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BACKGROUND: Photodynamic therapy (PDT) activates a photosensitizer by visible light to generate cytotoxic oxygen species that lead to cell death. With proper illumination, PDT is often used in applications on superficial and sub-surface lesions. Sporotrichosis infection occurs by Sporothrix fungi which causes a skin wound, worsened by Candida albicans infections. This study investigated the photosensitizing efficiency of the Ru(phen)2(pPDIp)(PF6)2 complex, RupPDIp, against S. brasiliensis and C. albicans. MATERIAL AND METHODS: RupPDIp efficiency against these fungi was tested using 450 nm (blue light and 36 J/cm2) and 525 nm (green light, 25.2 J/cm2) at 0.05-20 µM concentrations. To ensure PDT effectiveness, control groups were tested in the absence and in the presence of RupPDIp under light irradiation and in the dark. RESULTS: RupPDIp eliminated both fungi at ≤5.0 µM. Green light showed the best results, eliminating S. brasiliensis and C. albicans colonies at RupPDIp 0.5 µM and 0.05 µM, respectively. CONCLUSION: RupPDIp is a promising photosensitizer in aPDT, eliminating 106 CFU/mL of both fungi at 450 nm and 525 nm, with lower light doses and concentrations when treated with the green light compared to the blue light.

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There is a growing interest in the study of unspecialized mesenchymal stem cells, for there are still some discussions about their in vitro behavior. Regenerative medicine is a science undergoing improvement which develops treatments as cell therapy using somatic stem cells. In several studies, adipose tissue is presented as a source of multipotent adult cells that has several advantages over other tissue sources. This study aimed to characterize and evaluate the tagging of mesenchymal stem cells from the agoutis adipose tissue (Dasyprocta prymonolopha), with fluorescent intracytoplasmic nanocrystals. Fibroblast cells were observed, plastic adherent, with extended self-renewal, ability to form colonies, multipotency by differentiation into three lineages, population CD90 + and CD45 - expression, which issued high red fluorescence after the tagging with fluorescent nanocrystals by different paths and cryopreserved for future use. It is possible to conclude that mesenchymal stem cells from agouti adipose tissue have biological characteristics and in vitro behavior that demonstrate its potential for use in clinical tests.(AU)

Há um interesse crescente no estudo das células estaminais mesenquimais, não especializadas, pois ainda existem algumas discussões sobre seu comportamento in vitro. A medicina regenerativa é uma ciência em fase de crescimento que desenvolve tratamentos como terapia celular utilizando células estaminais somáticas. Em vários estudos, o tecido adiposo é apresentado como uma fonte de células adultas multipotentes que tem várias vantagens em relação a outras fontes de tecido. Este estudo teve como objetivo caracterizar e avaliar a marcação de células estaminais mesenquimais do tecido adiposo de cutias (Dasyprocta prymnolopha) com nanocristais intracitoplasmáticos fluorescentes. Observaram-se células fibroblásticas, aderentes ao plástico, com autorrenovação prolongada, capacidade de formar colônias, diferenciação em três linhagens, população CD90 + e expressão CD45, que emitiram alta fluorescência vermelha após a marcação com nanocristais fluorescentes por diferentes vias, e criopreservadas para uso futuro. É possível concluir que as células estaminais mesenquimais do tecido adiposo de cutias têm características biológicas e comportamentos in vitro que demonstram seu potencial para uso em testes clínicos.(AU)

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There is a growing interest in the study of unspecialized mesenchymal stem cells, for there are still some discussions about their in vitro behavior. Regenerative medicine is a science undergoing improvement which develops treatments as cell therapy using somatic stem cells. In several studies, adipose tissue is presented as a source of multipotent adult cells that has several advantages over other tissue sources. This study aimed to characterize and evaluate the tagging of mesenchymal stem cells from the agoutis adipose tissue (Dasyprocta prymonolopha), with fluorescent intracytoplasmic nanocrystals. Fibroblast cells were observed, plastic adherent, with extended self-renewal, ability to form colonies, multipotency by differentiation into three lineages, population CD90 + and CD45 - expression, which issued high red fluorescence after the tagging with fluorescent nanocrystals by different paths and cryopreserved for future use. It is possible to conclude that mesenchymal stem cells from agouti adipose tissue have biological characteristics and in vitro behavior that demonstrate its potential for use in clinical tests.(AU)

Há um interesse crescente no estudo das células estaminais mesenquimais, não especializadas, pois ainda existem algumas discussões sobre seu comportamento in vitro. A medicina regenerativa é uma ciência em fase de crescimento que desenvolve tratamentos como terapia celular utilizando células estaminais somáticas. Em vários estudos, o tecido adiposo é apresentado como uma fonte de células adultas multipotentes que tem várias vantagens em relação a outras fontes de tecido. Este estudo teve como objetivo caracterizar e avaliar a marcação de células estaminais mesenquimais do tecido adiposo de cutias (Dasyprocta prymnolopha) com nanocristais intracitoplasmáticos fluorescentes. Observaram-se células fibroblásticas, aderentes ao plástico, com autorrenovação prolongada, capacidade de formar colônias, diferenciação em três linhagens, população CD90 + e expressão CD45, que emitiram alta fluorescência vermelha após a marcação com nanocristais fluorescentes por diferentes vias, e criopreservadas para uso futuro. É possível concluir que as células estaminais mesenquimais do tecido adiposo de cutias têm características biológicas e comportamentos in vitro que demonstram seu potencial para uso em testes clínicos.(AU)

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Bioaccumulation of mercury and methylmercury in fish represents a serious risk to human beings. Extreme climate events like droughts may increase the trophic transfer of contaminants and net methylation of mercury. The present study assessed the influence of the 2014 drought on total mercury and methylmercury levels in fish from the lower Paraiba do Sul river basin. Contaminant levels were compared for Pimelodus fur, Pachyurus adspersus, Pimelodella lateristriga, Oligosarcus hepsetus, and Crenicichla lacustris captured in five sites in 2013 (N = 212) and 2014 (N = 231). The results indicate that levels of contaminants were higher during the drought in most species. Rainfall was weakly and negatively correlated with total mercury levels in most of the species. The weak relationship between these two variables was due to the indirect influence of rainfall on mercury bioaccumulation. In summary, drought increased the levels of two contaminants in fish.

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Excitons play a key role in technological applications since they have a strong influence on determining the efficiency of photovoltaic devices. Recently, it has been shown that the allotropes of phosphorus possess an optical band gap that can be tuned over a wide range of values including the near-infrared and visible spectra, which would make them promising candidates for optoelectronic applications. In this work we carry out ab initio many-body perturbation theory calculations to study the excitonic effects on the optical properties of two-dimensional phosphorus allotropes: the case of blue and black monolayers. We elucidate the most relevant optical transitions, exciton binding energy spectrum as well as real-space exciton distribution, particularly focusing on the absorption spectrum dependence on the incident light polarization. In addition, based on our results, we use a set of effective hydrogenic models, in which the electron-hole Coulomb interaction is included to estimate exciton binding energies and radii. Our results show an excellent agreement between the many-body methodology and the effective models.

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Defects in semiconductors can exhibit multiple charge states, which can be used for charge storage applications. Here we consider such charge storage in a series of oxygen deficient phases of TiO2, known as Magnéli phases. These Magnéli phases (TinO2n-1) present well-defined crystalline structures, i.e., their deviation from stoichiometry is accommodated by changes in space group as opposed to point defects. We show that these phases exhibit intermediate bands with an electronic quadruple donor transitions akin to interstitial Ti defect levels in rutile TiO2. Thus, the Magnéli phases behave as if they contained a very large pseudo-defect density: ½ per formula unit TinO2n-1. Depending on the Fermi Energy the whole material will become charged. These crystals are natural charge storage materials with a storage capacity that rivals the best known supercapacitors.

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Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements.

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A novel enzymatic platform for the sensing of H2O2 and glucose that uses L,L-diphenylalanine micro/nanostructures (FF-MNSs) as an enzyme support is shown. This platform is obtained by the self-assembly of poly(allylamine hydrochloride) (PAH), FF-MNSs, and microperoxidase-11 (MP11) anchored onto the peptide matrix, in two different crystal structures of FF-MNSs: hexagonal (P61) and orthorhombic (P22121). The electroactive area of the electrodes increases in the presence of FF-MNSs. We also demonstrate via theoretical calculations that the valence band energy of the orthorhombic structure allows it to be doped, similarly to p-type semiconductors, where PAH acts as a doping agent for the orthorhombic peptide structure, decreasing the band-gap by around 1 eV, which results in a smaller charge transfer resistance. These results are consistent with electrochemical impedance spectroscopy measurements, which further elucidate the role of the band structure of the orthorhombic FF-MNSs in the conductivity and electron transfer rates of the hybrid material. An effective communication between the electrode and the active site of a glucose oxidase enzyme through MP11-protein complexes occurs, paving the way for FF-MNSs in the orthorhombic phase for the future development of bioelectronics sensing devices.

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Recently, atomically well-defined cove-shaped graphene nanoribbons have been obtained using bottom-up synthesis. These nanoribbons have an optical gap in the visible range of the spectrum which make them candidates for donor materials in photovoltaic devices. From the atomistic point of view, their electronic and optical properties are not clearly understood. Therefore, in this work we carry out ab-initio density functional theory calculations combine with many-body perturbation formalism to study their electronic and optical properties. Through the comparison with experimental measurements, we show that an accurate description of the nanoribbon's optical properties requires the inclusion of electron-hole correlation effects. The energy, binding energy and the corresponding excitonic transitions involved are analyzed. We found that in contrast to zigzag graphene nanoribbons, the excitonic peaks in the absorption spectrum are a consequence of a group of transitions involving the first and second conduction and valence bands. Finally, we estimate some relevant optical properties that strengthen the potential of these nanoribbons for acting as a donor materials in photovoltaic.

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Graphane, hydrogenated graphene, can be patterned into electronic devices by selectively removing hydrogen atoms. The most simple of such devices is the so-called nanoroad, analogous to the graphene nanoribbon, where confinement-and the opening of a gap-is obtained without the need for breaking the carbon bonds. In this work we address the electronic transport properties of such systems considering different hydrogen impurities within the conduction channel. We show, using a combination of density functional theory and non-equilibrium Green's functions, that hydrogen leads to significant changes in the transport properties and in some cases to current polarization.