Nanochromics: old materials, new structures and architectures for high performance devices

Due to the development of nanoscience, the interest in electrochromism has increased and new assemblies of electrochromic materials at nanoscale leading to higher efficiencies and chromatic contrasts, low switching times and the possibility of color tuning have been developed. These advantages are reached due to the extensive surface area found in nanomaterials and the large amount of organic electrochromic molecules that can be easily attached onto inorganic nanoparticles, as TiO2 or SiO2. Moreover, the direct contact between electrolyte and nanomaterials produces high ionic transfer rates, leading to fast charge compensation, which is essential for high performance electrochromic electrodes. Recently, the layer-by-layer technique was presented as an interesting way to produce different architectures by the combination of both electrochromic nanoparticles and polymers. The present paper shows some of the newest insights into nanochromic science.

On modeling and evaluating multicomputer transcoding architectures for live-video streams

The pervasive and ubiquitous computing has motivated researches on multimedia adaptation which aims at matching the video quality to the user needs and device restrictions. This technique has a high computational cost which needs to be studied and estimated when designing architectures and applications. This paper presents an analytical model to quantify these video transcoding costs in a hardware independent way. The model was used to analyze the impact of transcoding delays in end-to-end live-video transmissions over LANs, MANs and WANs. Experiments confirm that the proposed model helps to define the best transcoding architecture for different scenarios.

Enzyme immobilisation on electroactive nanostructured membranes (ENM): Optimised architectures for biosensing

Electroactive nanostructured membranes have been produced by the layer-by-layer (LbL) technique, and used to make electrochemical enzyme biosensors for glucose by modification with cobalt hexacyanoferrate redox mediator and immobilisation of glucose oxidase enzyme. Indium tin oxide (ITO) glass electrodes were modified with up to three bilayers of polyamidoamine (PAMAM) dendrimers containing gold nanoparticles and poly(vinylsulfonate) (PVS). The gold nanoparticles were covered with cobalt hexacyanoferrate that functioned as a redox mediator, allowing the modified electrode to be used to detect H(2)O(2), the product of the oxidase enzymatic reaction, at 0.0 V vs. SCE. Enzyme was then immobilised by cross-linking with glutaraldehyde. Several parameters for optimisation of the glucose biosensor were investigated, including the number of deposited bilayers, the enzyme immobilisation protocol and the concentrations of immobilised enzyme and of the protein that was crosslinked with PAMAM. The latter was used to provide glucose oxidase with a friendly environment, in order to preserve its bioactivity. The optimised biosensor, with three bilayers, has high sensitivity and operational stability, with a detection limit of 6.1 mu M and an apparent Michaelis-Menten constant of 0.20 mM. It showed good selectivity against interferents and is suitable for glucose measurements in natural samples. (C) 2008 Elsevier B.V. All rights reserved.

The CATH classification revisited-architectures reviewed and new ways to characterize structural divergence in superfamilies

The latest version of CATH (class, architecture, topology, homology) (version 3.2), released in July 2008 (http://www.cathdb.info), contains 1 14215 domains, 2178 Homologous superfamilies and 1110 fold groups. We have assigned 20 330 new domains, 87 new homologous superfamilies and 26 new folds since CATH release version 3.1. A total of 28 064 new domains have been assigned since our NAR 2007 database publication (CATH version 3.0). The CATH website has been completely redesigned and includes more comprehensive documentation. We have revisited the CATH architecture level as part of the development of a `Protein Chart` and present information on the population of each architecture. The CATHEDRAL structure comparison algorithm has been improved and used to characterize structural diversity in CATH superfamilies and structural overlaps between superfamilies. Although the majority of superfamilies in CATH are not structurally diverse and do not overlap significantly with other superfamilies, similar to 4% of superfamilies are very diverse and these are the superfamilies that are most highly populated in both the PDB and in the genomes. Information on the degree of structural diversity in each superfamily and structural overlaps between superfamilies can now be downloaded from the CATH website.

The impact of spatial data redundancy on SOLAP query performance

Geographic Data Warehouses (GDW) are one of the main technologies used in decision-making processes and spatial analysis, and the literature proposes several conceptual and logical data models for GDW. However, little effort has been focused on studying how spatial data redundancy affects SOLAP (Spatial On-Line Analytical Processing) query performance over GDW. In this paper, we investigate this issue. Firstly, we compare redundant and non-redundant GDW schemas and conclude that redundancy is related to high performance losses. We also analyze the issue of indexing, aiming at improving SOLAP query performance on a redundant GDW. Comparisons of the SB-index approach, the star-join aided by R-tree and the star-join aided by GiST indicate that the SB-index significantly improves the elapsed time in query processing from 25% up to 99% with regard to SOLAP queries defined over the spatial predicates of intersection, enclosure and containment and applied to roll-up and drill-down operations. We also investigate the impact of the increase in data volume on the performance. The increase did not impair the performance of the SB-index, which highly improved the elapsed time in query processing. Performance tests also show that the SB-index is far more compact than the star-join, requiring only a small fraction of at most 0.20% of the volume. Moreover, we propose a specific enhancement of the SB-index to deal with spatial data redundancy. This enhancement improved performance from 80 to 91% for redundant GDW schemas.

Piaget segundo seus próprios argumentos

Neste artigo tivemos a intenção de oferecer ao leitor o resumo de um dos aspectos mais importantes da análise estrutural que realizamos, durante décadas, do texto de Jean Piaget, sobretudo as estreitas relações entre a Biologia e a Lógica na construção e na explicação do conhecimento científico. Nesse sentido, procuramos demonstrar que, a partir dos conceitos de implicação significante e de imagem mental criados por Piaget, um novo campo de investigações se abre, a saber, aquele que denominamos como o dos sistemas de significação não lógica, campo de suma relevância e que vem preencher uma secular lacuna entre a razão e a emoção até hoje presente nas pesquisas sobre os fenômenos normais e patológicos do psiquismo.

Eletrodos modificados por hidróxido de níquel: um estudo de revisão sobre suas propriedades estruturais e eletroquímicas visando suas aplicações em eletrocatálise, eletrocromismo e baterias secundárias

The present review paper describes the main features of nickel hydroxide modified electrodes covering its structural and electrochemical behavior and the newest advances promoted by nanostructured architectures. Important aspects such as synthetic procedures and characterization techniques such as X-Ray diffraction, Raman and Infrared spectroscopy, Electronic Microscopy and many others are detailed herein. The most important aspect concerning nickel hydroxide is related to its great versatility covering different fields in electrochemical-based devices such as batteries, electrocatalytic systems and electrochromic electrodes, the fundamental issues of these devices are also commented. Finally, some of the newest advances achieved in each field by the incorporation of nanomaterials will be shown.

Índices de preço para o transporte de cargas: o caso da soja

Esta pesquisa objetivou analisar metodologias para elaboração de índices de preços para o transporte de cargas. O estudo das principais fórmulas da Teoria Econômica culminou com a conclusão que os Índices de Fisher e Walsh são aqueles capazes de atender ao maior número de preceitos lógicos, estatísticos e econômicos. Em seguida, surgem os índices geométricos de Törnqvist, Vartia e Theil. Os Índices de Laspeyres e Paasche, apesar de apresentarem algumas limitações, acabam sendo amplamente utilizados, graças a maior capacidade de operacionalização. A pesquisa apresentou um estudo de caso para o transporte da soja em grão. Foram realizados quatro tratamentos. Obteve-se a variação acumulada no nível geral de preços para o transporte rodoviário de soja no Brasil, no período entre fevereiro de 1998 e março de 2002. De acordo com os resultados, essa variação acumulada teria sido de 76%.

Elementos protetores do leite materno na prevenção de doenças gastrintestinais e respiratórias

A Epistemologia Genética defende que o indivíduo passa por várias etapas de desenvolvimento ao longo da sua vida. O desenvolvimento é observado pela sobreposição do equilíbrio entre a assimilação e a acomodação, resultando em adaptação. Assim, nesta formulação, o ser humano assimila os dados que obtém do exterior, mas uma vez que já tem uma estrutura mental que não está vazia, precisa adaptar esses dados à estrutura mental já existe. O processo de modificação de si próprio é chamado de acomodação. Este esquema revela que nenhum conhecimento chega do exterior sem que sofra alguma alteração pelo indivíduo, sendo que tudo o que se aprende é influenciado por aquilo que já havia sido aprendido. A assimilação ocorre quando a informação é incorporada às estruturas já pré-existentes nessa dinâmica estrutura cognitiva, enquanto que a adaptação ocorre quando o organismo se modifica de alguma maneira de modo a incorporar dinamicamente a nova informação. Por fim, de um pensamento moderno que, buscando a síntese inusitada entre o biológico e o lógico-matemático, parece encontrar seus limites na desconstrução ainda mais inusitada a que tende sistematicamente todo o pensamento na atualidade: a de si mesmo se construindo de modo essencialmente esclarecido

A epistemologia genética de Piaget e o construtivismo

A Epistemologia Genética defende que o indivíduo passa por várias etapas de desenvolvimento ao longo da sua vida. O desenvolvimento é observado pela sobreposição do equilíbrio entre a assimilação e a acomodação, resultando em adaptação. Assim, nesta formulação, o ser humano assimila os dados que obtém do exterior, mas uma vez que já tem uma estrutura mental que não está vazia, precisa adaptar esses dados à estrutura mental já existe. O processo de modificação de si próprio é chamado de acomodação. Este esquema revela que nenhum conhecimento chega do exterior sem que sofra alguma alteração pelo indivíduo, sendo que tudo o que se aprende é influenciado por aquilo que já havia sido aprendido. A assimilação ocorre quando a informação é incorporada às estruturas já pré-existentes nessa dinâmica estrutura cognitiva, enquanto que a adaptação ocorre quando o organismo se modifica de alguma maneira de modo a incorporar dinamicamente a nova informação. Por fim, de um pensamento moderno que, buscando a síntese inusitada entre o biológico e o lógico-matemático, parece encontrar seus limites na desconstrução ainda mais inusitada a que tende sistematicamente todo o pensamento na atualidade: a de si mesmo se construindo de modo essencialmente esclarecido

Os conhecimentos tradicional e científico do Saco do Arraial, estuário da Lagoa do Patos (RS)

Ethno-sciences study the logical behind the traditional population knowledge about environmental process. This case study aims at describing the ethno-knowledge of artisanal fishermen on the hydrodynamics of the estuary around Coreia community (Saco do Arraial), located in Dos Patos Lagoon, in southern Brazil, from an ethnooceangraphic perspective. For this purpose, mental maps, open-ended and in-depth semi-structured interviewing and participative research have been used. As well as scientific knowledge, rains and winds were had main hydrodynamic effort of Saco do Arraial, although astronomic influence in located hydrodynamic has been just a perception of traditional knowledge. Soon, these data have shown another important way to perceive the Patos Lagoon.

SOME REMARKS ON THE YOGASUTRA

In this article are discussed some problems raised by T. S. Rukmani regarding the Yogasutra. According to Rukmani, yoga is not a coherent logical system. After stating the general goals of the yoga system, interpretations of some passages of the Yogasutra are formulated, and the defense is given that one must at least acknowledge the necessity of more exegetical investigation before judging the logical incoherence of the text. Finally, the problematic doctrine of living liberation in Yogasutra is exposed.

O Intuitivo e o Lógico no Conhecimento Matemático: análise de uma proposta pedagógica em relação a abordagens filosóficas atuais e ao contexto educacional da matemática

In this paper, we consider Meneghetti & Bicudo's proposal (2003) regarding the constitution of mathematical knowledge and analyze it with respect to the following two focuses: in relation to conceptions of mathematical knowledge following the fundamentalist crisis in mathematics; and in the educational context of mathematics. The investigation of the first focus is done analyzing new claims in mathematical philosophy. The investigation of the second focus is done firstly via a theoretical reflection followed by an examination of the implementation of the proposal in the process of development of didactic materials for teaching and learning Mathematics. Finally, we present the main results of the application of one of those materials.

Increasing the symmetry of drug crystals: a monoclinic conformational polymorph of the platelet antiaggregating agent ticlopidine hydrochloride

Ticlopidine hydrochloride (TICLID (R)) is a platelet antiaggregating agent whose use as a potent antithrombotic pharmaceutical ingredient is widespread, even though this drug has not been well characterized in the solid state. Only the crystal phase used for drug product manufacturing is known. Here, a new polymorph of ticlopidine hydrochloride was discovered and its structure was determined. While the antecedent polymorph crystallizes in the triclinic space group P (1) over bar, the new crystal phase was solved in the monoclinic space group P2(1)/c. Both polymorphs crystallize as racemic mixtures of enantiomeric (ticlopidine)(+) cations. Detailed geometrical and packing comparisons between the crystal structures of the two polymorphs have allowed us to understand how different supramolecular architectures are assembled. It was feasible to conclude that the main difference between the two polymorphs is a rotation of about 120 degrees on the bridging bond between the thienopyridine and o-chlorobenzyl moieties. The differential o-chlorobenzyl conformation is related to changeable patterns of weak intermolecular contacts involving this moiety, such as edge-to-face Cl center dot center dot center dot pi and C-H center dot center dot center dot pi interactions in the new polymorph and face-to-face pi center dot center dot center dot pi contacts in the triclinic crystal phase, leading to a symmetry increase in the ticlopidine hydrochloride solid state form described for the first time in this study. Other conformational features are slightly different between the two polymorphs, such as the thienopyridine puckerings and the o-chlorophenyl orientations. These conformational characteristics were also correlated to the crystal packing patterns.

Optimized architecture for Tyrosinase-containing Langmuir-Blodgett films to detect pyrogallol

The control of molecular architectures has been a key factor for the use of Langmuir-Blodgett (LB) films in biosensors, especially because biomolecules can be immobilized with preserved activity. In this paper we investigated the incorporation of tyrosinase (Tyr) in mixed Langmuir films of arachidic acid (AA) and a lutetium bisphthalocyanine (LuPc(2)), which is confirmed by a large expansion in the surface pressure isotherm. These mixed films of AA-LuPc(2) + Tyr could be transferred onto ITO and Pt electrodes as indicated by FTIR and electrochemical measurements, and there was no need for crosslinking of the enzyme molecules to preserve their activity. Significantly, the activity of the immobilised Tyr was considerably higher than in previous work in the literature, which allowed Tyr-containing LB films to be used as highly sensitive voltammetric sensors to detect pyrogallol. Linear responses have been found up to 400 mu M, with a detection limit of 4.87 x 10(-2) mu M (n = 4) and a sensitivity of 1.54 mu A mu M(-1) cm(-2). In addition, the Hill coefficient (h = 1.27) indicates cooperation with LuPc(2) that also acts as a catalyst. The enhanced performance of the LB-based biosensor resulted therefore from a preserved activity of Tyr combined with the catalytic activity of LuPc(2), in a strategy that can be extended to other enzymes and analytes upon varying the LB film architecture.