more optimal solutions found. The bi-objective
and many-objective problems are solved by a multi-objective genetic algorithm.
For a better analysis and comparison of the solutions found, the Pareto fronts are
used, enabling a better visualization of the solutions between the objectives. This
study aims to assist the decision-maker in choosing the best part print orientation
angles according to his/her preferences. The optimal solutions found confirmed
the effectiveness of the proposed approach.info:eu-repo/semantics/publishedVersio
A genetic algorithm for forest firefighting optimization
In recent years, a large number of fires have ravaged planet Earth. A forest fire is a natural phenomenon that destroys the forest ecosystem in a given area. There are many factors that cause forest fires, for example, weather conditions, the increase of global warming and human action. Currently, there has been a growing focus on determining the ignition sources responsible for forest fires. Optimization has been widely applied in forest firefighting problems, allowing improvements in the effectiveness and speed of firefighters’ actions. The better and faster the firefighting team performs, the less damage is done. In this work, a forest firefighting resource scheduling problem is formulated in order to obtain the best ordered sequence of actions to be taken by a single firefighting resource in combating multiple ignitions. The objective is to maximize the unburned area, i.e., to minimize the burned area caused by the ignitions. A problem with 10 fire ignitions located in the district of Braga, in Portugal, was solved using a genetic algorithm. The results obtained demonstrate the usefulness and validity of this approach.This work has been supported by FCT Fundação para a Ciência e Tecnologia within the R &D Units Project Scope UIDB/00319/2020 and PCIF/GRF/0141/2019: “O3F - An Optimization Framework to reduce Forest Fire” and the PhD grant reference UI/BD/150936/2021
Dehydration process influences the phenolic profile, antioxidant and antimicrobial properties of Galium aparine L.
Galium aparine L. is a very disseminated plant in temperate zones, commonly known as clivers or bedstraw,
belonging to the Rubiaceae family and it is traditionally used for its medicinal applications. In this study, G.
aparine hydromethanolic extracts and infusions were prepared from air-dried and freeze-dried samples in order
to assess their phenolic profile, antioxidant, antimicrobial, and cytotoxic properties. All the studied extracts
revealed a similar phenolic profile, but the hydromethanolic extract obtained from the freeze-dried sample
presented the highest concentration of phenolic compounds, followed by the respective infusion and the airdried
sample hydromethanolic extract. The major compound detected in the extracts was 5-O-caffeoylquinic acid
(from 145 to 163 mg/g extract). Regarding the bioactivity, in general, the extracts presenting higher phenolic
concentrations also revealed enhanced bioactive properties. The EC50 values obtained in the antioxidant activity
assays ranged from 13.5 to 884 μg/mL, with the freeze-dried sample hydromethanolic extract presenting the
highest activity (13.5–555 μg/mL). Similar conclusions could be made in terms of antimicrobial properties, with
this extract showing the lowest MIC (1.85–15 mg/mL), MBC (3.75–7.5 mg/mL), and MFC (3.75–20 mg/mL)
values. None of the extracts revealed cytotoxicity. The results obtained in this study suggested that G. aparine
extracts can be a good source of phenolic compounds with antioxidant and antimicrobial properties.The authors are grateful to the Foundation for Science and
Technology (FCT, Portugal) and FEDER under Programme PT2020 for
financial support to CIMO (UID/AGR/00690/2013); to FCT for L.
Barros research contract; to FCT for the grant attributed to C. Pereira
(SFRH/BPD/122650/2016) through the Programa Operacional Capital
Humano (POCH) supported by the European Social Fund and National
Funds of MCTES (Ministério da Ciência, Tecnologia, e Ensino Superior);
and to FEDER-Interreg España-Portugal programme for financial support
through the project 0377_Iberphenol_6_E. The authors are also
grateful to the Serbian Ministry of Education, Science and
Technological Development, grant number 173032 for financial support.info:eu-repo/semantics/publishedVersio
Evaluation of parasite and host phenolic composition and bioactivities − The practical case of Cytinus hypocistis (L.) L. and Halimium lasianthum (Lam.) Greuter
Cytinus hypocistis (L.) L. is a comestible holoparasite with great potential for cosmeceutical application. Although its high tannin content has been associated with its bioactive and inhibitory enzyme properties, this is the first report establishing a relationship between parasite and host (Halimium lasianthum (Lam.) Greuter) phenolic profile and bioactive properties. Thus, five extracts (aerial and root extracts of non-parasited and parasited H. lasianthum and C. hypocistis) were evaluated. The tentative identification of both species comprises 39 phenolic compounds. Hydrolysable tannins and flavonoids were the main identified groups in C. hypocistis and H. lasianthum extracts, respectively. Regarding bioactivities, C. hypocistis exhibited excellent antioxidant results both in Oxidative Haemolysis (OxHLIA) and inhibition of Thiobarbituric Acid Reactive Substances Formation (TBARS). The tested extracts presented antimicrobial inhibition, anti-inflammatory activity, and effective cytotoxicity against tumour cells. C. hypocistis exhibited the lowest cytotoxicity on a non-tumour cell line. Principal Component Analysis (PCA) was a suitable approach to analyse differences among samples, explaining up to 67% of data variability and suggesting no similarities between parasite and host phenolic composition and bioactivities. Therefore, this comparative study emphasises the significance of both species as a source of biologically active compounds.The authors are grateful to the Foundation for Science and Technology
(FCT, Portugal) for financial support through national funds
FCT/MCTES to CIMO (UIDB/00690/2020). A. R. Silva is grateful to FCT
and FSE for her Doctoral Grant (SFRH/BD/145834/2019). L. Barros, C.
Pereira, I. Dias, and R. C. Calhelha are grateful to F.C.T. and P.I. for their
contracts through the institutional scientific employment programme.
The authors are also thankful to the FEDER-Interreg Espa˜na-Portugal
programme for financial support through the project TRANSCoLAB:
0612_TRANS_CO_LAB_2_P and to ERDF through the Regional Operational
Program North 2020, within the scope of the Project GreenHealth
- Norte-01–0145-FEDER-000042. This research was also funded by the
Serbian Ministry of Education, Science and Technological Development
(Contract No. 451–03-9/2021–14/200007).info:eu-repo/semantics/publishedVersio
Ocimum basilicum var. Purpurascens leaves (red rubin basil): A source of bioactive compounds and natural pigments for the food industry
Ocimum basilicum var. purpurascens (red rubin basil) is a basil variety rich in anthocyanin compounds, commonly used in the food industry as an aromatic plant. In this study, the nutritional and chemical compositions of red rubin basil leaves were analysed, as well as, the antimicrobial activity and hepatotoxicity of their hydroethanolic extract. Carbohydrates were the main macronutrients present, with glucose being the major free sugar. Quinic acid was the most abundant organic acid, while γ-tocopherol was the highest tocopherol isoform found. α-Linolenic acid was the major fatty acid of the twenty identified compounds. Regarding polyphenols, twenty-six molecules were identified (thirteen non-anthocyanin and thirteen anthocyanin compounds), with rosmarinic acid being the main non-anthocyanin molecule and cyanidin-3-(6,6′-di-p-coumaroyl)-sophoroside-5-glcucoside the most abundant anthocyanin. These compounds could be related to the antimicrobial activity observed in this study. Thus, this variety could be considered a good source of value added molecules for the food industry.info:eu-repo/semantics/publishedVersio
Recovery of anthocyanins from passion fruit epicarp for food colorants: Extraction process optimization and evaluation of bioactive properties
The potential of passion fruit (Passiflora edulis Sims) epicarp to produce anthocyanin-based colorants with bioactive properties was evaluated. First, a five-level three-factor factorial design coupled with response surface methodology was implemented to optimize the extraction of anthocyanins from dark purple epicarps. The extraction yield and cyanidin-3-O-glucoside content were used as response criteria. The constructed models were fitted to the experimental data and used to calculate the optimal processing conditions (t = 38 min, T = 20 °C, S = 0% ethanol/water (v/v) acidified with citric acid to pH 3, and RS/L = 50 g/L) that lead to maximum responses (3.4 mg/g dried epicarp and 9 mg/g extract). Then, the antioxidant, antimicrobial, and cytotoxic activities of anthocyanin extracts obtained using the optimized method and a conventional extraction method were evaluated in vitro. The extract obtained by the optimized method revealed a higher bioactivity, in agreement with the higher cyanidin-3-O-glucoside content. This study highlighted the coloring and bioactive potential of a bio-based ingredient recycled from a bio-waste, which promotes a sustainable bioeconomy in the agri-food sector.This research was funded by the European Regional Development Fund (FEDER) through the Regional
Operational Program North 2020, within the scope of Project NORTE-01-0145-FEDER-023289: DeCodE, and project
Mobilizador Norte-01-0247-FEDER-024479: ValorNatural®, and also by the Interreg España-Portugal through
the project 0377_Iberphenol_6_E. National funding by the Portuguese Foundation for Science and Technology
(FCT, P.I., through the institutional scientific employment program-contract for J. Pinela, R.C. Calhelha and L.
Barros. Funding by the Ministry of Education, Science and Technological Development, Republic of Serbia, grant
No. 173032. Financial support (P.P. 0000 421S 140.08) from GAIN (Xunta de Galicia) to M.A. Prieto through
a post-doctoral (modality B) grant.
To the Portuguese Foundation for Science and Technology (FCT) and European Regional
Development Fund (ERDF – FEDER) under Program PT2020 for financial support to CIMO (UIDB/00690/2020).info:eu-repo/semantics/publishedVersio
Phytochemical composition and bioactive potential of Melissa officinalis L., Salvia officinalis L. and Mentha spicata L. extracts
Plants are rich in bioactive phytochemicals that often display medicinal properties. These can play an important role in the production of health-promoting food additives and the replacement of artificial ones. In this sense, this study aimed to characterise the polyphenolic profile and bioactive properties of the decoctions, infusions and hydroethanolic extracts of three plants: lemon balm (Melissa officinalis L.), sage (Salvia officinalis L.) and spearmint (Mentha spicata L.). Total phenolic content ranged from 38.79 mg/g extract to 84.51 mg/g extract, depending on the extract. The main phenolic compound detected in all cases was rosmarinic acid. The results highlighted that some of these extracts may have the ability to prevent food spoilage (due to antibacterial and antifungal effects) and promote health benefits (due to anti-inflammatory and antioxidant capacities) while not displaying toxicity against healthy cells. Furthermore, although no anti-inflammatory capacity was observed from sage extracts, these stood out for often displaying the best outcomes in terms of other bioactivities. Overall, the results of our research provide insight into the potential of plant extracts as a source of active phytochemicals and as natural food additives. They also support the current trends in the food industry of replacing synthetic additives and developing foods with added beneficial health effects beyond basic nutrition.info:eu-repo/semantics/publishedVersio
RVG29-Functionalized Lipid Nanoparticles for Quercetin Brain Delivery and Alzheimers Disease
Purpose: Lipid nanoparticles (SLN and NLC) were functionalized with the RVG29 peptide in order to target the brain and increase the neuronal uptake through the nicotinic acetylcholine receptors. These nanosystems were loaded with quercetin to take advantage of its neuroprotective properties mainly for Alzheimer's disease. Methods: The functionalization of nanoparticles with RVG29 peptide was confirmed by NMR and FTIR. Their morphology was assessed by transmission electron microscopy and nanoparticles size, polydispersity and zeta potential were determined by dynamic light scattering. The in vitro validation tests were conducted in hCMEC/D3 cells, a human blood-brain barrier model and thioflavin T binding assay was conducted to assess the process of amyloid-beta peptide fibrillation typical of Alzheimer's disease. Results: RVG29-nanoparticles displayed spherical morphology and size below 250 nm, which is compatible with brain applications. Zeta potential values were between −20 and −25 mV. Quercetin entrapment efficiency was generally higher than 80% and NLC nanoparticles were able to encapsulate up to 90%. The LDH assay showed that there is no cytotoxicity in hCMEC/D3 cell line and RVG29-nanoparticles clearly increased in 1.5-fold the permeability across the in vitro model of blood-brain barrier after 4 h of incubation compared with non-functionalized nanoparticles. Finally, this nanosystem was capable of inhibiting amyloid-beta aggregation in thioflavin T binding assay, suggesting its great potential for neuroprotection. Conclusions: RVG29-nanoparticles that simultaneously target the blood-brain barrier and induce neurons protection against amyloid-beta fibrillation proved to be an efficient way of quercetin delivery and a promising strategy for future approaches in Alzheimer's disease. [Figure not available: see fulltext.]. (c) 2020, Springer Science+Business Media, LLC, part of Springer Nature
Development of a natural preservative from chestnut flowers: ultrasound-assisted extraction optimization and functionality assessment
This study was carried out with the aim of optimizing the ultrasound-assisted extraction (UAE) of phenolic compounds from male chestnut flowers (C. sativa Mill) to develop a bioactive extract with potential to be used as a natural antioxidant preservative ingredient in the food in-dustry. Time (t, 1–39 min), solvent concentration (S, 0–100%), and ultrasonic power (P, 5–500 W) were used as the independent variables for a 5-level experimental circumscribed central composite design (CCCD) coupled with response surface methodology (RSM) to optimize the extraction of phenolic compounds by UAE. Regarding the variables, the three showed a significant effect on the extraction of phenolic compounds. The content of phenolic compounds (including flavonoids and tannins) and the extraction yield (extract weight gravimetrically assessed) were the response criteria for the optimization. Based on the statistically validated predictive polynomial models, it was possible to reach a maximum content of phenolic compounds at the global optimal conditions of 24 ± 3 min, 259 ± 16 W, and 51 ± 7% ethanol. Additionally, pentagalloyl-glucoside and trigalloyl-hexahydroxydiphenoyl-glucoside were the major phenolic compounds identified. The optimized extract was then analyzed for their biological properties. The bioactive potential of the chestnut flower extract obtained under these optimized conditions was evaluated using in vitro assays for antioxidant, anti-inflammatory, and antimicrobial activity, as well as cytotoxicity and hepatotoxicity tests. The results revealed that the enriched extract has antioxidant, antitumoral, and anti-inflammatory activities without toxicity issues. Overall, this study allowed to define the optimal conditions for the extraction of phenolic compounds from chestnuts male flowers by UAE, to obtain an enriched extract with biological properties that could be further used as a natural antioxidant ingredient with applications on functional foods.The authors are grateful to the Foundation for Science and Technology (FCT,
Portugal) for financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020). M.I.
Dias, R.C. Calhelha and L. Barros would like to thank the national funding by FCT, P.I., through
the institutional scientific employment program-contract. J. Pinela also thanks FCT for his contract
(CEECIND/01011/2018) under the individual scientific employment program-contract. The research
leading to these results was supported by MICINN supporting the Ramón and Cajal grant for
M.A. Prieto (RYC-2017-22891) and by Xunta de Galicia supporting the post-doctoral grant of M.
Fraga-Corral (ED481B-2019/096) and the program EXCELENCIA-ED431F 2020/12. To the project
AllNat for the contract of C. Caleja (Project AllNat POCI-01-0145-FEDER-030463) and to the Project
Mobilizador Norte-01-0247-FEDER-024479: ValorNatural® for the contract of E. Pereira.info:eu-repo/semantics/publishedVersio
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