The critical barrier to progress in dentine bonding with the etch-and-rinse technique

Objectives: The lack of durability in resin-dentine bonds led to the use of chlorhexidine as MMP-inhibitor to prevent the degradation of hybrid layers. Biomimetic remineralisation is a concept-proven approach in preventing the degradation of resin-dentine bonds. The purpose of this study is to examine the integrity of aged resin-dentine interfaces created with a nanofiller-containing etch-and-rinse adhesive after the application of these two approaches.Methods: The more established MMP-inhibition approach was examined using a parallel in vivo and in vitro ageing design to facilitate comparison with the biomimetic remineralisation approach using an in vitro ageing design. Specimens bonded without chlorhexidine exhibited extensive degradation of the hybrid layer after 12 months of in vivo ageing.Results: Dissolution of nanofillers could be seen within a water-rich zone within the adhesive layer. Although specimens bonded with chlorhexidine exhibited intact hybrid layers, water-rich regions remained in those hybrid layers and degradation of nanofillers occurred within the adhesive layer. Specimens subjected to in vitro biomimetic remineralisation followed by in vitro ageing demonstrated intrafibrillar collagen remineralisation within hybrid layers and deposition of mineral nanocrystals in nanovoids within the adhesive.Conclusions: The impact was realized by understanding the lack of an inherent mechanism to remove water from resin-dentine interfaces as the critical barrier to progress in bonding with the etch-and-rinse technique. The experimental biomimetic remineralisation strategy offers a creative solution for incorporating a progressive hydration mechanism to achieve this goal, which warrants its translation into a clinically applicable technique. (C) 2011 Elsevier Ltd. All rights reserved.

Is the environmental policies procedures a barrier to development of inland navigation and port management? A case of study in Brazil

The main objective of this article is to discuss the Brazilian environmental legislation and policies towards the development of navigation and port management. The research illustrated some difficulties faced by the country and make suggestions to overcome it. The construction of the environmental legal framework began in the early 1960s and resulted in a very complex system, as a consequence of policies adopted by the country. Nowadays Brazilian environmental policies are developed in democratic and participative way, although with elevated degree of bureaucracy and lack of integration among the several governmental agencies, which makes the approval of environmental certifications demand several years for new port projects or improvements, which delays the economic development of the country. Efforts have been made to simplify the licensing process. As result of this research two flowchart for environmental licenses of ports installation are shown: The first shows the process until 2009 and the second shows the process nowadays. This become an important issue due the fact that inland navigation is one of the less pollutant modes of transportation, and although, the process of environmental certification was simplified, if compare with 2009, it is still complex and time-consuming, delaying the development of the infrastructure. © 2012 Elsevier Ltd.

Leukocyte entry into the CNS of Leishmania chagasi naturally infected dogs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Scanning electron microscopy evaluation of the hard tissue barrier after pulp capping with calcium hydroxide, mineral trioxide aggregate (MTA) or ProRoot MTA

The aim of this study was to investigate the morphology and localisation of calcium hydroxide- and mineral trioxide aggregate (MTA)-induced hard tissue barriers after pulpotomy in dogs' teeth. Pulpotomies were performed on maxillary and mandibular premolars of five dogs. The teeth were assigned into three groups according to the pulp-capping agent used. The pulpal wounds were capped with calcium hydroxide (Ca(OH)(2) - control), MTA or ProRoot MTA, and the cavities were restored with amalgam. After a 90-day follow-up period, the dogs were euthanised and the teeth were examined under scanning electron microscopy (SEM). An image-processing and analysis software was used to delimit the perimeters of the root canal area and the hard tissue barrier to determine the percentage of root canal obliteration. SEM data were used to assess the morphology, localisation and extension of the reparative hard tissue barriers. ProRoot MTA was statistically different from MTA and Ca(OH)(2) (P < 0.05) regarding tissue barrier morphology. Localisation data showed that ProRoot MTA was significantly different from Ca(OH)(2) (P < 0.05) and similar to MTA (P > 0.01; P > 0.05). No statistically significant difference (P > 0.01; P > 0.05) was observed between MTA and Ca(OH)(2). A larger number of complete (centroperipheral) hard tissue barriers with predominance of dentinal tubules was observed to the ProRoot MTA when compared with the Ca(OH)(2) group.

Tribute to R.G. Boutilier: Skin colour and body temperature changes in basking Bokermannohyla alvarengai (Bokermann 1956)

In amphibians solar basking far from water sources is relatively uncommon since the highly permeable amphibian skin does not represent a significant barrier to the accompanying risk of losing water by evaporation. A South American frog, Bokermannohyla alvarengai (Bokermann 1956), however, spends a significant amount of the day exposed to full sun and relatively high temperatures. The means by which this frog copes with potentially high rates of evaporative water loss and high body temperatures are unknown. Thus, in this study, skin colour changes, body surface temperature, and evaporative water loss rates were examined under a mixture of field and laboratory conditions to ascertain whether changes in skin reflectivity play an important role in this animal's thermal and hydric balance. Field data demonstrated a tight correlation between the lightness of skin colour and frog temperature, with lighter frogs being captured possessing higher body temperatures. Laboratory experiments supported this relationship, revealing that frogs kept in the dark or at lower temperatures (20 degrees C) had darker skin colours, whereas frogs kept in the light or higher temperatures (30 degrees C) had skin colours of a lighter hue. Light exhibited a stronger influence on skin colour than temperature alone, suggesting that colour change is triggered by the increase in incident solar energy and in anticipation of changes in body temperature. This conclusion is corroborated by the observation that cold, darkly coloured frogs placed in the sun rapidly became lighter in colour during the initial warming up period (over the first 5 min), after which they warmed up more slowly and underwent a further, albeit slower, lightening of skin colour. Surprisingly, despite its natural disposition to bask in the sun, this species does not possess a 'waterproof' skin, since its rates of evaporative water loss were not dissimilar from many hylid species that live in arboreal or semi-aquatic environments. The natural history of B. alvarengai is largely unknown and, therefore, it is likely that the herein reported colour change and basking behaviour represent a complex interaction between thermoregulation and water balance with other ecologically relevant functions, such as crypsis.

Water regulation of actinomycin-D binding to DNA: the interplay among drug affinity, DNA long-range conformation, and hydration

Actiaomycin-D (actD) binds to natural DNA at two different classes of binding sites, weak and strong. The affinity for these sites is highly dependent on DNA se(sequence and solution conditions, and the interaction appears to be purely entropic driven Although the entropic character of this reaction has been attributed to the release of water molecules upon drug to DNA complex formation, the mechanism by which hydration regulates actD binding and discrimination between different classes of binding sites on natural DNA is still unknown. In this work, we investigate the role of hydration on this reaction using the osmotic stress method. We skew that the decrease of solution water activity, due to the addition of sucrose, glycerol ethylene glycol, and betaine, favors drug binding to the strong binding sites on DNA by increasing both the apparent binding affinity Delta G, and the number of DNA base pairs apparently occupied by the bound drug n(bp/actD). These binding parameters vary linearly with the logarithm of the molar fraction of water in solution log(X-w), which indicates the contribution of water binding to the energetic of the reaction. It is demonstrated that the hydration change measured upon binding increases proportionally to the apparent size of the binding site n(bp/uctD). This indicates that n(bp/actD) measured from the Scatchard plod is a measure of the size of the DNA molecule changing conformation due to ligand binding. We also find that the contribution of DNA deformation, gauged by n(bp/act) to the total free energy of binding Delta G, is given by Delta G = Delta G(local) + n(bp/actD) x delta G(DNA), where Delta G(local), = -8020 +/- 51 cal/mol of actD bound and delta G(DNa) = -24.1 +/- 1.7cal/mol of base pair at 25 degrees C. We interpret Delta G(local), as the energetic contribution due to the direct interactions of actD with the actual tetranucleotide binding site, and it n(bp/actB) X delta G(DNA) as that due to change inconformation, induced by binding, of it n(bp/actD) DNA base pairs flanking the local site. This interpretation is supported by the agreement found between the value of delta G(DNA) and the torsional free energy change measured independently. We conclude suggesting an allosteric model for ligand binding to DNA, such that the increase in binding affinity is achieved by increasing the relaxation of the unfavorable free energy of binding storage at the local site through a larger number of DNA base pairs. The new aspect on this model is that the size of the complex is not fixed but determined by solutions conditions, such as water activity, which modulate the energetic barrier to change helix conformation. These results may suggest that long-range allosteric transitions of duplex DNA are involved in the inhibition of RNA synthesis by actD, and more generally, in the regulation of transcription. (C) 2000 John Wiley & Sons, Inc.

Barriers to environmental management in clusters of small businesses in Brazil and Japan: from a lack of knowledge to a decline in traditional knowledge

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

PEDOT:PSS self-assembled films to methanol crossover reduction in Nafion (R) membranes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Barreiras à entrada no Setor Siderúrgico Brasileiro no período de 1993 a 2012

This study aims to identify and analyze the barriers to entry in the two technological routes (integrated and semi - integrated mills) , the Brazilian steel industry , specifically in the areas of Plans and Long , in the period 1993-2012 . Thus, the study is characterized as an exploratory - descriptive research, based on data collection from secondary sources. The competitiveness is influenced by structural market factor, among them the threat of new market entrants. The entrants can have their ticket inhibited by entry barriers. In the steel industry, it was identified that the main strong structural barriers are economic, the type of scale economy, highlighting the idle capacity, and sunk costs. Institutional and economic barriers, the diversification and product differentiation type, are considered moderate barriers. Economic barriers, the type absolute cost advantage and initial capital requirements, and strategic price barrier are considered weak. With this, one can consider that the input type which most closely approximates the market for national steel industries is blocked, since their main barriers are the structural type

Remoção mecânica de plantas aquáticas: análise econômica e operacional

A remoção de plantas aquáticas tem sido utilizada como opção ao controle químico e biológico, em razão de restrições ambientais em algumas regiões brasileiras. O objetivo deste trabalho foi desenvolver um modelo para análise econômica e operacional da remoção mecânica de plantas aquáticas, visando realizar estudo econômico comparativo com o controle químico. A operação foi estudada num reservatório de uma usina de bombeamento em Barra do Piraí-RJ. O sistema consiste de retroescavadeiras instaladas em balsas, usadas para cortar as plantas e liberá-las no fluxo de água. Antes da tomada d'água existe uma barreira flutuante que intercepta as plantas, as quais são removidas por um guindaste fixo nas margens. As plantas são armazenadas por algum tempo e depois descartadas. Existe, ainda, um sistema de limpeza das grades da tomada d'água. Dados do volume total de plantas descartadas foram coletados durante 14 meses, assim como foi avaliado o volume de biomassa produzido por área das principais espécies infestantes. A empreiteira que administra o serviço forneceu planilhas de custos e outro parâmetros operacionais. Um modelo foi desenvolvido para calcular custos por hectare de plantas removidas. Os resultados mostraram custo médio mensal de US$ 17.780,28 por hectare. Apesar do alto custo, o sistema de remoção demonstrou capacidade de controlar apenas 4,1% da área infestada no reservatório, na época da coleta dos dados. Simulando dados de uma aplicação de glyphosate, o controle químico custaria apenas 0,23% do custo da remoção. Análises de sensibilidade mostraram que a compactação das plantas para transporte, o volume de plantas produzidas por área e o custo do transporte são os parâmetros principais para a otimização.

Normas jurídicas para a restauração ecológica: uma barreira a mais a dificultar o êxito das iniciativas?

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Darunavir: A Critical Review of Its Properties, Use and Drug Interactions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Retificação da alumina com rebolo diamantado utilizando-se diferentes métodos de lubri-refrigeração

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fatigue behavior of PVD coated Ti-6Al-4V alloy

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Histology and ultrastructure of pericardial cells of Scaptotrigona postica latreille (Hymenoptera, Apidae) in workers and queens of different ages

The paper presents a study of the pericardial cells of Scaptotrigona postica an eusocial Brazilian stingless bee. Light and electron microscopy was used in a comparative study on workers and queens of different ages, exerting different functions in the colony. The pericardial cells are found only in the peticardial sinus, mainly in groups around the dorsal vessel. Each cell is enclosed by the basal membrane and its peripheral region is characterized by folds of the plasma membrane, which form canals and loops. The points where the plasma membrane folds is frequently closed by diaphragms, that along with the basal lamina form a barrier to substances from hemolymph. Along the membrane limiting the canals and loops, an intense endocytic activity through coated vesicles takes place indicating a selective absorption of hemolymph components. In older individuals, workers or queens, the cells exhibit larger quantities of cytoplasm inclusions, heterogeneous vacuoles containing the final products of intracellular digestion, and autophagic vacuoles with concentric membranous structures. The pericardial cells general morphology is in accordance with the role in processing metabolites captured from hemolymph and storage of indigested residues. (C) 2006 Elsevier Ltd. All rights reserved.