Lattice Model for water-solute mixtures

A lattice model for the study of mixtures of associating liquids is proposed. Solvent and solute are modeled by adapting the associating lattice gas (ALG) model. The nature of interaction solute/solvent is controlled by tuning the energy interactions between the patches of ALG model. We have studied three set of parameters, resulting on, hydrophilic, inert and hydrophobic interactions. Extensive Monte Carlo simulations were carried out and the behavior of pure components and the excess properties of the mixtures have been studied. The pure components: water (solvent) and solute, have quite similar phase diagrams, presenting: gas, low density liquid, and high density liquid phases. In the case of solute, the regions of coexistence are substantially reduced when compared with both the water and the standard ALG models. A numerical procedure has been developed in order to attain series of results at constant pressure from simulations of the lattice gas model in the grand canonical ensemble. The excess properties of the mixtures: volume and enthalpy as the function of the solute fraction have been studied for different interaction parameters of the model. Our model is able to reproduce qualitatively well the excess volume and enthalpy for different aqueous solutions. For the hydrophilic case, we show that the model is able to reproduce the excess volume and enthalpy of mixtures of small alcohols and amines. The inert case reproduces the behavior of large alcohols such as, propanol, butanol and pentanol. For last case (hydrophobic), the excess properties reproduce the behavior of ionic liquids in aqueous solution.Comment: 28 pages, 13 figure

Towards Scalable Visual Exploration of Very Large RDF Graphs

In this paper, we outline our work on developing a disk-based infrastructure for efficient visualization and graph exploration operations over very large graphs. The proposed platform, called graphVizdb, is based on a novel technique for indexing and storing the graph. Particularly, the graph layout is indexed with a spatial data structure, i.e., an R-tree, and stored in a database. In runtime, user operations are translated into efficient spatial operations (i.e., window queries) in the backend.Comment: 12th Extended Semantic Web Conference (ESWC 2015

Effect of hazelnut on serum lipid profile and fatty acid composition of erythrocyte phospholipids in children and adolescents with primary hyperlipidemia : a randomized controlled trial

Background & aim: Regular intake of nuts improves lipid profile and thus reduces the cardiovascular (CV) risk associated with hyperlipidemia. The aim of the study was to investigate the effect of a dietary intervention with hazelnuts (HZNs, 15-30 g/day, depending on patient weight) on serum lipid profile, anthropometric parameters and fatty acids (FAs) composition of erythrocyte phospholipids in children and adolescents with primary hyperlipidemia. Methods: Eight-week randomized, single blind, controlled, three-arm, parallel-group study. Sixty-six subjects were enrolled and randomized in 3 groups receiving: 1) hazelnuts with skin (HZN+S); 2) hazelnuts without skin (HZN-S); 3) dietary advices for hyperlipidemia only (controls). Before and after intervention, clinical parameters were measured and blood samples were collected for the evaluation of serum lipid levels and phospholipid FA composition of erythrocytes. Results: Two-way ANOVA showed a significant effect of time on serum low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C)/LDL-C ratio and non-HDL-C (p < 0.001), but not of treatment and time x treatment interaction. In particular, HZN+S and HZN-S significantly reduced the concentrations of LDL-C and increased HDL-C/LDL-C ratio. HZNs also had a favorable impact on FAs composition of erythrocyte phospholipids, as demonstrated by time x treatment interaction, with a significant increase of monounsaturated fatty acids (MUFAs) (p = 0.008) and MUFAs/saturated fatty acids (SFAs) ratio (p = 0.002) with respect to the control group. Conclusions: For the first time, we documented a positive effect of HZN consumption on lipid profile and FA composition of erythrocyte phospholipids in children with primary hyperlipidemia. Further studies are encouraged to better define HZN impact on the markers of CV risk in this population

Uso de mezclas de azoxistrobina y triazoles para controlar enfermedades de fin de ciclo de la soja

134-139Widely spread in Argentina, late season diseases (LSD), cause yield losses and seed quality changes. Leaf application of fungicides is an effective procedure to manage LSD under the current cropping conditions (monocrop and no-till system). The aims of the present study were 1) to determine causal agents of LSD, 2) to evaluate yield reduction caused by LSD and 3) to evaluate the efficiency of mixtures containing triazoles and strobirulins, sprayed during R3 or R5 reproductive stages to control LSD. Four experiments were carried out in a randomized complete block design, with four replicates in Armstrong, Santa Fe, Argentina, in a soybean cultivation area in the Pampeana Region. Two assays were performed in 2004/2005, and the remaining ones in 2005/2006 growing seasons. Two azoxystrobin mixtures, one with cyproconazole and the other with difenoconazole, and a mixture of the latter two were tested. The following pathogens were detected: Cercospora kikuchii, Colletotrichum truncatum, Septoria glycines, Glomerella glycines y Phomopsis sojae. All treatments presented higher yield than control, with 5 percent of statistic significance. It can be concluded that, under the present experimental conditions, characterized by frequent rains between R1 and R5.5, the tested mixtures efficiently controlled LSD

Random graphs with arbitrary degree distributions and their applications

Recent work on the structure of social networks and the internet has focussed attention on graphs with distributions of vertex degree that are significantly different from the Poisson degree distributions that have been widely studied in the past. In this paper we develop in detail the theory of random graphs with arbitrary degree distributions. In addition to simple undirected, unipartite graphs, we examine the properties of directed and bipartite graphs. Among other results, we derive exact expressions for the position of the phase transition at which a giant component first forms, the mean component size, the size of the giant component if there is one, the mean number of vertices a certain distance away from a randomly chosen vertex, and the average vertex-vertex distance within a graph. We apply our theory to some real-world graphs, including the world-wide web and collaboration graphs of scientists and Fortune 1000 company directors. We demonstrate that in some cases random graphs with appropriate distributions of vertex degree predict with surprising accuracy the behavior of the real world, while in others there is a measurable discrepancy between theory and reality, perhaps indicating the presence of additional social structure in the network that is not captured by the random graph.Comment: 19 pages, 11 figures, some new material added in this version along with minor updates and correction

Electron Capture Dissociation Mass Spectrometry of Tyrosine Nitrated Peptides

In vivo protein nitration is associated with many disease conditions that involve oxidative stress and inflammatory response. The modification involves addition of a nitro group at the position ortho to the phenol group of tyrosine to give 3-nitrotyrosine. To understand the mechanisms and consequences of protein nitration, it is necessary to develop methods for identification of nitrotyrosine-containing proteins and localization of the sites of modification.Here, we have investigated the electron capture dissociation (ECD) and collision-induced association (CID) behavior of 3-nitrotyrosine-containing peptides. The presence of nitration did not affect the CID behavior of the peptides. For the doubly-charged peptides, addition of nitration severely inhibited the production of ECD sequence fragments. However, ECD of the triply-charged nitrated peptides resulted in some singly-charged sequence fragments. ECD of the nitrated peptides is characterized by multiple losses of small neutral species including hydroxyl radicals, water and ammonia. The origin of the neutral losses has been investigated by use of activated ion (AI) ECD. Loss of ammonia appears to be the result of non-covalent interactions between the nitro group and protonated lysine side-chains

Identification and relative quantification of tyrosine nitration in a model peptide using two-dimensional infrared spectroscopy

Nitration of tyrosine in proteins and peptides is a post-translational modification that occurs under conditions of oxidative stress. It is implicated in a variety of medical conditions, including neurodegenerative and cardiovascular diseases. However, monitoring tyrosine nitration and understanding its role in modifying biological function remains a major challenge. In this work, we investigate the use of electron-vibration-vibration (EVV) two-dimensional infrared (2DIR) spectroscopy for the study of tyrosine nitration in model peptides. We demonstrate the ability of EVV 2DIR spectroscopy to differentiate between the neutral and deprotonated states of 3-nitrotyrosine, and we characterize their spectral signatures using information obtained from quantum chemistry calculations and simulated EVV 2DIR spectra. To test the sensitivity of the technique, we use mixed-peptide samples containing various levels of tyrosine nitration, and we use mass spectrometry to independently verify the level of nitration. We conclude that EVV 2DIR spectroscopy is able to provide detailed spectroscopic information on peptide side-chain modifications and to detect nitration levels down to 1%. We further propose that lower nitration levels could be detected by introducing a resonant Raman probe step to increase the detection sensitivity of EVV 2DIR spectroscopy. (Graph Presented)

An exceptionally well-preserved skeleton of Palaeothentes from the Early Miocene of Patagonia, Argentina: new insights into the anatomy of extinct paucituberculatan marsupials

International audienc

Eruptive papules during efalizumab (anti-CD11a) therapy of psoriasis vulgaris: a case series

BACKGROUND: Newer biological therapies for moderate-to-severe psoriasis are being used more frequently, but unexpected effects may occur. CASE PRESENTATIONS: We present a group of 15 patients who developed inflammatory papules while on efalizumab therapy (Raptiva, Genentech Inc, anti-CD11a). Immunohistochemistry showed that there were increased CD11b(+), CD11c(+ )and iNOS(+ )cells (myeloid leukocytes) in the papules, with relatively few CD3(+ )T cells. While efalizumab caused a decreased expression of CD11a on T cells, other circulating leukocytes from patients receiving this therapy often showed increased CD11b and CD11c. In the setting of an additional stimulus such as skin trauma, this may predispose to increased trafficking into the skin using these alternative β2 integrins. In addition, there may be impaired immune synapse formation, limiting the development of these lesions to small papules. There is little evidence for these papular lesions being "allergic" in nature as there are few eosinophils on biopsy, and they respond to minimal or no therapy even if efalizumab is continued. CONCLUSION: We hypothesize that these papules may represent a unique type of "mechanistic" inflammatory reaction, seen only in the context of drug-induced CD11a blockade, and not during the natural disease process