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2. Damping of Landau levels in neutral graphene at low magnetic fields: A phonon Raman scattering study

Author

Ardito, F. M., Mendes-de-Sa, T. G., Cadore, A. R., Gomes, P. F., Mafra, D. L., Barcelos, I. D., Lacerda, R. G., Iikawa, F., and Granado, E.

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Landau level broadening mechanisms in electrically neutral and quasineutral graphene were investigated through micro-magneto-Raman experiments in three different samples, namely, a natural single-layer graphene flake and a back-gated single-layer device, both deposited over Si/SiO2 substrates, and a multilayer epitaxial graphene employed as a reference sample. Interband Landau level transition widths were estimated through a quantitative analysis of the magnetophonon resonances associated with optically active Landau level transitions crossing the energy of the E_2g Raman-active phonon. Contrary to multilayer graphene, the single-layer graphene samples show a strong damping of the low-field resonances, consistent with an additional broadening contribution of the Landau level energies arising from a random strain field. This extra contribution is properly quantified in terms of a pseudomagnetic field distribution Delta_B = 1.0-1.7 T in our single-layer samples., Comment: 7 pages, 5 figures

Published
2016
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3. Effects of microcapsules with turmeric and green propolis supplementation on inflammatory markers in hemodialysis patients

Author

Britto, I.K., primary, Cardozo, L.F., additional, Couto, H., additional, de Paiva, B.R., additional, de Brito, J.S., additional, Teixeira, K.T., additional, Alvarenga, L., additional, Chermut, T.R., additional, Leite, P.E.C., additional, Delgado, V.P., additional, Berretta, A.A., additional, Ribeiro-Alves, M., additional, Ribeiro, M., additional, and Mafra, D., additional

Published
2023
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4. Uremic toxins and inflammatory profile of patients with chronic kidney disease: A cross-sectional study involving non-dialysis, hemodialysis and peritoneal dialysis

Author

Paiva, B.R., primary, Cardozo, L.F., additional, Ribeiro, M., additional, Ribeiro-Alves, M., additional, Nakao, L.S., additional, Baptista, B.G., additional, Reis, D.C.M.V., additional, de Brito, J.S., additional, Kemp, J.A., additional, Teixeira, K., additional, Moreira, L.D.S.G., additional, Fonseca, L., additional, Trigulho, L., additional, Alvarenga, L., additional, Fanton, S., additional, and Mafra, D., additional

Published
2023
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7. Phonon self-energy corrections to non-zero wavevector phonon modes in single-layer graphene

Author

Araujo, P. T., Mafra, D. L., Sato, K., Saito, R., Kong, J., and Dresselhaus, M. S.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Phonon self-energy corrections have mostly been studied theoretically and experimentally for phonon modes with zone-center (q = 0) wave-vectors. Here, gate-modulated Raman scattering is used to study phonons of a single layer of graphene (1LG) in the frequency range from 2350 to 2750 cm-1, which shows the G* and the G'-band features originating from a double-resonant Raman process with q \not= 0. The observed phonon renormalization effects are different from what is observed for the zone-center q = 0 case. To explain our experimental findings, we explored the phonon self-energy for the phonons with non-zero wave-vectors (q \not= 0) in 1LG in which the frequencies and decay widths are expected to behave oppositely to the behavior observed in the corresponding zone-center q = 0 processes. Within this framework, we resolve the identification of the phonon modes contributing to the G* Raman feature at 2450 cm-1 to include the iTO+LA combination modes with q \not= 0 and the 2iTO overtone modes with q = 0, showing both to be associated with wave-vectors near the high symmetry point K in the Brillouin zone.

Published
2012
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8. Characterizing top gated bilayer graphene interaction with its environment by Raman spectroscopy

Author

Mafra, D. L., Gava, P., Malard, L. M., Borges, R. S., Silva, G. G., Leon, J. A., Plentz, F., Mauri, F., and Pimenta, M. A.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

In this work we study the behavior of the optical phonon modes in bilayer graphene devices by applying top gate voltage, using Raman scattering. We observe the splitting of the Raman G band as we tune the Fermi level of the sample, which is explained in terms of mixing of the Raman (Eg) and infrared (Eu) phonon modes, due to different doping in the two layers. We theoretically analyze our data in terms of the bilayer graphene phonon self-energy which includes non-homogeneous charge carrier doping between the graphene layers. We show that the comparison between the experiment and theoretical model not only gives information about the total charge concentration in the bilayer graphene device, but also allows to separately quantify the amount of unintentional charge coming from the top and the bottom of the system, and therefore to characterize the interaction of bilayer graphene with its surrounding environment.

Published
2011
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9. On the inner Double-Resonance Raman scattering process in bilayer graphene

Author

Mafra, D. L., Moujaes, E. A., Nunes, R. W., and Pimenta, M. A.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

The dispersion of phonons and the electronic structure of graphene systems can be obtained experimentally from the double-resonance (DR) Raman features by varying the excitation laser energy. In a previous resonance Raman investigation of graphene, the electronic structure was analyzed in the framework of the Slonczewski-Weiss-McClure (SWM) model, considering the outer DR process. In this work we analyze the data considering the inner DR process, and obtain SWM parameters that are in better agreement with those obtained from other experimental techniques. This result possibly shows that there is still a fundamental open question concerning the double resonance process in graphene systems., Comment: 5 pages, 3 figures

Published
2010
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10. Observation of the Kohn anomaly near the K point of bilayer graphene

Author

Mafra, D. L., Malard, L. M., Doorn, S. K., Htoon, H., Nilsson, J., Neto, A. H. Castro, and Pimenta, M. A.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

The dispersion of electrons and phonons near the K point of bilayer graphene was investigated in a resonant Raman study using different laser excitation energies in the near infrared and visible range. The electronic structure was analyzed within the tight-binding approximation, and the Slonczewski-Weiss-McClure (SWM) parameters were obtained from the analysis of the dispersive behavior of the Raman features. A softening of the phonon branches was observed near the K point, and results evidence the Kohn anomaly and the importance of considering electron-phonon and electron-electron interactions to correctly describe the phonon dispersion in graphene systems., Comment: 4 pages, 4 figures

Published
2009
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11. Group theory analysis of electrons and phonons in N-layer graphene systems

Author

Malard, L. M., Mafra, D. L., Guimarães, M. H. D., Mazzoni, M. S. C., and Jorio, A.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

In this work we study the symmetry properties of electrons and phonons in graphene systems as function of the number of layers. We derive the selection rules for the electron-radiation and for the electron-phonon interactions at all points in the Brillouin zone. By considering these selection rules, we address the double resonance Raman scattering process. The monolayer and bilayer graphene in the presence of an applied electric field are also discussed., Comment: 8 pages, 6 figures

Published
2008
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16. Fermented food: Should patients with cardiometabolic diseases go back to an early neolithic diet?

Author

Mafra, D., Borges, N. A., Alvarenga, L., Ribeiro, M., Fonseca, L., Leal, V. O., Shiels, P. G., and Stenvinkel, P.

Subjects
*HEART metabolism disorders, *FERMENTED foods, *FOOD fermentation, *FOOD preservation, *CHRONIC kidney failure, *NEOLITHIC Period
Abstract

Fermentation has been used since the Early Neolithic period to preserve foods. It has inherent organoleptic and nutritive properties that bestow health benefits, including reducing inflammation and oxidative stress, supporting the growth of salutogenic microbiota, enhancing intestinal mucosal protection and promoting beneficial immunometabolic health effects. The fermentation of food with specific microbiota increases the production salutogenic bioactive compounds that can activate Nrf2 mediated cytoprotective responses and mitigate the effects of the 'diseasome of aging' and its associated inflammageing, which presents as a prominent feature of obesity, type-2 diabetes, cardiovascular and chronic kidney disease. This review discusses the importance of fermented food in improving health span, with special reference to cardiometabolic diseases. [ABSTRACT FROM AUTHOR]

Published
2023
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29. From bench to the hemodialysis clinic: protein-bound uremic toxins modulate NF-kappa B/Nrf2 expression

Author

Stockler-Pinto, M. B., Soulage, Christophe, Borges, N. A., Cardozo, Lfmf, Dolenga, C. J., Nakao, L. S., Pecoits, R., Fouque, Denis, Mafra, D., Cardiovasculaire, métabolisme, diabétologie et nutrition (CarMeN), Institut National de la Recherche Agronomique (INRA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Institut National de la Santé et de la Recherche Médicale (INSERM), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Hospices Civils de Lyon (HCL)

Subjects
Inflammation, [SDV]Life Sciences [q-bio], kappa-b, Uremic toxins, NF-kappa B, cardiovascular-disease, Urology & Nephrology, Nrf2, oxygen species production, Oxidative stress, p-cresyl sulfate, Chronic kidney disease, liquid-chromatography, nadph oxidase, chronic kidney-disease, indoxyl sulfate
Abstract

Uremic toxins produced by gut microbiota (indoxyl sulfate-IS, p-cresyl sulfate-p-CS, and indole-3-acetic acid-IAA) accumulate in hemodialysis (HD) patients and exhibit potent inflammatory effects. However, the impact of these toxins on nuclear E2-related factor 2 (Nrf2) and nuclear factor-kappa B (NF-kappa B) expression in HD patients remains poorly defined. The aim of this study was to evaluate the association between uremic toxins and Nrf2/NF-kappa B expression in vitro (RAW 264.7 macrophage-like cells) and in peripheral blood mononuclear cells from HD patients. Uremic toxins, C-reactive protein (CRP), interleukin-6 (IL-6) and malondialdehyde (MDA) levels were measured in fifteen HD patients and nine healthy individuals. RAW 264.7 macrophage-like cells were incubated with IS, as a prototype of protein-bound uremic toxin. Nrf2 and NF-kappa B expressions were analyzed by RT-qPCR. HD patients presented high levels of inflammatory markers, MDA and uremic toxins. In addition, they presented high NF-kappa B and low Nrf2 expression. Uremic toxins were positively correlated with NF-kappa B expression (IS, rho = 0.58, p \textless 0.003; p-CS, rho = 0.71, p \textless 0.001; IAA, rho = 0.62, p \textless 0.001) and negatively with Nrf2 (IS, rho = - 0.48, p = 0.01; p-CS, rho = - 0.46, p \textless 0.02). Uremic toxins also exhibited positive correlations with CRP and MDA levels. Multivariate analysis revealed that p-CS is a determinant factor of NF-kappa B expression. In RAW 264.7 culture, NF-kappa B mRNA expression was stimulated by IS, while Nrf2 was downregulated. Thus, uremic toxins may stimulate NF-kappa B mRNA and decrease Nrf2 expression in HD patients and, consequently, trigger inflammation and oxidative stress.

Published
2018

36. Hormones

Author

Gatti, G., primary, Lanzani, C., additional, Messaggio, E., additional, Casamassima, N., additional, Hamlyn, J., additional, Simonini, M., additional, Manunta, P., additional, Perri, A., additional, Vizza, D., additional, Lofaro, D., additional, Gigliotti, P., additional, Leone, F., additional, Papalia, T., additional, Bonofiglio, R., additional, Gawrys, O., additional, Gawarecka, K., additional, Swiezewska, E., additional, Masnyk, M., additional, Chmielewski, M., additional, Kompanowska-Jezierska, E., additional, Apponi, F., additional, Sinibaldi, V., additional, Giuliani, A., additional, Baldinelli, M., additional, Luciani, R., additional, Giordano, F., additional, Panzieri, G., additional, Punzo, G., additional, Mene, P., additional, Pirozzi, N., additional, Dusilova Sulkova, S., additional, Horacek, J., additional, Safranek, R., additional, Kalousova, M., additional, Malirova, E., additional, Dlabalova, B., additional, Kubisova, M., additional, Zak, P., additional, Sirotina, N., additional, Fidchenko, Y., additional, Smirnova, O., additional, Moraes, C. F., additional, Marinho, S. M., additional, Stockler-Pinto, M. B., additional, Barros, A. F., additional, Mafra, D., additional, Inoue, M., additional, Saito, T., additional, Ueno, K., additional, Yoshimura, A., additional, Yamamoto, H., additional, Saito, O., additional, Kusano, E., additional, Leal, V. O., additional, Barroso, S. G., additional, Rocha, G. S., additional, Boaventura, G. T., additional, Molsted, S., additional, Andersen, J. L., additional, Eidemak, I., additional, Harrison, A., additional, and Jorgensen, N., additional

Published
2013
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45. Protein-energy wasting, inflammation and oxidative stress in CKD 5D

Author

Rosales, L., primary, Vega, O., additional, Usvyat, L., additional, Thijssen, S., additional, Levin, N., additional, Kotanko, P., additional, Miyamoto, T., additional, Witasp, A., additional, Rashid Qureshi, A., additional, Heimburger, O., additional, Barany, P., additional, Nordfors, L., additional, Lindholm, B., additional, Stenvinkel, P., additional, Jesus Carrero, J., additional, Kalousova, M., additional, Benakova, H., additional, Kubena, A. A., additional, Dusilova-Sulkova, S., additional, Tesar, V., additional, Zima, T., additional, Lee, Y. J., additional, Kim, M. S., additional, Song, B. G., additional, Cho, S., additional, Kim, S. R., additional, Stockler-Pinto, M., additional, Lobo, J., additional, Moraes, C., additional, Barros, A., additional, Farage, N., additional, Boaventura, G., additional, Mafra, D., additional, Malm, O., additional, Matsuda, S., additional, Akaike, N., additional, Kajiwara, K., additional, Tovbin, D., additional, Kesari, S., additional, Sola-Del Valle, D., additional, Barasch, J., additional, Douvdevani, A., additional, Zlotnik, M., additional, Abd Elkadir, A., additional, Storch, S., additional, Sarikaya, M., additional, Sari, F., additional, Gunes, J., additional, Eren, M., additional, Cetinkaya, R., additional, Hwang, J.-C., additional, Ma, T.-L., additional, Wang, C.-T., additional, Ogawa, H., additional, Nagaya, T., additional, Ota, Y., additional, Sarai, M., additional, Oda, O., additional, Biavo, B., additional, Uezima, C., additional, Costa, M. E., additional, Barros, C., additional, Martins, J. P., additional, Ribeiro Jr, E., additional, Tzanno-Martins, C., additional, Honda, H., additional, Kimata, N., additional, Wakai, K., additional, Akizawa, T., additional, Droulias, J., additional, Filliponi, V., additional, Argyropoulos, C., additional, Fischer, R., additional, Papakonstantinou, C., additional, Papadopoulos, C., additional, Kouvelis, A., additional, Zervas, G., additional, Dampolia, E., additional, Zerefos, N., additional, Valis, D., additional, Sarcina, C., additional, Baragetti, I., additional, Uboldi, P., additional, Buzzi, L., additional, Garlaschelli, K., additional, Ferrario, F., additional, Terraneo, V., additional, Norata, G. D., additional, Catapano, A. L., additional, Pozzi, C., additional, Conti, G., additional, Santoro, D., additional, Caccamo, D., additional, Condello, S., additional, Pazzano, D., additional, Savica, V., additional, Jentile, R., additional, Fede, C., additional, Bellinghieri, G., additional, Zortcheva, R., additional, Ikonomov, V., additional, Galunska, B., additional, Paskalev, D., additional, Dobreva, D., additional, Ivanova, D., additional, Tsunoda, M., additional, Ikee, R., additional, Sasaki, N., additional, Sato, N., additional, Hashimoto, N., additional, Korol, L., additional, Dudar, I., additional, Migal, L., additional, Gonchar, Y., additional, Seleznova, I., additional, Ischenko, V., additional, Erkmen Uyar, M., additional, Tutal, E., additional, Bal, Z., additional, Ahmed, N., additional, Sezer, S., additional, Fedak, D., additional, Kuzniewski, M., additional, Pawlica, D., additional, Kusnierz-Cabala, B., additional, Solnica, B., additional, Drozdz, M., additional, Janda, K., additional, Sulowicz, W., additional, Kopec, J., additional, Banach, M., additional, and Leal, V., additional

Published
2011
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