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Your search keyword '"Pereira, André M."' showing total 235 results
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235 results on '"Pereira, André M."'

4. Freestanding and flexible composites of magnetocaloric Gd$_5$(Si,Ge)$_4$ microparticles embedded in thermoplastic poly(methyl methacrylate) matrix

Author

Andrade, Vivian M., Barroca, Nathalie B., Pires, Ana L., Belo, João H., Araújo, João P., and Pereira, André M.

Subjects
Condensed Matter - Materials Science, Physics - Applied Physics
Abstract

The implementation of processed magnetic materials onto thermoplastics can be an approach for practical application of brittle intermetallic materials with the advantage of enlarging the range of applications. In the present work, we evaluate the effect of blending magnetocaloric Gd$_5$Si$_{2.4}$Ge$_{1.6}$ micrometric particles with 3.4 $\mu$m in different weight fractions onto a flexible, transparent and non-magnetic poly(methyl methacrylate) (PMMA). A close to homogeneous grain distribution along the polymer surface were achiever by using a simple solvent casting method for evaluation of their magnetocaloric properties. From XRD analysis, it was found a relative unit cell volume reduction of $\sim$2.5$\times$10$^3$ ppm for the composite with 70 wt.\% of powder as a result of interfacial interactions between the components. Although PMMA does not influence the magnetic nature of microparticles main phase, a reduction on the amount of secondary monoclinic phase occurs for all produced composite samples. As a consequence, a weakening on the effect of secondary phases on the micropowder magnetocaloric response is observed as a result of hydrostatic pressure from the difference between thermal expansions of matrix and filler.

Published
2019

7. On the nature of the (de)coupling of the magnetostructural transition in Er$_5$Si$_4$

Author

Costa, Rui M., Belo, João H., Barbosa, Marcelo B., Algarabel, Pedro A., Magén, César, Morellon, Luis, Ibarra, Manuel R., Gonçalves, João N., Fortunato, Nuno M., Amaral, João S., Araújo, João P., and Pereira, André M.

Subjects
Condensed Matter - Materials Science
Abstract

In this report, a successful thermodynamical model was employed to understand the structural transition in Er$_5$Si$_4$, able to explain the decoupling of the magnetic and structural transition. This was achieved by the DFT calculations which were used to determine the energy differences at 0 K, using a LSDA+U approximation. It was found that the M structure as the stable phase at low temperatures as verified experimentally with a $\Delta F_0 = -$0.262 eV. Finally, it was achieved a variation of Seebeck coefficient ($\sim$ 6 $\mu$V) at the structural transition which allow to conclude that the electronic entropy variation is negligible in the transition., Comment: 17 pages, 3 figures, 1 table

Published
2017
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10. Magnetic Refrigeration Materials at Micro-Scale

Author

Belo, João H., primary, da Silva, Daniel J., additional, Ventura, João, additional, Araújo, João P., additional, Pereira, André M., additional, Pires, Ana L., additional, and de Oliveira, Joana Cassilda Rodrigues Espain, additional

Published
2022
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14. Spontaneous magnetization above $T_C$ in polycrystalline La$_{0.7}$Ca$_{0.3}$MnO$_3$ and La$_{0.7}$Ba$_{0.3}$MnO$_3$

Author

Turcaud, Jeremy A., Pereira, Andre M., Sandeman, Karl G., Amaral, João S., Morrison, Kelly, Berenov, Andrey, Daoud-Aladine, Aziz, and Cohen, Lesley F.

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

In the present work, spontaneous magnetization is observed in the inverse magnetic susceptibility of La$_{0.7}$Ca$_{0.3}$MnO$_3$ and La$_{0.7}$Ba$_{0.3}$MnO$_3$ compounds above $T_C$ up to a temperature $T^*$. From information gathered from neutron diffraction, dilatometry, and high-field magnetization data, we suggest that $T^*$ is related to the transition temperature of the low-temperature (high magnetic field) magnetic phase. In the temperature region between $T^*$ and $T_C$, the application of a magnetic field drives the system from the high-temperature to low-temperature magnetic phases, the latter possessing a higher magnetization., Comment: 7 pages, 8 figures

Published
2014
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17. A Photo‐Thermoelectric Twist to Wireless Energy Transfer: Radial Flexible Thermoelectric Device Powered by a High‐Power Laser Beam

Author

Maia, Margarida, primary, Pires, Ana L., additional, Rocha, Mariana, additional, Ferreira‐Teixeira, Sofia, additional, Robalinho, Paulo, additional, Frazão, Orlando, additional, Furtado, Cristina, additional, Califórnia, António, additional, Machado, Vasco, additional, Bogas, Sarah, additional, Ferreira, César, additional, Machado, João, additional, Sousa, Luís, additional, Luis, Uxia G., additional, San-Juan, Alejandro M. G., additional, Crespo, Pedro O., additional, Medina, Fermin N., additional, Sande, Carlos U., additional, Marino, Alejandro C., additional, González, Guillermo R., additional, Pereira, Andreia T., additional, Agelet, Fernando A., additional, Jamier, Raphael, additional, Roy, Philippe, additional, Leconte, Baptiste, additional, Auguste, Jean‐Louis, additional, and Pereira, André M., additional

Published
2023
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24. Development of pH-Sensitive Magnetoliposomes Containing Shape Anisotropic Nanoparticles for Potential Application in Combined Cancer Therapy

Author

Pacheco, Ana Rita F., primary, Cardoso, Beatriz D., additional, Pires, Ana, additional, Pereira, André M., additional, Araújo, João P., additional, Carvalho, Violeta M., additional, Rodrigues, Raquel O., additional, Coutinho, Paulo J. G., additional, Castelo-Grande, Teresa, additional, Augusto, Paulo A., additional, Barbosa, Domingos, additional, Lima, Rui A., additional, Teixeira, Senhorinha F. C. F., additional, Rodrigues, Ana Rita O., additional, and Castanheira, Elisabete M. S., additional

Published
2023
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32. Contributors

Author

Abouelkheir, Samia S., primary, Alonso, J., additional, Álvarez-Alonso, P., additional, Araújo, João P., additional, Ata-Allah, S.S., additional, Barandiarán, José Manuel, additional, Blanco, J.A., additional, Boekelheide, Zoe, additional, Chernenko, V.A., additional, Cruz, Inês F., additional, El-Gendy, Ahmed A., additional, Fernández Barquín, L., additional, Freire, Cristina, additional, García-Arribas, A., additional, Ghozlan, Hanan A., additional, Gorría, P., additional, Hadimani, Ravi L., additional, Harstad, Shane, additional, Hunagund, Shivakumar, additional, Hussein, Zainab A., additional, Ismail, S.M., additional, Jiles, David C., additional, Labib, Sh., additional, Lázpita, P., additional, Madugundo, Rajasekhar, additional, Mohamed, M.B., additional, Nair, Harikrishnan S., additional, Ni, Yan, additional, Pereira, Clara, additional, Pereira, André M., additional, Rama Rao, Neelam Venkata, additional, Sabry, Soraya A., additional, Salazar, Daniel, additional, Salazar-Jaramillo, Daniel, additional, Sánchez Llamazares, J.L., additional, Schönhöbel, Ana María, additional, Soin, Navneet, additional, Yehia, M., additional, and Zhang, Zhen, additional

Published
2018
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36. Magnetoliposomes Containing Multicore Nanoparticles and a New Antitumor Thienopyridine Compound with Potential Application in Chemo/Thermotherapy

Author

Lopes, Fábio A. C., primary, Fernandes, André V. F., additional, Rodrigues, Juliana M., additional, Queiroz, Maria-João R. P., additional, Almeida, Bernardo G., additional, Pires, Ana, additional, Pereira, André M., additional, Araújo, João P., additional, Castanheira, Elisabete M. S., additional, Rodrigues, Ana Rita O., additional, and Coutinho, Paulo J. G., additional

Published
2022
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37. Scalable Flexible Electromagnetic Interference Shielding Textiles Based on MWCNTs and PEDOT:PSS

Author

Sousa, Ana Rita, primary, Matos, Renata, additional, Barbosa, José R.M., additional, Soares, O. Salomé G.P., additional, Ferreira, João, additional, Santos, Gilda, additional, Silva, Augusta, additional, Morgado, José, additional, Soares, Patrícia, additional, Bunyaev, Sergey A., additional, Kakazei, Gleb N., additional, Freire, Cristina, additional, Pereira, M. Fernando R., additional, Pereira, André M., additional, and Pereira, Clara, additional

Published
2022
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39. Development of thermo-and pH-sensitive liposomal magnetic carriers for new potential antitumor thienopyridine derivatives

Author

Ribeiro, Beatriz C., Alvarez, Cristina A.R., Alves, Bárbara C., Rodrigues, Juliana M., Queiroz, Maria João R. P., Almeida, B. G., Pires, Ana, Pereira, André M., Araújo, João P., Coutinho, Paulo J. G., Rodrigues, Ana Rita Oliveira, Castanheira, Elisabete M. S., and Universidade do Minho

Subjects
Thienopyridine derivatives, Science & Technology, Cancer therapy, PH sensitive, Ciências Naturais::Ciências Físicas, Magnetic nanoparticles, Antitumor compounds, Mixed ferrite, Magnetoliposomes
Abstract

The development of stimuli-sensitive drug delivery systems is a very attractive area of current research in cancer therapy. The deep knowledge on the microenvironment of tumors has supported the progress of nanosystems’ ability for controlled and local fusion as well as drug release. Temperature and pH are two of the most promising triggers in the development of sensitive formulations to improve the efficacy of anticancer agents. Herein, magnetic liposomes with fusogenic sensitivity to pH and temperature were developed aiming at dual cancer therapy (by chemotherapy and magnetic hyperthermia). Magnetic nanoparticles of mixed calcium/manganese ferrite were synthesized by co-precipitation with citrate and by sol–gel method, and characterized by X-ray diffraction (XRD), scanning electron microscopy in transmission mode (STEM), and superconducting quantum interference device (SQUID). The citrate-stabilized nanoparticles showed a small-sized population (around 8 nm, determined by XRD) and suitable magnetic properties, with a low coercivity and high saturation magnetization (~54 emu/g). The nanoparticles were incorporated into liposomes of dipalmitoylphosphatidylcholine/cholesteryl hemisuccinate (DPPC:CHEMS) and of the same components with a PEGylated lipid (DPPC:CHEMS:DSPE-PEG), resulting in magnetoliposomes with sizes around 100 nm. Dynamic light scattering (DLS) and electrophoretic light scattering (ELS) measurements were performed to investigate the pH-sensitivity of the magnetoliposomes’ fusogenic ability. Two new antitumor thienopyridine derivatives were efficiently encapsulated in the magnetic liposomes and the drug delivery capability of the loaded nanosystems was evaluated, under different pH and temperature conditions., This research was funded by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of CF-UM-UP (UIDB/04650/2020) and through the research project PTDC/QUI-QFI/28020/2017 (POCI-01-0145-FEDER-028020), financed by the European Fund of Regional Development (FEDER), COMPETE2020, and Portugal 2020. J.M.R. acknowledges FCT, ESF (European Social Fund—North Portugal Regional Operational Program) and HCOP (Human Capital Operational Program) for a PhD grant (SFRH/BD/115844/2016).

Published
2022

41. Magnetoliposomes Containing Multicore Nanoparticles and a New Thienopyridine Antitumor Compound for Chemo/Thermotherapy

Author

Lopes, Fábio A. C., primary, Fernandes, André V. F., additional, Rodrigues, Juliana M., additional, Queiroz, Maria-João R. P., additional, Almeida, Bernardo G., additional, Pires, Ana, additional, Pereira, André M., additional, Araújo, João P., additional, Rodrigues, Ana Rita O., additional, Castanheira, Elisabete M. S., additional, and Coutinho, Paulo J. G., additional

Published
2022
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43. Development of Thermo- and pH-Sensitive Liposomal Magnetic Carriers for New Potential Antitumor Thienopyridine Derivatives

Author

Ribeiro, Beatriz C., primary, Alvarez, Cristina A. R., additional, Alves, Bárbara C., additional, Rodrigues, Juliana M., additional, Queiroz, Maria João R. P., additional, Almeida, Bernardo G., additional, Pires, Ana, additional, Pereira, André M., additional, Araújo, João P., additional, Coutinho, Paulo J. G., additional, Rodrigues, Ana Rita O., additional, and Castanheira, Elisabete M. S., additional

Published
2022
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44. Design of Electromagnetic Shielding Textiles Based on Industrial‐Grade Multiwalled Carbon Nanotubes and Graphene Nanoplatelets by Dip‐Pad‐Dry Process

Author

Sousa, Ana R., primary, Matos, Renata, additional, Barbosa, José R. M., additional, Ferreira, João, additional, Santos, Gilda, additional, Silva, Augusta, additional, Morgado, José, additional, Soares, Patrícia, additional, Bunyaev, Sergey A., additional, Kakazei, Gleb N., additional, Vilarinho, Rui, additional, Soares, Olívia Salomé, additional, Pereira, Manuel Fernando, additional, Freire, Cristina, additional, Pereira, Clara, additional, and Pereira, André M., additional

Published
2022
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47. Magnetoliposomes based on magnetic/plasmonic nanoparticles loaded with tricyclic lactones for combined cancer therapy

Author

Rio, Irina S.R., Rodrigues, Ana Rita O., Rodrigues, Juliana M., Queiroz, Maria João R.P., Calhelha, R. C., Ferreira, Isabel C.F.R., Almeida, Bernardo G., Pires, Ana, Pereira, André M., Araújo, João P., Castanheira, Elisabete M.S., Coutinho, Paulo J.G., Rio I.S.R., and Universidade do Minho

Subjects
Materials science, Saúde de qualidade, new antitumor drugs, Pharmaceutical Science, Nanoparticle, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Article, law.invention, Pharmacy and materia medica, law, Irradiation, Nanotecnologia [Engenharia e Tecnologia], Produção e consumo sustentáveis, thienopyridine derivatives, manganese ferrite/gold nanoparticles, Plasmonic nanoparticles, combined cancer therapy, Proteger a vida terrestre, Science & Technology, magnetoliposomes, 021001 nanoscience & nanotechnology, Fluorescence, Thienopy-ridine derivatives, 3. Good health, 0104 chemical sciences, RS1-441, SQUID, Magnetic core, Engenharia e Tecnologia::Nanotecnologia, gold nanoparticles, Nanocarriers, 0210 nano-technology, Superparamagnetism, Nuclear chemistry
Abstract

Liposome-like nanoarchitectures containing manganese ferrite nanoparticles covered or decorated with gold were developed for application in dual cancer therapy, combining chemotherapy and photothermia. The magnetic/plasmonic nanoparticles were characterized using XRD, UV/Visible absorption, HR-TEM, and SQUID, exhibiting superparamagnetic behavior at room temperature. The average size of the gold-decorated nanoparticles was 26.7 nm for MnFe2O4 with 5-7 nm gold nanospheres. The average size of the core/shell nanoparticles was 28.8 nm for the magnetic core and around 4 nm for the gold shell. Two new potential antitumor fluorescent drugs, tricyclic lactones derivatives of thienopyridine, were loaded in these nanosystems with very high encapsulation efficiencies (higher than 98%). Assays in human tumor cell lines demonstrate that the nanocarriers do not release the antitumor compounds in the absence of irradiation. Moreover, the nanosystems do not cause any effect on the growth of primary (non-tumor) cells (with or without irradiation). The drug-loaded systems containing the core/shell magnetic/plasmonic nanoparticles efficiently inhibit the growth of tumor cells when irradiated with red light, making them suitable for a triggered release promoted by irradiation., This research was funded by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of CF-UM-UP (UIDB/04650/2020) and through the research project PTDC/QUI-QFI/28020/2017 (POCI-01-0145-FEDER-028020), financed by the European Fund of Regional Development (FEDER), COMPETE2020, and Portugal2020. I.S.R.R. acknowledges FCT for a research grant under CF-UM-UP Strategic Funding (UID/FIS/04650/2019) and a PhD grant (2020.04431.BD). J.M.R. acknowledges FCT, ESF (European Social Fund—North Portugal Regional Operational Program) and HCOP (Human Capital Operational Program) for a PhD grant (SFRH/BD/115844/2016). The APC was also financed by FCT.

Published
2021

50. Flexible Composite Films Made of EMAA − Na + Ionomer: Evaluation of the Influence of Piezoelectric Particles on the Thermal and Mechanical Properties.

Author

Tita, Sandra P. S., Magalhães, Fernão D., Paiva, Diana, Bertochi, Maria A. Z., Teixeira, Guilhermina F., Pires, Ana L., Pereira, André M., and Tarpani, José R.

Subjects
SELF-healing materials, THERMAL properties, PIEZOELECTRIC composites, EPOXY resins, POLYMERIC composites, FILMMAKING
Abstract

Studies that aim to produce flexible films of composite materials based on ionomers-PZT, and volume fractions lower than 10% PZT, in order to monitor damage in aeronautical structures are seldom investigated. The growing emphasis on the use of polymers capable of self-healing after damage or activation by heating has motivated the application of self-healing ionomers as polymeric matrices in composites with piezoelectric particles aiming to monitor damage. Flexible composite films were developed based on the self-healing polymer matrix Surlyn® 8940 ionomer (DuPontTM—Wilmington, DE, USA) and PZT particles (connectivity 2–3) in volume fractions of 1, 3, 5 and 7%, with thickness around 50–100 µm. The choice of PZT volume fractions followed the preliminary requirement that establishes a final density, which is lower or at least close to the density of the materials used in aeronautical structures. Since the application of composites based on epoxy resin/carbon fibers has been increasing in the aeronautical segment, this material (with density lower than 1500 kg/m3) was chosen as a reference for the present work. Thus, due to self-healing (a characteristic of the matrix Surlyn® 8940) combined with recyclability, high flexibility and low thickness, the flexible composite films showed advantages to be applied on aeronautical structures, which present complex geometries and low-density materials. The manufactured films were characterized by SEM, XRD, DMA and mechanical tensile tests. The results were discussed mainly in terms of the volume fraction of PZT. X-ray diffraction patterns showed coexistent rhombohedral and tetragonal phases in the PZT particles-dispersed composite, which can potentialize the alignment of ferroelectric domains during polarization under strong electrical field, enhancing dielectric and piezoelectric properties toward sensing applications. DMA and tensile testing results demonstrated that the addition of PZT particles did not impair either dynamic or quasi-static mechanical performance of the flexible composite films. It was concluded that the PZT volume fraction should be lower than 3% because, for higher values, the molecular mobility of the polymer would suffer significant reductions. These findings, combined with the high flexibility and low density of the ceramic particle-filled thermoplastic polymer, render the developed flexible composite film a very promising candidate for strain and damage sensing in aeronautical structures. [ABSTRACT FROM AUTHOR]

Published
2022
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