Pseudoautotomy in Dendrophidion dendrophis and Mastigodryas bifossatus (Serpentes: Colubridae): Tail Morphology and breakage frequency

The micro and macro structures of the caudal vertebrae and muscles of Dendrophidion dendrophis and Mastigodryas bifossatus were described using histological slides, dissections, radiographs, and clearing and double staining of intact, broken, and healed tails. To analyze the relationship among the frequencies of healed tails we established two populations of D. dendrophis and six groups of M. bifossatus. We found that fractures of the tail in the two species are intervertebral, and there are no morphological and/or structural mechanisms that facilitate the urotomy, which is classified as non-specialized pseudoautotomy. The caudal vertebrae of D. dendrophis and M. bifossatus show minor differences in the shape of the condyle, cotyle, and border of the neural spine, and in the size and orientation of the hemapophysis and pleurapophysis. The absence of bleeding at the moment of tail breakage may indicate the presence of sphincters in the veins and arteries of D. dendrophis. The distal part of the last vertebrae retained in healed tails of D. dendrophis and M. bifossatus participates in the healing processes as a possible source of calcium in the formation of a calcified cap. We found high frequency of tail breakage in both species, which occurs in almost the entire length of the tail, with no specific areas of concentration. There was no difference in the frequencies of healed tails among males and females of different populations of D. dendrophis and M. bifossatus. Juveniles have lower breakage frequencies than adults in both species, except for populations of M. bifossatus from the Cerrado and Pampa. © 2013 by the American Society of Ichthyologists and Herpetologists.

Alkali activated materials based on fluid catalytic cracking catalyst residue (FCC): Influence of SiO2/Na2O and H 2O/FCC ratio on mechanical strength and microstructure

Reuse of industrial and agricultural wastes as supplementary cementitious materials (SCMs) in concrete and mortar productions contribute to sustainable development. In this context, fluid catalytic cracking catalyst residue (spent FCC), a byproduct from the petroleum industry and petrol refineries, have been studied as SCM in blended Portland cement in the last years. Nevertheless, another environmental friendly alternative has been conducted in order to produce alternative binders with low CO2 emissions. The use of aluminosilicate materials in the production of alkali-activated materials (AAMs) is an ongoing research topic which can present low CO2 emissions associated. Hence, this paper studies some variables that can influence the production of AAM based on spent FCC. Specifically, the influence of SiO 2/Na2O molar ratio and the H2O/spent FCC mass ratio on the mechanical strength and microstructure are assessed. Some instrumental techniques, such as SEM, XRD, pH and electrical conductivity measurements, and MIP are performed in order to assess the microstructure of formed alkali-activated binder. Alkali activated mortars with compressive strength up to 80 MPa can be formed after curing for 3 days at 65°C. The research demonstrates the potential of spent FCC to produce alkali-activated cements and the importance of SiO2/Na2O molar ratio and the H2O/spent FCC mass ratio in optimising properties and microstructure. © 2013 Elsevier Ltd. All rights reserved.

Biocompatibility and biomineralization assessment of a new root canal sealer and root-end filling material

Objective: This study investigated the short-term subcutaneous tissue reaction and biomineralization ability of two epoxy-based root canal sealers containing calcium hydroxide (MBP and MBPc) and ProRoot MTA. Materials and methods: Polyethylene tubes containing the materials were implanted into the dorsal connective tissue of Wistar rats (n = 52) for 7 or 30 days; empty implanted tubes served as controls. Specimens were stained with hematoxylin-eosin and von Kossa stain or left unstained for observation under polarized light. Qualitative and quantitative evaluations of all tissue reactions were performed. One-way anova and the Kruskal-Wallis test were used for statistical analysis (P < 0.05). Results: No significant differences were observed among the groups. All three materials induced mild-to-moderate tissue reactions at 7 days, which decreased over time. Dystrophic mineralization and birefringent structures were observed only in the ProRoot MTA ® group. Conclusion: Both MBP and MBPc appear to be biocompatible but do not stimulate biomineralization. © 2012 John Wiley & Sons A/S.

Morphotropic phase boundary and electrical properties of 1-x[Bi 0.5Na0.5]TiO3 -xBa[Zr0.25Ti 0.75]O3 lead-free piezoelectric ceramics

Lead-free solid solutions (1-x)Bi0.5Na0.5TiO 3 (BNT)-xBaZr0.25Ti0.75O3 (BZT) (x=0, 0.01, 0.03, 0.05, and 0.07) were prepared by the solid state reaction method. X-ray diffraction (XRD) and Rietveld refinement analyses of 1-x(BNT)-x(BZT) solid solution ceramic were employed to study the structure of these systems. A morphotropic phase boundary (MPB) between rhombohedral and cubic structures occured at the composition x=0.05. Raman spectroscopy exhibited a splitting of the (TO3) mode at x=0.05 and confirmed the presence of MPB region. Scanning electron microcopy (SEM) images showed a change in the grain shape with the increase of BZT into the BNT matrix lattice. The temperature dependent dielectric study showed a gradual increase in dielectric constant up to x=0.05 and then decrease with further increase in BZT content. Maximum coercive field, remanent polarization and high piezoelectric constant were observed at x=0.05. Both the structural and electrical properties show that the solid solution has an MPB around x=0.05. © 2012 Elsevier Ltd and Techna Group S.r.l.

A finite element approach for predicting the ultimate rotation capacity of RC beams

This paper presents a numerical approach to model the complex failure mechanisms that define the ultimate rotational capacity of reinforced concrete beams. The behavior in tension and compression is described by a constitutive damage model derived from a combination of two specific damage models [1]. The nonlinear behavior of the compressed region is treated by the compressive damage model based on the Drucker-Prager criterion written in terms of the effective stresses. The tensile damage model employs a failure criterion based on the strain energy associated with the positive part the effective stress tensor. This model is used to describe the behavior of very thin bands of strain localization, which are embedded in finite elements to represent multiple cracks that occur in the tensioned region [2]. The softening law establishes dissipation energy compatible with the fracture energy of the concrete. The reinforcing steel bars are modeled by truss elements with elastic-perfect plastic behavior. It is shown that the resulting approach is able to predict the different stages of the collapse mechanism of beams with distinct sizes and reinforcement ratios. The tensile damage model and the finite element embedded crack approach are able to describe the stiffness reduction due to concrete cracking in the tensile zone. The truss elements are able to reproduce the effects of steel yielding and, finally, the compressive damage model is able to describe the non-linear behavior of the compressive zone until the complete collapse of the beam due to crushing of concrete. The proposed approach is able to predict well the plastic rotation capacity of tested beams [3], including size-scale effects.

Expression, purification and molecular analysis of the human ZNF706 protein

Background: The ZNF706 gene encodes a protein that belongs to the zinc finger family of proteins and was found to be highly expressed in laryngeal cancer, making the structure and function of ZNF706 worthy of investigation. In this study, we expressed and purified recombinant human ZNF706 that was suitable for structural analysis in Escherichia coli BL21(DH3). Findings. ZNF706 mRNA was extracted from a larynx tissue sample, and cDNA was ligated into a cloning vector using the TOPO method. ZNF706 protein was expressed according to the E. coli expression system procedures and was purified using a nickel-affinity column. The structural qualities of recombinant ZNF706 and quantification alpha, beta sheet, and other structures were obtained by spectroscopy of circular dichroism. ZNF706's structural modeling showed that it is composed of α-helices (28.3%), β-strands (19.4%), and turns (20.9%), in agreement with the spectral data from the dichroism analysis. Conclusions: We used circular dichroism and molecular modeling to examine the structure of ZNF706. The results suggest that human recombinant ZNF706 keeps its secondary structures and is appropriate for functional and structural studies. The method of expressing ZNF706 protein used in this study can be used to direct various functional and structural studies that will contribute to the understanding of its function as well as its relationship with other biological molecules and its putative role in carcinogenesis. © 2013 Colombo et al.; licensee BioMed Central Ltd.

Trade, environment and development: implications for Caribbean countries

Includes bibliography

The Netherlands Antilles: trade and integration with CARICOM

Introduction The Netherlands Antilles is an autonomous entity within the Kingdom of the Netherlands and comprises a federation of five Caribbean islands: Bonaire and Curacao (the Leeward islands) which comprise 80 per cent of the population of 211,000 and Saba, St. Eustatius and the southern part of St. Maarten (the Windward islands). Like the other countries in the Kingdom, it enjoys full autonomy in internal matters as, for example, education, public health, justice and customs. It has a per capita income of about US$ 12,000. The Leeward Islands and the Windward Islands account for about 75 per cent (Curacao (70 per cent) and Bonaire (5 per cent)) and 25 percent respectively of the economy of the Netherlands Antilles. The Netherlands Antilles has its own currency, the Netherlands guilder, which is pegged to the United States dollar at a fixed rate since 1971. The economy has some unique features that stem from its close relations with the Netherlands, its undiversified nature and heavy dependence on tourism, offshore finance, oil refining and shipping, the high share of trade (exports of goods and services of about 75 per cent of GDP), its geographical characteristics, its common border with the French Republic on St. Maarten, its duty-free access for imports from Aruba, its de facto free trade zone (FTZ), partial dollarization, especially for the Windward Islands, and its highly regulated labor market (1). Adverse economic shocks in the last two decades affected particularly the offshore financial sector and the oil refinery and, to a lesser extent, tourism. The repeal of withholding taxes in the United States in the 1980s indirectly caused the collapse of a number of highly profitable offshore financial activities in Curacao, leading to significant drops in government revenue and contributions to foreign exchange earnings. The withdrawal of Shell from Curacao in 1986 and the (temporary) closure of the oil refinery which had been a mainstay of the Curacao economy for almost three quarters of a century was the second major shock. It was subsequently leased to the Venezuelan State Company, Petroleos de Venezuela Sociedad Anonima (PDVSA), which resumed operations and preserved employment. In the 1990s, the Windward Islands were bit by several devastating hurricanes, which destroyed much of the economic infrastructure on the islands, including about half of the number of available hotel rooms in St Maarten. Further negative shocks were related to the discontinuation of certain trade privileges on European markets for Overseas Countries and Territories (OCTs), the withdrawal by the Netherlands of certain tax privileges for Dutch pensioners residing in the Netherlands Antilles and disruptions in the availability of Solidarity Fund resources for the smaller islands. National income has been on the decline since 1997. GDP declined by about 6 per cent between 1997 and 1999. Underlying fiscal imbalances and structural weaknesses have also impacted negatively on the economy. In recent years, with recession high unemployment and migration have been experienced (2). The Netherlands Antilles has been able to survive thanks to additional aid from the Netherlands, large-scale spontaneous emigration (mostly to the Netherlands), some drop in international reserves, an increase in domestic debt and arrears and reduced outlays for the maintenance of public assets. From 1986 onwards, successive efforts at restoring macroeconomic balance, particularly with regard to public finance, were made, but were unsuccessful. Adjustment was also attempted in 1996 and 1997, but failed to meet the desired targets. In 1999, the government launched a new National Recovery Plan" (NRP). The NRP contains important medium-term structural adjustment measures aimed at restoring macroeconomic balance and conditions for revitalizing the economy. The NRP subsequently served as an important input into a comprehensive adjustment plan drawn up with the assistance of the International Monetary Fund (IMF) and reflected in the government's Memorandum of Economic Policies dated 15 September 2000. Beyond restoring macroeconomic balance and reforming the economic incentive framework, the government aims at establishing a Comprehensive Development Framework (CDF) for the formulation and implementation of a sustainable long-term growth strategy. It is against the above background that this study is undertaken. Its main objective is to assess the integration options facing the Netherlands Antilles (3) vis-a-vis the Caribbean Community (CARICOM). A secondary objective is to examine the above taking into account, inter alia, the level of trade between the Netherlands Antilles and CARICOM, the barriers to trade between the two groups of countries and the requirements for increasing trade between the two groups of countries. The Consultant was given an initial Draft Terms of Reference (Annex 1) with the intention of modifying it in the course of the interviews with all the stakeholders. The main idea that emerged from these interviews was a concern with some possible form of association with CARICOM. The Consultant was asked to exam the costs and benefits of various forms of association and to recommend an option. This adjustment of the Terms of Reference (TOR) was substantial and involved the Consultant having to do some interviews and collect documentation in CARICOM. The study essentially revolves around the search for a road map for the Netherlands Antilles. It is tackled in the first instance by describing the existing system of trade of the Netherlands Antilles with a view to determining the import and export structures and the specific nature and extent of trade in goods and services between the Netherlands Antilles and CARICOM. 1 Netherlands Antilles: Elements of a Strategy for Economic Recovery and Sustainable Growth. Interim Report of the World Bank Mission, 5-20 December 2000. 2 IMF, IMF Country Report No. 01/73 Kingdom of the Netherlands-Netherlands Antilles-Recent Development, Selected Issues and Statistical Appendix. May 2001 3 The Netherlands Antilles is a country within the Kingdom of the Netherlands. It contains five islands. Curacao and Bonaire (Leewards) and St Eustatius, Saba and St Maarten (The Windwards)"

Comportamento estrutural de lajes pré-moldadas treliçadas com adição de resíduos de borracha de pneu

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise experimental do comportamento de vigas mistas de concreto e alvenaria estrutural sujeitas à flexão simples

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Diagnósticos dos procedimentos executivos nos canteiros de obras de alvenaria estrutural

Pós-graduação em Engenharia Civil - FEIS

Avaliação da resistência à compressão da alvenaria estrutural

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aderência aço-concreto: uma análise do comportamento do concreto fabricado com resíduos de borracha

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo da reação álcali-agregado na tomada d'água da UHE Jaguari por meio de ensaios laboratoriais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Purification and structural characterization of snake venom proteins

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