VLT-FLAMES analysis of 8 giants in the bulge metal-poor globular cluster NGC 6522: oldest cluster in the Galaxy? Analysis of 8 giants in NGC 6522

Context. NGC 6522 has been the first metal-poor globular cluster identified in the bulge by Baade. Despite its importance, very few high-resolution abundance analyses of stars in this cluster are available. The bulge metal-poor clusters may be important tracers of the early chemical enrichment of the Galaxy. Aims. The main purpose of this study is to determine metallicity and elemental ratios in individual stars of NGC 6522. Methods. High-resolution spectra of 8 giants of the bulge's globular cluster NGC 6522 were obtained at the 8m VLT UT2-Kueyen telescope with the FLAMES+GIRAFFE spectrograph. Multiband V, I, J, K(s) photometry was used to derive effective temperatures as reference values. Spectroscopic parameters were derived from Fe I and Fe II lines, and adopted for the derivation of abundance ratios. Results. The present analysis provides a metallicity [Fe/H] = -1.0 +/- 0.2. The alpha-elements oxygen, magnesium and silicon show [O/Fe] = +0.4 +/- 0.3, [Mg/Fe] = [Si/Fe] = +0.25 +/- 0.15, whereas calcium and titanium show shallower ratios of [Ca/Fe] = [Ti/Fe] = +0.15 +/- 0.15. The neutron-capture r-process element europium appears to be overabundant by [Eu/Fe] = +0.4 +/- 0.4. The neutron-capture s-elements lanthanum and barium are enhanced by [La/Fe] = +0.35 +/- 0.2 and [Ba/Fe] = +0.5 +/- 0.5. The large internal errors, indicating the large star-to-star variation in the barium and europium abundances, are also discussed. Conclusions. The moderate metallicity combined to a blue horizontal branch (BHB), are characteristics similar to those of HP 1 and NGC 6558, pointing to a population of very old globular clusters in the Galactic bulge. Also, the abundance ratios in NGC 6522 resemble those in HP 1 and NGC 6558. The ultimate conclusion is that the bulge is old, and went through an early prompt chemical enrichment.

Random X Inactivation and Extensive Mosaicism in Human Placenta Revealed by Analysis of Allele-Specific Gene Expression along the X Chromosome

Imprinted inactivation of the paternal X chromosome in marsupials is the primordial mechanism of dosage compensation for X-linked genes between females and males in Therians. In Eutherian mammals, X chromosome inactivation (XCI) evolved into a random process in cells from the embryo proper, where either the maternal or paternal X can be inactivated. However, species like mouse and bovine maintained imprinted XCI exclusively in extraembryonic tissues. The existence of imprinted XCI in humans remains controversial, with studies based on the analyses of only one or two X-linked genes in different extraembryonic tissues. Here we readdress this issue in human term placenta by performing a robust analysis of allele-specific expression of 22 X-linked genes, including XIST, using 27 SNPs in transcribed regions. We show that XCI is random in human placenta, and that this organ is arranged in relatively large patches of cells with either maternal or paternal inactive X. In addition, this analysis indicated heterogeneous maintenance of gene silencing along the inactive X, which combined with the extensive mosaicism found in placenta, can explain the lack of agreement among previous studies. Our results illustrate the differences of XCI mechanism between humans and mice, and highlight the importance of addressing the issue of imprinted XCI in other species in order to understand the evolution of dosage compensation in placental mammals.

Crystallization and preliminary X-ray diffraction analysis of recombinant chlorocatechol 1,2-dioxygenase from Pseudomonas putida

Chlorocatechol 1,2-dioxygenase from the Gram-negative bacterium Pseudomonas putida (Pp 1,2-CCD) is considered to be an important biotechnological tool owing to its ability to process a broad spectrum of organic pollutants. In the current work, the crystallization, crystallographic characterization and phasing of the recombinant Pp 1,2-CCD enzyme are described. Reddish-brown crystals were obtained in the presence of polyethylene glycol and magnesium acetate by utilizing the vapour-diffusion technique in sitting drops. Crystal dehydration was the key step in obtaining data sets, which were collected on the D03B-MX2 beamline at the CNPEM/MCT - LNLS using a MAR CCD detector. Pp 1,2-CCD crystals belonged to space group P6(1)22 and the crystallographic structure of Pp 1,2-CCD has been solved by the MR-SAD technique using Fe atoms as scattering centres and the coordinates of 3-chlorocatechol 1,2-dioxygenase from Rhodococcus opacus (PDB entry 2boy) as the search model. The initial model, which contains three molecules in the asymmetric unit, has been refined to 3.4 A resolution.

Determination of uranium in phosphoric acid using neutron activation analysis

Phosphoric acid is generally obtained from an aqueous process starting with the reaction between phosphate rock and sulphuric acid. Due to their chemical similarity, uranium is usually associated with phosphate rock which during chemical processing is partitioned to phosphoric acid. Uranium determination in this matrix is a very important task because of its ingestion it could lead to radiological impact on the population. Therefore, a procedure was developed using an initial precipitation with calcium hydroxide and evaporation, followed by instrumental neutron activation analysis (INAA). The procedure was applied to analyse fourteen uranium enriched phosphoric acid samples.

Simultaneous optimization by neuro-genetic approach for analysis of plant materials by laser induced breakdown spectroscopy

A simultaneous optimization strategy based on a neuro-genetic approach is proposed for selection of laser induced breakdown spectroscopy operational conditions for the simultaneous determination of macronutrients (Ca, Mg and P), micro-nutrients (B, Cu, Fe, Mn and Zn), Al and Si in plant samples. A laser induced breakdown spectroscopy system equipped with a 10 Hz Q-switched Nd:YAG laser (12 ns, 532 nm, 140 mJ) and an Echelle spectrometer with intensified coupled-charge device was used. Integration time gate, delay time, amplification gain and number of pulses were optimized. Pellets of spinach leaves (NIST 1570a) were employed as laboratory samples. In order to find a model that could correlate laser induced breakdown spectroscopy operational conditions with compromised high peak areas of all elements simultaneously, a Bayesian Regularized Artificial Neural Network approach was employed. Subsequently, a genetic algorithm was applied to find optimal conditions for the neural network model, in an approach called neuro-genetic, A single laser induced breakdown spectroscopy working condition that maximizes peak areas of all elements simultaneously, was obtained with the following optimized parameters: 9.0 mu s integration time gate, 1.1 mu s delay time, 225 (a.u.) amplification gain and 30 accumulated laser pulses. The proposed approach is a useful and a suitable tool for the optimization process of such a complex analytical problem. (C) 2009 Elsevier B.V. All rights reserved.

Niobium hydrogenation process Effect of temperature and cooling rate from the hydrogenation temperature

High-purity niobium powder can be produced via the hydrogenation and dehydrogenation processes The present work aimed at the effect of temperature and cooling rate conditions on the niobium hydrogenation process using hydrogen gas The hydrogen contents of the materials were evaluated by weight change and chemical analysis X ray diffraction (XRD) was performed to identify and determine the lattice parameters of the formed hydride phases No hydrogenation took place under isothermal conditions only during cooling of the materials Significant hydrogenation occurred in the 500 C and 700 C experiments leading to the formation of a beta NbH(x) single phase material (C) 2010 Elsevier Ltd All rights reserved

Biomimetic oxidative treatment of spruce wood studied by pyrolysis-molecular beam mass spectrometry coupled with multivariate analysis and (13)C-labeled tetramethylammonium hydroxide thermochemolysis: implications for fungal degradation of wood

In this work, pyrolysis-molecular beam mass spectrometry analysis coupled with principal components analysis and (13)C-labeled tetramethylammonium hydroxide thermochemolysis were used to study lignin oxidation, depolymerization, and demethylation of spruce wood treated by biomimetic oxidative systems. Neat Fenton and chelator-mediated Fenton reaction (CMFR) systems as well as cellulosic enzyme treatments were used to mimic the nonenzymatic process involved in wood brown-rot biodegradation. The results suggest that compared with enzymatic processes, Fenton-based treatment more readily opens the structure of the lignocellulosic matrix, freeing cellulose fibrils from the matrix. The results demonstrate that, under the current treatment conditions, Fenton and CMFR treatment cause limited demethoxylation of lignin in the insoluble wood residue. However, analysis of a water-extractable fraction revealed considerable soluble lignin residue structures that had undergone side chain oxidation as well as demethoxylation upon CMFR treatment. This research has implications for our understanding of nonenzymatic degradation of wood and the diffusion of CMFR agents in the wood cell wall during fungal degradation processes.

LOW-INTENSITY PULSED ULTRASOUND PRODUCED AN INCREASE OF OSTEOGENIC GENES EXPRESSION DURING THE PROCESS OF BONE HEALING IN RATS

The aim of this study was to measure the temporal expression of osteogenic genes during the process of bone healing in low-intensity pulsed ultrasound (LIPUS) treated bone defects by means of histopathologic and real-time polymerase chain reaction (PCR) analysis. Animals were randomly distributed into two groups (n = 30): control group (bone defect without treatment) and LIPUS treated (bone defect treated with LIPUS). On days 7, 13 and 25 postinjury, 10 rats per group were sacrificed. Rats were treated with a 30 mW/cm(2) LIPUS. The results pointed out intense new bone formation surrounded by highly vascularized connective tissue presenting a slight osteogenic activity, with primary bone deposition was observed in the group exposed to LIPUS in the intermediary (13 days) and late stages of repair (25 days) in the treated animals. In addition, quantitative real-time polymerase chain reaction (RT-qPCR) showed an upregulation of bone morphogenetic protein 4 (BMP4), osteocalcin and Runx2 genes 7 days after the surgery. In the intermediary period, there was no increase in the expression. The expression of alkaline phosphatase, BMP4 and Runx2 was significantly increased at the last period. Our results indicate that LIPUS therapy improves bone repair in rats and upregulated osteogenic genes, mainly at the late stages of recovery. (E-mail: a.renno@unifesp.br) (C) 2010 Published by Elsevier Inc. on behalf of World Federation for Ultrasound in Medicine & Biology.

Studies of cases in power systems by Sensitivity Analysis oriented by OPF

This paper presents studies of cases in power systems by Sensitivity Analysis (SA) oriented by Optimal Power Flow (OPF) problems in different operation scenarios. The studies of cases start from a known optimal solution obtained by OPF. This optimal solution is called base case, and from this solution new operation points may be evaluated by SA when perturbations occur in the system. The SA is based on Fiacco`s Theorem and has the advantage of not be an iterative process. In order to show the good performance of the proposed technique tests were carried out on the IEEE 14, 118 and 300 buses systems. (C) 2010 Elsevier Ltd. All rights reserved.

Experimental Analysis of Structural Change and Rheological Behavior of Macromolecular Solutions with Guar and Xanthan Gums in Crossflow Microfiltration Processing

The present paper reports on the structural change and rheological behavior of mixtures of macromolecular suspensions (guar and xanthan gums) in crossflow microfiltration processing. Mixtures in suspension of guar and xanthan gums at low concentrations (1,000 ppm) and different proportions were processed by microfiltration with membrane of nominal pore size of 0.4 mu m. The rheological behavior of the mixtures was investigated in rotational viscometers at two different temperatures, 25 and 40 C, at the beginning and at the end of each experiment. The shear stress (t) in function of the shear rate (gamma) was fitted and analyzed with the power-law model. All the mixtures showed flow behavior index values (n) lower than 1, characterizing non-Newtonian fluids (pseudoplastic). The samples of both mixtures and permeates were also analyzed by absorbency spectroscopy in infrared radiation. The absorbency analysis showed that there is good synergism between xanthan and guar gums without structure modifications or gel formation in the concentration process by microfiltration.

Process oriented framework to support PLM implementation

Product lifecycle management (PLM) innovates as it defines both the product as a central element to aggregate enterprise information and the lifecycle as a new time dimension for information integration and analysis. Because of its potential benefits to shorten innovation lead-times and to reduce costs, PLM has attracted a lot of attention at industry and at research. However, the current PLM implementation stage at most organisations still does not apply the lifecycle management concepts thoroughly. In order to close the existing realisation gap, this article presents a process oriented framework to support effective PLM implementation. The framework central point consists of a set of lifecycle oriented business process reference models which links the necessary fundamental concepts, enterprise knowledge and software solutions to effectively deploy PLM. (c) 2007 Elsevier B.V. All rights reserved.

Non-linear boundary element formulation applied to contact analysis using tangent operator

This work presents a non-linear boundary element formulation applied to analysis of contact problems. The boundary element method (BEM) is known as a robust and accurate numerical technique to handle this type of problem, because the contact among the solids occurs along their boundaries. The proposed non-linear formulation is based on the use of singular or hyper-singular integral equations by BEM, for multi-region contact. When the contact occurs between crack surfaces, the formulation adopted is the dual version of BEM, in which singular and hyper-singular integral equations are defined along the opposite sides of the contact boundaries. The structural non-linear behaviour on the contact is considered using Coulomb`s friction law. The non-linear formulation is based on the tangent operator in which one uses the derivate of the set of algebraic equations to construct the corrections for the non-linear process. This implicit formulation has shown accurate as the classical approach, however, it is faster to compute the solution. Examples of simple and multi-region contact problems are shown to illustrate the applicability of the proposed scheme. (C) 2011 Elsevier Ltd. All rights reserved.

A BEM model applied to failure analysis of multi-fractured structures

Due to manufacturing or damage process, brittle materials present a large number of micro-cracks which are randomly distributed. The lifetime of these materials is governed by crack propagation under the applied mechanical and thermal loadings. In order to deal with these kinds of materials, the present work develops a boundary element method (BEM) model allowing for the analysis of multiple random crack propagation in plane structures. The adopted formulation is based on the dual BEM, for which singular and hyper-singular integral equations are used. An iterative scheme to predict the crack growth path and crack length increment is proposed. This scheme enables us to simulate the localization and coalescence phenomena, which are the main contribution of this paper. Considering the fracture mechanics approach, the displacement correlation technique is applied to evaluate the stress intensity factors. The propagation angle and the equivalent stress intensity factor are calculated using the theory of maximum circumferential stress. Examples of multi-fractured domains, loaded up to rupture, are considered to illustrate the applicability of the proposed method. (C) 2011 Elsevier Ltd. All rights reserved.

Interface shear strength of geosynthetics: Evaluation and analysis of inclined plane tests

The inclined plane test (IPT) is commonly performed to measure the interface shear strength between different materials as those used in cover systems of landfills. The test, when interpreted according to European test Standards provides the static interface friction angle, usually assumed for 50 mm displacement and denoted as phi(stat)(50). However, if interpreted considering the several phases of the sliding process, the test is capable of yielding more realistic information about the interface shear strength such as differentiating interfaces which exhibit the same value of phi(stat)(50) but different behavior for displacement less than 50 mm. In this paper, the IPT is used to evaluate the interface shear strength of some materials usually present in cover liner systems of landfill. The results of the tests were analyzed for both, the static and the dynamic phases of the sliding and were interpreted based on the static initial friction angle, phi(0), and the limit friction angle, phi(lim). It is shown that depending on the sliding behavior of the interfaces, phi(stat)(50), which is usually adopted as the designing parameter in stability analysis, can be larger than phi(0) and phi(lim). (C) 2009 Elsevier Ltd. All rights reserved.

Leak detection by inverse transient analysis in an experimental PVC pipe system

Leakage reduction in water supply systems and distribution networks has been an increasingly important issue in the water industry since leaks and ruptures result in major physical and economic losses. Hydraulic transient solvers can be used in the system operational diagnosis, namely for leak detection purposes, due to their capability to describe the dynamic behaviour of the systems and to provide substantial amounts of data. In this research work, the association of hydraulic transient analysis with an optimisation model, through inverse transient analysis (ITA), has been used for leak detection and its location in an experimental facility containing PVC pipes. Observed transient pressure data have been used for testing ITA. A key factor for the success of the leak detection technique used is the accurate calibration of the transient solver, namely adequate boundary conditions and the description of energy dissipation effects since PVC pipes are characterised by a viscoelastic mechanical response. Results have shown that leaks were located with an accuracy between 4-15% of the total length of the pipeline, depending on the discretisation of the system model.