Memória, imaginação e transpiração no processo de fabricação do passado: a ficcionalização de si em Infância e Angústia, de Graciliano Ramos

O objetivo deste trabalho é investigar a proposta literária do escritor alagoano Graciliano Ramos que conceituamos como ficcionalização de si, a qual consiste na utilização de observação, experiência, imaginação e transpiração como ingredientes da elaboração ficcional. Para atingir a tal objetivo, buscamos traçar um breve panorama político-cultural da década de 1930, no sentido de situar a formação ideológica e a produção mais significativa do autor Caetés (1933), S. Bernardo (1934), Angústia (1936) e Vidas Secas (1938). Prosseguimos com a construção de um amplo painel sobre o papel da memória na escrita de si, concluindo sobre a impossibilidade da fidelidade absoluta na reprodução do real, uma vez que esta passa necessariamente pela subjetividade da linguagem, o que lhe confere um inegável caráter ficcional. Conceituamos autobiografia e refletimos sobre as profundas alterações percebidas no gênero autobiográfico, inserindo a produção de Graciliano Ramos no contexto memorialista. Defendemos a ideia de que o escritor antecipa, na década de 30, o que na década de 70 será denominado como autoficção. Construída a fundamentação teórica necessária, passamos a analisar e discutir trechos do romance Angústia, em contraponto com Infância. Confrontando as leituras destas obras, pudemos perceber o aproveitamento ficcional de acontecimentos traumáticos da infância do autor narrados em Infância na elaboração da fase infantil do personagem Luís da Silva, de Angústia

A escrita de si e as representações do escritor em Cristovão Tezza

Esta dissertação se detém em duas das principais características da literatura brasileira contemporânea: a profusão de escritas de si e a recorrência de personagens-escritores na produção romanesca. Nesse contexto, a discussão concentra-se em algumas das obras de um dos mais consagrados escritores brasileiros da atualidade: Cristovão Tezza. Em se tratando das escritas de si, discutimos a respeito do premiado romance O filho eterno (2007), por ser uma narrativa que congrega elementos factuais e criação ficcional. Nesse sentido, fazer da relação com o próprio filho Down a matéria-prima de um romance significa enveredar pelos caminhos dos gêneros autobiográficos, estabelecendo um novo paradigma em relação a suas obras anteriores, já que, até então, nenhum espaço para a abordagem de elementos referenciais havia sido aberto. Na discussão dessa obra, consideramos que, apesar de se inclinar à autobiografia, o autor lhe distribui índices de ficcionalidade que colocam em xeque a veracidade do discurso, o que impossibilita a delimitação do gênero entre autobiografia e romance. Nesse caso, o que passa a estar em jogo é a ficcionalização do eu frente à criação literária. Num segundo momento, refletimos sobre a inserção de personagens-escritores na escrita tezziana, recurso amplamente utilizado pelo autor em diversas obras ficcionais, investigando os motivos e implicações dessa recorrência. Para empreender tal análise, recorremos às noções de metaficção e gesto literário, visto que a tematização do universo íntimo do escritor na esfera ficcional evidencia o ato de escrever e seu caráter problematizador. Por último, fazemos uma leitura comparada entre o romance de matiz biográfico O filho eterno e a autobiografia literária O espírito da prosa, tendo por premissa que esta pode funcionar como peça-chave na recepção daquele

A new low temperature synthesis route of fraipontite (Zn,Al)3(Si,Al)2O5(OH)4

A low temperature synthesis method based on the decomposition of urea at 90°C in water has been developed to synthesise fraipontite. This material is characterised by a basal reflection 001 at 7.44 Å. The trioctahedral nature of the fraipontite is shown by the presence of a 06l band around 1.54 Å, while a minor band around 1.51 Å indicates some cation ordering between Zn and Al resulting in Al-rich areas with a more dioctahedral nature. TEM and IR indicate that no separate kaolinite phase is present. An increase in the Al content however, did result in the formation of some SiO2 in the form of quartz. Minor impurities of carbonate salts were observed during the synthesis caused by to the formation of CO32- during the decomposition of urea.

Ordering of Ge islands on Si(001) substrates patterned by nanoindentation

Spatial organization of Ge islands, grown by physical vapor deposition, on prepatterned Si(001) substrates has been investigated. The substrates were patterned prior to Ge deposition by nanoindentation. Characterization of Ge dots is performed by atomic force microscopy and scanning electron microscopy. The nanoindents act as trapping sites, allowing ripening of Ge islands at those locations during subsequent deposition and diffusion of Ge on the surface. The results show that island ordering is intrinsically linked to the nucleation and growth at indented sites and it strongly depends on pattern parameters.

Catalyst-free growth and optical properties of vertically aligned ZnO Nanorod Arrays on Si substrates covered with thin buffer layers

Vertically aligned ZnO nanorods have been grown on silicon substrates pre-coated with thin, less than 10 nm, textured ZnO seeding layers via a vapor-solid mechanism. The ZnO seeding layers, which were essential for vertical alignment of ZnO nanorods without using any metal catalyst, were prepared by decomposing zinc acetate. The structure and the luminescence properties of the ZnO nanorods synthesized onto ZnO seeding layers were investigated and their morphologies were compared with those of single-crystalline GaN substrates and silicon substrates covered with sputtered ZnO flms. Patterning of ZnO seed layers using photolithography allowed the fabrication of patterned ZnO-nanorod arrays.

Towards a controlled growth of self-assembled nanostructures: shaping, ordering and localization in Ge/Si heteroepitaxy.

The strain-induced self-assembly of suitable semiconductor pairs is an attractive natural route to nanofabrication. To bring to fruition their full potential for actual applications, individual nanostructures need to be combined into ordered patterns in which the location of each single unit is coupled with others and the surrounding environment. Within the Ge/Si model system, we analyze a number of examples of bottom-up strategies in which the shape, positioning, and actual growth mode of epitaxial nanostructures are tailored by manipulating the intrinsic physical processes of heteroepitaxy. The possibility of controlling elastic interactions and, hence, the configuration of self-assembled quantum dots by modulating surface orientation with the miscut angle is discussed. We focus on the use of atomic steps and step bunching as natural templates for nanodot clustering. Then, we consider several different patterning techniques which allow one to harness the natural self-organization dynamics of the system, such as: scanning tunneling nanolithography, focused ion beam and nanoindentation patterning. By analyzing the evolution of the dot assembly by scanning probe microscopy, we follow the pathway which leads to lateral ordering, discussing the thermodynamic and kinetic effects involved in selective nucleation on patterned substrates.

Hydrogen gas sensing properties of Pt/Ta2O5 Schottky diodes based on Si and SiC substrates

In this paper, we fabricated Pt/tantalum oxide (Ta2O5) Schottky diodes for hydrogen sensing applications. Thin (4 nm) layer of Ta2O5 was deposited on silicon (Si) and silicon carbide (SiC) substrates by radio frequency (RF) sputtering technique. We compared the performance of these sensors at different elevated temperatures of 100 ∘C and 150 ∘C. At these temperatures, the sensor based on SiC exhibited a larger sensitivity while the sensor based on Si exhibited a faster response toward hydrogen gas. We discussed herein, the responses exhibited by the Pt/Ta2O5 based Schottky diodes demonstrated a promising potential for hydrogen sensing applications.

Driving Ge island ordering on nanostructured Si surfaces

Semiconductor epitaxial nanostructures have been recently proposed as the key building blocks of many innovative applications in materials science and technology. To bring their tremendous potential to fruition, a fine control of nanostructure size and placement is necessary. We present a detailed investigation of the self-ordering process in the prototype case of Ge/Si heteroepitaxy. Starting from a bottom-up strategy (step-bunching instabilities), our analysis moves to lithographic techniques (scanning tunneling lithography, nanomechanical stamping, focused ion beam patterning) with the aim of developing a hybrid approach in which the exogenous intervention is specifically designed to suit and harness the natural self-organization dynamics of the system.

Porous Ca-Si-based nanospheres : a potential intra-canal disinfectant-carrier for infected canal treatment

The aim of this study is to develop a new intra-canal disinfectant-carrier for infected canal treatment. To achieve this purpose, a new porous Ca-Si (CS)-based nanosphere was synthesized and characterized. Results showed that the nanospheres can infiltrate into dentinal tubules and released the ampicillin over one week time in a sustained manner. The release of ampicillin from spheres has significantly antibacterial property. Extensive and well-organized in vitro mineralization and crystallization of apatite were induced on the surface of dentin slices covered by CS nanospheres. All these features indicate that the porous CS nanospheres may be developed into a new intra-canal disinfectant-carrier for infected canal treatment.

Biological responses of human bone marrow mesenchymal stem cells to Sr-M-Si (M = Zn, Mg) silicate bioceramics

Strontium (Sr), Zinc (Zn), magnesium (Mg), and silicon (Si) are reported to be essential trace elements for the growth and mineralization of bone. We speculated that the combination of these bioactive elements in bioceramics may be effective to regulate the osteogenic property of boneforming cells. In this study, two Sr-containing silicate bioceramics, Sr2ZnSi2O7 (SZS) and Sr2MgSi2O7 (SMS), were prepared. The biological response of human bone marrow mesenchymal stem cells (BMSCs) to the two bioceramics (in the forms of powders and dense ceramic bulks) was systematically studied. In powder form, the effect of powder extracts on the viability and alkaline phosphatase (ALP) activity of BMSCs was investigated. In ceramic disc form, both direct and indirect coculture of BMSCs with ceramic discs were used to investigate their biological response, including attachment, proliferation, ALP activity, and bone-related genes expression. Beta-tricalcium phosphate (b-TCP) and akermanite (Ca2MgSi2O7, CMS) were used as control materials. The results showed that the Sr, Zn, and Si (or Sr, Mg, and Si)-containing ionic products from SZS and SMS powders enhanced ALP activity of BMSCs, compared to those from b-TCP. Both SZS and SMS ceramic discs supported the growth of BMSCs, and most importantly, significantly enhanced the ALP activity and bone-related genes expression of BMSCs as compared to b-TCP. The results suggest that the specific combination of bioactive ions (Sr, Zn, Si, e.g.) in bioceramics is a viable way to improve the biological performance of biomaterials, and the form of materials and surface properties were nonnegligible factors to influence cell response.