Isolation of salmonella typhimurium from dead blue and gold macaws (ara ararauna); Aislamiento de Salmonella typhimurium a partir de guacamayas azul y amarillo (Ara ararauna) muertas Vigo, Germán Blás; Origlia, Javier Anibal; Gornatti Churria, Carlos Daniel; Piscopo, Miguel Victor; Salve, Angela; Caffer, María I.; Pichel, Mariana; Binsztein, Norma; Leotta, Gerardo Anibal Dos polluelos de guacamayas azul y amarillo (Ara ararauna) murieron por una salmonelosis fatal en la Provincia de Buenos Aires, Argentina. Las aves se examinaron por histopatología y microbiología. La Salmonella enterica subespecies enterica serovar Typhimurium fue aislada de hígado, bazo, corazón, pulmón, riñón e intestino de ambas aves. Todas las cepas fueron susceptibles a ampicilina, cefalotina, cefotaxima, enrofloxacina, ácido nadilixico, gentamicina, estreptomicina, cloranfenicol, fosfomicina, tetraciclina, nitrofurantoina y la combinación trimetoprim-sulfametoxazol. El perfil XbaI de la Salmonella Typhimurium aislada de los dos animales que compartían la misma jaula fueron idénticos mediante electroforesis en gel de campos pulsantes (por sus siglas en inglés PFGE), y mostraron un patrón único comparado con 301 aislamientos que están incluidos en la base de datos nacional de patrones de PFGE de Salmonella, denominada PulseNet. Este es el primer reporte que describe casos fatales de salmonelosis en guacamayas azul y amarillo.; Two blue and gold macaw (Ara ararauna) chicks died of fatal salmonellosis in Buenos Aires Province, Argentina. The birds were histopathologically and microbiologically examined. Salmonella enterica subspecies enterica serovar Typhimurium was isolated from the liver, spleen, heart, lung, kidney, and intestine of both birds. All strains were susceptible to ampicillin, cephalothin, cefotaxime, enrofloxacin, nalidixic acid, gentamicin, streptomycin, chloramphenicol, fosfomycin, tetracycline, nitrofurantoin, and trimethoprim-sulfamethoxazole. The XbaI-PFGE profile of the Salmonella Typhimurium isolated from the two animals, which shared the same cage, was identical and showed a unique pattern compared with 301 isolates included in the PulseNet national database of Salmonella pulsed-field gel electrophoresis patterns. This is the first report that describes fatal cases of salmonellosis from blue and gold macaws.

Likelihood-Based Sufficient Dimension Reduction Cook, R. Dennis; Forzani, Liliana Maria We obtain the maximum likelihood estimator of the central subspace under conditional normality of the predictors given the response. Analytically and in simulations we found that our new estimator can preform much better than sliced inverse regression, sliced average variance estimation and directional regression, and that it seems quite robust to deviations from normality.

Design of multiproduct batch plants with units in series including process performance models Moreno, Marta Susana; Iribarren, Oscar Alberto; Montagna, Jorge Marcelo This work deals with the simultaneous optimization of process decision variables and the structure of multiproduct batch plants considering the duplication of units in series to perform a given unit operation. Performance process models allow expressing the size and time factors of the posynomial formulation as a function of the process variables with the highest impact on costs. They are added into the design problem and handled as extra constraints. Structural alternatives for the plant were defined in order to include the duplication of units in series. Thus, the problem is formulated as an optimization problem, using mixed integer nonlinear programming to minimize the total cost of the process, subjected to design specifications. The model application is illustrated with a process for the production of oleoresins. The convenience of including the duplication in series together with process variables in process optimization is tested through the resolution of various problem cases.

Liquid-Glassy Polymer Interphases: Diffusion Kinetics in Conditions of Unlimited Liquid Supply Tomba, Juan Pablo; Carella, Jose Maria; Pérez, Claudio Javier; Pastor, José M. We investigate evidences of diffusion controlled by mechanical relaxation of the glassy matrix, i.e. Case-II mechanism, in a series of liquid/glassy interphases formed by polystyrene (PS) and poly (phenylene oxide) (PPO) as liquid and glassy components respectively. Diffusion experiments were performed in conditions of unlimited supply of the liquid polymer, parallel to those in which Case-II has been effectively verified. Interphase profiles were obtained via optical sectioning with confocal Raman microspectroscopy. We observed that interphase diffusion kinetics were markedly Fickean, in contrast with interpretations from other authors that invoke Case-II to explain the mechanisms that rule interphase evolution in these systems. 

The correlation contracted schrodinger equation: An accurate solution of the G-particle-hole hypervirial Alcoba, Diego Ricardo; Valdemoro, C.; Tel, L. M.; Pérez-Romero, E. The equation obtained by mapping the matrix representation of the Schrödinger equation with the 2nd-order correlation transition matrix elements into the 2-body space is the so called correlation contracted Schrödinger equation (CCSE) (Alcoba, Phys Rev A 2002, 65, 032519). As shown by Alcoba (Phys Rev A 2002, 65, 032519) the solution of the CCSE coincides with that of the Schrödinger equation. Here the attention is focused in the vanishing hypervirial of the correlation operator (GHV), which can be identified with the anti-Hermitian part of the CCSE. A comparative analysis of the GHV and the anti-Hermitian part of the contracted Schrödinger equation (ACSE) indicates that the former is a stronger stationarity condition than the latter. By applying a Heisenberg-like unitary transformation to the G-particle-hole operator (Valdemoro et al., Phys Rev A 2000, 61, 032507), a good approximation of the expectation value of this operator as well as of the GHV is obtained. The method is illustrated for the case of the Beryllium isoelectronic series as well as for the Li2 and BeH2 molecules. The correlation energies obtained are within 98.80-100.09% of the full-configuration interaction ones. The convergence of these calculations was faster when using the GHV than with the ACSE. © 2009 Wiley Periodicals, Inc.

DFT Calculations of the Molecular Force Field of Vanadyl Nitrate, VO(NO3)3 Brandan, Silvia Antonia; Socolsky, Cecilia; Ben Altabef, Aída A structural and vibrational theoretical study for vanadyl nitrate was carried out. The Density Functional Theory (DFT) has been used to study vibrational properties. The structures were fully optimized at the B3LYP/6-31G *, B3LYP/6-311G *, and B3LYP/6-311 + G * levels of theory and the harmonic vibrational frequencies were evaluated at the same level. The calculated harmonic vibrational frequencies for vanadyl nitrate are consistent with their experimental IR and Raman spectra in gas and liquid phases. Through these calculations a precise knowledge of the normal modes of vibration was obtained, considering the coordination mode adopted by the nitrate group in the mirror plane as monodentate and bidentate. A total assignment of the observed bands in the vibrational spectra for vanadyl nitrate is proposed in this work. The nature of the V-O and V←O bonds in the compound was systematically and quantitatively investigated by means of the Natural Bond Order (NBO) analysis. The topological properties of the electronic charge density were analyzed employing Bader's Atoms in Molecules theory (AIM).

Temporal variation in abundance and fecundity of the invading copepod Eurytemora americana in Bahia Blanca Estuary during an unusual year Berasategui, Anabela Anhi; Hoffmeyer, Monica Susana; Biancalana, Florencia; Fernandez Severini, Melisa Daiana; Menendez, Maria Clara Temporal change of biotic and environmental variables was corroborated by a Mann–Whitney/Kruskal–Wallis non-parametric tests, with significant differences ( p 0.01) in all variables throughout the study. Abundance population results showed very high values in relation to those recorded in recent years in Bahı ́ a Blanca Estuary. This response could be due to the unusual combination of environmental factors (polar wave with temperatures 6 C and a drought period with high salinities, 32.7–36.6) recorded during the studied winter period. Significant positive correlations between abundance and salinity ( p < 0.01, n = 226), and hatching success ( p < 0.01, n = 25) as well as a significant negative correlation between abundance and chlorophyll a ( p < 0.01, n = 226) were found. Although E. americana shows a k-strategy within its annual pulse, it presented two markedly distinct behaviours depending on temporal environmental variability. From July to early september, when the estuary evidenced high salinity, low temperature and high food availability, E. Americana showed large females, large clutch size and high hatching success. When environmental conditions became unfavorable from September to October, small females, small clutch size and very low hatching success were observed. The latter is associated with diapause egg laying which ensures pop- ulation recruitment. According to our findings the particular combination of low temperatures, high salinities and high available food (i.e. variables which each year modulate its pulse) during 2007 winter– spring, favored the great development of E. americana . This invading species in its opportunistic role has managed to exploit a vacant niche in the estuary, developing two different behaviours within the k-strategy depending on change in environmental conditions.

Micromycetes on Austrocedrus chilensis. First record of Rebentischia from Argentina Bianchinotti, Maria Virginia; Sanchez, Romina Magali Rebentischia massalongii was collected growing on twigs from Austrocedrus chilensis. So far known only from the temperate zone of Europe and North America, this species is reported for the first time from Argentina and the Southern Hemisphere. The type specimen of R. costi, a species described from Brazil, was re-examined and is here considered an authentic species. A key to the accepted species of Rebentischia is provided.

Activation of Stat3 by heregulin/ErbB-2 through the co-option of progesterone receptor signaling drives breast cancer growth Proietti Anastasi, Cecilia Jazmín; Rosemblit, Cinthia; Beguelin, Wendy; Rivas, Martin Alfredo; Díaz Flaqué, María Celeste; Charreau, Eduardo Hernan; Schillaci, Roxana; Elizalde, Patricia Virginia Cross talk between the steroid hormone receptors for estrogen and progesterone (PR) and the ErbB family of receptor tyrosine kinases appears to be a hallmark of breast cancer growth, but its underlying mechanism remains poorly explored. Here we have highlighted signal transducer and activator of transcription 3 (Stat3) as a key protein activated by heregulin (HRG), a ligand of the ErbB receptors, through co-opted, ligand-independent PR function as a signaling molecule. Stat3 activation was an absolute requirement in HRG-induced mammary tumor growth, and targeting Stat3 effectively inhibited growth of breast cancer cells with activated HRG/ErbB-2 and PR. Our findings unravel a novel potential therapeutic intervention in PR- and ErbB-2-positive breast tumors, involving the specific blockage of PR signaling activity.

Spontaneous adsorption of 3,5-bis(3,5-dinitrobenzoylamino) benzoic acid onto carbon Paez, Julieta Irene; Strumia, Miriam Cristina; Passeggi, Mario Cesar Genaro; Ferron, Julio; Baruzzi, Ana Maria; Brunetti, Veronica Dendritic molecules contain multifunctional groups that can be used to efficiently control the properties of an electrode surface. We are developing strategies to generate a highly functionalized surface using multifunctional and rigid dendrons immobilized onto different substrates. In the present work, we explore the immobilization of a dendritic molecule: 3,5-bis(3,5-dinitrobenzoylamino) benzoic acid (D-NO2) onto carbon surfaces showing a simple and rapid way to produce conductive surfaces with electroactive chemical functions. The immobilized D-NO2 layer has been characterized using atomic force microscopy and cyclic voltammetry. D-NO2 adsorbs onto carbon surfaces spontaneously by dipping the electrode in dendron solutions. Reduction of this layer generates the hydroxylamine product. The resulting redox-active layer exhibits a well-behaved redox response for the adsorbed nitroso/hydroxylamine couple. The film permeability of the derivatized surface has been analyzed employing the electrochemical response of redox probes: Ru(NH3)6 3+/Ru(NH3)6 2+ and Fe(CN)6 3−/Fe(CN)6 4−. Electrocatalytic oxidation of nicotinamide adenine dinucleotide onto a modified carbon surface was also observed.

Design of dynamic experiments in modeling for optimization of batch processes Martínez, Ernesto Carlos; Cristaldi, Mariano Daniel; Grau, Ricardo José Antonio Finding optimal operating conditions fast with a scarce budget of experimental runs is a key problem to speeding up the development of innovative products and processes. Modeling for optimization is proposed as a systematic approach to bias data gathering for iterative policy improvement through experimental design using first-principles models. Designing dynamic experiments that are optimally informative in order to reduce the uncertainty about the optimal operating conditions is addressed by integrating policy iteration based on the Hamilton-Jacobi-Bellman optimality equation with global sensitivity analysis. A conceptual framework for run-to-run convergence of a model-based policy iteration algorithm is proposed. Results obtained in the fed-batch fermentation of penicillin G are presented. The well-known Bajpai and Reuss bioreactor model validated with industrial data is used to increase on a run-to-run basis the amount of penicillin obtained by input policy optimization and selective (re)estimation of relevant model parameters. A remarkable improvement in productivity can be gain using a simple policy structure after only two modeling runs despite initial modeling uncertainty.

Sunflower Lecithin: Application of a Fractionation Process with Absolute Ethanol Cabezas, Dario Marcelino; Diehl, Bernd W. K.; Tomás, Mabel Cristina Native or modified lecithins are widely used as a multifunctional ingredient in the food industry. A fractionation process of sunflower lecithin (a non GMO product) with absolute ethanol was used for obtaining enriched fractions in certain phospholipids under different experimental conditions (temperature 35-65 °C, time of fractionation 30-90 min, ethanol/lecithin ratio 2:1, 3:1). Phospholipid enrichment in PC and PI fractions was obtained and analyzed by 31P NMR determinations. The percent extraction coefficients for different phospholipids (%EPC, %EPE and %EPI) in both fractions were calculated. Values of %EPC in PC fractions significantly increased (p < 0.05) from 12.8 (35 °C, 30 min, 2:1) to 57.7 (65 °C, 90 min, 3:1) at increasing temperature and incubation time. %EPE varied from 3.0 to 18.3 in the same fraction while %EPI presented lower values (<3%) under all the conditions assayed. The study of the effect of the operating conditions on the fractionation process evidenced a relevant influence of temperature, incubation time and to a minor extent of the ethanol/lecithin ratio on the enriched fraction yield% and selectivity of the main phospholipids (PC, PI, PE) estimated by %EPL. Response surface methodology (RSM) was utilized to explain the influence of the different parameters to optimize this process.

AMPER-Argentina: pretonemas en oraciones interrogativas absolutas Gurlekian, Jorge Alberto; Toledo, Guillermo Andres Este trabajo es parte del Proyecto AMPER (Atlas Multimedia de la Prosodia del Espacio Románico). El área dialectal de estudio es el español de Buenos Aires. En el artículo se analizan las oraciones interrogativas absolutas SVO: un SN (núcleos sintácticos paroxítonos, proparoxítonos, oxítonos), un SV (núcleo paroxítono), un SPrep (núcleos paroxítonos, proparoxítonos, oxítonos). También se examinan los pretonemas según el modelo de entonación métrico y autosegmental (AM), y se observa la influencia de la frase fonológica (φ) en la representación fonológica de los acentos tonales. Los resultados de los pretonemas indican diferencias y no un único fraseo prosódico que caracterice a esta modalidad. Los primeros picos (P1) de la primera φ no muestran tonos más altos si se los compara con los P1 de oraciones declarativas. Se descarta un tono de frontera H% inicial. Estos hallazgos confirman otro estudio previo: la información sobre la modalidad interrogativa absoluta se encuentra fuera del pretonema, en el tonema final.; The present work belongs to project AMPER (Multimedia Atlas of Prosody of the Romanic Space). The dialectal area of study is the Spanish from Buenos Aires. This work analyses absolute interrogative sentences of the SVO-type: a NP (oxytone, paroxytone and proparoxytone heads), a VP (paroxytone head), a Prep. phrase (oxytone, paroxytone and proparoxytone heads). In addition, pretonemes are examined according to the intonation Autosegmental-metrical (AM) framework and the phonological phrase (f) influence is observed on the phonological representation of pitch accents. The pretoneme results indicate differences and not only one prosodic phrasing which may characterize this modality. The first peaks (P1) which belong to the first f do not show higher tones if compared to the P1 of declarative sentences. An initial frontier tone H% is discarded. These findings confirm a previous study: information regarding the absolute interrogative modality is out of the pretoneme, in the final toneme.

Arbuscular mycorrhizas and dark septate endophytes in bromeliads from South American arid environment Lugo, Mónica Alejandra; Molina, Mirta Graciela; Crespo, Esteban María Most plant roots are associated with glomalean fungi forming arbuscular mycorrhizas (AM) and a wide range are also colonized by ascomycetous dark septate endophytes (DSE). Bromeliaceae species can be epiphytic, rupicolous or terrestrial but their mycorrhizal status is poorly studied. We examined the AM and DSE status of 5 epiphytic and 4 terrestrial Bromeliaceae from an arid area of Central Argentina. The terrestrial species were either dually associated (AM and DSE) or non-associated whereas the epiphytes were only DSE colonized. Terrestrial Bromeliaceae that formed AM-DSE associations were likely responding to the arid conditions of the area and the availability of AM fungal (AMF) spores in the soil. The terrestrial Bromelia ubaniana was not colonized either by AMF or DSE. This could reflect its root morphology and high number of root hairs. DSE are endosymbiotic in the stressful ecosystems experienced by canopy epiphytes in the studied environment. The different fungal associations are discussed in relation to the three Bromeliaceae subfarniles and we suggest that environmental features determine the type of association formed by species in this plant family.

Predicting average regional yield and production of wheat in the Argentine Pampas by an artificial neural network approach Alvarez, Roberto A regional analysis of the effects of soil and climate factors on wheat yield was performed in the Argentine Pampas in order to obtain models suitable for yield estimation and regional grain production prediction. Soil data from soil surveys and climate data from meteorological records were employed. Grain production information from statistics at county level was integrated at a geomorphological level. The Pampas was divided into 10 geographical units and data from 10 growing season were used (1995-2004). Surface regression and artificial neural networks (ANN) methodologies were tested for analyzing the data. Wheat yield was correlated to soil available water holding capacity (SAWHC) in the upper 100 cm of the profiles (r2 = 0.39) and soil organic carbon (SOC) content (r2 = 0.26). The climate factor with stronger effect on yield was the rainfall/crop potential evapotranspiration ratio (R/CPET) during the fallow and vegetative crop growing cycle periods summed (r2 = 0.31). The phototermal quotient (PQ) during the pre-anthesis period had also a significant effect on yield (r2 = 0.05). A surface regression response model was developed that account for 64% of spatial and interannual yield variance, but this model could not perform a better yield prediction than the blind guess technique. An ANN was fitted to the data that accounted for 76% of yield variability. Comparing predicted versus observed yield a lower RMSE (P = 0.05) was obtained using the ANN than using the regression or the blind guess methods. Regional production estimations performed by the ANN showed a good agreement with observed data with a RMSE equivalent to 7% of the whole surveyed area production. As variables used for the ANN development may be available around 40-60 days before wheat harvest, the methodology may be used for wheat production forecasting in the Pampas.

Effect of the metabolic inhibitor, methimazole on the drug susceptibility of a triclabendazole-resistant isolate of Fasciola hepatica Devine, C.; Brennan, G.P.; Lanusse, Carlos Edmundo; Alvarez, Luis Ignacio; Trudgett, A.; Hoey, E.; Fairweather, I. A study has been carried out to investigate whether the action of triclabendazole (TCBZ) is altered in the presence of a metabolic inhibitor. The flavin monooxygenase system (FMO) was inhibited using methimazole (MTZ) to see whether a TCBZ-resistant isolate could be made more sensitive to TCBZ action. The Oberon TCBZ-resistant and Cullompton TCBZ-sensitive isolates were used for these experiments. The FMO system was inhibited by a 2-h pre-incubation in methimazole (100 m). Flukes were then incubated for a further 22 h in NCTC medium containing either MTZ; MTZ+nicotinamide adenine dinucleotide phosphate (NADPH) (1 nm); MTZ+NADPH+TCBZ (15 g/ml); or MTZ+NADPH+triclabendazole sulphoxide (TCBZ.SO) (15 g/ml). Morphological changes resulting from drug treatment and following metabolic inhibition were assessed using scanning electron microscopy. After treatment with either TCBZ or TCBZ.SO alone, there was greater surface disruption to the triclabendazole-susceptible than -resistant isolate. However, co-incubation with MTZ and TCBZ/TCBZ.SO lead to more severe surface changes to the TCBZ-resistant isolate than with each drug on its own; this was not seen for the TCBZ-susceptible Cullompton isolate. Results of this study support the concept of altered drug metabolism in TCBZ-resistant flukes and this process may play a role in the development of drug resistance.

Molybdenum Induces the Expression of a Protein Containing a New Heterometallic Mo-Fe Cluster in Desulfovibrio alaskensis Rivas, Maria Gabriela; Carepo, Marta S.P.; Mota, Cristiano S.; Korbas, Malgorzata; Durand, Marie-Claire; Lopes, Ana T.; Brondino, Carlos Dante; Pereira, Alice S.; George, Graham N.; Dolla, Alain; Moura, José J.G.; Moura, Isabel The characterization of a novel Mo-Fe protein (MorP) associated with a system that responds to Mo in Desulfovibrio alaskensis is reported. Biochemical characterization shows that MorP is a periplasmic homomultimer of high molecular weight (260 ± 13 kDa) consisting of 16-18 monomers of 15321.1 ± 0.5 Da. The UV/visible absorption spectrum of the as-isolated protein shows absorption peaks around 280, 320, and 570 nm with extinction coefficients of 18700, 12800, and 5000 M-1 cm-1, respectively. Metal content, EXAFS data and DFT calculations support the presence of a Mo-2S-[2Fe-2S]-2S-Mo cluster never reported before. Analysis of the available genomes from Desulfovibrio species shows that the MorP encoding gene is located downstream of a sensor and a regulator gene. This type of gene arrangement, called two component system, is used by the cell to regulate diverse physiological processes in response to changes in environmental conditions. Increase of both gene expression and protein production was observed when cells were cultured in the presence of 45 μM molybdenum. Involvement of this system in Mo tolerance of sulfate reducing bacteria is proposed.

Building up a nanotube in solution: docking of Janus-Cyclodextrin Rodriguez, Javier; Semino, Rocio; Laria, Daniel Hector Using molecular dynamics experiments, we analyze the association of "Janus" 6-amino-6-deoxy-2O-carboxymethyl-β-cyclodextrins (JCD) in aqueous solutions. In JCD dimers, the free energy associated with the primary-rim-secondary-rim docking shows a stable minimum of ∼-45 kcal mol-1. Trimers in solution are also remarkably stable, exhibiting minimal distortions in their spatial and orientational distributions. The resulting geometrical docking shows the incipient characteristics of flexible nanotubes in solution, with eventual water interchange between the central channel and the bulk at the junctions between monomers. Structural and dynamical properties of the trapped water filling the nanotube are dictated to a large exent by the charge density at the rims.

Detection of excision repaired DNA damage in the comet assay by using Ara-C and hydroxyurea in three different cell types Güerci, Alba Mabel; Liviac, D.; Marcos, R. Because of its characteristics, the comet assay has been used to evaluate the ability of virtually any type of eukaryotic cell to repair different kinds of DNA damage, including double and single strand breaks and base damage. The ability to detect excision repair sites using the alkaline version can be enhanced by the inclusion of repair inhibitors, DNA synthesis inhibitors, or chain terminators. In this sense, we evaluated the ability of hydroxyurea (HU) and cytosine arabinoside (Ara-C), for detecting lesions produced by the alkylating agents ethyl methanesulfonate (EMS) and methyl methanesulfonate (MMS) in three different cell systems. Two hundred cells for experimental point were analyzed in the alkaline version of the comet assay, and the results are evidences of the utility of the assay to detect alkylation of bases in the cells lines MRC-5 and TK-6, as the treatment with HU +Ara-C significantly increases both the basal and induced frequency of DNA damage. The use of whole blood, although it detected the effects of MMS, with and without repair inhibitors, failed to detect the effect of the selected dose of EMS and does not permit detection increases in the background level.

Catalytic disproportionation of N-alkylhydroxylamines bound to pentacyanoferrates Gutiérrez, María M.; Alluisetti, Graciela Beatriz; Olabe Iparraguirre, Jose Antonio; Amorebieta, Valentín Tomás The substituted hydroxylamines, CH3N(H)OH (N-methylhydroxylamine) and (CH3)2NOH (N,N-dimethylhydroxylamine), disproportionate catalytically to the corresponding alkylamines and oxidation products, only in the presence of [Fe(CN)5H2O]3−. Substitution kinetic measurements suggest an initial coordination step to Fe(ii). Two parallel N- and O-coordination modes are considered with the subsequent formation of Fe(iii), free aminyl (RNCH3) and nitroxide (RN(CH3)O) radicals (R = H, CH3). With CH3N(H)OH, bound nitrosomethane, CH3NO, has been characterized by UV-visible and IR spectroscopies. The mechanism is discussed on the basis of common and differential features with respect to the disproportionation of hydroxylamine catalyzed by the same Fe-fragment.