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Okon IB, Onate CA, Horchani R, Popoola OO, Omugbe E, William ES, Okorie US, Inyang EP, Isonguyo CN, Udoh ME, Antia AD, Chen WL, Eyube ES, Araujo JP, Ikot AN. Thermomagnetic properties and its effects on Fisher entropy with Schioberg plus Manning-Rosen potential (SPMRP) using Nikiforov-Uvarov functional analysis (NUFA) and supersymmetric quantum mechanics (SUSYQM) methods. Sci Rep 2023; 13:8193. [PMID: 37210425 DOI: 10.1038/s41598-023-34521-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 05/03/2023] [Indexed: 05/22/2023] Open
Abstract
Thermomagnetic properties, and its effects on Fisher information entropy with Schioberg plus Manning-Rosen potential are studied using NUFA and SUSYQM methods in the presence of the Greene-Aldrich approximation scheme to the centrifugal term. The wave function obtained was used to study Fisher information both in position and momentum spaces for different quantum states by the gamma function and digamma polynomials. The energy equation obtained in a closed form was used to deduce numerical energy spectra, partition function, and other thermomagnetic properties. The results show that with an application of AB and magnetic fields, the numerical energy eigenvalues for different magnetic quantum spins decrease as the quantum state increases and completely removes the degeneracy of the energy spectra. Also, the numerical computation of Fisher information satisfies Fisher information inequality products, indicating that the particles are more localized in the presence of external fields than in their absence, and the trend shows complete localization of quantum mechanical particles in all quantum states. Our potential reduces to Schioberg and Manning-Rosen potentials as special cases. Our potential reduces to Schioberg and Manning-Rosen potentials as special cases. The energy equations obtained from the NUFA and SUSYQM were the same, demonstrating a high level of mathematical precision.
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Affiliation(s)
- I B Okon
- Theoretical Physics Group, Department of Physics, University of Uyo, Uyo, Nigeria
| | - C A Onate
- Department of Physics, Kogi State University, Anyigba, Nigeria
| | - R Horchani
- Department of Physics, College of Science, Sultan Qaboos University, Muscat, Sultanate of Oman.
| | - O O Popoola
- Department of Physics, University of Ibadan, Ibadan, Nigeria
| | - E Omugbe
- Department of Physics, University of Agriculture and Environmental Sciences, Umuagwo, P.M.B. 1038, Imo State, Nigeria
| | - E S William
- Department of Physics, Federal University of Technology, Ikot Abasi, Nigeria
| | - U S Okorie
- Department of Physics, Akwa Ibom State University, Mkpat-Enin, Nigeria
| | - E P Inyang
- Department of Physics, National Open University of Nigeria, Jabi-Abuja, Nigeria
| | - C N Isonguyo
- Theoretical Physics Group, Department of Physics, University of Uyo, Uyo, Nigeria
| | - M E Udoh
- Theoretical Physics Group, Department of Physics, University of Uyo, Uyo, Nigeria
| | - A D Antia
- Theoretical Physics Group, Department of Physics, University of Uyo, Uyo, Nigeria
| | - W L Chen
- School of Intelligent Science and Information Engineering, Xi'an Peihua University, Xi'an, 710125, China
| | - E S Eyube
- Department of Physics, Faculty of Physical Sciences, Modibbo Adama University, P.M.B. 2076, Yola, Adamawa State, Nigeria
| | - J P Araujo
- Department of Mathematics, Instituto Federal de Educação, Ciência e Tecnologia do Sudeste de Minas Gerais, Juiz de Fora, Brazil
| | - A N Ikot
- Theoretical Physics Group, Department of Physics, University of Port Harcourt, Port Harcourt, Nigeria
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Onate CA, Okon IB, Oyewumi KJ, Falaye BJ, Eyube ES, Omugbe E, Onyeaju MC, Araujo JP. Energies of some halogen molecules for the improved Tietz potential model. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2098195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- C. A. Onate
- Physics Programme, Department of Physical Sciences, Landmark University, Omu-Aran, Nigeria
| | - I. B. Okon
- Theoretical Physics Group, Department of Physics, University of Uyo, Uyo, Nigeria
| | - K. J. Oyewumi
- Theoretical Physics Section, Department of Physics, University of Ilorin, Ilorin, Nigeria
| | - B. J. Falaye
- Department of Physics, Federal University Lafia, Lafia, Nigeria
| | - E. S. Eyube
- Department of Physics, Faculty of Physical Sciences, Modibbo Adama University, Yola, Nigeria
| | - E. Omugbe
- Physics Department Federal, University of Petroleum Resources Effurun, Effurun, Nigeria
- Department of science Laboratory TechnologyS, Delta State Polytechnic, Otefe, Oghara
| | - M. C. Onyeaju
- Theoretical Physics Group, Department of Physics, University of Port Harcourt, Harcourt, Nigeria
| | - J. P. Araujo
- Department of Mathematics, Instituto Federal do Sudeste de Minas Gerais, Juiz de Fora, Brazil
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Okon IB, Onate CA, Omugbe E, Okorie US, Edet CO, Antia AD, Araujo JP, Isonguyo CN, Onyeaju MC, William ES, Horchani R, Ikot AN. Aharonov–Bohm (AB) flux and thermomagnetic properties of Hellmann plus screened Kratzer potential as applied to diatomic molecules using Nikiforov–Uvarov-Functional-Analysis (NUFA) method. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2046295] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- I. B. Okon
- Theoretical Physics Group, Department of Physics, University of Uyo, Uyo, Nigeria
| | - C. A. Onate
- Department of Physical Sciences, Landmark University, Omu-Aran, Nigeria
| | - E. Omugbe
- Department of Physics, Federal University of Petroleum Resources, Effurun, Nigeria
| | - U. S. Okorie
- Department of Physics, Akwa Ibom State University, Uyo, Nigeria
| | - C. O. Edet
- Department of Physics, Cross River University of Technology, Calabar, Nigeria
| | - A. D. Antia
- Theoretical Physics Group, Department of Physics, University of Uyo, Uyo, Nigeria
| | - J. P. Araujo
- Department of Mathematics, Instituto Federal do Sudeste de Minas Gerais, Juiz de Fora, Brazil
| | - C. N. Isonguyo
- Theoretical Physics Group, Department of Physics, University of Uyo, Uyo, Nigeria
| | - M. C. Onyeaju
- Department of Physics, Cross River University of Technology, Calabar, Nigeria
| | - E. S. William
- Theoretical Physics Group, Department of Physics, University of Calabar, Calabar, Nigeria
| | - R. Horchani
- Department of Physics, College of Science, Sultan Qaboos University, Muscat, Sultanate of Oman
| | - A. N. Ikot
- Theoretical Physics Group, Department of Physics, University of Port Harcourt, Port Harcourt, Nigeria
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Nogueira V, Sousa CT, Araujo JP, Pereira R. Evaluation of the toxicity of nickel nanowires to freshwater organisms at concentrations and short-term exposures compatible with their application in water treatment. Aquat Toxicol 2020; 227:105595. [PMID: 32911330 DOI: 10.1016/j.aquatox.2020.105595] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 07/20/2020] [Accepted: 08/07/2020] [Indexed: 06/11/2023]
Abstract
In order to understand the potential impacts of nickel nanowires (Ni NWs) after reaching the aquatic environment, this research evaluated the toxicity of Ni NWs with different lengths (≤ 1.1, ≤11 and ≤ 80 μm) for several floating, planktonic and nektonic freshwater organisms. In this work, Ni NWs were synthesized by electrodeposition using anodized aluminum oxide (AAO) membranes. The toxicity of the NWs was assessed using a battery of aquatic species representative of key functions at the ecosystem level: the bacterium Aliivibrio fischeri, the algae Raphidocelis subcapitata, the macrophyte Lemna minor, the crustacean Daphnia magna and the zebrafish Danio rerio. Results indicated that for the concentrations tested (up to 2.5 mg L-1) the synthesized Ni NWs showed low toxicity. And although no lethal toxicity was observed for D. magna, at a sublethal level the feeding activity of the freshwater cladoceran was severely affected after exposure to Ni NWs. These findings showed that NWs can be accumulated in the gut of D. magna, even during a short exposure (24 h) directly impairing Daphnia nutrition and eventually populations growth. Consequently, this can also contribute to trophic transfer of NWs along the food chain. According to our results the toxicity of Ni NW may be mainly attributed to physical effects rather than chemical effects of Ni ions, considering that the concentrations of Ni NWs tested in this study were well below the toxicity thresholds reported in the literature for Ni ions and for Ni NMs.
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Affiliation(s)
- V Nogueira
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR) and Faculty of Sciences of the University of Porto, Rua do campo Alegre s/n, Porto, Portugal.
| | - C T Sousa
- Institute of Physics for Advanced Materials, Nanotechnology and Photonics (IFIMUP), Department Physics and Astronomy, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 678, 4169-007 Porto, Portugal.
| | - J P Araujo
- Institute of Physics for Advanced Materials, Nanotechnology and Photonics (IFIMUP), Department Physics and Astronomy, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 678, 4169-007 Porto, Portugal.
| | - R Pereira
- Sustainable Agrifood Production Research Center (GreenUPorto) and Faculty of Sciences of the University of Porto, Rua do campo Alegre s/n, Porto, Portugal.
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Bovo S, Ribani A, Muñoz M, Alves E, Araujo JP, Bozzi R, Charneca R, Di Palma F, Etherington G, Fernandez AI, García F, García-Casco J, Karolyi D, Gallo M, Gvozdanović K, Martins JM, Mercat MJ, Núñez Y, Quintanilla R, Radović Č, Razmaite V, Riquet J, Savić R, Schiavo G, Škrlep M, Usai G, Utzeri VJ, Zimmer C, Ovilo C, Fontanesi L. Genome-wide detection of copy number variants in European autochthonous and commercial pig breeds by whole-genome sequencing of DNA pools identified breed-characterising copy number states. Anim Genet 2020; 51:541-556. [PMID: 32510676 DOI: 10.1111/age.12954] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2020] [Indexed: 02/06/2023]
Abstract
In this study, we identified copy number variants (CNVs) in 19 European autochthonous pig breeds and in two commercial breeds (Italian Large White and Italian Duroc) that represent important genetic resources for this species. The genome of 725 pigs was sequenced using a breed-specific DNA pooling approach (30-35 animals per pool) obtaining an average depth per pool of 42×. This approach maximised CNV discovery as well as the related copy number states characterising, on average, the analysed breeds. By mining more than 17.5 billion reads, we identified a total of 9592 CNVs (~683 CNVs per breed) and 3710 CNV regions (CNVRs; 1.15% of the reference pig genome), with an average of 77 CNVRs per breed that were considered as private. A few CNVRs were analysed in more detail, together with other information derived from sequencing data. For example, the CNVR encompassing the KIT gene was associated with coat colour phenotypes in the analysed breeds, confirming the role of the multiple copies in determining breed-specific coat colours. The CNVR covering the MSRB3 gene was associated with ear size in most breeds. The CNVRs affecting the ELOVL6 and ZNF622 genes were private features observed in the Lithuanian Indigenous Wattle and in the Turopolje pig breeds respectively. Overall, the genome variability unravelled here can explain part of the genetic diversity among breeds and might contribute to explain their origin, history and adaptation to a variety of production systems.
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Affiliation(s)
- S Bovo
- Division of Animal Sciences, Department of Agricultural and Food Sciences, University of Bologna, Viale Fanin 46, Bologna, 40127, Italy
| | - A Ribani
- Division of Animal Sciences, Department of Agricultural and Food Sciences, University of Bologna, Viale Fanin 46, Bologna, 40127, Italy
| | - M Muñoz
- Departamento Mejora Genética Animal, INIA, Crta. de la Coruña, km. 7,5, Madrid, 28040, Spain
| | - E Alves
- Departamento Mejora Genética Animal, INIA, Crta. de la Coruña, km. 7,5, Madrid, 28040, Spain
| | - J P Araujo
- Centro de Investigação de Montanha, Instituto Politécnico de Viana do Castelo, Escola Superior Agrária, Refóios do Lima, Ponte de Lima, 4990-706, Portugal
| | - R Bozzi
- DAGRI - Animal Science Section, Università di Firenze, Via delle Cascine 5, Firenze, 50144, Italy
| | - R Charneca
- MED - Mediterranean Institute for Agriculture, Environment and Development, Universidade de Évora, Pólo da Mitra, Apartado 94, Évora, 7006-554, Portugal
| | - F Di Palma
- Earlham Institute, Norwich Research Park, Colney Lane, Norwich, NR47UZ, UK
| | - G Etherington
- Earlham Institute, Norwich Research Park, Colney Lane, Norwich, NR47UZ, UK
| | - A I Fernandez
- Departamento Mejora Genética Animal, INIA, Crta. de la Coruña, km. 7,5, Madrid, 28040, Spain
| | - F García
- Departamento Mejora Genética Animal, INIA, Crta. de la Coruña, km. 7,5, Madrid, 28040, Spain
| | - J García-Casco
- Departamento Mejora Genética Animal, INIA, Crta. de la Coruña, km. 7,5, Madrid, 28040, Spain
| | - D Karolyi
- Department of Animal Science, Faculty of Agriculture, University of Zagreb, Svetošimunska c. 25, Zagreb, 10000, Croatia
| | - M Gallo
- Associazione Nazionale Allevatori Suini, Via Nizza 53, Roma, 00198, Italy
| | - K Gvozdanović
- Faculty of Agrobiotechnical Sciences Osijek, University of Osijek, Vladimira Preloga 1, Osijek, 31000, Croatia
| | - J M Martins
- MED - Mediterranean Institute for Agriculture, Environment and Development, Universidade de Évora, Pólo da Mitra, Apartado 94, Évora, 7006-554, Portugal
| | - M J Mercat
- IFIP Institut Du Porc, La Motte au Vicomte, BP 35104, Le Rheu Cedex, 35651, France
| | - Y Núñez
- Departamento Mejora Genética Animal, INIA, Crta. de la Coruña, km. 7,5, Madrid, 28040, Spain
| | - R Quintanilla
- Programa de Genética y Mejora Animal, IRTA, Torre Marimon, Caldes de Montbui, Barcelona, 08140, Spain
| | - Č Radović
- Department of Pig Breeding and Genetics, Institute for Animal Husbandry, Belgrade-Zemun, 11080, Serbia
| | - V Razmaite
- Animal Science Institute, Lithuanian University of Health Sciences, R. Žebenkos 12, Baisogala, 82317, Lithuania
| | - J Riquet
- GenPhySE, INRA, Université de Toulouse, Chemin de Borde-Rouge 24, Auzeville Tolosane, Castanet Tolosan, 31326, France
| | - R Savić
- Faculty of Agriculture, University of Belgrade, Nemanjina 6, Belgrade-Zemun, 11080, Serbia
| | - G Schiavo
- Division of Animal Sciences, Department of Agricultural and Food Sciences, University of Bologna, Viale Fanin 46, Bologna, 40127, Italy
| | - M Škrlep
- Kmetijski Inštitut Slovenije, Hacquetova 17, Ljubljana, SI-1000, Slovenia
| | - G Usai
- AGRIS SARDEGNA, Loc. Bonassai, Sassari, 07100, Italy
| | - V J Utzeri
- Division of Animal Sciences, Department of Agricultural and Food Sciences, University of Bologna, Viale Fanin 46, Bologna, 40127, Italy
| | - C Zimmer
- Bäuerliche Erzeugergemeinschaft Schwäbisch Hall, Haller Str. 20, Wolpertshausen, 74549, Germany
| | - C Ovilo
- Departamento Mejora Genética Animal, INIA, Crta. de la Coruña, km. 7,5, Madrid, 28040, Spain
| | - L Fontanesi
- Division of Animal Sciences, Department of Agricultural and Food Sciences, University of Bologna, Viale Fanin 46, Bologna, 40127, Italy
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Muñoz M, Bozzi R, García-Casco J, Núñez Y, Ribani A, Franci O, García F, Škrlep M, Schiavo G, Bovo S, Utzeri VJ, Charneca R, Martins JM, Quintanilla R, Tibau J, Margeta V, Djurkin-Kušec I, Mercat MJ, Riquet J, Estellé J, Zimmer C, Razmaite V, Araujo JP, Radović Č, Savić R, Karolyi D, Gallo M, Čandek-Potokar M, Fernández AI, Fontanesi L, Óvilo C. Genomic diversity, linkage disequilibrium and selection signatures in European local pig breeds assessed with a high density SNP chip. Sci Rep 2019; 9:13546. [PMID: 31537860 PMCID: PMC6753209 DOI: 10.1038/s41598-019-49830-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 08/30/2019] [Indexed: 11/27/2022] Open
Abstract
Genetic characterization of local breeds is essential to preserve their genomic variability, to advance conservation policies and to contribute to their promotion and sustainability. Genomic diversity of twenty European local pig breeds and a small sample of Spanish wild pigs was assessed using high density SNP chips. A total of 992 DNA samples were analyzed with the GeneSeek Genomic Profiler (GGP) 70 K HD porcine genotyping chip. Genotype data was employed to compute genetic diversity, population differentiation and structure, genetic distances, linkage disequilibrium and effective population size. Our results point out several breeds, such as Turopolje, Apulo Calabrese, Casertana, Mora Romagnola and Lithuanian indigenous wattle, having the lowest genetic diversity, supported by low heterozygosity and very small effective population size, demonstrating the need of enhanced conservation strategies. Principal components analysis showed the clustering of the individuals of the same breed, with few breeds being clearly isolated from the rest. Several breeds were partially overlapped, suggesting genetic closeness, which was particularly marked in the case of Iberian and Alentejana breeds. Spanish wild boar was also narrowly related to other western populations, in agreement with recurrent admixture between wild and domestic animals. We also searched across the genome for loci under diversifying selection based on FST outlier tests. Candidate genes that may underlie differences in adaptation to specific environments and productive systems and phenotypic traits were detected in potentially selected genomic regions.
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Affiliation(s)
- M Muñoz
- Departamento Mejora Genética Animal, INIA, Madrid, Spain
| | - R Bozzi
- DAGRI, Animal Science Section, Università degli Studi di Firenze, Firenze, Italy
| | - J García-Casco
- Departamento Mejora Genética Animal, INIA, Madrid, Spain
| | - Y Núñez
- Departamento Mejora Genética Animal, INIA, Madrid, Spain
| | - A Ribani
- Department of Agricultural and Food Sciences, University of Bologna, Bologna, Italy
| | - O Franci
- DAGRI, Animal Science Section, Università degli Studi di Firenze, Firenze, Italy
| | - F García
- Departamento Mejora Genética Animal, INIA, Madrid, Spain
| | - M Škrlep
- Kmetijski inštitut Slovenije, Hacquetova ulica 17, SI-1000, Ljubljana, Slovenia
| | - G Schiavo
- Department of Agricultural and Food Sciences, University of Bologna, Bologna, Italy
| | - S Bovo
- Department of Agricultural and Food Sciences, University of Bologna, Bologna, Italy
| | - V J Utzeri
- Department of Agricultural and Food Sciences, University of Bologna, Bologna, Italy
| | - R Charneca
- Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), Universidade de Évora, Évora, Portugal
| | - J M Martins
- Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), Universidade de Évora, Évora, Portugal
| | - R Quintanilla
- IRTA, Programa de Genética y Mejora Animal, Barcelona, Spain
| | - J Tibau
- IRTA, Programa de Genética y Mejora Animal, Barcelona, Spain
| | - V Margeta
- Faculty of Agrobiotechnical Sciences Osijek, University of Osijek, Osijek, Croatia
| | - I Djurkin-Kušec
- Faculty of Agrobiotechnical Sciences Osijek, University of Osijek, Osijek, Croatia
| | - M J Mercat
- IFIP - Institut du Porc, Le Rheu, France
| | - J Riquet
- INRA, Génétique Physiologie et Système d'Elevage, Castanet-Tolosan, France
| | - J Estellé
- GABI, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - C Zimmer
- Bäuerliche Erzeugergemeinschaft Schwäbisch Hall, Wolpertshausen, Germany
| | - V Razmaite
- Animal Science Institute, Lithuanian University of Health Sciences, Baisogala, Lithuania
| | - J P Araujo
- Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Viana do Castelo, Escola Superior Agrária, Ponte de Lima, Portugal
| | - Č Radović
- Institute for Animal Husbandry-Pig Research Department, Autoput for Zagreb 16, 11080, Belgrade-Zemun, Serbia
| | - R Savić
- University of Belgrade, Faculty of agriculture, Nemanjina 6, 11080, Belgrade-Zemun, Serbia
| | - D Karolyi
- Department of Animal Science, University of Zagreb, Faculty of Agriculture, Zagreb, Croatia
| | - M Gallo
- Associazione Nazionale Allevatori Suini (ANAS), Roma, Italy
| | - M Čandek-Potokar
- Kmetijski inštitut Slovenije, Hacquetova ulica 17, SI-1000, Ljubljana, Slovenia
| | - A I Fernández
- Departamento Mejora Genética Animal, INIA, Madrid, Spain
| | - L Fontanesi
- Department of Agricultural and Food Sciences, University of Bologna, Bologna, Italy
| | - C Óvilo
- Departamento Mejora Genética Animal, INIA, Madrid, Spain.
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Hierro-Rodriguez A, Leite IT, Rocha-Rodrigues P, Fernandes P, Araujo JP, Jorge PAS, Santos JL, Teixeira JM, Guerreiro A. Hydrogen sensing via anomalous optical absorption of palladium-based metamaterials. Nanotechnology 2016; 27:185501. [PMID: 27003717 DOI: 10.1088/0957-4484/27/18/185501] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A palladium (Pd)-based optical metamaterial has been designed, fabricated and characterized for its application in hydrogen sensing. The metamaterial can replace Pd thin films in optical transmission schemes for sensing with performances far superior to those of conventional sensors. This artificial material consists of a palladium-alumina metamaterial fabricated using inexpensive and industrial-friendly bottom-up techniques. During the exposure to hydrogen, the system exhibits anomalous optical absorption when compared to the well-known response of Pd thin films, this phenomenon being the key factor for the sensor sensitivity. The exposure to hydrogen produces a large variation in the light transmission through the metamembrane (more than 30% with 4% in volume hydrogen-nitrogen gas mixture at room temperature and atmospheric pressure), thus avoiding the need for sophisticated optical detection systems. An optical homogenization model is proposed to explain the metamaterial response. These results contribute to the development of reliable and low-cost hydrogen sensors with potential applications in the hydrogen economy and industrial processes to name a few, and also open the door to optically study the hydrogen diffusion processes in Pd nanostructures.
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Affiliation(s)
- A Hierro-Rodriguez
- IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Rua Campo Alegre, 4169-007 Porto, Portugal. INESC-TEC (Coordinated by INESC-Porto), Rua Campo Alegre, 4169-007 Porto, Portugal
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Kumaresavanji M, Gomes IT, Apolinario A, Rolo AG, Almeida BG, Lopes AML, Araujo JP. Ordered La0.7Sr0.3MnO3 nanohole arrays fabricated on a nanoporous alumina template by pulsed laser ablation. Nanotechnology 2016; 27:125303. [PMID: 26890216 DOI: 10.1088/0957-4484/27/12/125303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Highly ordered nanohole arrays of [Formula: see text] manganite have been synthesized using pulsed laser deposition on nanoporous alumina template. Their structure and phase formation were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive x-ray spectroscopy (EDX) and x-ray diffraction (XRD). The magnetic measurements were performed with respect to temperature and field and exhibit a ferromagnetic to paramagnetic transition at 284 K. In addition, the temperature dependence of electrical resistance was measured at different magnetic fields and an insulating phase throughout all the temperatures was observed. The low temperature ferromagnetic insulating state is discussed by the presence of a canted ferromagnetic state induced by the nanoholes. The present work shows the feasibility of combining both the nanoporous alumina template and pulsed laser ablation for the fabrication of perovskite manganite nanohole arrays which can also be extended to fabricate other multicomponent oxide nanohole materials.
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Affiliation(s)
- M Kumaresavanji
- IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Department of Physics and Astronomy, Faculty of Sciences, University of Porto, Porto, Portugal
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Sudano MJ, Rascado TDS, Tata A, Belaz KRA, Santos VG, Valente RS, Mesquita FS, Ferreira CR, Araujo JP, Eberlin MN, Landim-Alvarenga FDC. 160 LIPIDOME SIGNATURES IN EARLY BOVINE EMBRYO DEVELOPMENT. Reprod Fertil Dev 2016. [DOI: 10.1071/rdv28n2ab160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Mammalian pre-implantation embryonic development is a complex, conserved, and well-orchestrated process involving dynamic molecular and structural changes. Understanding the membrane lipid profile fluctuation during this crucial period is fundamental to address cellular and molecular mechanisms governing embryogenesis. A full understanding of stage-specific lipid signatures in early bovine embryo development is, however, still lacking. The aim of the present work was to characterise stage-specific changes in lipid profiles during early bovine embryonic development. Immature oocytes were recovered from slaughterhouse-derived bovine ovaries and assigned among 5 in vitro developmental stages for lipid characterisation: immature oocytes, 2-cell embryos (32–40 h post-insemination), 8 to 16-cell embryos (72 h post-insemination), morulas (120 h post-insemination), and blastocysts (168 h post-insemination). Two different culture media were used for in vitro embryo production, SOFaaci medium supplemented with 2.5% of serum and serum-free SOF-BE1 medium. Cytoplasmic lipid droplets content and membrane phospholipids profiles for each development stage were assessed by lipid staining (Nile red; n = 5–9) and matrix-assisted laser desorption ionization as a mass spectrometry imaging (MALDI-MS; n = 5–9), respectively. For statistical analysis, univariate and multivariate models were used to compare lipid droplets content and membrane phospholipids profiles. Cytoplasmic lipid droplets content increased from minimum in the immature oocyte stage to maximum at the morula stage, followed by a sharp drop at the blastocyst stage (58.4 ± 10.5ac, 62.5 ± 9.4ac, 85.9 ± 8.2a, 148.3 ± 7.4b, 37.4 ± 9.9c of fluorescence intensity per embryo area, respectively, for immature oocyte, 2-cells, 8 to 16-cells, morulas, and blastocysts; abcP < 0.05). More cytoplasmic lipid droplets were detected in morulas and blastocyts cultured in SOFaaci than in SOF-BE1 (morulas, 162.6 ± 11.3 v. 137.1 ± 9.2 of fluorescence intensity per embryo area, respectively, P < 0.05; blastocysts, 49.9 ± 9.9 v. 20.7 ± 9.9 of fluorescence intensity per embryo area, respectively, P < 0.05). Characteristic dynamic changes of unsaturation level, acyl chain length and class composition (phosphatidylcholines, sphingomyelins, and phosphatidylethanolamines) of phospholipid profiles were observed during early embryo development. This study provides a comprehensive analysis, involving lipid staining and mass spectrometry evaluation, of stage-specific lipid signatures during bovine in vitro embryo development. These results may be useful for assessing the role of specific lipid species during important events of embryogenesis.
Research was supported by CNPq, FAPESP, and FAPERGS.
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Araujo JP, Lorenzo JM, Cerqueira J, Vazquez JA, Pires P, Cantalapiedra J, Franco D. Minhota breed cattle: carcass characterisation and meat quality affected by sex and slaughter age. Anim Prod Sci 2016. [DOI: 10.1071/an14989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This work focuses on the effect of slaughter age (6 and 9 months) and sex on carcass characteristics and meat quality of the Minhota cattle breed. In this study, data from 52 cattle (34 entire males and 18 females) were used for the carcass and meat characterisation. Regarding carcass characteristics, entire male carcasses (158 kg and 223 kg for animals of 6 and 9 months, respectively), were heavier than female carcasses (130 kg and 161 kg for animals of 6 and 9 months, respectively), with better dressing percentages, increased lengths, thicknesses and depths and compactness indexes. The quality of meat from carcasses of both entire males and females had strong luminosity (L*), a pale pink tone (lower a*-value) and high yellowness. Mean tenderness of Longissimus thoracis, expressed as shear force, was below 5.5 kg/cm2, without significant differences (P > 0.05) between either the slaughter age or sex.
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11
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Fernández-García MP, Teixeira JM, Machado P, Oliveira MRFF, Maia JM, Pereira C, Pereira AM, Freire C, Araujo JP. Automatized and desktop AC-susceptometer for the in situ and real time monitoring of magnetic nanoparticles' synthesis by coprecipitation. Rev Sci Instrum 2015; 86:043904. [PMID: 25933868 DOI: 10.1063/1.4918723] [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] [Received: 12/24/2014] [Accepted: 04/09/2015] [Indexed: 06/04/2023]
Abstract
The main purpose of this work was to design, develop, and construct a simple desktop AC susceptometer to monitor in situ and in real time the coprecipitation synthesis of magnetic nanoparticles. The design incorporates one pair of identical pick-up sensing coils and one pair of Helmholtz coils. The picked up signal is detected by a lock-in SR850 amplifier that measures the in- and out-of-phase signals. The apparatus also includes a stirrer with 45°-angle blades to promote the fast homogenization of the reaction mixture. Our susceptometer has been successfully used to monitor the coprecipitation reaction for the synthesis of iron oxide nanoparticles.
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Affiliation(s)
- M P Fernández-García
- IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Departamento de Física e Astronomía, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - J M Teixeira
- IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Departamento de Física e Astronomía, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - P Machado
- IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Departamento de Física e Astronomía, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - M R F F Oliveira
- Departamento de Ciência de Computadores, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - J M Maia
- IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Departamento de Física e Astronomía, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - C Pereira
- REQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - A M Pereira
- IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Departamento de Física e Astronomía, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - C Freire
- REQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - J P Araujo
- IFIMUP and IN-Institute of Nanoscience and Nanotechnology, Departamento de Física e Astronomía, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
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12
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Tröger W, Dietrich M, Araujo JP, Correia JG, Haas H. The Nuclear Quadrupole Interaction of 204mPb in Cadmium Monitored by γ–γ –Perturbed Angular Correlations. ACTA ACUST UNITED AC 2014. [DOI: 10.1515/zna-2002-6-753] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
For the first time the nuclear probe 204mPb was produced at the on-line isotope separator ISOLDE at CERN and used for time differential perturbed angular correlation experiments. The electric field gradient of 204mPb at room temperature in Cd metal was determined to be = 19(1) 1021 V/m2. Ab initio-calculations of the electric field gradient for the impurities Pt to Bi in cadmium were performed with the full-potential linearized augmented plane waves code WIEN97 to interpret this result. For Au, Hg and Pb, where experimental results are now available, these agree with the calculations within 10 %.
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Affiliation(s)
- W. Tröger
- Technische Physik, Universität des Saarlandes, Saarrücken, Germany
| | - M. Dietrich
- Technische Physik, Universität des Saarlandes, Saarbrücken, Germany
- EP-Division CERN, Geneva, Switzerland
| | - J. P. Araujo
- Physics Department, University of Porto, Portugal
- EP-Division CERN, Geneva, Switzerland
| | - J. G. Correia
- Physics Department, Instituto Tecnológico e Nuclear (I.T.N.), Sacavém, Portugal
- EP-Division CERN, Geneva, Switzerland
| | - H. Haas
- Bereich Strukturforschung, Hahn-Meitner-Institut Berlin, Germany
- EP-Division CERN, Geneva, Switzerland
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13
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Proenca MP, Ventura J, Sousa CT, Vazquez M, Araujo JP. Angular first-order reversal curves: an advanced method to extract magnetization reversal mechanisms and quantify magnetostatic interactions. J Phys Condens Matter 2014; 26:116004. [PMID: 24590238 DOI: 10.1088/0953-8984/26/11/116004] [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
The magnetic properties of ordered hexagonal arrays of Co nanowires (NWs) and nanotubes (NTs) with diameters of 50 nm and interwire/tube distances of 105 nm were studied using first-order reversal curves (FORCs). We report an advanced analysis of angle dependent first-order reversal curves (AFORCs), measured by changing the angle of the applied magnetic field from θ = 0° (parallel to the wire/tube axis) to 90° (perpendicular). This method allowed us to determine the magnetization reversal mode and to retrieve quantitative information on the magnetostatic interactions between NWs and between NTs. In particular, we found a sharp increase in the coercivity distribution of the NT arrays for θ > 70°, which is attributed to a transition between vortex and transverse reversal modes. Local magnetic interactions are found to prevail in the Co NT arrays, steadily increasing from θ = 0° to 90°. However, in the Co NW arrays the mean magnetic interactions decrease as θ increases, going from ones similar to local interactions to ones smaller than them.
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Affiliation(s)
- M P Proenca
- IFIMUP and IN-Institute of Nanoscience and Nanotechnology and Departamento de Física e Astronomia, Universidade de Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal
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14
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Proenca MP, Merazzo KJ, Vivas LG, Leitao DC, Sousa CT, Ventura J, Araujo JP, Vazquez M. Co nanostructures in ordered templates: comparative FORC analysis. Nanotechnology 2013; 24:475703. [PMID: 24176913 DOI: 10.1088/0957-4484/24/47/475703] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
A comparative study on the structural and magnetic properties of highly ordered hexagonal arrays of Co nanoholes, nanowires, nanopillars and nanotubes, with tuned pore/wire/tube diameters, is here presented. The magnetic interactions and their dependence on the geometric features of the arrays were studied using first-order reversal curves (FORCs). For all nanostructures we observe an increase of the magnetostatic interactions with the templates' pore diameter, with the higher (smaller) values found for the nanowire (nanohole) arrays. For the smallest diameters studied (35 nm), all types of arrays could be considered as almost isolated nanostructures, where local interactions prevail. In particular, both nanotube and nanohole arrays exhibit considerable local magnetostatic interactions coming from the stray fields within each void or empty core. On the other hand, the coercivity is found to decrease with diameter for the elongated nanostructures, while it increases with the pore diameter for the nanohole arrays. This behavior is associated with the magnetization reversal mechanisms present in each array. This work highlights a versatile route to tailor the size, geometrical arrangement and magnetostatic interactions of ordered arrays and demonstrates their importance for the tuning of the magnetic behavior of nanometric devices.
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Affiliation(s)
- M P Proenca
- Instituto de Ciencia de Materiales de Madrid, CSIC, E-28049 Madrid, Spain. IFIMUP and IN-Institute of Nanoscience and Nanotechnology and Departamento Física e Astronomia, Universidade Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal
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15
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Lourenco P, Silva S, Frioes F, Alvelos M, Amorim M, Torres-Ramalho P, Teles MJ, Guimaraes JT, Araujo JP, Bettencourt P. The nutritional marker pre-albumin is strongly associated with adverse outcome in heart failure. Eur Heart J 2013. [DOI: 10.1093/eurheartj/eht309.p2734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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16
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Leitao DC, Ventura J, Teixeira JM, Sousa CT, Pinto S, Sousa JB, Michalik JM, De Teresa JM, Vazquez M, Araujo JP. Correlations among magnetic, electrical and magneto-transport properties of NiFe nanohole arrays. J Phys Condens Matter 2013; 25:066007. [PMID: 23315433 DOI: 10.1088/0953-8984/25/6/066007] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In this work, we use anodic aluminum oxide (AAO) templates to build NiFe magnetic nanohole arrays. We perform a thorough study of their magnetic, electrical and magneto-transport properties (including the resistance R(T), and magnetoresistance MR(T)), enabling us to infer the nanohole film morphology, and the evolution from granular to continuous film with increasing thickness. In fact, different physical behaviors were observed to occur in the thickness range of the study (2 nm < t < 100 nm). For t < 10 nm, an insulator-to-metallic crossover was visible in R(T), pointing to a granular film morphology, and thus being consistent with the presence of electron tunneling mechanisms in the magnetoresistance. Then, for 10 nm < t < 50 nm a metallic R(T) allied with a larger anisotropic magnetoresistance suggests the onset of morphological percolation of the granular film. Finally, for t > 50 nm, a metallic R(T) and only anisotropic magnetoresistance behavior were obtained, characteristic of a continuous thin film. Therefore, by combining simple low-cost bottom-up (templates) and top-down (sputtering deposition) techniques, we are able to obtain customized magnetic nanostructures with well-controlled physical properties, showing nanohole diameters smaller than 35 nm.
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Affiliation(s)
- D C Leitao
- INESC-MN and IN, Rua Alves Redol 9, 1000-029 Lisboa, Portugal.
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17
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Rascado TS, Guastali MD, Paschoal DM, Sudano MJ, Vergara LE, Mazieiro RR, Landim FC, Araujo JP. 208 COMPARISON OF THE EXPRESSION OF SOX2 AND Stat3 IN BOVINE BLASTOCYST AND HATCHED BLASTOCYST. Reprod Fertil Dev 2013. [DOI: 10.1071/rdv25n1ab208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The investigation of the transcription factors involved in the regulation of pluripotency in pre-implantation embryos of cattle provides important information regarding the early embryonic development and derivation of embryonic stem cells. The present experiment aimed to compare the level of expression of SOX 2 and Stat3, pluripotency markers, in bovine blastocysts (D7) and hatched blastocysts (D10), because it is known that around hatching, the inner cell mass (ICM) differentiates into hypoblast and epiblast. Cumulus–oocyte complexes were matured in TCM 199 for 24 h and fertilized with frozen–thawed sperm. Presumptive zygotes were cultured in SOFaaci for 7 days (group 1) and for 10 days (group 2). All embryos were washed 3 times in PBS, pooled, and frozen at –80°C until RNA extraction. For quantification of SOX2 and Stat3 mRNA levels, total RNA was isolated from pools of 7 embryos per replicate (n = 3) and for each examined developmental stage using RNeasy Micro Kit (Qiagen). The reverse transcriptase Superscript III (Invitrogen) was used for the synthesis of cDNA (cDNA), and the qPCR was performed with the Gotaq qPCR Master Mix (Promega, Madison, WI, USA). As negative control, cDNA was replaced by nuclease-free water in the qPCR reaction. Quantification of expression was determined by the relative standard curve method and normalized to the housekeeping gene YWHAZ. Standard curves for SOX2, Stat 3, and YWHAZ were derived from 10-fold serial dilutions of bovine DNA and gave correlation coefficients greater than 0.99 and efficiencies greater than 94%. The data from 3 replicates were analysed by ANOVA, and it was found that the level of SOX2 abundance is 9.8-fold higher in D7 blastocyst cells compared with D10 blastocyst cells, and the level of Stat 3 transcription is 1.5-fold higher in blastocyst cells than in hatched blastocysts. The expression of pluripotency markers SOX2 and Stat3 was significantly higher in embryos with 7 days of development because at this stage the MCI had not yet begun the process of differentiation.
Support of FAPESP is acknowledged.
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Leitao DC, Ventura J, Sousa CT, Teixeira JM, Sousa JB, Jaafar M, Asenjo A, Vazquez M, De Teresa JM, Araujo JP. Tailoring the physical properties of thin nanohole arrays grown on flat anodic aluminum oxide templates. Nanotechnology 2012; 23:425701. [PMID: 23037925 DOI: 10.1088/0957-4484/23/42/425701] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The introduction of voids in a magnetic thin-film alters the stray field distribution and enables the tailoring of the corresponding physical properties. Here we present a detailed study on thin magnetic nanohole arrays (NhAs) grown on top of hexagonally-ordered anodic aluminum oxide (AAO) substrates. We address the effect of AAO topography on the corresponding electrical and magneto-transport properties. Optimization of the AAO topography led to NhAs with improved resistance and magnetoresistance responses, while retaining their most important feature of enhanced coercivity. This opens new pathways for the growth of more complex structures on AAO substrates, a crucial aspect for their technological viability.
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Affiliation(s)
- D C Leitao
- INESC-MN and IN, Rua Alves Redol 9, 1000-029 Lisboa, Portugal.
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19
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Mattoso CRS, Takahira RK, Beier SL, Araujo JP, Corrente JE. Evaluation of von Willebrand Factor During Pregnancy, Lactation and Oestrous Cycle in Bitches Affected and Unaffected by von Willebrand Disease. Reprod Domest Anim 2012; 48:416-22. [DOI: 10.1111/rda.12089] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 08/25/2012] [Indexed: 11/29/2022]
Affiliation(s)
- CRS Mattoso
- School of Veterinary Medicine and Animal Science; São Paulo State University; Botucatu; São Paulo; Brazil
| | - RK Takahira
- School of Veterinary Medicine and Animal Science; São Paulo State University; Botucatu; São Paulo; Brazil
| | - SL Beier
- School of Veterinary Medicine, Agricultural and Animal Sciences Center; Santa Catarina State University; Lages; Santa Catarina; Brazil
| | - JP Araujo
- Biosciences Institute; São Paulo State University; Botucatu; São Paulo; Brazil
| | - JE Corrente
- Biosciences Institute; São Paulo State University; Botucatu; São Paulo; Brazil
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20
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Sousa CT, Apolinario A, Leitao DC, Pereira AM, Ventura J, Araujo JP. Precise control of the filling stages in branched nanopores. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm14828e] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Teixeira JM, Ventura J, Araujo JP, Sousa JB, Wisniowski P, Cardoso S, Freitas PP. Resonant tunneling through electronic trapping states in thin MgO magnetic junctions. Phys Rev Lett 2011; 106:196601. [PMID: 21668184 DOI: 10.1103/physrevlett.106.196601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Indexed: 05/30/2023]
Abstract
We report an inelastic electron tunneling spectroscopy study on MgO magnetic junctions with thin barriers (0.85-1.35 nm). Inelastic electron tunneling spectroscopy reveals resonant electronic trapping within the barrier for voltages V>0.15 V. These trapping features are associated with defects in the barrier crystalline structure, as confirmed by high-resolution transmission electron microscopy. Such defects are responsible for resonant tunneling due to energy levels that are formed in the barrier. A model was applied to determine the average location and energy level of the traps, indicating that they are mostly located in the middle of the MgO barrier, in accordance with the high-resolution transmission electron microscopy data and trap-assisted tunneling conductance theory. Evidence of the influence of trapping on the voltage dependence of tunnel magnetoresistance is shown.
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Affiliation(s)
- J M Teixeira
- IFIMUP and IN-Institute of Nanoscience and Nanotechnology, and Departamento de Fisica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal.
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22
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Teixeira JM, Lusche R, Ventura J, Fermento R, Carpinteiro F, Araujo JP, Sousa JB, Cardoso S, Freitas PP. Versatile, high sensitivity, and automatized angular dependent vectorial Kerr magnetometer for the analysis of nanostructured materials. Rev Sci Instrum 2011; 82:043902. [PMID: 21529020 DOI: 10.1063/1.3579497] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Magneto-optical Kerr effect (MOKE) magnetometry is an indispensable, reliable, and one of the most widely used techniques for the characterization of nanostructured magnetic materials. Information, such as the magnitude of coercive fields or anisotropy strengths, can be readily obtained from MOKE measurements. We present a description of our state-of-the-art vectorial MOKE magnetometer, being an extremely versatile, accurate, and sensitivity unit with a low cost and comparatively simple setup. The unit includes focusing lenses and an automatized stepper motor stage for angular dependent measurements. The performance of the magnetometer is demonstrated by hysteresis loops of Co thin films displaying uniaxial anisotropy induced on growth, MnIr/CoFe structures exhibiting the so called exchange bias effect, spin valves, and microfabricated flux guides produced by optical lithography.
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Affiliation(s)
- J M Teixeira
- IFIMUP and IN-Institute of Nanoscience and Nanotechnology, and Departamento de Fisica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal.
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23
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Pereira AM, Soares JC, Ventura J, Sousa JB, Araujo JP, Oliveira JCRE. Influence of micro-channel shape and magnetic material on the magneto-refrigeration process of integrated circuits. J Nanosci Nanotechnol 2010; 10:2590-2593. [PMID: 20355468 DOI: 10.1166/jnn.2010.1421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We developed a two dimensional transient numerical model that solves the first step of heat transfer of an active magnetic regenerative refrigerator (AMR) using the heat conduction equation for an adiabatic system. For micro-refrigeration, an AMR device is constituted by a magnetic material, placed on a silicon wafer containing micro-channels where a heat exchanging fluid flows. The magnetic materials used in the simulations are the promising the Gd5Si2Ge2, La(Fe0.88Si0.22)13 and La0.66Sr0.33MnO3 compounds, because they exhibit a giant magnetocaloric effect near room temperature. We considered different initial conditions, namely different micro-channel shapes, sizes and separations, aiming to increase the performance of the micro-cooler device. The influence of the thickness of the magnetic material on refrigeration power is also studied.
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Affiliation(s)
- A M Pereira
- IN, IFIMUP unit, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
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Ventura J, Teixeira JM, Araujo JP, Sousa JB, Ferreira R, Freitas PP, Langer J, Ocker B, Maass W. Influence of pinholes on MgO-tunnel junction barrier parameters obtained from current-voltage characteristics. J Nanosci Nanotechnol 2010; 10:2731-2734. [PMID: 20355492 DOI: 10.1166/jnn.2010.1377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Magnetic tunnel junctions (MTJs) with thin barriers are already used as read sensors in recording media. However, the presence of pinholes across such few A thick barriers cannot be excluded and one needs to investigate their effect on the MTJ-transport properties. By applying large electrical currents we could change the electrical resistance of the studied MgO MTJs (due to pinhole-size variations), and study how pinholes influence the barrier parameters (thickness t and height phi) obtained by fitting current-voltage characteristics to Simmons' model. We found that, with decreasing resistance, the barrier thickness (height) decreases (increases). These results were well reproduced by a model of parallel-resistances, allowing us to estimate pinhole-free barrier parameters.
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Affiliation(s)
- J Ventura
- IN, IFIMUP Unit, Rua do Campo Alegre, 687, 4169-007, Porto, Portugal
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Leitao DC, Sousa CT, Ventura J, Carpinteiro F, Correia JG, Amado MM, Sousa JB, Araujo JP. Influence of surface pre-treatment in the room temperature fabrication of nanoporous alumina. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/pssc.200779430] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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26
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Oliveira MCS, Oliveira-Sequeira TCG, Araujo JP, Amarante AFT, Oliveira HN. Babesia spp. infection in Boophilus microplus engorged females and eggs in São Paulo State, Brazil. Vet Parasitol 2005; 130:61-7. [PMID: 15893070 DOI: 10.1016/j.vetpar.2005.03.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/10/2005] [Indexed: 11/27/2022]
Abstract
Babesia spp. infections were investigated in Bos taurus x Bos indicus dairy cows and calves and in Boophilus microplus engorged female ticks and eggs. Blood samples and engorged female ticks were collected from 25 cows and 27 calves. Babesia spp. was detected in ticks by microscopic examination of hemolymph of engorged female and by squashes of egg samples. Cattle infection was investigated in blood thin smears and by DNA amplification methods (PCR and nested PCR), using specific primers for Babesia bovis and Babesia bigemina. Merozoites of B. bovis (3 animals) and B. bigemina (12 animals) were detected exclusively in blood smears of calves. DNA amplification methods revealed that the frequency of B. bigemina infection in calves (92.6%) and in cows (84%) and of B. bovis in calves (85.2%) and in cows (100%) did not differ significantly (P > 0.05). Babesia spp. infection was more frequent in female ticks and eggs collected from calves (P < 0.01) than from cows, especially in those which had patent parasitemia. Hatching rates of B. microplus larvae were assessed according to the origin of engorged females, parasitemia of the vertebrate host, frequency and intensity of infection in engorged female tick, and frequency of egg infection. Hatching rate was lower in samples collected from calves (P < 0.01) than from cows, and in those in which Babesia spp. was detected in egg samples (P < 0.01).
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Affiliation(s)
- M C S Oliveira
- Embrapa-Pecuária Sudeste, Rodovia Washington Luiz, km 234, Caixa Postal 339, CEP 13560-970 São Carlos, SP, Brazil.
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Oliveira-Sequeira TCG, Oliveira MCS, Araujo JP, Amarante AFT. PCR-based detection of Babesia bovis and Babesia bigemina in their natural host Boophilus microplus and cattle. Int J Parasitol 2005; 35:105-11. [PMID: 15619521 DOI: 10.1016/j.ijpara.2004.09.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Revised: 09/10/2004] [Accepted: 09/12/2004] [Indexed: 11/19/2022]
Abstract
PCR and nested-PCR methods were used to assess the frequency of Babesia bovis and Babesia bigemina infection in Boophilus microplus engorged females and eggs and in cattle reared in an area with endemic babesiosis. Blood and the engorged female ticks were from 27 naturally infested calves and 25 crossbred cows. The frequency of both Babesia species was similar in calves and cows (P>0.05). Babesia bovis was detected in 23 (85.2%) calves and in 25 (100%) cows and B. bigemina was detected in 25 (92.6%) calves and in 21 (84%) cows. Mixed infections with the both Babesia species were identified in 42 animals, 21 in each age category. Of female ticks engorged on calves, 34.9% were negative and single species infection with B. bigemina (56.2%) was significantly more frequent (P<0.01) than with B. bovis (4.7%). Most of the females (60.8%) engorged on cows did not show Babesia spp. infection and the frequency of single B. bovis infection (17.6%) was similar (P>0.05) to the frequency of single B. bigemina infection (15.9%). Mixed Babesia infection was lower (P<0.01) than single species infection in female ticks engorged either in cows (5.7%) or in calves (4.3%). An egg sample from each female was analysed for the presence of Babesia species. Of the egg samples from female ticks infected with B. bovis, 26 (47.3%) were infected while from those from female ticks infected with B. bigemina 141 (76.6%) were infected (P<0.01). The results showed that although the frequency of both species of Babesia was similar in calves and cows, the infectivity of B. bigemina was higher to ticks fed on calves while to those ticks fed on cows the infectivity of both Babesia species was similar.
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Affiliation(s)
- T C G Oliveira-Sequeira
- Departamento de Parasitologia, Instituto de Biociências, Unesp, Botucatu, SP 18618-000, Brazil.
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