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Oliveira IS, Lima JS, Freitas A, Bezerra CG, Azevedo S, Machado LD. Investigating size effects in graphene-BN hybrid monolayers: a combined density functional theory-molecular dynamics study. RSC Adv 2021; 11:12595-12606. [PMID: 35423788 PMCID: PMC8697127 DOI: 10.1039/d1ra00316j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 03/18/2021] [Indexed: 12/28/2022] Open
Abstract
We combine Density Functional Theory (DFT) and classical Molecular Dynamics (MD) simulations to study graphene-boron nitride (BN) hybrid monolayers spanning a wide range of sizes (from 2 nm to 100 nm). Our simulations show that the elastic properties depend on the fraction of BN contained in the monolayer, with Young's modulus values decreasing as the BN concentration increases. Furthermore, our calculations reveal that the mechanical properties are weakly anisotropic. We also analyze the evolution of the stress distribution during our MD simulations. Curiously, we find that stress does not concentrate on the graphene-BN interface, even though fracture always starts in this region. Hence, we find that fracture is caused by the lower strength of C-N and C-B bonds, rather than by high local stress values. Still, in spite of the fact that the weaker bonds in the interface region become a lower fraction of the total as size increases, we find that the mechanical properties of the hybrid monolayers do not depend on the size of the structure, for constant graphene/BN concentrations. Our results indicate that the mechanical properties of the hybrid monolayers are independent of scale, so long as the graphene sheet and the h-BN nanodomain decrease or increase proportionately.
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Affiliation(s)
- I S Oliveira
- Departamento de Física, CCEN, Universidade Federal da Paraíba Caixa Postal 5008 58051-970 João Pessoa PB Brazil
| | - J S Lima
- Departamento de Física, Universidade Federal do Rio Grande do Norte 59072-970 Natal RN Brazil
| | - A Freitas
- Departamento de Física, Universidade Federal do Rio Grande do Norte 59072-970 Natal RN Brazil
| | - C G Bezerra
- Departamento de Física, Universidade Federal do Rio Grande do Norte 59072-970 Natal RN Brazil
| | - S Azevedo
- Departamento de Física, CCEN, Universidade Federal da Paraíba Caixa Postal 5008 58051-970 João Pessoa PB Brazil
| | - L D Machado
- Departamento de Física, Universidade Federal do Rio Grande do Norte 59072-970 Natal RN Brazil
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Nascimento M, Chencarek B, Souza AM, Sarthour RS, Coutinho B, Correia MD, Oliveira IS. Enhanced NMR relaxation of fluids confined to porous media: A proposed theory and experimental tests. Phys Rev E 2019; 99:042901. [PMID: 31108641 DOI: 10.1103/physreve.99.042901] [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: 11/12/2018] [Indexed: 06/09/2023]
Abstract
We propose a theory to account for the NMR relaxation of water protons in situations in which the fluid is confined to porous structures exhibiting a scarce distribution of paramagnetic centers on their surface. Though much of what is stated and assumed concerns the response of water, the model has sufficiently general features to be able to explain proton relaxation of other polar fluids under similar conditions. One of the main results of the paper is to show that the local anisotropy introduced by the dominant dipolar coupling in the relaxation rates of active surface elements induces a measurable dependence on sample orientation in the overall relaxation rates of the saturating fluid provided its confining structure is not statistically isotropic. Measurements of T_{1} proton relaxation on water saturating microcapillary tubes are performed to reveal the effect.
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Affiliation(s)
- M Nascimento
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150 Ed. Cesar Lattes, Urca, Rio de Janeiro, RJ. CEP 22290-180, Brazil
- Centro de Pesquisas e Desenvolvimento Leopoldo Américo Miguez de Mello-CENPES/PETROBRAS, Av. Horácio Macedo, 950, Cidade Universitária, Rio de Janeiro, RJ 21941-915, Brazil
| | - B Chencarek
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150 Ed. Cesar Lattes, Urca, Rio de Janeiro, RJ. CEP 22290-180, Brazil
| | - A M Souza
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150 Ed. Cesar Lattes, Urca, Rio de Janeiro, RJ. CEP 22290-180, Brazil
| | - R S Sarthour
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150 Ed. Cesar Lattes, Urca, Rio de Janeiro, RJ. CEP 22290-180, Brazil
| | - B Coutinho
- Centro de Pesquisas e Desenvolvimento Leopoldo Américo Miguez de Mello-CENPES/PETROBRAS, Av. Horácio Macedo, 950, Cidade Universitária, Rio de Janeiro, RJ 21941-915, Brazil
| | - M D Correia
- Centro de Pesquisas e Desenvolvimento Leopoldo Américo Miguez de Mello-CENPES/PETROBRAS, Av. Horácio Macedo, 950, Cidade Universitária, Rio de Janeiro, RJ 21941-915, Brazil
| | - I S Oliveira
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150 Ed. Cesar Lattes, Urca, Rio de Janeiro, RJ. CEP 22290-180, Brazil
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Sousa GA, Oliveira IS, Silva-Freitas FV, Viana AFSC, Neto BPS, Cunha FVM, Gonçalves RLG, Lima Filho ACM, Amaral MPM, Oliveira RDCM, Fernandes PD, Maciel JKS, da Silva TMS, Souza MDFV, Oliveira FA. Gastroprotective effect of ethanol extracts of cladodes and roots of Pilosocereus gounellei (A. Weber ex K. Schum.) Bly. Ex Rowl (Cactaceae) on experimental ulcer models. J Ethnopharmacol 2018; 218:100-108. [PMID: 29471086 DOI: 10.1016/j.jep.2018.02.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [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: 06/11/2016] [Revised: 09/07/2017] [Accepted: 02/05/2018] [Indexed: 06/08/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Pilosocereus gounellei Cactaceae), popularly known as "xique xique", is a species native from Caatinga region of Northeast Brazil, which is used by traditional communities in folk medicine for a variety of health problems, especially inflammatory processes and gastritis. AIM OF THE STUDY The present study investigates the possible gastric antiulceractivity of ethanol extracts obtained from the cladodes and roots of Pilosocereus gounellei (EECPG and EERPG, respectively) and mechanisms of action underlying this effect. MATERIALS AND METHODS Mice were used for the evaluation of the acute toxicity, and mice and rats to study the gastroprotective activity. The gastroprotective action of EECPG and EERPG was analyzed in the absolute ethanol in mice, ischemia-reperfusion and cold restraint stress in rats. In the investigation of the gastroprotective mechanisms of EECPG and EERPG, the participation of the NO and prostaglandins, the levels of the non-protein sulfhydril groups (NP-SH) and the catalase activity using the ethanol-induced gastric mucosa lesion model and the quantification of the gastric mucus and the antisecretory activity through pylorus ligature model in rats were analyzed. RESULTS The animals did not present any signs of acute toxicity for the EECPG and EERPG, and it was not possible to calculate the DL50. EECPG and EERPG (200 and 400 mg/kg) exhibited a significant gastroprotective effect in absolute ethanol, ischemia-reperfusion-induced and cold restraint stress gastric lesion models. Gastroprotection of EECPG and EERPG (200 mg/kg) was significantly decreased in pre-treated mice with L-NAME. Our studies revealed that EECPG and EERPG (200 mg/kg) prevented the decrease of the non-protein sulfhydril groups (NPSH) and increased the catalase levels in ethanol-treated animals. However, the gastric secretion parameters (volume, [H+], pH) did not show any alteration. CONCLUSIONS Our results indicate that the ethanolic extract from the cladodes and roots of Pilosocereus gounellei exhibits a significant gastroprotection, because it inhibits the formation of gastric lesions using different models. The participation of the nitric oxide, prostaglandins, the non-protein sulfhydril groups (NP-SH), catalase seem to be involved in the gastroprotection activity of the EECPG and EERPG. Nevertheless, this activity does not seem to be related to antisecretory mechanisms.
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Affiliation(s)
- Glaubert A Sousa
- Medicinal Plants Research Center, Federal University of Piauí, (unnumbered), 64049-550 Teresina, Piauí, Brazil.
| | - Irisdalva S Oliveira
- Medicinal Plants Research Center, Federal University of Piauí, (unnumbered), 64049-550 Teresina, Piauí, Brazil.
| | - Francilene V Silva-Freitas
- Medicinal Plants Research Center, Federal University of Piauí, (unnumbered), 64049-550 Teresina, Piauí, Brazil.
| | - Ana Flávia S C Viana
- Rua Capitao Francisco Pedro, 1016, Bairro: Rodolfo Teófilo, 60430372 Fortaleza, Ceará, Brazil.
| | - Benedito P S Neto
- Medicinal Plants Research Center, Federal University of Piauí, (unnumbered), 64049-550 Teresina, Piauí, Brazil.
| | - Francisco Valmor M Cunha
- Medicinal Plants Research Center, Federal University of Piauí, (unnumbered), 64049-550 Teresina, Piauí, Brazil.
| | - Rodrigo L G Gonçalves
- Medicinal Plants Research Center, Federal University of Piauí, (unnumbered), 64049-550 Teresina, Piauí, Brazil.
| | - Antônio Carlos M Lima Filho
- Medicinal Plants Research Center, Federal University of Piauí, (unnumbered), 64049-550 Teresina, Piauí, Brazil.
| | - Maurício P M Amaral
- Medicinal Plants Research Center, Federal University of Piauí, (unnumbered), 64049-550 Teresina, Piauí, Brazil.
| | - Rita de Cássia M Oliveira
- Medicinal Plants Research Center, Federal University of Piauí, (unnumbered), 64049-550 Teresina, Piauí, Brazil.
| | - Pedro D Fernandes
- Department of Agroecology and Agriculture, Center of Agricultural and Environmental Sciences, University of Paraiba State, 351, Baraúnas Street, Campina Grande, PB 58429-500, Brazil.
| | - Jéssica K S Maciel
- Post-Graduation Program in Development and Technological Innovation in Medicines, Health Science Center, Federal University of Paraiba, Campus I, João Pessoa PB 58051-900, Brazil.
| | - Tânia Maria S da Silva
- Postgraduate Program in Development and Technological Innovation in Medicines, Departmente of Molecular Sciences, Rural Federal University of Pernambuco, Campus Dois Irmãos Recife, PE 52171-900, Brazil.
| | - Maria de Fátima V Souza
- Post-Graduation Program in Development and Technological Innovation in Medicines, Health Science Center, Federal University of Paraiba, Campus I, João Pessoa PB 58051-900, Brazil.
| | - Francisco A Oliveira
- Medicinal Plants Research Center, Federal University of Piauí, (unnumbered), 64049-550 Teresina, Piauí, Brazil.
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Ferreira IDL, Oliveira IS. Efetividade de Materiais Reembasadores em Prótese Total: uma Revisão de Propriedades. J Health Scie 2018. [DOI: 10.17921/2447-8938.2017v19n5p33] [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: 11/24/2022] Open
Abstract
Este estudo visa avaliar as propriedades e, por conseguinte, a eficácia dos reembasadores definitivos e temporários, de acordo com as necessidades específicas de cada paciente. Utilizou-se as bases de dados BVS e Scielo, com os descritores: denture liners, complete denture, dental materials, encontrando-se 23 artigos publicados no período entre 2012 e 2016, sendo 12 selecionados através da análise dos objetivos e resultados alcançados, a fim de levantar dados que propusessem uma avaliação da durabilidade e propriedades mecânicas dos reembasadores. Os materiais de reembasamento do tipo rígido, geralmente utilizados nas técnicas de reembasamento definitivo, conhecidos como “hard liners” apresentam menor porosidade e propagação de calor, maior longevidade e equilíbrio na coloração, se comparado às resinas resilientes, também chamadas de “soft liners”, mais comuns na utilização de técnicas de reembasamento temporário. A eficiência dos materiais de reembasamento é medida por meio da capacidade de adesão a base da prótese, biocompatibilidade, ausência de desgaste na coloração, dimensão estável e propriedade insípida e inodora. A indicação dos materiais e a técnica utilizada, portanto, apresenta especificidade a depender do caso clínico.Palavras-chave: Denture Liners. Complete Denture. Dental Materials.
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Mendonça AKR, Bastos ACN, Lima AL, Silva JC, Oliveira IS, Filho EJA, Lemos MVS, Motoyama PRP, Mendonça JS, Mendes TAD. Uso dos Oxalatos no Tratamento da Hipersensibilidade Dentinária: uma Revisão de Literatura. J Health Scie 2018. [DOI: 10.17921/2447-8938.2017v19n5p169] [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: 11/24/2022] Open
Abstract
O objetivo deste estudo é avaliar a eficácia dos Oxalatos (OX) de cálcio e potássio no tratamento da hipersensibilidade dentinária. Revisou-se a literatura de artigos publicados no período de 2007 a 2017 nas bases de dados PubMed, Bireme e Science Direct, no idioma Inglês, utilizando os seguintes descritores: Calcium Oxalate, Hypersensitivy e Dentin. Foram encontrados 16 artigos, realizou-se uma leitura crítica dos resumos e títulos. Desses, 14 são estudos in vitro, 1 estudo clínico e 1 revisão de literatura, sendo excluídos artigos que fugiam do objetivo do estudo. Selecionou-se 9 artigos mediante a relevância ao tema. A hipersensibilidade dentinária (HD) é caracterizada por uma dor transitória ocasionada quando dente é submetido a estímulos químicos, térmicos, tácteis e osmóticos. O oxalato de cálcio ou de potássio irá agir na terapêutica da HD, através da oclusão desses túbulos dentinários expostos, formando cristais insolúveis provenientes da reação do ácido oxálico com o cálcio ou potássio, podendo ligar-se a ânions presentes nas proteínas em dentina, dessa forma irá diminuir o fluxo dos fluidos entre o dente e o meio oral reduzindo a sintomatologia dolorosa. Porém as condições do meio oral influenciam na durabilidade, já que há uma penetrabilidade de apenas 2 a 3 micrômetros sendo resistentes ao desafio ácido. A dentina tratada com OX podem apresentar alterações na sua estrutura. Não há avaliações suficientes ao longo prazo, necessitando-se de mais investigações sobre novas formulações de pastas e géis a base de OX, além de mais estudos clínicos.Palavras-chave: Calcium Oxalate. Hypersensitivy.e Dentin.
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Mendes TAD, De Paula DM, Oliveira IS, Mendonça JS, Feitosa VP. Utilização Técnicas com o Etanol Absoluto como Pré-Tratamento para Cimentação de Pinos de Fibra de Vidro à Dentina Radicular. J Health Scie 2018. [DOI: 10.17921/2447-8938.2017v19n5p60] [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: 11/24/2022] Open
Abstract
O presente trabalho objetivou avaliar a utilização de técnicas com o etanol absoluto (EA) como pré-tratamento para cimentação de pino de fibra de vidro à dentina radicular. Foram utilizadas 25 raízes mesiais de primeiros molares humanos inferiores. Posteriormente, os condutos foram preparados de acordo com uma broca indicada pelo fabricante para os pinos de numeração 3 (Angelus). Foram formulados cimentos resinosos duais experimentais, sendo um hidrofóbico para as técnicas com o uso de EA e outro um convencional para o CONTROLE. Os protocolos de cimentação com EA foram feitos pela técnica úmida etanólica (TUE) trocando as soluções a cada 15 seg por 1 min ou pela técnica de saturação (SAT) de dentina com EA por 1 min sem troca. Daí os grupos foram divididos da seguinte maneira: 1-CONTROLE: ácido fosfórico (OPA) + ativador + “primer” + “Bond” + cimento 2-TUE: OPA + TUE + cimento 3-TUE+B: OPA + TUE+ ativador + ”Bond” + cimento 4-SAT: OPA + SAT + cimento 5-SAT+B: OPA + SAT + ativador + “Bond” + cimento. Após a cimentação, os espécimes foram armazenados em água destilada por 7 dias a 37ºC e em seguida seccionados com 1 mm de espessura para a realização do teste de push-out (n5). Foi realizado o teste ANOVA um fator e Tukey (p<0,05). O SAT+B (15,55±2,91 MPa) e TUE+B (15,32±2,68 MPa) mostraram os melhores resultados de resistência de união. Isso comprova que o uso de EA como pré-tratamento de cimentação de pino de fibra de vidro melhora a resistência de união de maneira imediata, quando associada com um bond hidrofóbico.Palavras-chave: Etanol. Cimento Resinoso. Dentina.
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Peterson JPS, Sarthour RS, Souza AM, Oliveira IS, Goold J, Modi K, Soares-Pinto DO, Céleri LC. Experimental demonstration of information to energy conversion in a quantum system at the Landauer limit. Proc Math Phys Eng Sci 2016; 472:20150813. [PMID: 27274690 DOI: 10.1098/rspa.2015.0813] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Landauer's principle sets fundamental thermodynamical constraints for classical and quantum information processing, thus affecting not only various branches of physics, but also of computer science and engineering. Despite its importance, this principle was only recently experimentally considered for classical systems. Here we employ a nuclear magnetic resonance set-up to experimentally address the information to energy conversion in a quantum system. Specifically, we consider a three nuclear spins [Formula: see text] (qubits) molecule-the system, the reservoir and the ancilla-to measure the heat dissipated during the implementation of a global system-reservoir unitary interaction that changes the information content of the system. By employing an interferometric technique, we were able to reconstruct the heat distribution associated with the unitary interaction. Then, through quantum state tomography, we measured the relative change in the entropy of the system. In this way, we were able to verify that an operation that changes the information content of the system must necessarily generate heat in the reservoir, exactly as predicted by Landauer's principle. The scheme presented here allows for the detailed study of irreversible entropy production in quantum information processors.
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Affiliation(s)
- J P S Peterson
- Centro Brasileiro de Pesquisas Físicas , Rua Dr Xavier Sigaud 150, 22290-180 Rio de Janeiro, Brazil
| | - R S Sarthour
- Centro Brasileiro de Pesquisas Físicas , Rua Dr Xavier Sigaud 150, 22290-180 Rio de Janeiro, Brazil
| | - A M Souza
- Centro Brasileiro de Pesquisas Físicas , Rua Dr Xavier Sigaud 150, 22290-180 Rio de Janeiro, Brazil
| | - I S Oliveira
- Centro Brasileiro de Pesquisas Físicas , Rua Dr Xavier Sigaud 150, 22290-180 Rio de Janeiro, Brazil
| | - J Goold
- The Abdus Salam International Centre for Theoretical Physics (ICTP) , Trieste, Italy
| | - K Modi
- School of Physics and Astronomy, Monash University , Victoria 3800, Australia
| | - D O Soares-Pinto
- Instituto de Física de São Carlos, Universidade de São Paulo , CP 369, 13560-970, São Carlos, SP, Brazil
| | - L C Céleri
- Instituto de Física, Universidade Federal de Goiás , Caixa Postal 131 74001-970, Goiânia, Brazil
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Batalhão TB, Souza AM, Sarthour RS, Oliveira IS, Paternostro M, Lutz E, Serra RM. Irreversibility and the Arrow of Time in a Quenched Quantum System. Phys Rev Lett 2015; 115:190601. [PMID: 26588367 DOI: 10.1103/physrevlett.115.190601] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Indexed: 06/05/2023]
Abstract
Irreversibility is one of the most intriguing concepts in physics. While microscopic physical laws are perfectly reversible, macroscopic average behavior has a preferred direction of time. According to the second law of thermodynamics, this arrow of time is associated with a positive mean entropy production. Using a nuclear magnetic resonance setup, we measure the nonequilibrium entropy produced in an isolated spin-1/2 system following fast quenches of an external magnetic field. We experimentally demonstrate that it is equal to the entropic distance, expressed by the Kullback-Leibler divergence, between a microscopic process and its time reversal. Our result addresses the concept of irreversibility from a microscopic quantum standpoint.
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Affiliation(s)
- T B Batalhão
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Avenida dos Estados 5001, 09210-580 Santo André, São Paulo, Brazil
- Faculty of Physics, University of Vienna, Boltzmangasse 5, Vienna A-1090, Austria
| | - A M Souza
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Rio de Janeiro, Brazil
| | - R S Sarthour
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Rio de Janeiro, Brazil
| | - I S Oliveira
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Paternostro
- Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Queen's University, Belfast BT7 1NN, United Kingdom
| | - E Lutz
- Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - R M Serra
- Department of Physics, University of York, York YO10 5DD, United Kingdom
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Auccaise R, Araujo-Ferreira AG, Sarthour RS, Oliveira IS, Bonagamba TJ, Roditi I. Spin squeezing in a quadrupolar nuclei NMR system. Phys Rev Lett 2015; 114:043604. [PMID: 25679893 DOI: 10.1103/physrevlett.114.043604] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Indexed: 06/04/2023]
Abstract
We have produced and characterized spin-squeezed states at a temperature of 26 °C in a nuclear magnetic resonance quadrupolar system. The experiment was carried out on 133Cs nuclei of spin I=7/2 in a sample of lyotropic liquid crystal. The source of spin squeezing was identified as the interaction between the quadrupole moment of the nuclei and the electric field gradients present within the molecules. We use the spin angular momentum representation to describe formally the nonlinear operators that produce the spin squeezing on a Hilbert space of dimension 2I+1=8. The quantitative and qualitative characterization of this spin-squeezing phenomenon is expressed by a squeezing parameter and squeezing angle developed for the two-mode Bose-Einstein condensate system, as well as by the Wigner quasiprobability distribution function. The generality of the present experimental scheme points to potential applications in solid-state physics.
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Affiliation(s)
- R Auccaise
- Departamento de Física, Universidade Estadual de Ponta Grossa, Av. Carlos Cavalcanti, 4748, 84030-900 Ponta Grossa, Paraná, Brazil
| | - A G Araujo-Ferreira
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, São Paulo, Brazil
| | - R S Sarthour
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Rio de Janeiro, Brazil
| | - I S Oliveira
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Rio de Janeiro, Brazil
| | - T J Bonagamba
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, São Paulo, Brazil
| | - I Roditi
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Rio de Janeiro, Brazil
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Correia MD, Souza AM, Sinnecker JP, Sarthour RS, Santos BCC, Trevizan W, Oliveira IS. Superstatistics model for T₂ distribution in NMR experiments on porous media. J Magn Reson 2014; 244:12-17. [PMID: 24819425 DOI: 10.1016/j.jmr.2014.04.013] [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] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 04/10/2014] [Accepted: 04/12/2014] [Indexed: 06/03/2023]
Abstract
We propose analytical functions for T2 distribution to describe transverse relaxation in high- and low-fields NMR experiments on porous media. The method is based on a superstatistics theory, and allows to find the mean and standard deviation of T2, directly from measurements. It is an alternative to multiexponential models for data decay inversion in NMR experiments. We exemplify the method with q-exponential functions and χ(2)-distributions to describe, respectively, data decay and T2 distribution on high-field experiments of fully water saturated glass microspheres bed packs, sedimentary rocks from outcrop and noisy low-field experiment on rocks. The method is general and can also be applied to biological systems.
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Affiliation(s)
- M D Correia
- Petróleo Brasileiro S.A., PETROBRAS, Centro de Pesquisas Leopoldo Miguez de Mello, CENPES, Av. Horácio Macedo, 950, Cidade Universitária, Rio de Janeiro, RJ CEP: 21.941-915, Brazil; Centro Brasileiro de Pesquisas Físicas, CBPF, Rua Dr. Xavier Sigaud, 150, Urca, Rio de Janeiro, RJ CEP: 22290-180, Brazil.
| | - A M Souza
- Centro Brasileiro de Pesquisas Físicas, CBPF, Rua Dr. Xavier Sigaud, 150, Urca, Rio de Janeiro, RJ CEP: 22290-180, Brazil
| | - J P Sinnecker
- Centro Brasileiro de Pesquisas Físicas, CBPF, Rua Dr. Xavier Sigaud, 150, Urca, Rio de Janeiro, RJ CEP: 22290-180, Brazil
| | - R S Sarthour
- Centro Brasileiro de Pesquisas Físicas, CBPF, Rua Dr. Xavier Sigaud, 150, Urca, Rio de Janeiro, RJ CEP: 22290-180, Brazil
| | - B C C Santos
- Petróleo Brasileiro S.A., PETROBRAS, Centro de Pesquisas Leopoldo Miguez de Mello, CENPES, Av. Horácio Macedo, 950, Cidade Universitária, Rio de Janeiro, RJ CEP: 21.941-915, Brazil
| | - W Trevizan
- Petróleo Brasileiro S.A., PETROBRAS, Centro de Pesquisas Leopoldo Miguez de Mello, CENPES, Av. Horácio Macedo, 950, Cidade Universitária, Rio de Janeiro, RJ CEP: 21.941-915, Brazil
| | - I S Oliveira
- Centro Brasileiro de Pesquisas Físicas, CBPF, Rua Dr. Xavier Sigaud, 150, Urca, Rio de Janeiro, RJ CEP: 22290-180, Brazil
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11
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Silva FV, Oliveira IS, Figueiredo KA, Júnior FBM, Costa DA, Chaves MH, Amaral MPM, Almeida FRC, Oliveira FA, Oliveira RCM. Anti-inflammatory and antinociceptive effects of Sterculia striata A. St.-Hil. & Naudin (Malvaceae) in rodents. J Med Food 2014; 17:694-700. [PMID: 24476221 DOI: 10.1089/jmf.2013.0062] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [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: 11/13/2022] Open
Abstract
The present work reports the anti-inflammatory and antinociceptive activities of the ethanol extract obtained from the stem bark of Sterculia striata A. St.-Hil. & Naudin (Ss-EtOH) in the experimental models of edema induced by carrageenan, dextran, or histamin and nociception induced by chemical stimuli, such as acetic acid, formalin, capsaicin, or glutamate. The Ss-EtOH (50 mg/kg) promoted a marked inhibition on the hind paw edema induced by carrageenan or dextran (30% and 73%, respectively). Besides, Ss-EtOH (25 mg/kg) exhibited a slight activity (30%) on the hind paw edema induced by histamin. The Ss-EtOH (12.5 and 25 mg/kg) showed the antinociceptive activity on chemical stimuli induced by acetic acid (65.59% and 38.37%, respectively), formalin, in the initial (35.08% and 31.5%, respectively) and late phases (44.09% and 83.57%, respectively), capsaicin (43.77% and 51.31%, respectively), or glutamate (36.6% and 52.12%, respectively). Regarding the possible mechanism involved in the antinociceptive effect, Ss-EtOH (12.5 mg/kg) showed a decrease in the antinociceptive effect (65.8%) in the acetic acid model after pretreatment with naloxone. Thus, opioid mechanisms might be underlying this response.
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Affiliation(s)
- Francilene V Silva
- 1 Medicinal Plants Research Center, Federal University of Piauí , Teresina, PI, Brazil
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12
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Paula FM, Silva IA, Montealegre JD, Souza AM, deAzevedo ER, Sarthour RS, Saguia A, Oliveira IS, Soares-Pinto DO, Adesso G, Sarandy MS. Observation of environment-induced double sudden transitions in geometric quantum correlations. Phys Rev Lett 2013; 111:250401. [PMID: 24483731 DOI: 10.1103/physrevlett.111.250401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Indexed: 06/03/2023]
Abstract
Correlations in quantum systems exhibit a rich phenomenology under the effect of various sources of noise. We investigate theoretically and experimentally the dynamics of quantum correlations and their classical counterparts in two nuclear magnetic resonance setups, as measured by geometric quantifiers based on trace norm. We consider two-qubit systems prepared in Bell diagonal states, and perform the experiments in real decohering environments resulting from Markovian local noise which preserves the Bell diagonal form of the states. We then report the first observation of environment-induced double sudden transitions in the geometric quantum correlations, a genuinely nonclassical effect not observable in classical correlations. The evolution of classical correlations in our physical implementation reveals in turn the finite-time relaxation to a pointer basis under nondissipative decoherence, which we characterize geometrically in full analogy with predictions based on entropic measures.
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Affiliation(s)
- F M Paula
- Instituto de Física, Universidade Federal Fluminense, Avenida General Milton Tavares de Souza s/n, Gragoatá, 24210-346 Niterói, Rio de Janeiro, Brazil
| | - I A Silva
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, São Paulo, Brazil
| | - J D Montealegre
- Instituto de Física, Universidade Federal Fluminense, Avenida General Milton Tavares de Souza s/n, Gragoatá, 24210-346 Niterói, Rio de Janeiro, Brazil
| | - A M Souza
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Brazil
| | - E R deAzevedo
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, São Paulo, Brazil
| | - R S Sarthour
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Brazil
| | - A Saguia
- Instituto de Física, Universidade Federal Fluminense, Avenida General Milton Tavares de Souza s/n, Gragoatá, 24210-346 Niterói, Rio de Janeiro, Brazil
| | - I S Oliveira
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Brazil
| | - D O Soares-Pinto
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, São Paulo, Brazil
| | - G Adesso
- School of Mathematical Sciences, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - M S Sarandy
- Instituto de Física, Universidade Federal Fluminense, Avenida General Milton Tavares de Souza s/n, Gragoatá, 24210-346 Niterói, Rio de Janeiro, Brazil
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13
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Viana AFSC, Fernandes HB, Silva FV, Oliveira IS, Freitas FFBP, Machado FDF, Costa CLS, Arcanjo DDR, Chaves MH, Oliveira FA, Oliveira RCM. Gastroprotective activity of Cenostigma macrophyllum Tul. var. acuminata Teles Freire leaves on experimental ulcer models. J Ethnopharmacol 2013; 150:316-323. [PMID: 24035848 DOI: 10.1016/j.jep.2013.08.047] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [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: 04/30/2013] [Revised: 08/23/2013] [Accepted: 08/25/2013] [Indexed: 06/02/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Cenostigma macrophyllum Tul. var. acuminata Teles Freire (Leguminosae-Caesalpinioideae), popularly known in Brazil as "caneleiro", is widely used in folk medicine against gastrointestinal diseases. In previous studies, the ethanol extract of leaves from Cenostigma macrophyllum Tul. var. acuminata Teles Freire had shown antinociceptive, anti-inflammatory, antibacterial, antioxidant and antiulcerogenic activities. AIM OF THE STUDY The aim of this study was to assess the gastroprotective effect of the hydroalcoholic fraction of leaves of Cenostigma macrophyllum Tul. var. acuminata Teles Freire (Cm-FHA), as well as to elucidate the possible underlying mechanisms of action. MATERIALS AND METHODS Mice were used for the evaluation of the acute toxicity, and mice and rats to study the gastroprotective activity. The potential gastroprotective of Cm-FHA was assessed on different gastric ulcer models in rodents, such as absolute ethanol, HCl/ethanol, ischemia-reperfusion, cold restraint stress and indomethacin. The participation of prostaglandins, NO-synthase pathway and ATP-sensitive potassium channels (KATP) in gastroprotective activity of Cm-FHA were evaluated after treatment with a cyclooxygenase inhibitor (indomethacin), a NO-synthase inhibitor (L-NAME) and a KATP channel blocker (glibenclamide 5mg/kg), respectively. Likewise, the catalase activity was determinated in order to assess the possible participation of antioxidant mechanisms. RESULTS No signs of acute toxicity was observed after oral acute administration of Cm-FHA, considering the analyzed parameters. Likewise, Cm-FHA promoted a protective effect against gastric ulcers induced by absolute ethanol (lesion inhibition by 40% at both 100 and 200mg/kg), HCl/ethanol (lesion inhibition by 50 or 48% at 100 or 200mg/kg, respectively), ischemia-reperfusion (lesion inhibition by 49 or 90% at 100 or 200mg/kg, respectively) and cold restraint stress (lesion inhibition by 63 or 76% at 100 or 200mg/kg, respectively), as well as a increase of catalase activity was observed. Otherwise, Cm-FHA was not able to protect gastric mucosa against indomethacin-induced lesions. Nitric oxide release, the of KATP channels opening and antioxidant activity are the possibly involved in the Cm-FHA-induced gastroprotective activity. CONCLUSION This study corroborates the folk medicine use of Cenostigma macrophyllum for treatment of gastric ulcers, as well as reinforces this species as a valuable source of promising natural drugs with gastroprotective activity.
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Affiliation(s)
- A F S C Viana
- Medicinal Plants Research Center, Federal University of Piauí, Teresina, Brazil
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14
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Silva IA, Girolami D, Auccaise R, Sarthour RS, Oliveira IS, Bonagamba TJ, deAzevedo ER, Soares-Pinto DO, Adesso G. Measuring bipartite quantum correlations of an unknown state. Phys Rev Lett 2013; 110:140501. [PMID: 25166969 DOI: 10.1103/physrevlett.110.140501] [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] [Received: 12/18/2012] [Indexed: 06/03/2023]
Abstract
We report the experimental measurement of bipartite quantum correlations of an unknown two-qubit state. Using a liquid state Nuclear Magnetic Resonance setup and employing geometric discord, we evaluate the quantum correlations of a state without resorting to prior knowledge of its density matrix. The method is applicable to any 2 ⊗ d system and provides, in terms of number of measurements required, an advantage over full state tomography scaling with the dimension d of the unmeasured subsystem. The negativity of quantumness is measured as well for reference. We also observe the phenomenon of sudden transition of quantum correlations when local phase and amplitude damping channels are applied to the state.
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Affiliation(s)
- I A Silva
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, São Paulo, Brazil
| | - D Girolami
- School of Mathematical Sciences, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - R Auccaise
- Empresa Brasileira de Pesquisa Agropecuária, Rua Jardim Botânico 1024, 22460-000 Rio de Janeiro, Brazil
| | - R S Sarthour
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Brazil
| | - I S Oliveira
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Brazil
| | - T J Bonagamba
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, São Paulo, Brazil
| | - E R deAzevedo
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, São Paulo, Brazil
| | - D O Soares-Pinto
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, São Paulo, Brazil
| | - G Adesso
- School of Mathematical Sciences, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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15
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Abstract
For the past decade, nuclear magnetic resonance (NMR) has been established as a main experimental technique for testing quantum protocols in small systems. This Theme Issue presents recent advances and major challenges of NMR quantum information possessing (QIP), including contributions by researchers from 10 different countries. In this introduction, after a short comment on NMR-QIP basics, we briefly anticipate the contents of this issue.
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Affiliation(s)
- R M Serra
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, R. Santa Adélia 166, 09210-170 Santo André, São Paulo, Brazil.
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16
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Sousa JA, Oliveira IS, Silva FV, Costa DA, Chaves MH, Oliveira FA, Nunes PHM, Oliveira RCM. Gastroprotective Activity of Sterculia striata A. St. Hil. & Naudin (Malvaceae) in Rodents. Z NATURFORSCH C 2012. [DOI: 10.1515/znc-2012-3-408] [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] [Indexed: 11/15/2022]
Abstract
The Sterculia striata ethanolic extract (Ss-EtOH) inhibited gastric lesions induced by ethanol, HCl/ethanol, and ischemia/reperfusion, but not those induced by indomethacin, and did not alter the gastric secretion. Ss-EtOH restored the catalase activity and content of nonprotein sulfhydryl groups in the stomach of mice treated with ethanol. The gastroprotection induced by Ss-EtOH in the ethanol-induced gastric lesion model was abolished by NG-nitro- L-arginine methyl ester (L-NAME) pretreatment, suggesting the involvement of nitric oxide and antioxidant compounds, but not prostaglandins, in this activity. Lupeol obtained from Ss-EtOH promoted gastroprotection as well as the extract at the same dose, and it must therefore contribute to the observed effects
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Affiliation(s)
- Joubert A. Sousa
- Medicinal Plants Research Center, Federal University of Piauí, Av. Nossa Senhora de Fátima s/n, 64049-550 Teresina, PI, Brazil
| | - Irisdalva S. Oliveira
- Medicinal Plants Research Center, Federal University of Piauí, Av. Nossa Senhora de Fátima s/n, 64049-550 Teresina, PI, Brazil
| | - Francilene V. Silva
- Medicinal Plants Research Center, Federal University of Piauí, Av. Nossa Senhora de Fátima s/n, 64049-550 Teresina, PI, Brazil
| | - Danielly A. Costa
- Department of Chemistry, Federal University of Piauí, Teresina, PI, Brazil
| | - Mariana H. Chaves
- Department of Chemistry, Federal University of Piauí, Teresina, PI, Brazil
| | - Francisco A. Oliveira
- Medicinal Plants Research Center, Federal University of Piauí, Av. Nossa Senhora de Fátima s/n, 64049-550 Teresina, PI, Brazil
| | - Paulo H. M. Nunes
- Medicinal Plants Research Center, Federal University of Piauí, Av. Nossa Senhora de Fátima s/n, 64049-550 Teresina, PI, Brazil
- Department of Biophysics and Physiology, Federal University of Piauí, Teresina, PI, Brazil
| | - Rita C. M. Oliveira
- Medicinal Plants Research Center, Federal University of Piauí, Av. Nossa Senhora de Fátima s/n, 64049-550 Teresina, PI, Brazil
- Department of Biophysics and Physiology, Federal University of Piauí, Teresina, PI, Brazil
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17
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Sousa JA, Oliveira IS, Silva FV, Costa DA, Chaves MH, Oliveira FA, Nunes PHM, Oliveira RCM. Gastroprotective activity of Sterculia striata A. St. Hil. & Naudin (Malvaceae) in rodents. Z NATURFORSCH C 2012; 67:163-171. [PMID: 22624332] [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] [Indexed: 06/01/2023]
Abstract
The Sterculia striata ethanolic extract (Ss-EtOH) inhibited gastric lesions induced by ethanol, HCl/ethanol, and ischemia/reperfusion, but not those induced by indomethacin, and did not alter the gastric secretion. Ss-EtOH restored the catalase activity and content of nonprotein sulfhydryl groups in the stomach of mice treated with ethanol. The gastroprotection induced by Ss-EtOH in the ethanol-induced gastric lesion model was abolished by N(G)-nitroL-arginine methyl ester (L-NAME) pretreatment, suggesting the involvement of nitric oxide and antioxidant compounds, but not prostaglandins, in this activity. Lupeol obtained from Ss-EtOH promoted gastroprotection as well as the extract at the same dose, and it must therefore contribute to the observed effects.
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Affiliation(s)
- Joubert A Sousa
- Medicinal Plants Research Center, Federal University of Piauí, Av. Nossa Senhora de Fátima s/n, 64049-550 Teresina, PI, Brazil
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18
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Sousa JA, Oliveira IS, Silva FV, Costa DA, Chaves MH, Oliveira FA, Nunes PHM, Oliveira RCM. Gastroprotective Activity of Sterculia striata A. St. Hil. Naudin (Malvaceae) in Rodents. Z NATURFORSCH C 2012. [DOI: 10.5560/znc.2012.67c0163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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19
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Lacorte GA, Oliveira IS, Fonseca CG. Population structure and demographic inferences concerning the endangered onychophoran species Epiperipatus acacioi (Onychophora: Peripatidae). Genet Mol Res 2011; 10:2775-85. [PMID: 22095603 DOI: 10.4238/2011.november.9.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Epiperipatus acacioi (Onychophora: Peripatidae) is an endemic species of the Atlantic rainforest in southeastern Brazil, with a restricted known distribution, found only in two nearby areas (Tripuí and Itacolomi). Mitochondrial gene COI sequences of 93 specimens collected across the known range of E. acacioi were used to assess the extant genetic diversity and patterns of genetic structure, as well as to infer the demographic history of this species. We found considerable variability within the populations, even though there has been recent environmental disturbance in these habitats. The samples from the two areas where this species is found showed significantly different COI sequences and constitute two distinct populations [exact test of sample differentiation (P = 0.0008) and pairwise F(ST) analyses (F(ST) = 0.214, P < 0.00001)]. However, there was little genetic differentiation among samples from different sampling sites within populations, suggesting that the potential for dispersal of E. acacioi greater than would have been expected, based on their cryptic behavior and reduced vagility. Mismatch analyses and neutrality tests revealed evidence of recent population expansion processes for both populations, possibly related to variations in the past distribution of this species.
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Affiliation(s)
- G A Lacorte
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.
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20
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Tozoni JR, Teles J, Auccaise R, Oliveira-Silva R, Rivera-Ascona C, Vidoto ELG, Guimarães AP, Oliveira IS, Bonagamba TJ. Multi-quantum echoes in GdAl2 zero-field high-resolution NMR. J Magn Reson 2011; 212:265-273. [PMID: 21813306 DOI: 10.1016/j.jmr.2011.07.003] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 07/04/2011] [Accepted: 07/04/2011] [Indexed: 05/31/2023]
Abstract
In this paper we present a series of high-resolution zero-field NMR spectra of the polycrystalline intermetallic compound GdAl(2). The spectra were obtained with the sample at 4.2K in the ordered magnetic state and in the absence of an external static magnetic field. Using a sequence composed of two RF pulses, we obtained up to five multi-quantum echoes for the (27)Al nuclei, which were used to construct the zero-field NMR spectra. The spectra obtained from the FID observed after the second pulse and the even echoes exhibited higher resolution than the odd ones. In order to explain such behavior, we propose a model in which there are two regions inside the sample with different inhomogeneous spectral-line broadenings. Moreover, with the enhanced resolution from the FID signal, we were able to determine quadrupolar couplings with great precision directly from the respective spectra. These results were compared with those obtained from the quadrupolar oscillations of the echo signals, and showed good agreement. Similar data were also obtained from (155)Gd and (157)Gd nuclei.
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Affiliation(s)
- J R Tozoni
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, São Carlos 13560-970, SP, Brazil
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21
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Auccaise R, Céleri LC, Soares-Pinto DO, deAzevedo ER, Maziero J, Souza AM, Bonagamba TJ, Sarthour RS, Oliveira IS, Serra RM. Environment-induced sudden transition in quantum discord dynamics. Phys Rev Lett 2011; 107:140403. [PMID: 22107179 DOI: 10.1103/physrevlett.107.140403] [Citation(s) in RCA: 8] [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] [Received: 04/19/2011] [Indexed: 05/31/2023]
Abstract
Nonclassical correlations play a crucial role in the development of quantum information science. The recent discovery that nonclassical correlations can be present even in separable (nonentangled) states has broadened this scenario. This generalized quantum correlation has been increasing in relevance in several fields, among them quantum communication, quantum computation, quantum phase transitions, and biological systems. We demonstrate here the occurrence of the sudden-change phenomenon and immunity against some sources of noise for the quantum discord and its classical counterpart, in a room temperature nuclear magnetic resonance setup. The experiment is performed in a decohering environment causing loss of phase relations among the energy eigenstates and exchange of energy between system and environment, resulting in relaxation to the Gibbs ensemble.
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Affiliation(s)
- R Auccaise
- Empresa Brasileira de Pesquisa Agropecuária, Rua Jardim Botânico 1024, 22460-000 Rio de Janeiro, Rio de Janeiro, Brazil
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22
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Auccaise R, Maziero J, Céleri LC, Soares-Pinto DO, deAzevedo ER, Bonagamba TJ, Sarthour RS, Oliveira IS, Serra RM. Experimentally witnessing the quantumness of correlations. Phys Rev Lett 2011; 107:070501. [PMID: 21902378 DOI: 10.1103/physrevlett.107.070501] [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] [Received: 04/06/2011] [Indexed: 05/31/2023]
Abstract
The quantification of quantum correlations (other than entanglement) usually entails labored numerical optimization procedures also demanding quantum state tomographic methods. Thus it is interesting to have a laboratory friendly witness for the nature of correlations. In this Letter we report a direct experimental implementation of such a witness in a room temperature nuclear magnetic resonance system. In our experiment the nature of correlations is revealed by performing only few local magnetization measurements. We also compared the witness results with those for the symmetric quantum discord and we obtained a fairly good agreement.
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Affiliation(s)
- R Auccaise
- Empresa Brasileira de Pesquisa Agropecuária, Rio de Janeiro, Brazil
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de Carvalho KIM, Fernandes HB, Machado FDF, Oliveira IS, Oliveira FA, Nunes PHM, Lima JT, Almeida JRGS, Oliveira RCM. Antiulcer activity of ethanolic extract of Encholirium spectabile Mart. ex Schult & Schult f. (Bromeliaceae) in rodents. Biol Res 2011; 43:459-465. [PMID: 21526273] [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] [Indexed: 05/30/2023] Open
Abstract
This study evaluated the antiulcer activity of an ethanolic extract of Encholirium spectabile (ES-EtOH) by using different standard experimental models of induced acute gastric ulceration. ES-EtOH (100 mg/kg p.o) protected the gastric mucosa against ulceration that was induced by absolute ethanol (53%), ethanol/HCl (75%), ibuprofen (52 %) and ischemia/reperfusion (43 %). It also restored catalase activity and non-protein sulfhydryl group concentration in the gastric wall of mice that had been treated with ethanol. The pre-treatment of mice with N-nitro-L-arginine (70 mg/kg i.p.) abolished the protective activity of ES-EtOH, which indicates that prostaglandins, antioxidant compounds and nitric oxide synthase activity are involved in the gastroprotective activity of the extract.
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Taha MO, Miranda-Ferreira R, Fagundes DJ, Simões RS, Monteiro HP, Oliveira-Júnior IS, Oliveira IS, Soares KRM, Martins MCL, Monteiro HP, Balbino AT, Rodrigues FF, Arruda TB, Abrão MS, Jurkiewicz A, Caricati-Neto A. Effects of 5'-adenosine triphosphate on intestinal ischemia-reperfusion in rabbits. Transplant Proc 2010; 42:461-4. [PMID: 20304165 DOI: 10.1016/j.transproceed.2010.01.036] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To study whether treatment with 5'-adenosine triphosphate (ATP), an agonist of P2 purine receptors, attenuated intestinal dysfunction caused by ischemia (I) and/or reperfusion (R), rabbits were treated with ATP (15 mgxkg(-1), intravenously) or saline solution (SS) 60 minutes before I by occlusion of the superior mesenteric artery and/or R (120 minutes). After I or I/R isolated 2-cm jejunal segments were mounted in an organ bath to study nerve-mediated contractions stimulated by electrical pulses or KCl using a digital recording system. Thin jejunal slices were stained (hematoxylin and eosin) for optical microscopy. Compared to a sham group, the jejunal contractions were similar to sham hosts among I + ATP, but reduced in I + SS, I/R + SS, and I/R + ATP groups. The jejunal-enteric nerves were damaged in I + SS, I/R + SS, and I/R + ATP, but not the I + ATP group. These results suggested that ATP attenuated intestinal dysfunction produced by I, but not that caused by R.
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Affiliation(s)
- M O Taha
- Department of Pharmacoloy, Federal University São Paulo (UNIFESP), Brazil.
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Moraes de Carvalho KI, Fernandes HB, Frota Machado FD, Oliveira IS, Oliveira FA, Nunes PHM, Lima JT, Silva Almeida JRG, Meneses Oliveira RC. Antiulcer activity of ethanolic extract of Encholirium spectabile Mart. ex Schult & Schult f. (Bromeliaceae) in rodents. Biol Res 2010. [DOI: 10.4067/s0716-97602010000400011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Crokidakis N, Soares-Pinto DO, Reis MS, Souza AM, Sarthour RS, Oliveira IS. Finite-size analysis of a two-dimensional Ising model within a nonextensive approach. Phys Rev E Stat Nonlin Soft Matter Phys 2009; 80:051101. [PMID: 20364941 DOI: 10.1103/physreve.80.051101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 08/28/2009] [Indexed: 05/29/2023]
Abstract
In this work we present a thorough analysis of the phase transitions that occur in a ferromagnetic two-dimensional Ising model, with only nearest-neighbors interactions, in the framework of the Tsallis nonextensive statistics. We performed Monte Carlo simulations on square lattices with linear sizes L ranging from 32 up to 512. The statistical weight of the Metropolis algorithm was changed according to the nonextensive statistics. Discontinuities in the m(T) curve are observed for q< or =0.5 . However, we have verified only one peak on the energy histograms at the critical temperatures, indicating the occurrence of continuous phase transitions. For the 0.5<q< or =1.0 regime, we have found continuous phase transitions between the ordered and the disordered phases, and determined the critical exponents via finite-size scaling. We verified that the critical exponents alpha , beta , and gamma depend on the entropic index q in the range 0.5<q< or =1.0 in the form alpha(q)=(10q2-33q+23)/20 , beta(q)=(2q-1)/8 , and gamma(q)=(q2-q+7)/4 . On the other hand, the critical exponent nu does not depend on q . This suggests a violation of the scaling relations 2beta+gamma=dnu and alpha+2beta+gamma=2 and a nonuniversality of the critical exponents along the ferro-paramagnetic frontier.
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Affiliation(s)
- N Crokidakis
- Instituto de Física, Universidade Federal Fluminense, Av. Litorânea s/n, 24210-340 Niterói, RJ, Brazil.
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Auccaise R, Teles J, Sarthour RS, Bonagamba TJ, Oliveira IS, deAzevedo ER. A study of the relaxation dynamics in a quadrupolar NMR system using Quantum State Tomography. J Magn Reson 2008; 192:17-26. [PMID: 18295520 DOI: 10.1016/j.jmr.2008.01.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Revised: 01/11/2008] [Accepted: 01/13/2008] [Indexed: 05/25/2023]
Abstract
This article reports a relaxation study in an oriented system containing spin 3/2 nuclei using quantum state tomography (QST). The use of QST allowed evaluating the time evolution of all density matrix elements starting from several initial states. Using an appropriated treatment based on the Redfield theory, the relaxation rate of each density matrix element was measured and the reduced spectral densities that describe the system relaxation were determined. All the experimental data could be well described assuming pure quadrupolar relaxation and reduced spectral densities corresponding to a superposition of slow and fast motions. The data were also analyzed in the context of Quantum Information Processing, where the coherence loss of each qubit of the system was determined using the partial trace operation.
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Affiliation(s)
- R Auccaise
- Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Rio de Janeiro 22290-180, RJ, Brazil.
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Teles J, deAzevedo ER, Auccaise R, Sarthour RS, Oliveira IS, Bonagamba TJ. Quantum state tomography for quadrupolar nuclei using global rotations of the spin system. J Chem Phys 2007; 126:154506. [PMID: 17461646 DOI: 10.1063/1.2717179] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this paper, we describe a quantum state tomography method based on global rotations of the spin system which, together with a coherence selection scheme, enables the complete density matrix reconstruction. The main advantage of this technique, in respect to previous proposals, is the use of much shorter rf pulses, which decreases significantly the time necessary for algorithm quantum state tomography. In this case, under adequate experimental conditions, the rf pulses correspond to simple spatial rotations of the spin states, and its analytical description is conveniently given in the irreducible tensor formalism. Simulated results show the feasibility of the method for a single spin 72 nucleus. As an experimental result, we exemplify the application of this method by tomographing the steps during the implementation of the Deutsch algorithm. The algorithm was implemented in a (23)Na quadrupole nucleus using the strongly modulated pulses technique. We also extended the tomography method for a 3-coupled homonuclear spin 12 system, where an additional evolution under the internal Hamiltonian is necessary for zero order coherences evaluation.
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Affiliation(s)
- J Teles
- Instituto de Física de São Carlos, Universidade de São Paulo, P.O. Box 369, São Carlos 13560-970, São Paulo, Brazil.
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Bonk FA, deAzevedo ER, Sarthour RS, Bulnes JD, Freitas JCC, Guimarães AP, Oliveira IS, Bonagamba TJ. Quantum logical operations for spin 3/2 quadrupolar nuclei monitored by quantum state tomography. J Magn Reson 2005; 175:226-34. [PMID: 15921938 DOI: 10.1016/j.jmr.2005.04.009] [Citation(s) in RCA: 2] [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: 01/08/2005] [Revised: 04/05/2005] [Accepted: 04/05/2005] [Indexed: 05/02/2023]
Abstract
This article presents the realization of many self-reversible quantum logic gates using two-qubit quadrupolar spin 3/2 systems. Such operations are theoretically described using propagation matrices for the RF pulses that include the effect of the quadrupolar evolution during the pulses. Experimental demonstrations are performed using a generalized form of the recently developed method for quantum state tomography in spin 3/2 systems. By doing so, the possibility of controlling relative phases of superimposed pseudo-pure states is demonstrated. In addition, many aspects of the effect of the quadrupolar evolution, occurring during the RF pulses, on the quantum operations performance are discussed. Most of the procedures presented can be easily adapted to describe selective pulses of higher spin systems (>3/2) and for spin 1/2 under J couplings.
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Affiliation(s)
- F A Bonk
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, São Carlos, 13560-970 SP, Brazil
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Oliveira IS. Matrix Treatment of Electrical Current: Current Echoes. Phys Rev Lett 1996; 77:139-142. [PMID: 10061791 DOI: 10.1103/physrevlett.77.139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Oliveira IS, Nishimura K, Stone NJ, Isikawa Y, Zákouck D, Doran D. Low-temperature nuclear orientation on the Kondo system CexNd1-xNi. Phys Rev B Condens Matter 1994; 49:11886-11889. [PMID: 10010059 DOI: 10.1103/physrevb.49.11886] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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