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Akrout M, Ben Difallah B, Kharrat M, Dammak M, Pereira A, Oliveira FJ, Duarte I. On the Structural, Thermal, Micromechanical and Tribological Characterizations of Cu-Filled Acrylonitrile Butadiene Styrene Micro-Composites. Materials (Basel) 2023; 16:6428. [PMID: 37834565 PMCID: PMC10573974 DOI: 10.3390/ma16196428] [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] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 09/17/2023] [Accepted: 09/25/2023] [Indexed: 10/15/2023]
Abstract
The purpose of this work was to investigate the structural, thermal, micromechanical and tribological properties of novel polymer/metal composite materials for bearing applications. Copper (Cu)-filled Acrylonitrile Butadiene Styrene (ABS) composites were mixed in a laboratory scale by an internal mixer with two blade impellers, and then injection-molded. Neat ABS, ABS+5wt% Cu, ABS+10wt% Cu, and ABS+15wt% Cu were the four materials that were tested. The dispersion of Cu particles in the ABS matrix was investigated using Scanning Electron Microscopy (SEM) and a micro-tomography scan. The filler particles have a uniform distribution in the matrix, according to the observations. The incorporation of Cu filler also refined an increase in the glass transition temperature from Differential Scanning Calorimetry (DSC) and less intensity in the amorphous phase by X-ray diffraction (XRD). Nanoindentation tests were carried out to characterize the micro-mechanical behavior of the composites. Friction and wear analysis were also examined using a pin-on-disk tribometer. Compared with neat ABS, all the micro-composites showed much higher indentation hardness, Vickers hardness, and indentation elastic modulus. It was also concluded that the incorporation of Cu filler into ABS simultaneously improved the friction and wear properties of the composites, which contributed to the suitability of the micro-filled composites with hard metallic particles for a wider range of mechanical components for bearing applications.
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Affiliation(s)
- Mabrouka Akrout
- Laboratory of Electromechanical Systems, National School of Engineers of Sfax, University of Sfax, Soukra Road, Km 3.5, PO Box 1173, Sfax 3038, Tunisia; (M.A.); (B.B.D.); (M.D.)
| | - Basma Ben Difallah
- Laboratory of Electromechanical Systems, National School of Engineers of Sfax, University of Sfax, Soukra Road, Km 3.5, PO Box 1173, Sfax 3038, Tunisia; (M.A.); (B.B.D.); (M.D.)
| | - Mohamed Kharrat
- Laboratory of Electromechanical Systems, National School of Engineers of Sfax, University of Sfax, Soukra Road, Km 3.5, PO Box 1173, Sfax 3038, Tunisia; (M.A.); (B.B.D.); (M.D.)
| | - Maher Dammak
- Laboratory of Electromechanical Systems, National School of Engineers of Sfax, University of Sfax, Soukra Road, Km 3.5, PO Box 1173, Sfax 3038, Tunisia; (M.A.); (B.B.D.); (M.D.)
| | - António Pereira
- Department of Mechanical Engineering, Centre for Mechanical Technology and Automation (TEMA), University of Aveiro, 3810-193 Aveiro, Portugal; (A.P.); (I.D.)
- LASI—Intelligent Systems Associate Laboratory, 4800-058 Guimarães, Portugal
| | - Filipe J. Oliveira
- CICECO, Department of Materials Engineering and Ceramics, University of Aveiro, 3810-193 Aveiro, Portugal;
| | - Isabel Duarte
- Department of Mechanical Engineering, Centre for Mechanical Technology and Automation (TEMA), University of Aveiro, 3810-193 Aveiro, Portugal; (A.P.); (I.D.)
- LASI—Intelligent Systems Associate Laboratory, 4800-058 Guimarães, Portugal
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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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Sharma DK, Girão AV, Chapon P, Neto MA, Oliveira FJ, Silva RF. Advances in RF Glow Discharge Optical Emission Spectrometry Characterization of Intrinsic and Boron-Doped Diamond Coatings. ACS Appl Mater Interfaces 2022; 14:7405-7416. [PMID: 35077132 DOI: 10.1021/acsami.1c20785] [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] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Accurate determination of the effective doping range within diamond thin films is important for fine-tuning of electrical conductivity. Nevertheless, it is not easily attainable by the commonly adopted techniques. In this work, pulsed RF glow discharge optical emission spectrometry (GD-OES) combined with ultrafast sputtering (UFS) is applied for the first time to acquire elemental depth profiles of intrinsic diamond coatings and boron content bulk distribution in films. The GD-OES practical advances presented here enabled quick elemental profiling with noteworthy depth resolution and determination of the film interfaces. The erosion rates and layer thicknesses were measured using differential interferometric profiling (DIP), demonstrating a close correlation between the coating thickness and the carbon/hydrogen gas ratio. Moreover, DIP and the adopted semiquantification methodology revealed a nonhomogeneous bulk distribution of boron within the diamond crystalline structure, i.e., boron doping is both substitutional and interstitial within the diamond framework. DIP measurements also showed that effective boron doping is not linearly correlated to the increasing content introduced into the diamond coating. This is a finding well supported by X-ray diffraction (XRD) Rietveld refinement and X-ray photoelectron spectroscopy (XPS). This work demonstrates the advantage of applying advanced GD-OES operation modes due to its ease of use, affordability, accuracy, and high-speed depth profile analysis capability.
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Affiliation(s)
- Dhananjay K Sharma
- CICECO, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal
- Institute of Physics of the Czech Academy of Sciences, Cukrovarnicka 10, 16200 Prague, Czech Republic
- Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, 166 27 Prague 6, Czech Republic
| | - Ana V Girão
- CICECO, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal
| | | | - Miguel A Neto
- CICECO, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Filipe J Oliveira
- CICECO, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Rui F Silva
- CICECO, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal
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Neto MD, Stoppa A, Neto MA, Oliveira FJ, Gomes MC, Boccaccini AR, Levkin PA, Oliveira MB, Mano JF. Fabrication of Quasi-2D Shape-Tailored Microparticles using Wettability Contrast-Based Platforms. Adv Mater 2021; 33:e2007695. [PMID: 33644949 DOI: 10.1002/adma.202007695] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/04/2021] [Indexed: 06/12/2023]
Abstract
The ability to fabricate materials with ultrathin architectures enables the breakthrough of low-dimensional structures with high surface area that showcase distinctive properties from their bulk counterparts. They are exploited in a wide range of fields, including energy harvesting, catalysis, and biomedicine. Despite such versatility, the fine tuning of the lateral dimensions and geometry of these structures remains challenging. Prepatterned platforms gain significant attention as enabling technologies to process materials with highly controlled shapes and dimensions. Herein, different nanometer-thick particles of various lateral sizes and geometries (e.g., squares, circles, triangles, hexagons) are processed with high precision and definition, taking advantage of the wettability contrast of oleophilic-oleophobic patterned surfaces. Quasi-2D polymeric microparticles with high shape- and size-fidelity can be retrieved as freestanding objects in a single step. These structures show cell-mediated pliability, and their integration in gravity-enforced human adipose-derived stem cell spheroids leads to an enhanced metabolic activity and a modulated secretion of proangiogenic factors.
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Affiliation(s)
- Mafalda D Neto
- Department of Chemistry, CICECO - Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, Aveiro, 3810-193, Portugal
| | - Aukha Stoppa
- Department of Chemistry, CICECO - Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, Aveiro, 3810-193, Portugal
- Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Erlangen, 91058, Germany
| | - Miguel A Neto
- Department of Chemistry, CICECO - Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, Aveiro, 3810-193, Portugal
| | - Filipe J Oliveira
- Department of Chemistry, CICECO - Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, Aveiro, 3810-193, Portugal
| | - Maria C Gomes
- Department of Chemistry, CICECO - Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, Aveiro, 3810-193, Portugal
| | - Aldo R Boccaccini
- Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Erlangen, 91058, Germany
| | - Pavel A Levkin
- Karlsruhe Institute of Technology, Institute of Biological and Chemical Systems (IBCS-FMS), Hermann-von-Helmholtz Pl.1, Eggenstein-Leopoldshafen, 76344, Germany
| | - Mariana B Oliveira
- Department of Chemistry, CICECO - Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, Aveiro, 3810-193, Portugal
| | - João F Mano
- Department of Chemistry, CICECO - Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, Aveiro, 3810-193, Portugal
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Sevivas N, Teixeira FG, Portugal R, Direito-Santos B, Espregueira-Mendes J, Oliveira FJ, Silva RF, Sousa N, Sow WT, Nguyen LTH, Ng KW, Salgado AJ. Mesenchymal Stem Cell Secretome Improves Tendon Cell Viability In Vitro and Tendon-Bone Healing In Vivo When a Tissue Engineering Strategy Is Used in a Rat Model of Chronic Massive Rotator Cuff Tear. Am J Sports Med 2018; 46:449-459. [PMID: 29053925 DOI: 10.1177/0363546517735850] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Massive rotator cuff tears (MRCTs) represent a major clinical concern, especially when degeneration and chronicity are involved, which highly compromise healing capacity. PURPOSE To study the effect of the secretome of mesenchymal stem cells (MSCs) on tendon cells (TCs) followed by the combination of these activated TCs with an electrospun keratin-based scaffold to develop a tissue engineering strategy to improve tendon-bone interface (TBi) healing in a chronic MRCT rat model. STUDY DESIGN Controlled laboratory study. METHODS Human TCs (hTCs) cultured with the human MSCs (hMSCs) secretome (as conditioned media [CM]) were combined with keratin electrospun scaffolds and further implanted in a chronic MRCT rat model. Wistar-Han rats (N = 15) were randomly assigned to 1 of 3 groups: untreated lesion (MRCT group, n = 5), lesion treated with a scaffold only (scaffold-only group, n = 5), and lesion treated with a scaffold seeded with hTCs preconditioned with hMSCs-CM (STC_hMSC_CM group, n = 5). After sacrifice, 16 weeks after surgery, the rotator cuff TBi was harvested for histological analysis and biomechanical testing. RESULTS The hMSCs secretome increased hTCs viability and density in vitro. In vivo, a significant improvement of the tendon maturing score was observed in the STC_hMSC_CM group (mean ± standard error of the mean, 15.6 ± 1.08) compared with the MRCT group (11.0 ± 1.38; P < .05). Biomechanical tests revealed a significant increase in the total elongation to rupture (STC_hMSC_CM, 11.99 ± 3.30 mm; scaffold-only, 9.89 ± 3.47 mm; MRCT, 5.86 ± 3.16 mm; P < .05) as well as a lower stiffness (STC_hMSC_CM, 6.25 ± 1.74 N/mm; scaffold-only, 6.72 ± 1.28 N/mm; MRCT, 11.54 ± 2.99 N/mm; P < .01). CONCLUSION The results demonstrated that hMSCs-CM increased hTCs viability and density in vitro. Clear benefits also were observed when these primed cells were integrated into a tissue engineering strategy with an electrospun keratin scaffold, as evidenced by improved histological and biomechanical properties for the STC_hMSC_CM group compared with the MRCT group. CLINICAL RELEVANCE This work supports further investigation into the use of MSC secretome for priming TCs toward a more differentiated phenotype, and it promotes the tissue engineering strategy as a promising modality to help improve treatment outcomes for chronic MRCTs.
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Affiliation(s)
- Nuno Sevivas
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal.,Orthopaedics Department, Hospital de Braga and Hospital Privado de Braga, Braga, Portugal.,Clínica Espregueira-Mendes, FIFA Medical Centre of Excellence, Estádio do Dragão, Porto, Portugal
| | - Fábio Gabriel Teixeira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | | | - Bruno Direito-Santos
- Orthopaedics Department, Hospital de Braga and Hospital Privado de Braga, Braga, Portugal
| | - João Espregueira-Mendes
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal.,Clínica Espregueira-Mendes, FIFA Medical Centre of Excellence, Estádio do Dragão, Porto, Portugal.,3B's Research Group, Biomaterials, Biodegradables and Biomimetics, Department of Polymer Engineering, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Guimarães, Portugal
| | - Filipe J Oliveira
- CICECO, Department of Materials and Ceramic Engineering, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
| | - Rui F Silva
- CICECO, Department of Materials and Ceramic Engineering, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Wan Ting Sow
- School of Materials Science and Engineering, Nanyang Technological University, Singapore
| | - Luong T H Nguyen
- School of Materials Science and Engineering, Nanyang Technological University, Singapore
| | - Kee Woei Ng
- School of Materials Science and Engineering, Nanyang Technological University, Singapore
| | - António J Salgado
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
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Silva EL, Gouvêa CP, Quevedo MC, Neto MA, Archanjo BS, Fernandes AJS, Achete CA, Silva RF, Zheludkevich ML, Oliveira FJ. All-Diamond Microelectrodes as Solid State Probes for Localized Electrochemical Sensing. Anal Chem 2015; 87:6487-92. [DOI: 10.1021/acs.analchem.5b00756] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Eduardo L. Silva
- CICECO
− Aveiro Institute of Materials, Department of Materials and
Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Cristol P. Gouvêa
- Materials
Metrology Division, INMETRO, 25250-020, Duque
de Caxias, Rio de Janeiro, Brazil
| | - Marcela C. Quevedo
- CICECO
− Aveiro Institute of Materials, Department of Materials and
Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Miguel A. Neto
- CICECO
− Aveiro Institute of Materials, Department of Materials and
Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Braulio S. Archanjo
- Materials
Metrology Division, INMETRO, 25250-020, Duque
de Caxias, Rio de Janeiro, Brazil
| | | | - Carlos A. Achete
- Materials
Metrology Division, INMETRO, 25250-020, Duque
de Caxias, Rio de Janeiro, Brazil
| | - Rui F. Silva
- CICECO
− Aveiro Institute of Materials, Department of Materials and
Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Mikhail L. Zheludkevich
- CICECO
− Aveiro Institute of Materials, Department of Materials and
Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal
- MagIC, Institute
of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck Str. 1, 21502 Geesthacht, Germany
| | - Filipe J. Oliveira
- CICECO
− Aveiro Institute of Materials, Department of Materials and
Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal
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Gonçalves EM, Oliveira FJ, Silva RF, Neto MA, Fernandes MH, Amaral M, Vallet-Regí M, Vila M. Three-dimensional printed PCL-hydroxyapatite scaffolds filled with CNTs for bone cell growth stimulation. J Biomed Mater Res B Appl Biomater 2015; 104:1210-9. [PMID: 26089195 DOI: 10.1002/jbm.b.33432] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [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: 10/10/2014] [Revised: 01/12/2015] [Accepted: 03/30/2015] [Indexed: 11/09/2022]
Abstract
A three-phase [nanocrystalline hydroxyapatite (HA), carbon nanotubes (CNT), mixed in a polymeric matrix of polycaprolactone (PCL)] composite scaffold produced by 3D printing is presented. The CNT content varied between 0 and 10 wt % in a 50 wt % PCL matrix, with HA being the balance. With the combination of three well-known materials, these scaffolds aimed at bringing together the properties of all into a unique material to be used in tissue engineering as support for cell growth. The 3D printing technique allows producing composite scaffolds having an interconnected network of square pores in the range of 450-700 μm. The 2 wt % CNT scaffold offers the best combination of mechanical behaviour and electrical conductivity. Its compressive strength of ∼4 MPa is compatible with the trabecular bone. The composites show typical hydroxyapatite bioactivity, good cell adhesion and spreading at the scaffolds surface, this combination of properties indicating that the produced 3D, three-phase, scaffolds are promising materials in the field of bone regenerative medicine. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1210-1219, 2016.
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Affiliation(s)
- Elsa M Gonçalves
- CICECO, Materials and Ceramic Engineering Department, University of Aveiro, Campus de Santiago, 3810-193, Portugal
| | - Filipe J Oliveira
- CICECO, Materials and Ceramic Engineering Department, University of Aveiro, Campus de Santiago, 3810-193, Portugal
| | - Rui F Silva
- CICECO, Materials and Ceramic Engineering Department, University of Aveiro, Campus de Santiago, 3810-193, Portugal
| | - Miguel A Neto
- CICECO, Materials and Ceramic Engineering Department, University of Aveiro, Campus de Santiago, 3810-193, Portugal
| | - M Helena Fernandes
- Fac. Medicina Dentária, Laboratory for Bone Metabolism and Regeneration, Univ. do Porto, Portugal
| | - Margarida Amaral
- CICECO, Materials and Ceramic Engineering Department, University of Aveiro, Campus de Santiago, 3810-193, Portugal
| | - María Vallet-Regí
- Facultad de Farmacia, Departamento de Química Inorgánica y Bioinorgánica, Universidad Complutense de Madrid. Plaza de Ramón y Cajal s/n, 28040, Madrid, Spain
| | - Mercedes Vila
- Facultad de Farmacia, Departamento de Química Inorgánica y Bioinorgánica, Universidad Complutense de Madrid. Plaza de Ramón y Cajal s/n, 28040, Madrid, Spain.,TEMA-NRD, Mechanical Engineering Department, University of Aveiro, 3810-193, Portugal
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Mata D, Oliveira FJ, Neto MA, Belmonte M, Bastos AC, Lopes MA, Gomes PS, Fernandes MH, Silva RF. Smart electroconductive bioactive ceramics to promote in situ electrostimulation of bone. J Mater Chem B 2015; 3:1831-1845. [PMID: 32262256 DOI: 10.1039/c4tb01628a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Biomaterials can still be reinvented to become simple and universal bone regeneration solutions. Following this roadmap, conductive CNT-based "smart" materials accumulate exciting grafting qualities for tuning the in vitro cellular phenotype. Biphasic electrical stimulation of human osteoblastic cells was performed in vitro on either dielectric bioactive bone grafts or conductive CNT-reinforced composites. The efficiency of the electrical stimuli delivery, as well as the effect of stimulation on cellular functions were investigated. Conductive substrates boosted the local culture medium conductivity and the confinement of the exogenous electrical fields. Hence, bone cell proliferation, DNA content and mRNA expression were maximized on the conductive substrates yielding superior stimuli delivering efficiency over dielectric ones. These findings are suggestive that bioactive bone grafts with electrical conductivity are capable of high spatial and temporal control of bone cell stimulation.
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Affiliation(s)
- Diogo Mata
- CICECO, Materials and Ceramic Eng. Dept., Univ. of Aveiro, 3810-193 Aveiro, Portugal.
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Silva EL, Silva RF, Zheludkevich M, Oliveira FJ. Novel electrochemical method of fast and reproducible fabrication of metallic nanoelectrodes. Rev Sci Instrum 2014; 85:095109. [PMID: 25273774 DOI: 10.1063/1.4895639] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A novel electrochemical wire etching method of fabrication of ultrasharp nanoelectrodes is reported. Tungsten wires can be sharpened to less than 10 nm tip radius in a reproducible manner in less than 1 min by using controllable hydrodynamic electrolyte flow combined with optimized electrochemical etching parameters. The method relies on the variations of the electric field at the surface of a metal wire, while the electrolyte solution is in motion, rather than on the ionic gradient generated in a static solution.
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Affiliation(s)
- E L Silva
- CICECO - Department of Materials and Ceramics Engineering, University of Aveiro, Aveiro, Portugal
| | - R F Silva
- CICECO - Department of Materials and Ceramics Engineering, University of Aveiro, Aveiro, Portugal
| | - M Zheludkevich
- CICECO - Department of Materials and Ceramics Engineering, University of Aveiro, Aveiro, Portugal
| | - F J Oliveira
- CICECO - Department of Materials and Ceramics Engineering, University of Aveiro, Aveiro, Portugal
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Mata D, Oliveira FJ, Ferro M, Gomes PS, Fernandes MH, Lopes MA, Silval RF. Multifunctional carbon nanotube/bioceramics modulate the directional growth and activity of osteoblastic cells. J Biomed Nanotechnol 2014; 10:725-43. [PMID: 24734525 DOI: 10.1166/jbn.2014.1749] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Biomaterials can still be reinvented to become simple and universal bone regeneration solutions. Following this roadmap, a bone graft of carbon nanotube (CNT)/glass/hydroxyapatite (HA) with controlled CNT agglomeration state was designed with multifunctionalities able to stimulate the bone cell phenotype. The preparation route, the mechanical and electrical behavior and the in vitro profiles of degradation and osteocompatibility were described. A non-destructive dynamic route was found to have a higher influence than the Diels-Alder functionalization one on controlling the CNT agglomerate state in the ceramic-matrix composite. Biologically safe CNT agglomerates, with diameter sizes below 3 microm homogenously distributed, were obtained in non-functionalized and functionalized composites. Yet, the lowest CNT damage and the highest mechanical and electrical properties were found for the non-functionalized materials. Even though that these composites present higher degradation rate at pH:3 than the ceramic matrix, the CNT agglomerates are released with safe diameter sizes. Also, non-functionalized composites allowed cellular adhesion and modulated the orientation of the cell growth, with a proliferation/differentiation relationship favoring osteoblastic functional activity. Findings offer further contributions for bone tissue engineering by showing that multifunctional bone grafts with high electroconductivity, and integrating CNT agglomerates with maximized interfacing area, allow the in situ control of bone cell functions.
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Mata D, Oliveira FJ, Ferreira NM, Araújo RF, Fernandes AJS, Lopes MA, Gomes PS, Fernandes MH, Silva RF. Processing strategies for smart electroconductive carbon nanotube-based bioceramic bone grafts. Nanotechnology 2014; 25:145602. [PMID: 24622290 DOI: 10.1088/0957-4484/25/14/145602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Electroconductive bone grafts have been designed to control bone regeneration. Contrary to polymeric matrices, the translation of the carbon nanotube (CNT) electroconductivity into oxide ceramics is challenging due to the CNT oxidation during sintering. Sintering strategies involving reactive-bed pressureless sintering (RB + P) and hot-pressing (HP) were optimized towards prevention of CNT oxidation in glass/hydroxyapatite (HA) matrices. Both showed CNT retentions up to 80%, even at 1300 °C, yielding an increase of the electroconductivity in ten orders of magnitude relative to the matrix. The RB + P CNT compacts showed higher electroconductivity by ∼170% than the HP ones due to the lower damage to CNTs of the former route. Even so, highly reproducible conductivities with statistical variation below 5% and dense compacts up to 96% were only obtained by HP. The hot-pressed CNT compacts possessed no acute toxicity in a human osteoblastic cell line. A normal cellular adhesion and a marked orientation of the cell growth were observed over the CNT composites, with a proliferation/differentiation relationship favouring osteoblastic functional activity. These sintering strategies offer new insights into the sintering of electroconductive CNT containing bioactive ceramics with unlimited geometries for electrotherapy of the bone tissue.
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Affiliation(s)
- D Mata
- I3N, Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal
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12
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Almeida FA, Salgueiredo E, Oliveira FJ, Silva RF, Baptista DL, Peripolli SB, Achete CA. Interfaces in nano-/microcrystalline multigrade CVD diamond coatings. ACS Appl Mater Interfaces 2013; 5:11725-11729. [PMID: 24164667 DOI: 10.1021/am403401s] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The interfaces of multilayered CVD diamond films grown by the hot-filament technique were characterized with high detail using HRTEM, STEM-EDX, and EELS. The results show that at the transition from micro- (MCD) to nanocrystalline diamond (NCD), a thin precursor graphitic film is formed, irrespectively of the NCD gas chemistry used (with or without argon). On the contrary, the transition of the NCD to MCD grade is free of carbon structures other than diamond, the result of a higher substrate temperature and more abundant atomic H in the gas chemistry. At those transitions WC nanoparticles could be found due to contamination from the filament, being also present at the first interface of the MCD layer with the silicon nitride substrate.
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Affiliation(s)
- Flávia A Almeida
- Department of Materials and Ceramic Engineering, CICECO, University of Aveiro , 3810-193 Aveiro, Portugal
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13
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Rodrigues SP, Paiva JM, De Francesco S, Amaral MI, Oliveira FJ, Silva RF. Artifact level produced by different femoral head prostheses in CT imaging: diamond coated silicon nitride as total hip replacement material. J Mater Sci Mater Med 2013; 24:231-239. [PMID: 23053807 DOI: 10.1007/s10856-012-4778-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 09/25/2012] [Indexed: 06/01/2023]
Abstract
Commercial femoral head prostheses (cobalt-chromium alloy, yttria partially stabilized zirconia (Y-PSZ) and alumina) and new silicon nitride ceramic ones (nanocrystalline diamond coated and uncoated) were compared in terms of artifact level production by computed tomography (CT). Pelvis examination by CT allows the correct diagnosis of some pathologies (e.g. prostate and colon cancer) and the evaluation of the prosthesis-bone interface in post-operative joint surgery. Artifact quantification is rarely seen in literature despite having a great potential to grade biomaterials according to their imaging properties. Materials' characteristics (density and effective atomic number), size and geometry of the prostheses can cause more or less artifact. A quantification procedure based on the calculation of four statistical parameters for the Hounsfield pixel values (mean, standard deviation, mean squared error and worst case error) is presented. CT sequential and helical scanning modes were performed. Results prove the artifact reproducibility and indicate that the cobalt-chromium and Y-PSZ are the most artifact-inducing materials, while alumina and silicon nitride (diamond coated and uncoated) ceramic ones present a low level of artifact. Considering the excellent biocompatibility and biotribological behaviour reported in earlier works, combined with the high medical imaging quality here assessed, diamond coated silicon nitride ceramics are arising as new materials for joint replacement.
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Affiliation(s)
- Simone P Rodrigues
- CICECO, Department of Ceramics and Glass Engineering, University of Aveiro, Aveiro, Portugal.
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14
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Bernardes A, Manata F, Rosenvinge C, Coutinho L, Marinho C, Oliveira FJ. Spontaneous rupture of a hepatic sarcoma in an adult resembling hydatid cyst. Rev Esp Enferm Dig 2009; 101:584-5. [PMID: 19785501 DOI: 10.4321/s1130-01082009000800013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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15
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Silva FG, Neto MA, Fernandes AJS, Costa FM, Oliveira FJ, Silva RF. Adhesion and wear behaviour of NCD coatings on Si3N4 by micro-abrasion tests. J Nanosci Nanotechnol 2009; 9:3938-3943. [PMID: 19504945 DOI: 10.1166/jnn.2009.ns93] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Nanocrystalline diamond (NCD) coatings offer an excellent alternative for tribological applications, preserving most of the intrinsic mechanical properties of polycrystalline CVD diamond and adding to it an extreme surface smoothness. Silicon nitride (Si3N4) ceramics are reported to guarantee high adhesion levels to CVD microcrystalline diamond coatings, but the NCD adhesion to Si3N4 is not yet well established. Micro-abrasion tests are appropriate for evaluating the abrasive wear resistance of a given surface, but they also provide information on thin film/substrate interfacial resistance, i.e., film adhesion. In this study, a comparison is made between the behaviour of NCD films deposited by hot-filament chemical vapour deposition (HFCVD) and microwave plasma assisted chemical vapour deposition (MPCVD) techniques. Silicon nitride (Si3N4) ceramic discs were selected as substrates. The NCD depositions by HFCVD and MPCVD were carried out using H2-CH4 and H2-CH4-N2 gas mixtures, respectively. An adequate set of growth parameters was chosen for each CVD technique, resulting in NCD films having a final thickness of 5 microm. A micro-abrasion tribometer was used, with 3 microm diamond grit as the abrasive slurry element. Experiments were carried out at a constant rotational speed (80 r.p.m.) and by varying the applied load in the range of 0.25-0.75 N. The wear rate for MPCVD NCD (3.7 +/- 0.8 x 10(-5) mm3 N(-1) m(-1)) is compatible with those reported for microcrystalline CVD diamond. The HFCVD films displayed poorer adhesion to the Si3N4 ceramic substrates than the MPCVD ones. However, the HFCVD films show better wear resistance as a result of their higher crystallinity according to the UV Raman data, despite evidencing premature adhesion failure.
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Affiliation(s)
- F G Silva
- Mechanical Engineering Department, Porto Superior Engineering Institute, ISEP 4200-072 Porto, Portugal
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16
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Perdigoto R, Sequeira C, Tomé L, Ferrão J, Silva N, Geraldes J, Furtado E, Oliveira FJ. Sirolimus: efficacy in liver transplant patients with nephrotoxicity and renal insufficiency. Transplant Proc 2007; 39:2519-21. [PMID: 17954163 DOI: 10.1016/j.transproceed.2007.07.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Nephrotoxicity is a complication of patients undergoing orthotopic liver transplantation. Herein we present several factors that play an important role in this complication.
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Affiliation(s)
- R Perdigoto
- Liver Transplantation Unit, Coimbra University Hospital, 3000-075 Coimbra, Portugal.
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17
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Rivas Chirino L, da Silva Viana J, Tavares CA, Palmeiro A, Oliveira FJ. Use of a Blood Gas Analyzer to Measure Blood Hemoglobin During Liver Transplantation: A Study of 935 Paired Samples. Transplant Proc 2006; 38:810-1. [PMID: 16647478 DOI: 10.1016/j.transproceed.2006.01.051] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- L Rivas Chirino
- Faculty of Medicine, University of Coimbra and University Hospitals of Coimbra, Coimbra, Portugal.
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18
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Perdigoto R, Furtado AL, Furtado E, Oliveira FJ, Geraldes B, Mota O, Ferrāo J, Tome L, Viana J. The Coimbra University Hospital experience in liver transplantation in patients with familial amyloidotic polyneuropathy. Transplant Proc 2003; 35:1125. [PMID: 12947884 DOI: 10.1016/s0041-1345(03)00334-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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19
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Srivastava RM, Oliveira FJ, da Silva LP, de Freitas Filho JR, Oliveira SP, Lima VL. Synthesis and hypolipidemic activity of N-phthalimidomethyl tetra-O-acyl-α-d-mannopyranosides. Carbohydr Res 2001; 332:335-40. [PMID: 11376613 DOI: 10.1016/s0008-6215(01)00088-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A facile synthesis of anomerically pure phthalimidomethyl 2,3,4,6-tetra-O-acetyl- and phthalimidomethyl 2,3-di-O-acetyl-4,6-di-O-benzoyl-alpha-D-mannopyranosides (6 and 9b) starting from N-hydroxymethylphthalimide and tri-O-acetyl-D-glucal is described. Compounds 3, 6, 8, 9a and 9b have been tested for their hypolipidemic activity in mice. All these compound showed significant reduction of plasma cholesterol and triglyceride levels. Compound 9b has been found to possess the highest activity.
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Affiliation(s)
- R M Srivastava
- Departamento de Química Fundamental, Universidade Federal de Pernambuco, Cidade Universitária, 50.740-540, PE, Recife, Brazil.
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Paiva A, Pereira SV, Ballesteros R, Freitas A, Perdigoto R, Mota O, Ferrão J, Tomé L, Furtado E, Cipriano MA, Geraldes B, Oliveira FJ, Furtado AL, Regateiro FJ. Cytokine-producing T lymphocytes as a marker of prognosis and rejection episodes in orthotopic liver transplantation. Transplant Proc 2001; 33:1528-30. [PMID: 11267409 DOI: 10.1016/s0041-1345(00)02584-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- A Paiva
- Histocompatibility Centre, Coimbra University Hospital, Coimbra, Portugal
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21
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Abstract
Oxidative stress as a mediator of hepatic tissue damage concurrent with Leishmania (L.) chagasi infection was investigated. Chemiluminescence in liver supernatant of hamsters infected with Leishmania (L.) chagasi showed a ratio of 1.53/ mg protein and 2.10/liver weight 90 days after infection when compared with the control. The malondialdehyde (MDA) levels also increased significantly both with and without addition of Fe3+/ascorbic acid in the reaction mixture, with a ratio of 2.12 and 1.55/mg protein or 2.91 and 2.12/liver weight, respectively. The parasite burden in the spleen, as a measure of infection severity, was 9.1+/-1.33 x 10(8) parasites/organ. On the 10th day of infection, the chemiluminescence also was significantly higher in infected hamsters than in the controls (ratio = 1.36/mg protein or 1.34/liver weight); however, the MDA levels were not different from those of controls. After 90 days of infection, significant correlations were observed between chemiluminescence and MDA concentration with and without the presence of Fe3+/ascorbic acid (r = 0.54, P = 0.0001; r = 0.56, P = 0.0001; respectively). The high infection/control ratio of both chemiluminescence and MDA concentration and the significant correlation between those events strongly indicate the occurrence of oxidative stress and lipid peroxidation as a mechanism of liver damage in cases of chronic infection by L. chagasi. The significant increase in chemiluminescence at 10 days of infection demonstrates that oxidative stress occurs very early, first consuming the antioxidants and then inducing lipid peroxidative damage later in the chronic stage of this disease.
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Affiliation(s)
- F J Oliveira
- Department of Pathological Science, University of Londrina, Parana, Brasil
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22
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Perdigoto R, Paiva A, Freitas A, Coimbra HB, Mota O, Ferrão J, Tomé L, Furtado E, Cipriano MA, Geraldes B, Oliveira FJ, Furtado AL. Peripheral blood lymphocyte phenotype can predict rejection episodes after orthotopic liver transplantation. Transplant Proc 1999; 31:2418-20. [PMID: 10500650 DOI: 10.1016/s0041-1345(99)00457-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- R Perdigoto
- Liver Transplant Unit, Coimbra University Hospital, Portugal
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23
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Oliveira FJ, Ferrao H, Furtado E, Batista H, Santos MS. Total gastrectomy for gastric adenocarcinoma. Analysis of 115 consecutive patients. Hepatogastroenterology 1999; 46:2044-7. [PMID: 10430395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
BACKGROUND/AIMS There was a tendency to use more extensive operations for the treatment of gastric cancer during the last decade particularly in Europe. This retrospective study was carried out to review our recent experience with total gastrectomy for gastric adenocarcinoma. METHODOLOGY One hundred and fifteen patients treated for gastric cancer by total gastrectomy from 1987 to 1996 were analyzed. At the time of surgery 22.3% of patients were older than 70 years of age. RESULTS Fifty eight cancers (50.4%) were located in the distal third of the stomach, forty-seven (41%) were smaller than 6 cm and seventy-one (61.7%) were of the diffuse type. In 74.9% the tumor had penetrated through the serosa. The mortality and morbidity rates were 6.1% and 35.1% respectively. Age was a major determining factor with respect to hospital mortality and post-operative complications. CONCLUSIONS Irrespective of personal attitudes, gastrectomy does not have to be total to be curative, and many total gastrectomies performed in Western countries with "curative intent" are noncurative procedures. Nevertheless, to achieve a curative oncologic resection, total gastrectomy is required with growing frequency.
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Affiliation(s)
- F J Oliveira
- IInd Department of Surgery, University Hospital of Coimbra, Portugal
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24
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Oliveira FJ, Furtado E, Ferrao H, Conceicao L, Baptista H. Total gastrectomy for gastric cancer in elderly patients. Hepatogastroenterology 1999; 46:616-9. [PMID: 10228870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
BACKGROUND/AIMS The increased average life expectancy and the changing patterns in gastric carcinoma have resulted in a considerable rise in the number of older patients requiring total gastrectomy. Results of total gastrectomy for gastric cancer in elderly patients are presented. METHODOLOGY Between January 1987 and December 1996, 115 patients underwent total gastrectomy for gastric adenocarcinoma. At the time of surgery, 25 (21.8%) patients were older than 70 years. The results achieved in these patients were compared with those observed in 90 younger ones. RESULTS The hospital mortality and morbidity rates for the elderly patients were 16% and 56%, respectively; for the younger ones they were 3.3% and 30%, respectively. No difference was seen between the two age groups concerning the average post-operative hospital stay. CONCLUSIONS In our series, age was a major determinant with respect to post-operative morbidity and mortality. However, age alone could not be clearly defined as a determining risk factor considering that the accompanying illness and preexisting factors predispose for poor prognosis.
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Affiliation(s)
- F J Oliveira
- Second Department of Surgery, University Hospital of Coimbra, Portugal
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25
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Affiliation(s)
- A Furtado
- Servico Urologia e Transplantacao, Hospitais da Universidade de Coimbra, Portugal
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26
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Lopes J, da Silva MA, Borsato AM, de Oliveira VD, Oliveira FJ. [Aedes (Stegomyia) aegypti L. and associated culicidae fauna in a urban area of southern Brazil]. Rev Saude Publica 1993; 27:326-33. [PMID: 8209165 DOI: 10.1590/s0034-89101993000500002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Some aspects of the ecology of eleven species of Culicidae that were found breeding in recipients in an urban area of Southern Brazil are presented. A great variety of recipients were listed as efficient breeding sites. Apparently Aedes aegypti has been recently introduced into the region and was limited to two areas of the city. Culex quinquefasciatus, Cx. coronator, Ae. aegypti, Ae. fluviatilis e Limatus durhamii were the predominant species.
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Affiliation(s)
- J Lopes
- Departamento de Biologia Animal e Vegetal, Universidade Estadual de Londrina, PR, Brasil
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27
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Oliveira F, Oliveira FJ, Martins MI, Martinho F, Campos JM, Silveira JM. [Gastric leiomyoblastoma. Apropos of 4 cases]. Acta Gastroenterol Belg 1986; 49:609-16. [PMID: 3661072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Abstract
On 9 April 1984, commercial airlines enroute from Tokyo, Japan, to Anchorage, Alaska, reported an unusual mushroom-shaped cloud at about 38.5 degrees N, 146.0 degrees E. On 8 and 9 April the intensity of volcanism from Kaitoku Seamount (26.0 degrees N, 140.8 degrees E), as indicated by T-phase recordings on an array of ocean bottom hydrophones, reached a maximum level and then declined rapidly. An examination was made of the possible relation of the cloud to eruptions of Kaitoku through an analysis of pilot depositions, satellite photos, wind charts, signal strengths and spectra of known man-made underwater explosions, as well as ascent rates of volcanic plumes and cumulonimbus clouds.
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de Oliveira F, Oliveira FJ. Congenital posterolateral diaphragmatic hernia in the adult. Can J Surg 1984; 27:610-1. [PMID: 6498658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Bochdalek's hernia, congenital posterolateral diaphragmatic hernia, is common in children but rarely occurs in adults. The authors report two such adult cases. One of the hernias was on the left and the other on the right. Both patients had gastrointestinal symptoms. The approach was abdominal in one and thoracoabdominal in the other. There were no operative or postoperative complications. The possibility of congenital posterolateral diaphragmatic hernia must be considered in the differential diagnosis of patients who have recurrent gastrointestinal and respiratory complaints. A complete roentgenologic examination is necessary in order to make an accurate diagnosis preoperatively. Because of the danger of strangulation of the hernia, operation should be carried out as soon as the diagnosis is made.
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30
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Oliveira FJ, Conçalves O, Santos JD, Martinho F, Oliveira F. [Perforations of the small intestine in closed injuries of the abdomen. Apropos of 63 cases]. J Chir (Paris) 1984; 121:97-100. [PMID: 6715446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The records of 63 patients with small bowel perforation after blunt abdominal trauma admitted to the Department of Surgical Pathology, University Hospital of Coimbra, from 1965 to 1981, have been reviewed to establish patterns of injury and to discuss their pathogenesis and operative management. The authors believe that injuries to the small intestine following blunt abdominal trauma are more common than is generally appreciated. Proper treatment is frequently delayed because these injuries are not recognized promptly. Factors contributing to this delay are the trivial nature of some of the responsible accidents and the often negative results of diagnostic aids.
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Maigne C, Oliveira FJ, Fourtanier G, Fournier D, Manelfe A, Escat J. [Surgery of biliary lithiasis in patients over 75 years of age. Apropos of 139 cases]. Sem Hop 1983; 59:1323-6. [PMID: 6306813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The authors report the results of the surgical removal of bilestones in 139 patients over 75 years of age, taken from a series of 1 179 cases. The low mortality (4.3%) and morbidity rates are due to a non-aggressive protocol, especially in the treatment of choledocholithiasis. They conclude that advanced age does not necessarily imply a need for systematic alteration of the therapeutic approach.
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Maigne C, Oliveira FJ, Fourtanier G, Fournier D, Manelfe A, Escat J. [Surgery of biliary lithiasis in subjects over 75 years of age. Apropos of 139 cases]. Ann Chir 1983; 37:8-11. [PMID: 6847105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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33
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de Oliveira F, Oliveira FJ, Queirós A. Traumatic diaphragmatic hernias: a report of 19 cases. Can J Surg 1982; 25:658-9, 662. [PMID: 7139422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
From an analysis of 19 patients with traumatic diaphragmatic hernias with respect to the type of injury, associated injuries, clinical and radiologic features, diagnosis, surgical management and causes of death and from a review of the literature, the authors draw a number of conclusions. 1. Careful clinical examination coupled with an accurate interpretation of the roentgenograms should detect most cases of traumatic rupture of the diaphragm. 2. Impairment of respiratory function, possibility of strangulation and incarceration of the abdominal viscera demand early repair. 3. The choice of incision and approach depends on the stage at which the rupture is recognized (early or late), the site of rupture and the associated injuries. 4. Careful assessment of respiratory function should be made in order to prevent postoperative complications; in some cases respiration must be assisted. 5. Although the mortality in patients with traumatic diaphragmatic rupture is still relatively high, the deaths sould not be related to the rupture per se, or to its repair, but rather to the associated injuries.
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