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Nassar KI, Tayari F, Benamara M, Teixeira SS, Graça MPF. Exploring bismuth-doped polycrystalline ceramic Ba 0.75Bi 0.25Ni 0.7Mn 0.3O 3: synthesis, structure, and electrical properties for advanced electronic applications. RSC Adv 2023; 13:24023-24030. [PMID: 37577096 PMCID: PMC10413953 DOI: 10.1039/d3ra05038f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 08/06/2023] [Indexed: 08/15/2023] Open
Abstract
This manuscript investigates the structural and electrical properties of a Ba0.75Bi0.25Ni0.7Mn0.3O3 (BNMO) perovskite compound synthesized through the sol-gel method. The orthorhombic crystal structure of the sample is confirmed by X-ray diffraction analysis. The electrical conductivity of BNMO is found to increase with frequency, indicating the presence of local charge carriers. The AC electrical conductivity follows Jonscher's equation, exhibiting a plateau at low frequencies and a power-law behavior at high frequencies. The activation energy for conduction is determined to be 0.654 eV. Impedance spectroscopy reveals the presence of grain and grain boundary contributions, which are modeled using an R-CPE combination circuit. Analysis of the electrical modulus demonstrates non-Debye type relaxation and indicates the presence of charge carrier hopping between Mn2+ and Mn3+ ions. The activation energy obtained from the relaxation peaks of the modulus is found to be 0.674 eV. The dielectric constant exhibits high values that increase with temperature. This observation suggests that the capacitance behavior holds promising potential for energy storage applications, making it a suitable candidate for various technological uses.
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Affiliation(s)
- Kais Iben Nassar
- University of Sfax, Faculty of Sciences of Sfax, Materials Physics Laboratory B. P1171 3000 Sfax Tunisia
- I3N-Aveiro, Department of Physics, University of Aveiro 3810-193 Aveiro Portugal
| | - Faouzia Tayari
- University of Sfax, Faculty of Sciences of Sfax, Materials Physics Laboratory B. P1171 3000 Sfax Tunisia
| | - Majdi Benamara
- University of Gabes, Faculty of Sciences of Gabes, Laboratory of Physics of Materials and Nanomaterials Applied to the Environment Erriadh 6079 Gabes Tunisia
| | | | - Manuel Pedro F Graça
- I3N-Aveiro, Department of Physics, University of Aveiro 3810-193 Aveiro Portugal
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Guler E, Nur Hazar-Yavuz A, Tatar E, Morid Haidari M, Sinemcan Ozcan G, Duruksu G, Graça MPF, Kalaskar DM, Gunduz O, Emin Cam M. Oral empagliflozin-loaded tri-layer core-sheath fibers fabricated using tri-axial electrospinning: Enhanced in vitro and in vivo antidiabetic performance. Int J Pharm 2023; 635:122716. [PMID: 36791999 DOI: 10.1016/j.ijpharm.2023.122716] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 02/16/2023]
Abstract
Empagliflozin (EM) was successfully loaded in polycaprolactone/poly (L-lactic acid)/polymethyl methacrylate (PCL/PLA/PMMA) fibers. In the rat β-cell line (BRIN-BD11), the insulin expression ratio of pancreatic β-cells was stimulated at high and low glucose by culturing with tri-layer EM-loaded fiber (EMF) for 48 h. The expression ratios of glucokinase and GLUT-2 proteins increased after EMF treatment. According to the in vitro drug release test, 97% of all drug contained in fibers was released in a controlled manner for 24 h. The pharmacokinetic test revealed that the bioavailability was improved ∼4.8-fold with EMF treatment compared to EM-powder and blood glucose level was effectively controlled for 24 h with EMF. Oral administration of EMF exhibited a better sustainable anti-diabetic activity even in the half-dosage than EM-powder in streptozotocin/nicotinamide-induced T2DM rats. The levels of GLP-1, PPAR-γ, and insulin were increased while the levels of SGLT-2 and TNF-α were decreased with EMF treatment. Also, EMF recovered the histopathological changes in the liver, pancreas, and kidney in T2DM rats and protected pancreatic β-cells. Consequently, EMF is suggested as an unprecedented and promotive treatment approach for T2DM with a higher bioavailability and better antidiabetic effect compared to conventional dosage forms.
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Affiliation(s)
- Ece Guler
- Department of Pharmacology, Faculty of Pharmacy, Marmara University, Istanbul 34854, Turkey; Center for Nanotechnology and Biomaterials Application and Research, Marmara University, Istanbul 34722, Turkey; UCL Division of Surgery and Interventional Science, Royal Free Hospital Campus, University College London, Rowland Hill Street, NW3 2PF, UK
| | - Ayse Nur Hazar-Yavuz
- Department of Pharmacology, Faculty of Pharmacy, Marmara University, Istanbul 34854, Turkey
| | - Esra Tatar
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Marmara University, Istanbul 34854, Turkey
| | - Mohammad Morid Haidari
- Department of Pharmacology, Faculty of Pharmacy, Marmara University, Istanbul 34854, Turkey
| | - Gul Sinemcan Ozcan
- Stem Cell and Gene Therapies Research and Applied Center, Medical Faculty, Kocaeli University, Kocaeli 41380, Turkey
| | - Gokhan Duruksu
- Stem Cell and Gene Therapies Research and Applied Center, Medical Faculty, Kocaeli University, Kocaeli 41380, Turkey
| | | | - Deepak M Kalaskar
- UCL Division of Surgery and Interventional Science, Royal Free Hospital Campus, University College London, Rowland Hill Street, NW3 2PF, UK
| | - Oguzhan Gunduz
- Center for Nanotechnology and Biomaterials Application and Research, Marmara University, Istanbul 34722, Turkey; Department of Metallurgy and Material Engineering, Faculty of Technology, Marmara University, Istanbul 34722, Turkey
| | - Muhammet Emin Cam
- Department of Pharmacology, Faculty of Pharmacy, Marmara University, Istanbul 34854, Turkey; Center for Nanotechnology and Biomaterials Application and Research, Marmara University, Istanbul 34722, Turkey; UCL Division of Surgery and Interventional Science, Royal Free Hospital Campus, University College London, Rowland Hill Street, NW3 2PF, UK; Biomedical Engineering Department, University of Aveiro, 3810-193 Aveiro, Portugal; Genetic and Metabolic Diseases Research and Investigation Center, Marmara University, 34854 Istanbul, Turkey.
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Prezas PR, Soares MJ, Borges JP, Silva JC, Oliveira FJ, Graça MPF. Bioactivity Enhancement of Plasma-Sprayed Hydroxyapatite Coatings through Non-Contact Corona Electrical Charging. Nanomaterials (Basel) 2023; 13:1058. [PMID: 36985952 PMCID: PMC10058569 DOI: 10.3390/nano13061058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/05/2023] [Accepted: 03/10/2023] [Indexed: 06/18/2023]
Abstract
Atmospheric plasma spray (APS) remains the only certified industrial process to produce hydroxyapatite (Hap) coatings on orthopaedic and dental implants intended for commercialization. Despite the established clinical success of Hap-coated implants, such as hip and knee arthroplasties, a concern is being raised regarding the failure and revision rates in younger patients, which are increasing rapidly worldwide. The lifetime risk of replacement for patients in the 50-60 age interval is about 35%, which is significantly higher than 5% for patients aged 70 or older. Improved implants targeted at younger patients are a necessity that experts have been alerted to. One approach is to enhance their bioactivity. For this purpose, the method with the most outstanding biological results is the electrical polarization of Hap, which remarkably accelerates implant osteointegration. There is, however, the technical challenge of charging the coatings. Although this is straightforward on bulk samples with planar faces, it is not easy on coatings, and there are several problems regarding the application of electrodes. To the best of our knowledge, this study demonstrates, for the first time, the electrical charging of APS Hap coatings using a non-contact, electrode-free method: corona charging. Bioactivity enhancement is observed, establishing the promising potential of corona charging in orthopedics and dental implantology. It is found that the coatings can store charge at the surface and bulk levels up to high surface potentials (>1000 V). The biological in vitro results show higher Ca2+ and P5+ intakes in charged coatings compared to non-charged coatings. Moreover, a higher osteoblastic cellular proliferation is promoted in the charged coatings, indicating the promising potential of corona-charged coatings when applied in orthopedics and dental implantology.
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Affiliation(s)
- Pedro R. Prezas
- I3N and Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Manuel J. Soares
- I3N and Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal
| | - João P. Borges
- I3N-CENIMAT, New University of Lisbon, 1099-085 Lisbon, Portugal
| | - Jorge C. Silva
- I3N-CENIMAT, New University of Lisbon, 1099-085 Lisbon, Portugal
| | - Filipe J. Oliveira
- CICECO and Materials Engineering Department, University of Aveiro, 3810-193 Aveiro, Portugal
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Silva Neto JF, Pereira WO, Cavalcante LA, Oliveira Neto JG, Graça MPF, Gavinho SR, Amaral FMB, Santos AO, Sombra ASB, Mendes F, Macêdo AAM. Extraction, Purification and Electrical Characterization of Gross Galactomannan and Purified Galactomannan Obtained from Adenanthera pavonina L. Seeds. Chem Biodivers 2023; 20:e202200888. [PMID: 36703594 DOI: 10.1002/cbdv.202200888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 01/11/2023] [Indexed: 01/28/2023]
Abstract
Aiming of self-sustainable production, the search for biodegradable and biocompatible materials has brought with it the need to know the physicochemical and dielectric characteristics of polysaccharide-based composite structures, which can be used as important and promising raw materials for biotechnology and electronic industries. Galactomannans are polysaccharides, extracted from seeds and microbiological sources, consisting of mannose and galactose. In this context, this work aimed to extract, purify and characterize by XRD, FTIR and impedance spectroscopy galactomannan obtained from seeds of Adenanthera pavonina L. The purification process was made with ethyl alcohol at concentrations of 70, 80 and 90 %. Polymeric films were prepared by solvent slow evaporation at low temperatures. XRD measurements revealed that Galactomannan from Adenanthera pavonina L., after purification, has a semi-crystalline structure due to the identification of two peaks the first between 5.849° and 6.118° and the second between 20.011° and 20.247°. FTIR spectra showed the functional groups associated with monosaccharides of the galactomannan from Adenanthera pavonina L. seeds, as well as the typical polysaccharide bands and peaks, confirmed by literature data. The impedance results give an increment on the state-of-the-art of this biomaterial by showing the existence of dielectric relaxations, independent of the degree of purification, using the dielectric modulus formalism. The permittivity analysis reveals the presence of water in the structure of the film, whose dipoles contribute to the relatively high value of the dielectric constant. From the results obtained, it can be concluded that purified galactomannan has the potential for possible applications in the electronics industry as a green and eco-friendly dielectric material.
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Affiliation(s)
- J F Silva Neto
- Instituto Federal do Maranhão - Campus Imperatriz, Laboratório de Pesquisa, 65919-050, Imperatriz, Brasil
| | - W O Pereira
- Universidade Federal do Maranhão, CCSST, 65900-410, Imperatriz, Brasil
| | - L A Cavalcante
- Instituto Federal do Maranhão - Campus Imperatriz, Laboratório de Pesquisa, 65919-050, Imperatriz, Brasil
| | - J G Oliveira Neto
- Universidade Federal do Maranhão, CCSST, 65900-410, Imperatriz, Brasil
| | - M P F Graça
- I3N and Physics Department, Aveiro University, 3810-193, Aveiro, Portugal
| | - S R Gavinho
- I3N and Physics Department, Aveiro University, 3810-193, Aveiro, Portugal
| | - F M B Amaral
- Politécnico de Coimbra, ESTeSC, Departamento de Ciências Complementares, DCC, Rua 5 de Outubro - SM Bispo, Apartado 7006, 3046-854 Coimbra, Coimbra, Portugal
| | - A O Santos
- Universidade Federal do Maranhão, CCSST, 65900-410, Imperatriz, Brasil
| | - A S B Sombra
- Universidade Federal do Ceará - Campus Pici, LOCEM-Laboratório de Telecomunicações e Ciência e Engenharia de Materiais, Departamento de Física, Avenida Humberto Monte, s/n - Pici, 60440-593, Fortaleza, Brasil
| | - Fernando Mendes
- Politécnico de Coimbra, ESTeSC, Unidade Cientifico-Pedagógica de Ciências Biomédicas Laboratoriais, UCPCBL, Rua 5 de Outubro - SM Bispo, Apartado 7006, 3046-854 Coimbra, Coimbra, Portugal
| | - A A M Macêdo
- Instituto Federal do Maranhão - Campus Imperatriz, Laboratório de Pesquisa, 65919-050, Imperatriz, Brasil
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Gavinho SR, Pádua AS, Sá-Nogueira I, Silva JC, Borges JP, Costa LC, Graça MPF. Fabrication, Structural and Biological Characterization of Zinc-Containing Bioactive Glasses and Their Use in Membranes for Guided Bone Regeneration. Materials (Basel) 2023; 16:956. [PMID: 36769963 PMCID: PMC9919611 DOI: 10.3390/ma16030956] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 01/11/2023] [Accepted: 01/17/2023] [Indexed: 06/18/2023]
Abstract
Polymeric membranes are widely used in guided bone regeneration (GBR), particularly in dentistry. In addition, bioactive glasses can be added to the polymers in order to develop a matrix that is osteoconductive and osteoinductive, increasing cell adhesion and proliferation. The bioactive glasses allow the insertion into its network of therapeutic ions in order to add specific biological properties. The addition of zinc into bioactive glasses can promote antibacterial activity and induce the differentiation and proliferation of the bone cells. In this study, bioactive glasses containing zinc (0.25, 0.5, 1 and 2 mol%) were developed and structurally and biologically characterized. The biological results show that the Zn-containing bioactive glasses do not present significant antibacterial activity, but the addition of zinc at the highest concentration does not compromise the bioactivity and promotes the viability of Saos-2 cells. The cell culture assays in the membranes (PCL, PCL:BG and PCL:BGZn2) showed that zinc addition promotes cell viability and an increase in alkaline phosphatase (ALP) production.
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Affiliation(s)
- Sílvia R. Gavinho
- I3N and Physics Department, Aveiro University, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Ana Sofia Pádua
- I3N-CENIMAT and Physics Department, NOVA School of Science and Technology, Campus de Caparica, 2829-516 Caparica, Portugal
| | - Isabel Sá-Nogueira
- Associate Laboratory i4HB, Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal
- UCIBIO—Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal
| | - Jorge C. Silva
- I3N-CENIMAT and Physics Department, NOVA School of Science and Technology, Campus de Caparica, 2829-516 Caparica, Portugal
| | - João P. Borges
- I3N-CENIMAT and Materials Science Department, NOVA School of Science and Technology, Campus de Caparica, 2829-516 Caparica, Portugal
| | - Luis C. Costa
- I3N and Physics Department, Aveiro University, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Manuel Pedro F. Graça
- I3N and Physics Department, Aveiro University, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
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Gavinho SR, Pádua AS, Sá-Nogueira I, Silva JC, Borges JP, Costa LC, Graça MPF. Biocompatibility, Bioactivity, and Antibacterial Behaviour of Cerium-Containing Bioglass ®. Nanomaterials (Basel) 2022; 12:nano12244479. [PMID: 36558332 PMCID: PMC9783236 DOI: 10.3390/nano12244479] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 05/31/2023]
Abstract
The main reason for the increased use of dental implants in clinical practice is associated with aesthetic parameters. Implants are also presented as the only technique that conserves and stimulates natural bone. However, there are several problems associated with infections, such as peri-implantitis. This disease reveals a progressive inflammatory action that affects the hard and soft tissues surrounding the implant, leading to implant loss. To prevent the onset of this disease, coating the implant with bioactive glasses has been suggested. In addition to its intrinsic function of promoting bone regeneration, it is also possible to insert therapeutic ions, such as cerium. Cerium has several advantages when the aim is to improve osseointegration and prevent infectious problems with dental implant placement. It promotes increased growth and the differentiation of osteoblasts, improves the mechanical properties of bone, and prevents bacterial adhesion and proliferation that may occur on the implant surface. This antibacterial effect is due to its ability to disrupt the cell wall and membrane of bacteria, thus interfering with vital metabolic functions such as respiration. In addition, its antioxidant effect reverses oxidative stress after implantation in bone. In this work, Bioglass 45S5 with CeO2 with different percentages (0.25, 0.5, 1, and 2 mol%) was developed by the melt-quenching method. The materials were analyzed in terms of morphological, structural, and biological (cytotoxicity, bioactivity, and antibacterial activity) properties. The addition of cerium did not promote structural changes to the bioactive glass, which shows no cytotoxicity for the Saos-2 cell line up to 25 mg/mL of extract concentration for all cerium contents. For the maximum cerium concentration (2 mol%) the bioactive glass shows an evident inhibitory effect for Escherichia coli and Streptococcus mutans bacteria. Furthermore, all samples showed the beginning of the deposition of a CaP-rich layer on the surface of the material after 24 h.
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Affiliation(s)
- Sílvia R. Gavinho
- I3N and Physics Department, Aveiro University, 3810-193 Aveiro, Portugal
| | - Ana Sofia Pádua
- I3N-CENIMAT, New University of Lisbon, 2825-097 Caparica, Portugal
| | - Isabel Sá-Nogueira
- Associate Laboratory i4HB—Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal
- UCIBIO—Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University Lisbon, 2819-516 Caparica, Portugal
| | - Jorge C. Silva
- I3N-CENIMAT, New University of Lisbon, 2825-097 Caparica, Portugal
| | - João P. Borges
- I3N-CENIMAT, New University of Lisbon, 2825-097 Caparica, Portugal
| | - Luis C. Costa
- I3N and Physics Department, Aveiro University, 3810-193 Aveiro, Portugal
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Abdouli K, Hassini F, Cherif W, Prezas PR, Graça MPF, Valent MA, Messaoudi O, Elgharbi S, Dhahri A, Manai L. Investigation of the structural, electrical, and dielectric properties of La 0.5Sm 0.2Sr 0.3Mn 1-x Cr x O 3 for electrical application. RSC Adv 2022; 12:16805-16822. [PMID: 35754884 PMCID: PMC9171900 DOI: 10.1039/d2ra01006b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 05/15/2022] [Indexed: 11/25/2022] Open
Abstract
In the present research, polycrystalline samples of La0.5Sm0.2Sr0.3Mn1−xCrxO3 are prepared using the self-combustion method. Then, we have studied their crystalline structure, and dielectric and electrical properties. The X-ray diffraction study shows that all the samples exhibit a single phase with orthorhombic structure (space group Pnma). The studied samples were also characterized by complex impedance spectroscopy in a wide range of temperatures and frequency. AC conductivity analyses are used to study the transport property of the investigated samples. These analyses indicate that the conduction mechanism is strongly dependent on temperature and frequency. It is also found that the conductivity decreases with Cr concentration. Complex impedance analysis confirms the contributions of grain and grain boundaries in the conduction mechanism. Finally, the impedance spectra, characterized by the appearance of semicircle arcs at different temperatures, were well modeled in terms of equivalent electrical circuits to explain the impedance results. In the present research, polycrystalline samples of La0.5Sm0.2Sr0.3Mn1−xCrxO3 are prepared using the self-combustion method.![]()
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Affiliation(s)
| | - F Hassini
- Research Unit of Valorization and Optimization of Exploitation of Resources, Faculty of Science and Technology of Sidi Bouzid, Kairouan University 9100 Sidi Bouzid Tunisia.,Laboratory of Physical Chemistry of Materials, Physics Department, Faculty of Sciences of Monastir, Monastir University 5019 Monastir Tunisia
| | - W Cherif
- Sfax University, Faculty of Sciences B. P. 1171 3000 Tunisia
| | - P R Prezas
- I3N - University of Aveiro Aveiro Portugal
| | | | - M A Valent
- I3N - University of Aveiro Aveiro Portugal
| | - O Messaoudi
- Physics Department, College of Sciences, University of Ha'il Saudi Arabia
| | - S Elgharbi
- Department of Chemistry, College of Science, University of Hail Ha'il Kingdom of Saudi Arabia
| | - Ahmed Dhahri
- Department of Physics, College of Science and Humanities - Dawadmi, Shaqra University Riyadh Saudi Arabia
| | - L Manai
- Physics Department, College of Sciences, University of Ha'il Saudi Arabia
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Marouani Y, Massoudi J, Noumi M, Benali A, Dhahri E, Sanguino P, Graça MPF, Valente MA, Costa BFO. Electrical conductivity and dielectric properties of Sr doped M-type barium hexaferrite BaFe 12O 19. RSC Adv 2021; 11:1531-1542. [PMID: 35424123 PMCID: PMC8693603 DOI: 10.1039/d0ra09465j] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 12/15/2020] [Indexed: 11/30/2022] Open
Abstract
The hexaferrite Ba1-x Sr x Fe12O19 compounds with x = 0, 0.5 and 1 were synthesized by the autocombustion method. X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM) were used for structural and morphological studies.
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Affiliation(s)
- Y Marouani
- University of Coimbra, CFisUC, Physics Department 3004-516 Coimbra Portugal
- Laboratoire de Physique Appliquée, Faculté des Sciences, Université de Sfax 3000 Tunisia
| | - J Massoudi
- Laboratoire de Physique Appliquée, Faculté des Sciences, Université de Sfax 3000 Tunisia
| | - M Noumi
- Laboratoire de Physique Appliquée, Faculté des Sciences, Université de Sfax 3000 Tunisia
| | - A Benali
- University of Coimbra, CFisUC, Physics Department 3004-516 Coimbra Portugal
- Laboratoire de Physique Appliquée, Faculté des Sciences, Université de Sfax 3000 Tunisia
- I3N, PhysicsDepartment, Universityof Aveiro 3810-193 Portugal
| | - E Dhahri
- Laboratoire de Physique Appliquée, Faculté des Sciences, Université de Sfax 3000 Tunisia
| | - P Sanguino
- University of Coimbra, CEMMPRE, Mechanical Engineering Department 3030-788 Coimbra Portugal
| | - M P F Graça
- I3N, PhysicsDepartment, Universityof Aveiro 3810-193 Portugal
| | - M A Valente
- I3N, PhysicsDepartment, Universityof Aveiro 3810-193 Portugal
| | - B F O Costa
- University of Coimbra, CFisUC, Physics Department 3004-516 Coimbra Portugal
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Pavani K, Suresh Kumar J, Srikanth K, Soares MJ, Pereira E, Neves AJ, Graça MPF. Highly efficient upconversion of Er 3+ in Yb 3+ codoped non-cytotoxic strontium lanthanum aluminate phosphor for low temperature sensors. Sci Rep 2017; 7:17646. [PMID: 29247223 PMCID: PMC5732271 DOI: 10.1038/s41598-017-17725-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 11/21/2017] [Indexed: 11/15/2022] Open
Abstract
Er3+ and Er3+/Yb3+ melilite-based SrLaAl3O7 (SLA) phosphors were synthesized by a facile Pechine method. The differences in emission intensities of 4I13/2 → 4I15/2 transition in NIR region when excited with Ar+ and 980 nm lasers were explained in terms of energy transfer mechanisms. Temperature and power dependence of upconversion bands in the visible region centered at 528, 548 and 660 nm pertaining to 2H11/2, 4S3/2 and 4F9/2 → 4I15/2 transitions were investigated. Fluorescence intensity ratio (FIR) technique was used to explore temperature sensing behaviour of the thermally coupled levels 2H11/2/4S3/2 of Er3+ ions in the phosphors within the temperature range 14–300 K and the results were extrapolated up to 600 K. Anomalous intensity trend observed in Er3+ doped SLA phosphor was discussed using energy level structure. Cytotoxicity of phosphors has been evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in Bluegill sunfish cells (BF-2). The non-cytotoxic nature and high sensitivity of the present phosphors pay a way for their use in vitro studies and provide potential interest as a thermo graphic phosphor at the contact of biological products.
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Affiliation(s)
- K Pavani
- Department of Physics & I3N, University of Aveiro, 3810-193, Aveiro, Portugal.
| | - J Suresh Kumar
- Department of Physics & I3N, University of Aveiro, 3810-193, Aveiro, Portugal
| | - K Srikanth
- CESAM-Centre for Environmental and Marine Studies & Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal
| | - M J Soares
- Department of Physics & I3N, University of Aveiro, 3810-193, Aveiro, Portugal
| | - E Pereira
- CESAM-Centre for Environmental and Marine Studies & Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal
| | - A J Neves
- Department of Physics & I3N, University of Aveiro, 3810-193, Aveiro, Portugal
| | - M P F Graça
- Department of Physics & I3N, University of Aveiro, 3810-193, Aveiro, Portugal
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Graça MPF, Nico C, Peres M, Valente MA, Monteiro T. Study of the optical and dielectric properties of TiO2 nanocrystals prepared by the Pechini method. J Nanosci Nanotechnol 2012; 12:8600-8606. [PMID: 23421250 DOI: 10.1166/jnn.2012.6819] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Titanium oxide nanocrystals synthesized by the Pechini method were calcinated at temperatures between 300 and 1000 degrees C. The crystalline structure was analysed by X-ray diffraction, scanning electron microscopy (SEM) and Raman spectroscopy. A phase transition from the anatase to rutile crystalline phase was found to occur at temperatures near 500 degrees C. The samples were characterized by photoluminescence (PL) and dielectric spectroscopy. The influence of the calcination temperature on the visible and near infrared luminescence is discussed. A correlation between the structural properties, luminescence and dielectric properties are discussed.
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Affiliation(s)
- M P F Graça
- Departamento de Física e 13N, Universidade de Aveiro, 3810-193 Aveiro, Portugal
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