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Sakharova NA, Antunes JM, Pereira AFG, Chaparro BM, Parreira TG, Fernandes JV. Numerical Evaluation of the Elastic Moduli of AlN and GaN Nanosheets. Materials (Basel) 2024; 17:799. [PMID: 38399050 PMCID: PMC10890007 DOI: 10.3390/ma17040799] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 02/02/2024] [Accepted: 02/05/2024] [Indexed: 02/25/2024]
Abstract
Two-dimensional (2D) nanostructures of aluminum nitride (AlN) and gallium nitride (GaN), called nanosheets, have a graphene-like atomic arrangement and represent novel materials with important upcoming applications in the fields of flexible electronics, optoelectronics, and strain engineering, among others. Knowledge of their mechanical behavior is key to the correct design and enhanced functioning of advanced 2D devices and systems based on aluminum nitride and gallium nitride nanosheets. With this background, the surface Young's and shear moduli of AlN and GaN nanosheets over a wide range of aspect ratios were assessed using the nanoscale continuum model (NCM), also known as the molecular structural mechanics (MSM) approach. The NCM/MSM approach uses elastic beam elements to represent interatomic bonds and allows the elastic moduli of nanosheets to be evaluated in a simple way. The surface Young's and shear moduli calculated in the current study contribute to building a reference for the evaluation of the elastic moduli of AlN and GaN nanosheets using the theoretical method. The results show that an analytical methodology can be used to assess the Young's and shear moduli of aluminum nitride and gallium nitride nanosheets without the need for numerical simulation. An exploratory study was performed to adjust the input parameters of the numerical simulation, which led to good agreement with the results of elastic moduli available in the literature. The limitations of this method are also discussed.
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Affiliation(s)
- Nataliya A. Sakharova
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE)—Advanced Production and Intelligent Systems, Associated Laboratory (ARISE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.M.A.); (A.F.G.P.); (T.G.P.); (J.V.F.)
| | - Jorge M. Antunes
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE)—Advanced Production and Intelligent Systems, Associated Laboratory (ARISE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.M.A.); (A.F.G.P.); (T.G.P.); (J.V.F.)
- Abrantes High School of Technology, Polytechnic Institute of Tomar, Quinta do Contador, Estrada da Serra, 2300-313 Tomar, Portugal;
| | - André F. G. Pereira
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE)—Advanced Production and Intelligent Systems, Associated Laboratory (ARISE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.M.A.); (A.F.G.P.); (T.G.P.); (J.V.F.)
| | - Bruno M. Chaparro
- Abrantes High School of Technology, Polytechnic Institute of Tomar, Quinta do Contador, Estrada da Serra, 2300-313 Tomar, Portugal;
| | - Tomás G. Parreira
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE)—Advanced Production and Intelligent Systems, Associated Laboratory (ARISE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.M.A.); (A.F.G.P.); (T.G.P.); (J.V.F.)
| | - José V. Fernandes
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE)—Advanced Production and Intelligent Systems, Associated Laboratory (ARISE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.M.A.); (A.F.G.P.); (T.G.P.); (J.V.F.)
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Fernandes JV, Pereira AFG, Antunes JM, Chaparro BM, Sakharova NA. Numerical Simulation Study of the Mechanical Behaviour of 1D and 2D Germanium Carbide and Tin Carbide Nanostructures. Materials (Basel) 2023; 16:5484. [PMID: 37570189 PMCID: PMC10419946 DOI: 10.3390/ma16155484] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/21/2023] [Accepted: 08/02/2023] [Indexed: 08/13/2023]
Abstract
One-dimensional (nanotubes) and two-dimensional (nanosheets) germanium carbide (GeC) and tin carbide (SnC) structures have been predicted and studied only theoretically. Understanding their mechanical behaviour is crucial, considering forthcoming prospects, especially in batteries and fuel cells. Within this framework, the present study aims at the numerical evaluation of the elastic properties, surface Young's and shear moduli and Poisson's ratio, of GeC and SnC nanosheets and nanotubes, using a nanoscale continuum modelling approach. A robust methodology to assess the elastic constants of the GeC and SnC nanotubes without of the need for numerical simulation is proposed. The surface Young's and shear moduli of the GeC and SnC nanotubes and nanosheets are compared with those of their three-dimensional counterparts, to take full advantage of 1D and 2D germanium carbide and tin carbide in novel devices. The obtained outcomes establish a solid basis for future explorations of the mechanical behaviour of 1D and 2D GeC and SnC nanostructures, where the scarcity of studies is evident.
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Affiliation(s)
- José V. Fernandes
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Advanced Production and Intelligent Systems, Associated Laboratory (ARISE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.V.F.); (A.F.G.P.); (J.M.A.)
| | - André F. G. Pereira
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Advanced Production and Intelligent Systems, Associated Laboratory (ARISE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.V.F.); (A.F.G.P.); (J.M.A.)
| | - Jorge M. Antunes
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Advanced Production and Intelligent Systems, Associated Laboratory (ARISE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.V.F.); (A.F.G.P.); (J.M.A.)
- Abrantes High School of Technology, Polytechnic Institute of Tomar, Quinta do Contador, Estrada da Serra, 2300-313 Tomar, Portugal;
| | - Bruno M. Chaparro
- Abrantes High School of Technology, Polytechnic Institute of Tomar, Quinta do Contador, Estrada da Serra, 2300-313 Tomar, Portugal;
| | - Nataliya A. Sakharova
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Advanced Production and Intelligent Systems, Associated Laboratory (ARISE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.V.F.); (A.F.G.P.); (J.M.A.)
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Carneiro Í, Fernandes JV, Simões S. Microstructural Characterization of Al/CNTs Nanocomposites after Cold Rolling. Nanomaterials (Basel) 2023; 13:1362. [PMID: 37110947 PMCID: PMC10143326 DOI: 10.3390/nano13081362] [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: 03/14/2023] [Revised: 04/05/2023] [Accepted: 04/11/2023] [Indexed: 06/19/2023]
Abstract
The deformation behaviour of aluminium reinforced by carbon nanotubes (Al/CNTs) nanocomposites during cold rolling was investigated in this work. Deformation processes after production by conventional powder metallurgy routes may be an efficient approach to improve the microstructure and mechanical properties by decreasing the porosity. Metal matrix nanocomposites have enormous potential to produce advanced components, mainly in the mobility industry, with powder metallurgy being one of the most reported production processes. For this reason, it is increasingly important to study the deformation behaviour of nanocomposites. In this context, nanocomposites were produced via powder metallurgy. Advanced characterization techniques carried out the microstructural characterization of the as-received powders and produced nanocomposites. The microstructural characterization of the as-received powders and produced nanocomposites was carried out through optical microscopy (OM), and scanning and transmission electron microscopy (SEM and TEM), complemented by electron backscattered diffraction (EBSD). The powder metallurgy route followed by cold rolling is reliable for Al/CNTs nanocomposites. The microstructural characterization shows that the nanocomposites exhibit a different crystallographic orientation than the Al matrix. CNTs in the matrix influence grain rotation during sintering and deformation. Mechanical characterization revealed that during deformation, there is an initial decrease in the hardness and tensile strength for the Al/CNTs and Al matrix. The initial decrease was attributed to the Bauschinger effect being more significant for the nanocomposites. The difference in the mechanical properties of the nanocomposites and Al matrix was attributed to distinct texture evolution during cold rolling.
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Affiliation(s)
- Íris Carneiro
- DEMM—Department of Metallurgical and Materials Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal;
- LAETA/INEGI—Institute of Science and Innovation in Mechanical and Industrial Engineering, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
- School of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - José V. Fernandes
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), ARISE, Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal
| | - Sónia Simões
- DEMM—Department of Metallurgical and Materials Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal;
- LAETA/INEGI—Institute of Science and Innovation in Mechanical and Industrial Engineering, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
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Sakharova NA, Antunes JM, Pereira AFG, Chaparro BM, Fernandes JV. Elastic Properties of Single-Walled Phosphide Nanotubes: Numerical Simulation Study. Nanomaterials (Basel) 2022; 12:nano12142360. [PMID: 35889584 PMCID: PMC9324117 DOI: 10.3390/nano12142360] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 02/06/2023]
Abstract
After a large-scale investigation into carbon nanotubes, significant research efforts have been devoted to discovering and synthesizing other nanotubes formed by chemical elements other than carbon. Among them, non-carbon nanotubes based on compounds of the elements of the 13th group of the periodic table and phosphorus. These inorganic nanotubes have proved to be more suitable candidates than carbon nanotubes for the construction of novel electronic and optical-electronic nano-devices. For this reason, until recently, mainly the structural and electrical properties of phosphide nanotubes were investigated, and studies to understand their mechanical behavior are infrequent. In the present work, the elastic properties of single-walled boron phosphide, aluminum phosphide, gallium phosphide and indium phosphide nanotubes were numerically evaluated using a nanoscale continuum modelling (also called molecular structural mechanics) approach. The force field constants required to assess the input parameters for numerical simulations were calculated for boron phosphide, aluminum phosphide, gallium phosphide and indium phosphide nanostructures using two different methods. The influence of input parameters on the elastic properties evaluated by numerical simulation was studied. A robust methodology to calculate the surface elastic moduli of phosphide nanotubes is proposed.
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Affiliation(s)
- Nataliya A. Sakharova
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.M.A.); (A.F.G.P.); (J.V.F.)
- Correspondence: ; Tel.: +351-239-790-700
| | - Jorge M. Antunes
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.M.A.); (A.F.G.P.); (J.V.F.)
- Abrantes High School of Technology, Polytechnic Institute of Tomar, Quinta do Contador, Estrada da Serra, 2300-313 Tomar, Portugal;
| | - André F. G. Pereira
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.M.A.); (A.F.G.P.); (J.V.F.)
| | - Bruno M. Chaparro
- Abrantes High School of Technology, Polytechnic Institute of Tomar, Quinta do Contador, Estrada da Serra, 2300-313 Tomar, Portugal;
| | - José V. Fernandes
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.M.A.); (A.F.G.P.); (J.V.F.)
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Sakharova NA, Antunes JM, Pereira AFG, Chaparro BM, Fernandes JV. On the Determination of Elastic Properties of Single-Walled Boron Nitride Nanotubes by Numerical Simulation. Materials (Basel) 2021; 14:ma14123183. [PMID: 34207737 PMCID: PMC8228917 DOI: 10.3390/ma14123183] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/28/2021] [Accepted: 05/31/2021] [Indexed: 01/24/2023]
Abstract
The elastic properties of chiral and non-chiral single-walled boron nitride nanotubes in a wide range of their chiral indices and diameters were studied. With this aim, a three-dimensional finite element model was used to assess their rigidities and, subsequently, elastic moduli and Poisson’s ratio. An extensive study was performed to understand the impact of the input parameters on the results obtained by numerical simulation. For comparison, the elastic properties of single-walled boron nitride nanotubes are shown together with those obtained for single-walled carbon nanotubes.
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Affiliation(s)
- Nataliya A. Sakharova
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.M.A.); (A.F.G.P.); (B.M.C.); (J.V.F.)
- Correspondence: ; Tel.: +35-12-3979-0700
| | - Jorge M. Antunes
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.M.A.); (A.F.G.P.); (B.M.C.); (J.V.F.)
- Polytechnic Institute of Tomar, Quinta do Contador, Estrada da Serra, 2300-313 Tomar, Portugal
| | - André F. G. Pereira
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.M.A.); (A.F.G.P.); (B.M.C.); (J.V.F.)
| | - Bruno M. Chaparro
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.M.A.); (A.F.G.P.); (B.M.C.); (J.V.F.)
- Polytechnic Institute of Tomar, Quinta do Contador, Estrada da Serra, 2300-313 Tomar, Portugal
| | - José V. Fernandes
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (J.M.A.); (A.F.G.P.); (B.M.C.); (J.V.F.)
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Silva MK, Gomes HSS, Silva OLT, Campanelli SE, Campos DMO, Araújo JMG, Fernandes JV, Fulco UL, Oliveira JIN. Identification of promiscuous T cell epitopes on Mayaro virus structural proteins using immunoinformatics, molecular modeling, and QM:MM approaches. Infect Genet Evol 2021; 91:104826. [PMID: 33781966 DOI: 10.1016/j.meegid.2021.104826] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 03/11/2021] [Accepted: 03/23/2021] [Indexed: 10/21/2022]
Abstract
The Mayaro virus (MAYV) belongs to genus Alphavirus (family Togaviridae) and has been reported in several countries, especially in tropical regions of America. Due to its outbreaks and potential lack of medication, an effective vaccine formulation is strongly required. This study aimed to predict promiscuous T cell epitopes from structural polyproteins of MAYV using an immunoinformatics approach. For this purpose, consensus sequences were used to identify short protein sequences capable of binding to MHC class I and class II alleles. Our analysis pointed out 4 MHC-I/TCD8+ and 21 MHC-II/TCD4+ epitopes on capside (1;3), E1 (2;5), E2 (1;10), E3 (0;2), and 6 K (0;1) proteins. These predicted epitopes were characterized by high antigenicity, immunogenicity, conservancy, non-allergenic, non-toxic, and good population coverage rate values for North and South American geographical areas. Afterwards, we used the crystal structure of human toll-like receptor 3 (TLR3) ectodomain as a template to predict, through docking essays, the placement of a vaccine prototype at the TLR3 receptor binding site. Finally, classical and quantum mechanics/molecular mechanics (QM:MM) computations were employed to improve the quality of docking calculations, with the QM part of the simulations being accomplished by using the density functional theory (DFT) formalism. These results provide important insights into the advancement of diagnostic platforms, the development of vaccines, and immunotherapeutic interventions.
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Affiliation(s)
- Maria K Silva
- Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil
| | - Heloísa S S Gomes
- Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil
| | - Ohana L T Silva
- Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil
| | - Stephany E Campanelli
- Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil
| | - Daniel M O Campos
- Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil
| | - Josélio M G Araújo
- Departamento de Microbiologia e Parasitologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil
| | - José V Fernandes
- Departamento de Microbiologia e Parasitologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil
| | - Umberto L Fulco
- Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil
| | - Jonas I N Oliveira
- Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil.
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Pereira AFG, Antunes JM, Fernandes JV, Sakharova N. Mechanical Characterisation of Single-Walled Carbon Nanotube Heterojunctions: Numerical Simulation Study. Materials (Basel) 2020; 13:ma13225100. [PMID: 33198189 PMCID: PMC7696267 DOI: 10.3390/ma13225100] [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: 10/13/2020] [Revised: 11/03/2020] [Accepted: 11/09/2020] [Indexed: 06/11/2023]
Abstract
The elastic properties of single-walled carbon nanotube heterojunctions were investigated using conventional tensile, bending and torsion tests. A three-dimensional finite element model was built in order to describe the elastic behaviour of cone heterojunctions (armchair-armchair and zigzag-zigzag). This comprehensive systematic study, to evaluate the tensile, bending and torsional rigidities of heterojunctions, enabled the formulation analytical methods for easy assessment of the elastic properties of heterojunctions using a wide range of their geometrical parameters.
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Affiliation(s)
- André F. G. Pereira
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (A.F.G.P.); (J.M.A.); (J.V.F.)
| | - Jorge M. Antunes
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (A.F.G.P.); (J.M.A.); (J.V.F.)
- Polytechnic Institute of Tomar, Quinta do Contador, Estrada da Serra, 2300-313 Tomar, Portugal
| | - José V. Fernandes
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (A.F.G.P.); (J.M.A.); (J.V.F.)
| | - Nataliya Sakharova
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (A.F.G.P.); (J.M.A.); (J.V.F.)
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Sakharova NA, Pereira AFG, Antunes JM, Fernandes JV. Mechanical Characterization of Multiwalled Carbon Nanotubes: Numerical Simulation Study. Materials (Basel) 2020; 13:E4283. [PMID: 32992932 PMCID: PMC7579541 DOI: 10.3390/ma13194283] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/20/2020] [Accepted: 09/22/2020] [Indexed: 11/16/2022]
Abstract
The elastic properties of armchair and zigzag multiwalled carbon nanotubes were investigated under tensile, bending, and torsion loading conditions. A simplified finite element model of the multiwalled carbon nanotubes, without taking into account the van der Waals interactions between layers, was used to assess their tensile, bending, and torsional rigidities and, subsequently, Young's and shear moduli. Relationships between the tensile rigidity and the squares of the diameters of the outer and inner layers in multiwalled carbon nanotubes, and between the bending and torsional rigidities with the fourth powers of the diameters of the outer and inner layers, were established. These relationships result in two consistent methods, one for assessment to the Young's modulus of armchair and zigzag multiwalled carbon nanotubes, based on tensile and bending rigidities, and the other to evaluate shear modulus using tensile, bending, and torsional rigidities. This study provides a benchmark regarding the determination of the mechanical properties of nonchiral multiwalled carbon nanotubes by nanoscale continuum modeling approach.
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Affiliation(s)
- Nataliya A. Sakharova
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), DeptMech Engn, Univ Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (A.F.G.P.); (J.M.A.); (J.V.F.)
| | - André F. G. Pereira
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), DeptMech Engn, Univ Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (A.F.G.P.); (J.M.A.); (J.V.F.)
| | - Jorge M. Antunes
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), DeptMech Engn, Univ Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (A.F.G.P.); (J.M.A.); (J.V.F.)
- Escola Superior de Tecnologia de Abrantes, Instituto Politécnico de Tomar, Rua 17 de Agosto de 1808, 2200-370 Abrantes, Portugal
| | - José V. Fernandes
- Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), DeptMech Engn, Univ Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal; (A.F.G.P.); (J.M.A.); (J.V.F.)
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Carneiro Í, Viana F, Vieira MF, Fernandes JV, Simões S. EBSD Analysis of Metal Matrix Nanocomposite Microstructure Produced by Powder Metallurgy. Nanomaterials (Basel) 2019; 9:nano9060878. [PMID: 31212784 PMCID: PMC6631311 DOI: 10.3390/nano9060878] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 06/06/2019] [Accepted: 06/07/2019] [Indexed: 11/24/2022]
Abstract
The development of metal nanocomposites reinforced by carbon nanotubes (CNTs) remains a focus of the scientific community due to the growing need to produce lightweight advanced materials with unique mechanical properties. However, for the successful production of these nanocomposites, there is a need to consolidate knowledge about how reinforcement influences the matrix microstructure and which are the strengthening mechanisms promoting the best properties. In this context, this investigation focuses on the study of the reinforcement effect on the microstructure of an Ni-CNT nanocomposites produced by powder metallurgy. The microstructural evolution was analysed by electron backscattered diffraction (EBSD). The EBSD results revealed that the dispersion/mixing and pressing processes induce plastic deformation in the as-received powders. The dislocation structures produced in those initial steps are partially eliminated in the sintering process due to the activation of recovery and recrystallization mechanisms. However, the presence of CNTs in the matrix has a significant effect on the dislocation annihilation, thus reducing the recovery of the dislocation structures.
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Affiliation(s)
- Íris Carneiro
- CEMMPRE, Department of Metallurgical and Materials Engineering, University of Porto, R. Dr. Roberto Frias, 4200-465 Porto, Portugal.
| | - Filomena Viana
- CEMMPRE, Department of Metallurgical and Materials Engineering, University of Porto, R. Dr. Roberto Frias, 4200-465 Porto, Portugal.
- INEGI-Institute of Science and Innovation in Mechanical and Industrial Engineering, R. Dr. Roberto Frias, 4200-465 Porto, Portugal.
| | - Manuel F Vieira
- CEMMPRE, Department of Metallurgical and Materials Engineering, University of Porto, R. Dr. Roberto Frias, 4200-465 Porto, Portugal.
- INEGI-Institute of Science and Innovation in Mechanical and Industrial Engineering, R. Dr. Roberto Frias, 4200-465 Porto, Portugal.
| | - José V Fernandes
- CEMMPRE, Department of Mechanical Engineering, University of Coimbra, Rua Luís Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra, Portugal.
| | - Sónia Simões
- CEMMPRE, Department of Metallurgical and Materials Engineering, University of Porto, R. Dr. Roberto Frias, 4200-465 Porto, Portugal.
- INEGI-Institute of Science and Innovation in Mechanical and Industrial Engineering, R. Dr. Roberto Frias, 4200-465 Porto, Portugal.
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Medeiros AS, Costa DMP, Branco MSD, Sousa DMC, Monteiro JD, Galvão SPM, Azevedo PRM, Fernandes JV, Jeronimo SMB, Araújo JMG. Dengue virus in Aedes aegypti and Aedes albopictus in urban areas in the state of Rio Grande do Norte, Brazil: Importance of virological and entomological surveillance. PLoS One 2018. [PMID: 29534105 PMCID: PMC5849307 DOI: 10.1371/journal.pone.0194108] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Vector control remains the sole effective method to prevent dengue virus (DENV) transmission, although a vaccine for dengue has recently become available and testing of its efficacy and coverage is being performed in multiple places. Entomological surveillance is a key factor in alerting authorities to possible outbreaks, but until now natural DENV infection of mosquito populations has been scarcely used as an early warning system to monitor fluctuating prevalence of infected mosquitoes. The purpose of this study was to determine the burden of adult and larval/pupae of Aedes aegypti and Aedes albopictus with DENV in urban areas in the state of Rio Grande do Norte, Brazil. METHODOLOGY/PRINCIPAL FINDINGS Immature insect forms (larvae and pupae) were collected from April 2011 to March 2012, whereas the collection of adults was conducted along 3 years: May 2011 to April 2014. Total RNAs of the samples were extracted and the nested reverse transcriptase PCR assay for detecting and typing DENV was performed. Of the 1333 immature insects collected during the study period, 1186 (89%) were A. aegypti and 147 (11%) A. albopictus. DENV-4 was identified in pools of A. aegypti larvae. The rate of DENV infection in immature A. aegypti was expressed as MIR = 3.37. DENV wasnot detected in immature A. albopictus. A total of 1360 adult female mosquitoes of the Aedes genus were captured from May 2011 to April 2014. Of this total, 1293 were A. aegypti (95%) and 67 were A. albopictus (5%). From the 130 pools studied, 27 (20.7%) were positive for DENV. DENV-1 was identified in 2/27 (7.4%) pools; 1of A. albopictus and 1 of A. aegypti. DENV-2 was identified in only 1/27 (3.7%) A. aegypti pools. DENV-4 was the most prevalent, identified in 24/27 (88.8%) of the positive pools, with 19 being of A. aegypti and 5 of A. albopictus pools. The minimum infection rate for adults of the Aedes genus was 19.8, considering both A. aegypti and A. albopictus. CONCLUSIONS/SIGNIFICANCE This work represents the most complete study to date on the interaction between dengue viruses and Aedes mosquitoes in the State of Rio Grande do Norte, and raises important questions about a possible role of A. albopictus in the transmission of dengue virus in Brazil.
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Affiliation(s)
- Arlinete S. Medeiros
- Post-GraduateHealth Program, Health Sciences Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Department of Microbiology and Parasitology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
- Laboratory of Virology, Institute of Tropical Medicine, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Diego M. P. Costa
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Department of Microbiology and Parasitology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Mário S. D. Branco
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Department of Microbiology and Parasitology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Daíse M. C. Sousa
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Department of Microbiology and Parasitology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Joelma D. Monteiro
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Department of Microbiology and Parasitology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Sílvio P. M. Galvão
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Department of Microbiology and Parasitology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | | | - José V. Fernandes
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Department of Microbiology and Parasitology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Selma M. B. Jeronimo
- Post-GraduateHealth Program, Health Sciences Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
- Immunogenetics Laboratory, Department of Biochemistry, Biosciences Center, Federal University of Rio Grande do Norte, Natal, Brazil
- Laboratory of Complex Diseases, Institute of Tropical Medicine, Federal University of Rio Grande do Norte, Natal, Brazil
- Institute of Science and Technology of Tropical Diseases, Brasília, Brazil
| | - Josélio M. G. Araújo
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Department of Microbiology and Parasitology, Biosciences Center, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
- Laboratory of Virology, Institute of Tropical Medicine, Federal University of Rio Grande do Norte, Natal, Brazil
- * E-mail:
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Branco MSD, Sousa DMC, Sousa DMC, Monteiro JD, Costa DMP, Almeida Junior RF, Lima TLC, Farias KJS, Medeiros RC, Queiroz MGL, Gil LHVG, Fernandes JV, Nogueira RMR, Araújo JMG. Dengue in the State of Rio Grande do Norte, Brazil, 2010-2012. Trop Med Int Health 2015; 20:1707-10. [PMID: 26426773 DOI: 10.1111/tmi.12612] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To present results of virological surveillance and epidemiological aspects of dengue in the State of Rio Grande do Norte, Brazil. METHODS A total of 1581 cases, reported from 2010 to 2012 at various health centres in the state, were analysed by viral isolation and/or RT-PCR for viral detection and typing. To identify whether different genotypes were circulating in the state during this period, sequencing of the complete E gene for DENV (1485 bp in length) was performed directly from patient serum samples. RESULTS All four serotypes of dengue virus circulated in Rio Grande do Norte, with the introduction of DENV-4 in the state in 2011. In 2012, DENV-4 represented 100% of positive confirmed cases. 53.97% of cases occurred in Natal. Case numbers peaked in April (21%) and May (23%). Genetic characterisation of circulating strains confirmed the circulation of genotypes V, south-east Asian/American and II, respectively, for DENV-1, DENV-2 and DENV-4. CONCLUSIONS This work furthers a better understanding of dengue viruses in the State of Rio Grande do Norte. Strengthening control efforts in the region is important considering the impact of dengue.
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Affiliation(s)
- Mário S D Branco
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Federal University of Rio Grande do Norte, Natal, Brazil.,Laboratory of Flavivirus, Oswaldo Cruz Institute, Rio de Janeiro, Brazil
| | - Denise M C Sousa
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Daíse M C Sousa
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Joelma D Monteiro
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Diego M P Costa
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Renato F Almeida Junior
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Tábata L C Lima
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Kleber J S Farias
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Federal University of Rio Grande do Norte, Natal, Brazil
| | | | | | - Laura H V G Gil
- Department of Virology and Experimental Therapy, Aggeu Magalhães Research Center, Recife, Brazil
| | - José V Fernandes
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Rita M R Nogueira
- Laboratory of Flavivirus, Oswaldo Cruz Institute, Rio de Janeiro, Brazil
| | - Josélio M G Araújo
- Laboratory of Molecular Biology for Infectious Diseases and Cancer, Federal University of Rio Grande do Norte, Natal, Brazil
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Fernandes JV, Meissner RV, Carvalho MG, Fernandes TA, Azevedo PR, Sobrinho JS, Prado JC, Villa LL. Prevalence of human papillomavirus in archival samples obtained from patients with cervical pre-malignant and malignant lesions from Northeast Brazil. BMC Res Notes 2010; 3:96. [PMID: 20377903 PMCID: PMC2857859 DOI: 10.1186/1756-0500-3-96] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 04/08/2010] [Indexed: 12/03/2022] Open
Abstract
Background Human Papillomavirus (HPV) is considered as a necessary, but not sufficient, cause of cervical cancer. In this study, we aimed to assess the prevalence of HPV in a series of pre-malignant and malignant cervical lesion cases, to identify the virus genotypes, and to assess their distribution pattern according to lesion type, age range, and other considered variables. The samples were submitted to histopathological revision examination and analysed by polymerase chain reaction (PCR) for the presence of HPV DNA, followed by HPV typing by dot blot hybridisation. Findings Of the analysed samples, 53.7% showed pre-malignant cervical lesions, and 46.3% presented with cervical cancer. Most cancer samples (84.1%) were classified as invasive carcinoma. The mean age of these cancer patients was 47.3 years. The overall HPV prevalence was 82.4% in patients with pre-malignant lesions and 92.0% in the cancer patients. HPV 16 was the most prevalent type, followed by HPV 18 and 58, including both single and double infections. Double infection was detected in 11.6% of the samples, and the most common combination was HPV 16+18. Conclusions Cervical cancer appears to occur in women in a lower age range in the studied area, compared to the situation in other Brazilian regions. Furthermore, among the patients with CIN 3 and those with cancer, we observed a higher proportion of married women, women with more than one sexual partner, smokers, and individuals with less than an elementary education, relative to their counterparts. Findings The overall HPV prevalence was 82.4% in patients with pre-malignant lesions and 92.0% in the cervical cancer patients from Northeast Brazil. HPV 16 was the most prevalent type, followed by HPV 18 and 58. The most common double infection was HPV 16+18. Cervical cancer appears to occur in women in a lower age range in the Northeast Brazil. Among the patients with CIN 3 and those with cancer, we observed a higher proportion of married women, women with more than one sexual partner, smokers, and individuals with less than an elementary education, relative to their counterparts.
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Affiliation(s)
- José V Fernandes
- Department of Microbiology and Parasitology, Federal University of Rio Grande do Norte, Av, Sen, Salgado Filho, S/N, Lagoa Nova, CEP: 59072-970, Natal, RN, Brazil.
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Fernandes TAAM, Lima GLF, De Souza FCG, Fernandes JV, Meissner RV. Evaluation of the polymorphisms in the exons 2 to 4 of the TP53 in cervical carcinoma patients from a Brazilian population. Cell Mol Biol (Noisy-le-grand) 2008; 54 Suppl:OL1025-OL1031. [PMID: 18954551] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2007] [Accepted: 11/11/2007] [Indexed: 05/27/2023]
Abstract
The majority of TP53 polymorphisms and cervical cancer association studies have only analyzed codon 72 polymorphism. Eight polymorphisms were reported in the region encompassing exon 2 to 4 of TP53 that codify the aminoterminal p53 region containing domains involved in the transcription transactivation and apoptosis induction. We investigated if the polymorphisms present in this region were associated with cervical cancer risk. A total of 140 samples (83 from Brazilian patients with cervical carcinoma and 57 from Brazilian healthy women) were analyzed by PCR and DNA sequencing. Only three from the eight TP53 polymorphisms described in the analyzed region were polymorphic within our samples: the 11827 base from intron 2, the 16bp duplication in the intron3 and the codon 72 (Arg>Pro) from exon 4. No statistically significant association was observed between polymorphisms from intron 2 and the 16bp duplication from intron 3 with cervical cancer. No statistically significant difference in the frequency of homozygotes for Arg in relation to other genotypes was found when comparing patient and healthy groups (OR=0.70; 95% CI= 0.31-1.56; p= 0.222). However, Arg/Pro heterozygotes were more frequent within HPV positive cancer patients than in healthy women (p=0.023; OR (Arg/Pro:Pro/Pro)= 5.82; 95% CI: 1.22-30.78; p=0.024).
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Affiliation(s)
- T A A M Fernandes
- Universidade Federal do Rio Grande do Norte Centro de Biociências, Programa de Pós-Graduaĉão em Genética e Biologia Molecular, Natal, Brazil
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Fernandes JV, Fonseca SM, Azevedo JC, Maranhão HDS, Fonseca MH, Dantas MT, Meissner RDV. [Rotavirus detection in feces of children with acute diarrhea]. J Pediatr (Rio J) 2000; 76:300-4. [PMID: 14647660 DOI: 10.2223/jped.6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVE: To determine the prevalence of rotavirus in the etiology of acute diarrhea in children from Natal city, RN, Brazil and investigate the existence or not of a seasonal distribution of this pathogen in our environment.METHODS: Fecal samples from 1,903 children (boys and girls) with ages ranging from 1 month to 10 years, living in Natal-RN, who presented acute diarrhea episodes in a period from January 1996 to December 1998, were analyzed. We searched viral particles directly in the feces by a passive agglutination reaction using anti-rotavirus specific-group monoclonal antibodies coated latex particles.RESULTS: 151 children (7.9%) of the studied population presented a positive reaction, revealing the presence of rotavirus particles in feces. Considering, however, only the children (ages from 1 to 24 months) who are more susceptible to rotavirus infection, we verified that from 1,065 examined children, 136 of them (12.8%) presented positive reaction for rotavirus, and the great majority of all children with positive reaction (96.3%) had ages ranging from 6 to 24 months. Analysis of the distribution of the cases of rotavirus infection in the three year revealed that the incidence of infection was higher in July, August, and September.CONCLUSIONS: The results indicated rotavirus infections have an important role in the etiology of acute diarrhea cases. The majority of the acute diarrhea cases positive for rotavirus occurred during the first two years of life, reaching mainly children from 6 to 24 months, with the highest incidence of infection during the months of July, August, and September.
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Affiliation(s)
- J V Fernandes
- Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil
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Fernandes JV, Braz RDF, Neto FV, da Silva MA, da Costa NF, Ferreira AM. [Prevalence of serologic markers of hepatitis B virus in hospital personnel]. Rev Saude Publica 1999; 33:122-8. [PMID: 10413929 DOI: 10.1590/s0034-89101999000200003] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [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: 11/21/2022] Open
Abstract
OBJECTIVE To verify the prevalence of the anti-HBc, anti-HBs and HBsAg markers of hepatitis B virus, and to identify the risk factors determining occupational infection with this virus among hospital personnel. METHODS Samples of serum from 210 persons both male and female who work in different occupations at a hospital university, were analysed. The technique employed was the immunoenzymatic assay using commercial kits. RESULTS As a control group, samples of serum from 45 volunteer blood donors were utilized. It was verified that 20.5% of the hospital personnel presented a positive reaction to at least one of the markers songht, as against 6.6% of the control group. The prevalence of each marker separately was: anti-HBc 8.1%, anti-HBs 5.2%, and HBsAg 2.9% in the hospital personnel; and 4.4%, 2.2% and 0.0% in the control group. The simultaneous presence of the anti-HBc and anti-HBs markers was detected in 4.3% of the workers. In the control group, the presence of the anti-HBc and anti-HBs markers was detected, isolately, with respective prevalences of 4.4% and 2.2%. Those who presented the highest rates of positivite reaction were: laboratory technicians 24.0%, nurses 23.6%, physicians 20.8%, and cleaning personnel 18.2%. CONCLUSIONS The findings suggest that direct contact with patients and handling of blood and other body fluids are risk factors related to occupational infection with HBV. Therefore, it is recommended that hospital personnel be vaccinated against hepatitis B.
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Affiliation(s)
- J V Fernandes
- Departamento de Microbiologia e Parasitologia da Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN, Brasil.
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