Rare earth centers properties and electron trapping in SnO2 thin films produced by sol-gel route

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Photoluminescence of Eu(3+) ion in SnO(2) obtained by sol-gel

Photoluminescence data of Eu-doped SnO(2) xerogels are presented, yielding information on the symmetry of Eu(3+) luminescent centers, which can be related to their location in the matrix: at lattice sites, substituting to Sn(4+), or segregated at particles surface. Influence of doping concentration and/or particle size on the photoluminescence spectra obtained by energy transfer from the matrix to Eu(3+) sites is investigated. Results show that a better efficiency in the energy transfer processes is obtained for high symmetry Eu(3+) sites and low doping levels. Emission intensity from (5)D(0) -> (7)F(1) transition increases as the temperature is raised from 10 to 240 K, under excitation at 266 nm laser line, because in this transition the multiphonon emission becomes significant only above 240 K. As an extension of this result, we predict high effectiveness for room temperature operation of Eu-based optical communication devices. X-ray diffraction data show that the impurity excess inhibits particle growth, which may influence the asymmetry ratio of luminescence spectra.

Indirect optical transitions from carriers trapped on the delta doping and on the parabolic quantum well

In this work, doped AlGaAs/GaAs parabolic quantum wells (PQW) with different well widths (from 1000 angstrom up to 3000 angstrom) were investigated by means of photoluminescence (PL) measurements. In order to achieve the 2DEG inside the PQW Si delta doping is placed at both side of the well. We have observed that the thickness of this space layer plays a major rule on the characteristics of the 2DEG. It has to be thicker enough to prevent any diffusions of Si to the well and thin enough to allow electrons migration inside the well. From PL measurement, we have observed beside the intra well transitions, indirect transitions involving still trapped electron on the delta doping and holes inside the PQW. For the thinness sample, we have measured a well defined PL peak at low energy side of the GaAs bulk emission. With the increasing of the well thickness this peak intensity decreases and for the thickest sample it almost disappears. Our theoretical calculation indicated that carriers (electron and holes) are more placed at the center of the PQW. In this way, when the well thickness increases the distance between electrons on the delta doping and holes on the well also increases, it decreases the probability of occurrence of these indirect optical transitions. (C) 2012 Published by Elsevier B.V. Selection and/or peer-review under responsibility of Universidade Federal de Juiz de Fora, Brazil.

A escrita do tempo e a poética do espaço:história e espaço no livro Geografia do Brasil Holandês de Luís da Câmara Cascudo

In 1956, Luís da Câmara Cascudo published his book Geografia do Brasil Holandês. In this book, he studied and described a space - the Dutch Brazil - from a geographical and historical perspective. To do this, he articulated both perspectives from the point of view of his own reading of the History of Nordeste , establishing a dialogue with the historiographical tradition of the study of the Dutch Brazil in Pernambuco. When portraying the Dutch presence in Nordeste, Cascudo articulated a drama in which the Dutch would have their history described as a typically tragic plot, portrayed as if they were already condemned to failure in advance. To this tragedy he opposed a predominantly comic Portuguese plot, as if the Portuguese victory over the Dutch was as desirable as inevitable for the space of Nordeste . When narrating the clash between the Dutch and the Portuguese for the space of Nordeste , however, Cascudo ended up delineating his own place of speech, as a spokesperson for the identity of the potiguar space in opposition to the pernabucano space described by Freyre and Gonsalves de Mello. In this way, the space of Rio Grande do Norte would have its own identity, constructed from de Dutch absence and constituted from the Portuguese legacy contrarily to the space of Pernambuco, narrated from an articulation and a conciliation of the Flemish and Lusitan legacy, even though highlighting the latter. While the Dutch would had been a constant presence in the history of Pernambuco for Freyre and Gonsalves de Mello, they wouldn t have gone beyond legend in the space of Rio Grande do Norte, removed from its geography and erased from its history. When describing de geography of the potiguar space, therefore, Cascudo articulates the inexistence of the History of a time dominated by the Fleming with the search of a Portuguese space, trough the narration of its origins and constitution, as well as the registry of the characteristics of its legacy

"O núcleo supraquiasmático e o folheto intergeniculado do mocó (Kerodon rupestris): Projeções retinianas e caracterização imuno-histoquímica

In this study, two circadian related centres, the suprachiasmatic nucleus (SCN) and the intergeniculate leaflet (IGL) were evaluated in respect to their cytoarchitecture, retinal afferents and chemical content of major cells and axon terminals with a tract tracer and immunohistochemical techniques in the rock cavy (Kerodon rupestris), a Brazilian caviidae rodent species. The rock cavy SCN is innervated in its ventral portion by terminals from the predominantly contralateral retina. It also contains neurophisin and vasoactive intestinal polypeptide immunoreactive cell bodies and neuropeptide Y and enkephalin immunopositive fibres and terminals and is marked by intense GFAP immunoreactivity. The IGL receives a predominantly contralateral retinal projection, contains neuropeptide Y and nitric oxide synthase producing neurons and enkephalin immunopositive terminals and is characterized by dense GFAP immunoreactivity. This is the first report examining the neural circadian system in a crepuscular rodent species for which circadian properties have been described. The results are discussed comparing with what has been described for other species and in the context of the functional significance of these centres

Centros rombencefálicos de processamento auditivo do sagui (Callithrix jacchus): uma análise citoarquitetônica e neuroquímica

The auditory system is composed by a set of relays from the outer ear to the cerebral cortex. In mammals, the central auditory system is composed by cochlear nuclei, superior olivary complex, inferior colliculus and medial geniculate body. In this study, the auditory rombencephalic centers, the cochlear nuclear complex and the superior olivary complex were evaluated from the cytoarchitecture and neurochemical aspects, thorough Nissl staining and immunohistochemical techniques to reveal specific neuron nuclear protein (NeuN), glutamate (Glu), glutamic acid decarboxilase (GAD), enkephalin (ENK), serotonin (5-HT), choline acetyltransferase (ChAT) and calcium-binding proteins calbindin (CB), calretinin (CR), and parvalbumin (PV). The common marmoset (Callithrix jacchus), a little native primate of the Brazilian atlantic forest was used as an experimental animal. As results, it was noted that the cochlear nuclear complex is composed by anteroventral, posteroventral and dorsal nuclei, and the superior olivary complex is constituted by the lateral and medial superior olivary nuclei and the trapezoid body nucleus. Glu, GAD, ENK, ChAT, CB, CR, PV-immunoreactive cells, fibers and terminals besides besides only 5-HT terminals were found unhomogeneously in all nuclei, of both complex. The emerging data are discussed in a comparative and functional context, and represent an important contribution to knowledge of the central auditory pathways in the common marmoset, and then in primates

Assinaturas antropogênicas de elementos maiores e traços em poeira urbana na cidade do Natal-RN

Although there are many studies on urban dust contamination by heavy metals in developed countries, little attention has been paid to this type of study in developing countries, including Brazil. Therefore, a series of investigations were performed to provide signatures of heavy metals in urban dust and assess the potential sources in the city of Natal - RN-Brazil. The fraction of these sediments was studied to pass through a sieve of 63 micrometers. For the study analyzed two groups of samples, one collected in September 2009 at the end of the rainy season (9 samples) and one collected in January 2010 in the dry season (21 samples). So in all, thirty sediment samples were collected from the street. Then, in Fluorescence Spectrometry X-rays were determined major elements SiO2, Na2O, K2O, Al2O3, MgO, P2O5, Fe2O3, MnO, TiO2 and CaO, and trace Rb, Cr, Ni, Cu, Zn, Sr and Pb by an ICPOES was determined Zn, V, Na, K, Ni, Mn, Mg, P, Fe, Cr, Cu, Pb, Ba, Ca and Al from leaching HCl 0.5 mol L-1 . The results of the concentrations of elements show that the greater presence of these occurs in the dry season, except for Si which is higher in the rainy season. Analyses by geoaccumulation Index (IGEO) Enrichment Factor (EF), Contamination Factor (CF), analysis correlation and Hierarchical Cluster, confirm that Zn, Cu and Pb is anthropogenic character. Zinc may be derived from various sources related to motor vehicles or the road signs and street grids. The elements Na, K, Mg and Ca may be related to droplets suspended in air containing cations and anions present in seawater (salty), common in Christmas throughout the year, brought by winds SE-NW. The elements Na, Mg, Ca and K are the most abundant in seawater and were analyzed in this study. This indicates that the source of these additional elements detected by analyzing the contamination factor may be the very sea. Moreover, Ni, Fe, Cr and Ba can be either as a source of anthropogenic geogênica. The source of Ca is different, because it comes in lime and paint (painting guides of buildings and streets) in construction materials, but may also be present in sediments in the fragments of shells or carbonate bioclasts common in the coastal area

Evidence of reciprocal connections between the dorsal raphe nucleus and the retina in the monkey Cebus apella

Possible connections between the retina and the raphe nuclei were investigated in the monkey Cebus apella by intraocular injection of cholera toxin B subunit (CTb). CTb-positive fibers were seen in the lateral region of the dorsal raphe nucleus (DR) on the side contralateral to the injection, and a few labeled perikarya were observed in the lateral portion of the DR on the ipsilateral side. Our findings suggest that direct and reciprocal connections between the retina and DR may exist in Cebus apella. These connections might be part of an important pathway through which the light/dark cycle influences the Activity and/or functional status of raphe neurons, with potential effects on a broad set of neural and behavioral circuits. (c) 2007 Elsevier B.V. All rights reserved.

Processos sócio-ambientais relacionados às situações de degradação na região do Rio Doce, Natal/RN

Natal is a medium-sized coastal city (800.000 inhabitants), capital of the State of Rio Grande do Norte, in the Northeast of Brazil. According to statistics published by the IBGE (2000), the area of Natal that stretches from Redinha to Lagoa Azul holds about 12% of the municipal population. Part of this area is bordered by a watercourse, the Rio Doce, which has been afflicted by a range of socio-environmental problems over the years. This study was carried out with the aims of 1) identifying the socio-environmental processes related to urban expansion, with an emphasis on those causing environmental degradation in this region; b) analysing the perception of the target population in relation to the environment it occupies; and c) determining the socioeconomic profile of the local residents and the sanitary facilities available to them. A survey was carried out by conducting interviews and completing questionnaires with the residents to assess the situation both qualitatively and quantitatively in the communities of Caiana, Pajussara Sítio, Gramoré Povoado and Gramoré Sítio, as well as by conducting bibliographical and documentary research. It was discovered that the sanitary conditions of the riverside dwellers are precarious and only 1% of the houses in the suburbs mentioned are connected to the public sewers. It was established that the Rio Doce is intensively exploited through the extraction of sand for the building trade, irrigation of riverside vegetable plots and use of the water for bathing, washing of clothes and leisure. It was also found that about 40% of the population resident in this area has migrated from the rural zone, which is one of the factors rendering it difficult for them to adapt to the urban setting. Such information can be of use to the authorities in the environmental planning of these districts and their sustainable development

Acquired hepatocerebral degeneration and hepatic encephalopathy: correlations and variety of clinical presentations in overt and subclinical liver disease

A degeneração hepatocerebral adquirida (AHD) e a degeneração hepatolenticular podem ter apresentações clínicas semelhantes, mas quando uma doença hepática crônica e achados motores atípicos coexistem, a distinção entre AHD e encefalopatia hepática (HE) pode ser ainda mais complicada. Descrevemos três casos de AHD (dois tendo HE) com diferentes achados em neuroimagem, doenças hepáticas distintas e apresentações motoras semelhantes, todos com hipertensão arterial e perda de peso antes das manifestações motoras. O diagnóstico e a fisiopatologia são comentados e comparados com relatos prévios. Concluímos que existem muitas correlações entre HE, degeneração hepatolenticular e AHD, mas a sobreposição de HE e AHD pode ser mais comum dependendo do conhecimento clínico e da acurácia dos critérios diagnósticos adotados para cada enfermidade. Como a AHD não é considerada prioridade na lista de transplante hepático, o prognóstico dos pacientes com AHD permanece ruim, e a interrupção do fluxo nos shunts portossistêmicos deve ser sempre considerada.

Informações nutricionais de carnes ovinas em rótulos comerciais, comparativamente às obtidas em análises laboratoriais

Objetivou-se estudar as informações nutricionais de carnes ovinas comercializadas, comparativamente às determinadas por análises laboratoriais, utilizando-se 18 ovinos Ile de France x Ideal (cordeiros não castrados, ovelhas adultas de descarte e capões adultos de descarte). Os cordeiros foram desmamados com 17 kg e abatidos aos 32 kg. As ovelhas e capões, com 55 kg. As informações nutricionais dos rótulos de carne ovina embalada foram obtidas através do contato direto com 19 empresas que comercializam carne ovina. A maioria das empresas avaliadas não utiliza a informação nutricional na rotulagem da carne ovina embalada e também não descrimina a categoria ovina dos cortes da carcaça disponibilizados para venda. Os valores das informações nutricionais, analisadas laboratorialmente, da carne ovina evidenciaram, de modo geral, diferenças entre as categorias ovinas e seus respectivos cortes da carcaça para: valor calórico, teor de carboidratos, proteínas, gorduras totais, colesterol, cálcio e ferro. As empresas estudadas, de maneira geral, desconhecem ou ignoram tais diferenças entre as categorias e os cortes da carcaça ovina quanto às informações nutricionais, sendo necessário melhorar os rótulos comerciais dos cortes da carcaça ovina, a fim de informar o consumidor, de maneira mais simples, sobre o produto que está sendo adquirido para o consumo.

Short-term vs long-term calcium hydroxide therapy after immediate tooth replantation: a histomorphometric study in monkey's teeth

Endodontic treatment is an important step of tooth replantation protocols, but the ideal moment for definitive obturation of replanted teeth has not yet been established. In this study, a histomorphometric analysis was undertaken to evaluate the repair process on immediate replantation of monkeys teeth after calcium hydroxide (CH) therapy for 1 and 6 months followed by root canal filling with a CH-based sealer (Sealapex (R)). The maxillary and mandibular lateral incisors of five female Cebus apella monkeys were extracted, kept in sterile saline for 15 min, replanted and splinted with stainless steel orthodontic wire and composite resin for 10 days. In Group I (control), definitive root canal filling was performed before tooth extraction. In Groups II and III, CH therapy started after removal of splint, and definitive root canal filling was performed 1 and 6 months later, respectively. The animals were euthanized 9 months after replantation, and specimens were processed for histomorphometric analysis. In all groups, epithelial attachment occurred at the cementoenamel junction or very close to this region; the areas of resorption on root surface had small extension and depth and were repaired by newly formed cementum; and the periodontal ligament was organized. Statistical analysis of the scores obtained for the histomorphometric parameters did not show any statistically significant difference (P = 0.1221) among the groups. The results suggests that when endodontic treatment is initiated 10 days after immediate replantation and an antibiotic regimen is associated, definitive root canal filling can be performed after a short-term CH therapy.

Early healing after elevation of the maxillary sinus floor applying a lateral access: a histological study in monkeys

AimTo describe the early healing within the void obtained after the elevation of the sinus mucosa and simultaneous implant installation without the use of any grafting material in monkeys.Material and methodsImplants were installed simultaneously with the elevation of the maxillary sinus using the lateral approach in eight monkeys without the use of grafting material. The healing after 4, 10, 20 and 30 days was evaluated in the area distal to the implants. Paraffin sections were prepared and analyzed using qualitative histological methods.ResultsThe healing process was initiated by the formation of a coagulum and followed by a provisional matrix and woven bone. Subsequently, a parallel-fiber bone replaced woven bone. The dimension of the elevated area shrank during the healing process. Sprouts of woven bone, present to a moderate extent after 4 days, were more numerous after 10 and 20 days. Newly formed bone originated from the sinus walls and septa, while there was no evidence of participation of the Schneiderian membrane in this process. After 30 days, the window access appeared to be closed by a layer of newly formed trabecular bone.ConclusionsThe coagulum that filled the void distal to the implant after simultaneous elevation of the sinus floor gave rise to newly formed bone. However, the void occupied by the coagulum shrank substantially. The Schneiderian membrane did not provide a basis for new bone formation in the early phase of healing.To cite this article:Scala A, Botticelli D, Rangel IG Jr, de Oliveira JA, Okamoto R, Lang NP. Early healing after elevation of the maxillary sinus floor applying a lateral access: a histological study in monkeys.Clin. Oral Impl. Res. 21, 2010; 1320-1326.doi: 10.1111/j.1600-0501.2009.01964.x.

Effects of cyclosporin, phenytoin, and nifedipine on the synthesis and degradation of gingival collagen in tufted capuchin monkeys (Cebus apella): Histochemical and MMP-1 and -2 and collagen I gene expression analyses

Background: The purpose of this experimental study was to evaluate the collagen fiber distribution histologically after phenytoin, cyclosporin, or nifedipine therapy and to correlate it with collagen I and matrix metalloproteinase (MMP)-1 and -2 gene expression levels.Methods: Gingival samples from the canine area were obtained from 12 male monkeys (Cebus apella). The mesial part of each sample was assessed by reverse transcription-polymerase chain reaction, whereas the distal part was processed histologically for picrosirius red and hematoxylin and eosin stainings, as well as for collagen IV immunostaining. One week after the first biopsy, the animals were assigned to three groups that received daily oral dosages of cyclosporin, phenytoin, or nifedipine for 120 days. Additional gingival samples were obtained on days 52 and 120 of treatment from two animals from each group on the opposite sides from the first biopsies.Results: Picrosirius red staining showed a predominance of mature collagen fibers in the control group. Conversely, there was an enlargement of areas occupied by immature collagen fibers in all groups at days 52 and 120, which was not uniform over each section. There was a general trend to lower levels of MMP-1 gene expression on day 52 and increased levels on day 120. Phenytoin led to increased levels of MMP-2 and collagen I gene expression on day 120, whereas the opposite was observed in the nifedipine group.Conclusion: Cyclosporin, phenytoin, and nifedipine led to phased and drug-related gene expression patterns, resulting in impaired collagen metabolism, despite the lack of prominent clinical signs.

Lack of influence of the Schneiderian membrane in forming new bone apical to implants simultaneously installed with sinus floor elevation: an experimental study in monkeys

Aim: To describe the early healing processes around the implants installed after elevation of the sinus mucosa applying the lateral access technique without the use of grafting material.Material and methods: Immediately after the elevation of the maxillary sinus Schneiderian membrane by the lateral approach in eight monkeys, implants were installed without the use of grafting material. The healing of the tissue around the implants was evaluated after 4, 10, 20 and 30 days. Ground sections were prepared and analyzed histologically.Results: After 4 days of healing, the formation of coagulum and provisional matrix was documented within the elevated area. At 10-day interval, sprouts of woven bone were in continuity with the parent bone, and partly in contact with the implant surface at the base of the augmented area. While bone-to-implant contact increased after 20 and 30 days, the area underneath the Schneiderian membrane appeared reduced in volume and condensed toward the apex of the implants. The sinus mucosa was to some extent collapsed onto the implant surface and on the newly formed bone.Conclusions: The void initially occupied by the coagulum after sinus membrane elevation shrank substantially during the observation period. A lack of influence of the Schneiderian membrane in bone formation apical to implants was documented in the early phase of healing.