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Search Results: 1 - 10 of 5601 matches for " Renato Westermeier "
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Secondary zoospores in the algal endoparasite Maullinia ectocarpii (Plasmodiophoromycota)
Parodi,Elisa R.; Cáceres,Eduardo J.; Westermeier,Renato; Müller,Dieter G.;
Biocell , 2010,
Abstract: the present paper deals with the ultrastructure of zoospores produced by the plasmodiophorid maullinia ectocarpii, living in the marine algal host ectocarpus siliculosus. the zoospores described here are very similar to secondary zoospores of polymyxa graminis and phagomyxa sp.(the latter an algal endoparasite, also). our results indicate that m. ectocarpii produces two types of plasmodia, and suggest that is a species with a complete life cycle, as it is known for all the plasmodiophormycota that have been studied. sporogenic and sporangial plasmodia produce, respectively, primary zoospores with parallel flagella within thick walled resting sporangia, and secondary zoospores with opposite flagella within thin walled sporangia.
Secondary zoospores in the algal endoparasite Maullinia ectocarpii (Plasmodiophoromycota)
Elisa R. Parodi,Eduardo J. Cáceres,Renato Westermeier,Dieter G. Müller
Biocell , 2010,
Abstract: The present paper deals with the ultrastructure of zoospores produced by the plasmodiophorid Maullinia ectocarpii, living in the marine algal host Ectocarpus siliculosus. The zoospores described here are very similar to secondary zoospores of Polymyxa graminis and Phagomyxa sp.(the latter an algal endoparasite, also). Our results indicate that M. ectocarpii produces two types of plasmodia, and suggest that is a species with a complete life cycle, as it is known for all the Plasmodiophormycota that have been studied. Sporogenic and sporangial plasmodia produce, respectively, primary zoospores with parallel flagella within thick walled resting sporangia, and secondary zoospores with opposite flagella within thin walled sporangia.
Performance tests of an AGIPD 0.4 assembly at the beamline P10 of PETRA III
J. Becker,A. Marras,A. Klyuev,F. Westermeier,U. Trunk,H. Graafsma
Physics , 2013, DOI: 10.1088/1748-0221/8/06/P06007
Abstract: The Adaptive Gain Integrating Pixel Detector (AGIPD) is a novel detector system, currently under development by a collaboration of DESY, the Paul Scherrer Institute in Switzerland, the University of Hamburg and the University of Bonn, and is primarily designed for use at the European XFEL. To verify key features of this detector, an AGIPD 0.4 test chip assembly was tested at the P10 beamline of the PETRA III synchrotron at DESY. The test chip successfully imaged both the direct synchrotron beam and single 7.05 keV photons at the same time, demonstrating the large dynamic range required for XFEL experiments. X-ray scattering measurements from a test sample agree with standard measurements and show the chip's capability of observing dynamics at the microsecond time scale.
Some Remarks on Energy Storage and Energetic Complementarity  [PDF]
Renato M. Brito
Energy and Power Engineering (EPE) , 2017, DOI: 10.4236/epe.2017.99031
Abstract: This letter to the editor presents some notes related to the technological and economic limitations of the means actually available for energy storage and highlights the role that can be played by the notion of energetic complementarity in order to make feasible alternatives for a better use of the energy resources at our disposal. The notion of complementarity may represent a major advance in the design of energy generation projects, but its application depends on a broader conception of the projects and the contexts in which they are included.
Insulin-Increased L-Arginine Transport Requires A2A Adenosine Receptors Activation in Human Umbilical Vein Endothelium
Enrique Guzmán-Gutiérrez, Francisco Westermeier, Carlos Salomón, Marcelo González, Fabián Pardo, Andrea Leiva, Luis Sobrevia
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0041705
Abstract: Adenosine causes vasodilation of human placenta vasculature by increasing the transport of arginine via cationic amino acid transporters 1 (hCAT-1). This process involves the activation of A2A adenosine receptors (A2AAR) in human umbilical vein endothelial cells (HUVECs). Insulin increases hCAT-1 activity and expression in HUVECs, and A2AAR stimulation increases insulin sensitivity in subjects with insulin resistance. However, whether A2AAR plays a role in insulin-mediated increase in L-arginine transport in HUVECs is unknown. To determine this, we first assayed the kinetics of saturable L-arginine transport (1 minute, 37°C) in the absence or presence of nitrobenzylthioinosine (NBTI, 10 μmol/L, adenosine transport inhibitor) and/or adenosine receptors agonist/antagonists. We also determined hCAT-1 protein and mRNA expression levels (Western blots and quantitative PCR), and SLC7A1 (for hCAT-1) reporter promoter activity. Insulin and NBTI increased the extracellular adenosine concentration, the maximal velocity for L-arginine transport without altering the apparent Km for L-arginine transport, hCAT-1 protein and mRNA expression levels, and SLC7A1 transcriptional activity. An A2AAR antagonist ZM-241385 blocked these effects. ZM241385 inhibited SLC7A1 reporter transcriptional activity to the same extent in cells transfected with pGL3-hCAT-1?1606 or pGL3-hCAT-1?650 constructs in the presence of NBTI + insulin. However, SLC7A1 reporter activity was increased by NBTI only in cells transfected with pGL3-hCAT-1?1606, and the ZM-241385 sensitive fraction of the NBTI response was similar in the absence or in the presence of insulin. Thus, insulin modulation of hCAT-1 expression and activity requires functional A2AAR in HUVECs, a mechanism that may be applicable to diseases associated with fetal insulin resistance, such as gestational diabetes.
Gestational Diabetes Reduces Adenosine Transport in Human Placental Microvascular Endothelium, an Effect Reversed by Insulin
Carlos Salomón, Francisco Westermeier, Carlos Puebla, Pablo Arroyo, Enrique Guzmán-Gutiérrez, Fabián Pardo, Andrea Leiva, Paola Casanello, Luis Sobrevia
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0040578
Abstract: Gestational diabetes mellitus (GDM) courses with increased fetal plasma adenosine concentration and reduced adenosine transport in placental macrovascular endothelium. Since insulin modulates human equilibrative nucleoside transporters (hENTs) expression/activity, we hypothesize that GDM will alter hENT2-mediated transport in human placental microvascular endothelium (hPMEC), and that insulin will restore GDM to a normal phenotype involving insulin receptors A (IR-A) and B (IR-B). GDM effect on hENTs expression and transport activity, and IR-A/IR-B expression and associated cell signalling cascades (p42/44 mitogen-activated protein kinases (p42/44mapk) and Akt) role in hPMEC primary cultures was assayed. GDM associates with elevated umbilical whole and vein, but not arteries blood adenosine, and reduced hENTs adenosine transport and expression. IR-A/IR-B mRNA expression and p42/44mapk/Akt ratios (‘metabolic phenotype’) were lower in GDM. Insulin reversed GDM-reduced hENT2 expression/activity, IR-A/IR-B mRNA expression and p42/44mapk/Akt ratios to normal pregnancies (‘mitogenic phenotype’). It is suggested that insulin effects required IR-A and IR-B expression leading to differential modulation of signalling pathways restoring GDM-metabolic to a normal-mitogenic like phenotype. Insulin could be acting as protecting factor for placental microvascular endothelial dysfunction in GDM.
On the orthogonalization of arbitrary Boolean formulae
Renato Bruni
Advances in Decision Sciences , 2005, DOI: 10.1155/jamds.2005.61
Abstract: The orthogonal conjunctive normal form of a Boolean function is a conjunctive normal form in which any two clauses contain at least a pair of complementary literals. Orthogonal disjunctive normal form is defined similarly. Orthogonalization is the process of transforming the normal form of a Boolean function to orthogonal normal form. The problem is of great relevance in several applications, for example, in the reliability theory. Moreover, such problem is strongly connected with the well-known propositional satisfiability problem. Therefore, important complexity issues are involved. A general procedure for transforming an arbitrary CNF or DNF to an orthogonal one is proposed. Such procedure is tested on randomly generated Boolean formulae.
Potential Energy Surfaces Using Algebraic Methods Based on Unitary Groups
Renato Lemus
Advances in Physical Chemistry , 2011, DOI: 10.1155/2011/593872
Abstract: This contribution reviews the recent advances to estimate the potential energy surfaces through algebraic methods based on the unitary groups used to describe the molecular vibrational degrees of freedom. The basic idea is to introduce the unitary group approach in the context of the traditional approach, where the Hamiltonian is expanded in terms of coordinates and momenta. In the presentation of this paper, several representative molecular systems that permit to illustrate both the different algebraic approaches as well as the usual problems encountered in the vibrational description in terms of internal coordinates are presented. Methods based on coherent states are also discussed. 1. Introduction The description of molecular systems involves the solution of the corresponding Schr?dinger equation. This task is so difficult that an approach involving just numerical methods needs powerful computers even for three-or four-particle systems. An alternative approach is based on choosing the basis functions in such a way that they resemble the exact eigenfunctions as much as possible. The suitable basis are obtained by making approximations that simplify the Hamiltonian of the molecule. The advantage of this method is that the functions reproduce correctly the gross features of the spectrum, and consequently they provide a better physical insight in understanding the solutions. The first step in simplifying the molecular problem consists in taking advantage of the large difference between the nucleus and electron masses, a fact that leads to the Born-Oppenheimer approximation [1, 2]. As a result of this approximation the original Schr?dinger equation is split into two coupled equations, one corresponding to the electronic degrees of freedom which is solved for many nuclear geometries and the other one associated with the rotation-vibration Schr?dinger equation for the nuclei whose potential is basically provided by the electronic energy [3, 4]. On the other hand, the rotation-vibration Schr?dinger equation is usually solved making the rigid-rotor approximation together with the harmonic oscillator approximation. The total wave function is then approximated as the direct product of three contributions: electronic, rotational, and vibrational wave functions. Corrections to this description are allowed by introducing the braking of the Born-Oppenheimer approximation, distortion effects, anharmonicity, centrifugal distortion, and Coriolis coupling [3–5]. Within the Born-Oppenheimer approximation the potential energy surface (PES) is provided by the solution of
Ecological Gradients Influencing Waterbird Communities in Black Water Lakes in the Anavilhanas Archipelago, Central Amazonia
Renato Cintra
International Journal of Ecology , 2012, DOI: 10.1155/2012/801683
Abstract: For the first time, and in a large spatial scale, the influence of ecological properties on the aquatic bird community of black water lakes in Brazilian Amazonia is evaluated. Bird surveys were conducted in 45 lakes. A total of 3626 individuals in 48 bird species were recorded; of these, 31 are aquatic, and 18 of these are primarily piscivorous. Bird richness and abundance were not significantly related to lake shape and productivity but were influenced by hydrological period (low versus high), water depth, transparency, lake isolation, and habitat richness. Matrices of bird species by lake were subjected to multivariate analyses (NMDS) to evaluate how these parameters influence bird community. The variation in bird species composition was positively correlated to lake depth and isolation and negatively correlated to water transparency and habitat richness. The results indicate that period, lake physical characteristics (depth, water transparency), isolation, and habitat richness are determinants of aquatic bird community composition in the black water lake systems of Amazonia.
Quantum Numbers and the Eigenfunction Approach to Obtain Symmetry Adapted Functions for Discrete Symmetries
Renato Lemus
Symmetry , 2012, DOI: 10.3390/sym4040667
Abstract: The eigenfunction approach used for discrete symmetries is deduced from the concept of quantum numbers. We show that the irreducible representations (irreps) associated with the eigenfunctions are indeed a shorthand notation for the set of eigenvalues of the class operators (character table). The need of a canonical chain of groups to establish a complete set of commuting operators is emphasized. This analysis allows us to establish in natural form the connection between the quantum numbers and the eigenfunction method proposed by J.Q. Chen to obtain symmetry adapted functions. We then proceed to present a friendly version of the eigenfunction method to project functions.
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