Galectins as immunoregulators during infectious processes: from microbial invasion to the resolution of the disease Rabinovich, Gabriel Adrián; Gruppi, Adriana Recent evidence has implicated galectins, a family of evolutionarily conserved carbohydrate-binding proteins, as regulators of immune cell homeostasis and host-pathogen interactions. Galectins operate at different levels of innate and adaptive immune responses, by modulating cell survival and cell activation or by influencing the Th1/Th2 cytokine balance. Furthermore, galectins may contribute to host-pathogen recognition and may serve as receptors for specific interactions of pathogens with their insect vectors. Here we will explore the influence of galectins in immunological processes relevant to microbial infection and will summarize exciting recent work related to the specific interactions between galectins and their glycoconjugate ligands as critical determinants of pathogen recognition. Understanding the role of galectin-sugar interactions during the course of microbial infections might contribute to defining novel targets for disease prevention and immune intervention.

Compressional and shear wave velocities in uncemented sediment containing gas hydrate Yun, Tae Sup; Francisca, Franco Matias; Santamarina, J. Carlos; Ruppel, Carola The competing hypotheses for gas hydrate formation at the particle scale in sediments describe processes of pore-filling, frame-building, or cementation. New measurements of compressional (VP) and shear wave (VS) velocities in fine-grained sands subjected to low confinement and monitored during formation of tetrahydrofuran hydrate indicate that hydrate nucleates in the pore space (presumably at grain boundaries) and grows with limited impact on the sediment shear stiffness, VP, and VS until crystals begin to interact with the granular skeleton at ∼40% hydrate concentration. VS increases significantly more than VP at higher hydrate concentrations, reflecting larger changes in the specimen's shear stiffness than its bulk stiffness. The results indicate that seismic velocities and/or their ratio (VP/VS) have limited capability for locating hydrate or constraining hydrate concentrations.

Rendimiento de la técnica de enjambrado artificial como alternativa para el control de Loque Americana Albo, Graciela Noemí; Reynaldi, Francisco José; Casanova, Luciana; Dimenna, S. E. La loque americana (LA) una enfermedad causada por la bacteria esporulada Paenibacillus larvae subsp. larvae  que se encuentra ampliamente distribuida tanto a nivel mundial  como en Argentina. Los objetivos del presente trabajo fueron: 1- Evaluar el rendimiento de la técnica de enjambrado artificial en otoño, con y sin el agregado de antibióticos, a través de la medición porcentual de recurrencia de la enfermedad y la muerte de colonias. 2- Determinar el gasto de alimento artificial (energético y proteico) para obtener un  desarrollo satisfactorio del paquete. La técnica de enjambrado artificial sólo resulta exitosa con el uso de antibiítico lueo del paqueteado en colmenas con una infección sobre la cría no mayor a grado 2 y con una población de abejas adultas no inferior a nivel 2. El porcentaje de recurrencia  es del 1%.

Effects of pH and ionic strength on the adsorption of phosphate and arsenate at the goethite-water interface Antelo, Juan; Avena, Marcelo Javier; Fiol, Sarah; López, Rocío; Arce, Florencio The surface properties of a well-crystallized synthetic goethite have been studied by acid-base potentiometric titrations, electrophoresis, and phosphate and arsenate adsorption isotherms at different pH and electrolyte concentrations. The PZC and IEP of the studied goethite were 9.3±0.1 and 9.3±0.2, respectively. Phosphate and arsenate adsorption decrease as the pH increases in either 0.1 or 0.01 M KNO3 solutions. Phosphate adsorption is more sensitive to changes in pH and ionic strength than that of arsenate. The combined effects of pH and ionic strength result in higher phosphate adsorption in acidic media at most ionic strengths, but result in lower phosphate adsorption in basic media and low ionic strengths. The CD-MUSIC model yields rather good fit of the experimental data. For phosphate it was necessary to postulate the presence of three inner-sphere surface complexes (monodentate nonprotonated, bidentate nonprotonated, and bidentate protonated). In contrast, arsenate could be well described by postulating only the presence of the two bidenate species. A small improvement of the arsenate adsorption data could be achieved by assuming the presence of a monodentate protonated species. Model predictions are in agreement with spectroscopic evidence, which suggest, especially for the case of arsenate, that mainly bidentate inner-sphere complexes are formed at the goethite-water interface.

Increased Monooxygenase Activity Associated with Resistance to Permethrin in Pediculus humanus capitis (Anoplura: Pediculidae) from Argentina Gonzalez Audino, Paola Andrea; Barrios, S.; Vassena, Claudia Viviana; Mougabure Cueto, Gastón Adolfo; Zerba, Eduardo Nicolás; Picollo, Maria Ines We studied the profile of permethrin resistance in head lice populations infesting children 6-12 years old in schools and children´s homes in & around Buenos Aires, Argentina. Five permethrin resistant populations with different levels of resistance -Hogar Loyola (HL), Republica de Turquia (RT), Hogar Mitre (HM), Guardia de Honor (GH), Ricardo Guiraldes (RG)- and one susceptible population, Bandera Argentina (BA) were collected. Their level of resistance was evaluated and results showed resistance ratios (RR) of 13 for HL, 16 for RT, 22 for HM, 61 for GH and 69 for RG. In order to elucidate the possible involvement of the cytochrome P450 monooxygenase system in conferring permethrin resistance, ethoxycoumarin-O-deethylase (ECOD) activity was measured in abdomens of individual third instar nymphs and adults using a fluorometric assay.  The ECOD activity was lower in the susceptible BA population (4.7 ng/insect) than in the resistant ones (13.7 ng/insect for RG, 12.3 ng/insect for GH, 8.6 ng/insect for RT, 8.2 ng/insect for HL). ECOD activity was significantly correlated with the level of resistance in the field populations (r= 0.97, p=0.0009) suggesting a role for cytochrome monooxygenase P450 system in permethrin resistance by P. humanus capitis.

Sorghum kernel weight: Growth patterns from different positions within the panicle Gambin, Brenda Laura; Borras, Lucas The influence of genotype and panicle position on sorghum [Sorghum bicolor (L.) Moench] kernel growth is poorly understood. In the present study, sorghum kernel weight (KW) differences during grain filling were analyzed by kernel water relationships previously described in other crops. Eight commercial genotypes differing in KW were used, and KW, water content, kernel volume, kernel moisture content, and kernel density were measured in two positions within the panicle (apical and basal) throughout the grain-filling period. At physiological maturity (PM), KW ranged from 16.5 to 25.1 mg kernel-1, and a significant (p < 0.05) genotype x position interaction was detected. Independently of final KW, apical kernels always exhibited a higher rate (p < 0.001) and a shorter duration of grain filling (p < 0.001) than basal kernels. Maximum water content was related to kernel growth rate but not to final KW. Basal kernels reached maximum kernel volume after attaining maximum water content, with dry matter accumulation affecting kernel volume determination. Kernel density increased with a similar pattern regardless of genotype or panicle position when related to the kernel moisture decline, but at PM, basal kernels were always more dense than apical ones. Differences in the kernel desiccation pattern and in the critical moisture content for biomass accumulation helped explain differences in the grain-filling duration between positions. A general kernel growth curve based on kernel moisture content was impossible to obtain because of the differences in kernel growth patterns within the panicle.

Acerca de la inevitabilidad de la interpretación jurídica Navarro, Pablo Eugenio El objetivo principal de este trabajo es clarificar y refutar la tesis de la indeterminacion interpetativa (TI). Sin embargo, este trabajo no pretende ofrecer un argumento definitivo contra ninguna escuela o doctrina particular, sino que trata de iluminar rasgos del derecho que han sido indebidamente pasados por alto o que han sido descuidados en el debate contemporáneo. En gran medida, TI parece plausible por la ambigüedad sistemática en que son utilizadas algunas de las principales expresiones en cuestión, i.e., ?caso?, ?norma general?, norma ?individual?, etc. Una vez que se despejan las confusiones que subyacen a TI también es posible advertir por qué razón es frecuente considerar imprescindible a la interpretación de las normas jurídicas, y en qué sentido TI es una exageración de otras ideas valiosas para el análisis de la identificación y aplicación del derecho

New Steiglitz-Mcbride adaptive lattice notch filters Cousseau, Juan Edmundo; Scoppa, Juan P.; Doñate, Pedro Darío Two novel adaptive notch filters are presented. The updating algorithms are based on the Steiglitz-McBride error criterion minimization and the basic realizations of the notch filters are all-pass based lattice filters. The proposed realizations represent an extension of a previous ad-hoc scheme for adaptive notch filtering and avoid finding the roots of a high order polynomial to obtain the unknown frequencies of interest. Since the structure is based on the lattice realization, suitable properties with finite length precision realizations can be expected. Computer simulations are included to verify the adaptive filter performance when compared with alternative realizations.

A mathematical model for zoning of protected natural areas Verdiell, Adriana Beatriz; Sabatini, M.; Maciel, Maria Cristina; Rodríguez Iglesias, Ricardo Manuel When formulated in mathematical terms, the problem of zoning a protected natural area subject to both box and spatial constraints results in a combinatorial optimization problem belonging to the NP-hard class. This fact and the usual dimension of the problem (regularly in the tens of thousands order) suggest the need to apply a heuristic approach. In this contribution we describe a quantitative method for zoning protected natural areas based on a simulated annealing algorithm. Building upon previous work by Bos (1993), we introduce three main innovations (a quadratic function of distance between land units, a non-symmetric matrix of compatibilities among uses, and a spatial connection constraint) that make the approach applicable for ecological purposes. When applied to solving small-size simulated problems, the results were indistinguishable from those obtained via an exact, enumerative method. A coarse-scale zoning of Talampaya National Park (Argentina) rendered maps remarkably similar to those produced by subject area experts using a non-quantitative consensus-seeking approach. Results are encouraging and show particular potential for the periodical update of zoning of protected natural areas. Such a capability is crucial for application in developing countries where both human and financial resources are usually scarce but still critical for updating zoning and management plans.

Interaction of catechol and gallic acid with titanium dioxide in aqueous suspensions. 1. Equilibrium studies Araujo, Paula Zulema; Morando, Pedro Juan; Blesa, Miguel Angel The adsorption isotherms of catechol (1,2-dihydroxybenzene) and gallic acid (3,4,5-trihydroxybenzoic acid) onto titanium dioxide (Degussa P-25) were measured at various pH values and room temperature using attenuated total reflection Fourier transform infrared (FTIR-ATR) data, processed by singular value decomposition. The affinity is largely pH independent, although the deprotonatation of the carboxylic group in gallic acid might produce a slight increase in the affinity. Catechol was shown to form two complexes, with Langmuir stability constants log K of 4.66 (strong mode) and 3.65 (weak mode). Both complexes have the same spectral signature, and mononuclear and binuclear chelate structures are proposed for them. Gallic acid chemisorbs by complexation through two -OH groups and forms one complex only, log K= 4.70. The third -OH and the pendant carboxylate do not influence much the stability of the surface complex. Comparison with literature data demonstrates that the affinity of 4-chlorocatechol is also similar, whereas 2,3-dihidroxynaphthalene and 4-nitrocatechol form more stable complexes, probably because of the solvation contribution to the overall Gibbs adsorption energy. All quoted constants refer to the surface complexation equilibria written as follows: (≡Ti-OH) 2 + H2L = (≡Ti)2-L + 2H2O, i.e., as electroneutral processes. The FTIR-ATR spectra of the surface complexes are also discussed. © 2005 American Chemical Society.

A constitutive equation and generalized Gassmann modulus for multimineral porous media Carcione, Jose M.; Helle, Hans B.; Santos, Juan Enrique; Ravazzoli, Claudia Leonor We derive the time-domain stress-strain relation for a porous medium composed of n - 1 solid frames and a saturating fluid. The relation holds for nonuniform porosity and can be used for numerical simulation of wave propagation. The strain-energy density can be expressed in such a way that the two phases (solid and fluid) can be mathematically equivalent. From this simplified expression of strain energy, we analogize two-, three-, and n-phase porous media and obtain the corresponding coefficients (stiffnesses). Moreover, we obtain an approx imation for the generalized Gassmann modulus. The Gassmann modulus is the bulk modulus of a saturated porous medium whose matrix (frame) is homogeneous. That is, the medium consists of two homogeneous constituents: a mineral composing the frame and a fluid. Gassmann's modulus is obtained at the low-frequency limit of Biot's theory of poroelasticity. Here, we assume that all constituents move in phase, a condition similar to the dynamic compatibility condition used by Biot, by which the P-wave velocity is equal to Gassmann's velocity at all frequencies. Our results are compared with those of the Berryman-Milton (BM) model, which provides an exact generalization of Gassmann's modulus to the three-phase case. The model is then compared to the wet-rock moduli obtained by static finite-element simulations on digitized images of microstructure and is used to fit experimental data for shaly sandstones. Finally, an example of a multimineral rock (n > 3) saturated with different fluids is given.

Sensitized photooxidation of thyroidal hormones. Evidence for heavy atom effect on singlet molecular oxygen [O2(1Δ g)]-mediated photoreactions Miskoski, Sandra; Soltermann, Arnaldo Teseo; Molina, Patricia Gabriela; Günther, Mauricio German; Zanocco, Antonio L.; Garcia, Norman Andino Thyronine derivatives are essential indicators of thyroid gland diseases in clinical diagnosis and are currently used as standards for developing ordinary biochemical assays. Photo-oxidation of gland hormones of the thyronine (TN) family and structurally related compounds (TN, 3,5-dliodothyronine,3,3′,5- triiodothyronine and 3,3′,5,5′-tetraiodothyronine or thyroxine) was studied using rose bengal, eosin and perinaphthenone (PN) as dye sensitizers. Tyrosine (Tyr) and two iodinated derivatives (3-iodotyrosine and 3,5-diiodotyrosine) were also included in the study for comparative purposes. Irradiation of aqueous solutions of substrates containing xanthene dyes with visible light triggers a complex series of competitive interactions, which include the triplet excited state of the dye (3Xdye*) and singlet molecular oxygen [O2(1Δg,)]- mediated and superoxide ion-mediated reactions. Rate constants for interaction with the 3Xdye*, attributed to an electron transfer process, are in the order of 108-109 M-1 s-1 depending on the dye and the particular substrate. The photosensitization using PN follows a pure Type-II (O2(1Δg) mediated) mechanism. The presence of the phenolic group in Tyr, TN and iodinated derivatives dominates the kinetics of photooxidation of these compounds. The reactive rate constants, kγ, and the quotient between reactive and overall rate constants (kγ/kt, values, in the range of 0.7-0.06) behave in an opposite fashion compared with the overall rate constants and oxidation potentials. This apparent inconsistency was interpreted on the basis of an internal heavy atom effect, favoring the intersystem-crossrag deactivation route within the encounter complex with the concomitant reduction of effective photooxidation.

Cambios del fósforo en suelos bajo diferentes rotaciones de cultivos Suñer, Liliana; Galantini, Juan Alberto; Rosell, Ramon Antonio Los contenidos de fósforo (P) total del suelo pueden ser relativamente altos, desde 200 a 5000 µg g-1 (Kuo, 1996), pero la capacidad del suelo de proveer P es muy variable. En la región pampeana, sólo una pequeña fracción que varía de 5 a 20 µg P g-1 está disponible para los cultivos (García, 2001). De esta manera, aún cuando la reserva de P total en el suelo exceda ampliamente los requerimientos del cultivo, éste podría sufrir deficiencias.

Análisis Textural de Cuarzo Hidrotermal del Depósito El Pantanito, provincia de Mendoza: nuevos aportes sobre su génesis; Hydrothermal quartz textural analysis from El Pantanito epithermal ore deposit, province of Mendoza: New contributions on its genesis. Rubinstein, Nora Alicia; Gargiulo, Maria Florencia El análisis textural del cuarzo hidrotermal del depósito El Pantanito, permitió realizar nuevos aportes sobre la génesis de esta mineralización epitermal de Au de baja sulfuración. Este depósito se localiza en el Bloque de San Rafael, provincia de Mendoza y está alojado en una secuencia volcánica permo-triásica, con características geoquímicas transicionales entre un régimen de subducción y uno de intraplaca continental. La ocurrencia conjunta de pseudomorfos de cuarzo según calcita, sílice coloforme - crustiforme y adularia, permite establecer que el nivel de erosión se encuentra dentro de la paleozona de ebullición ascendente. La superposición de texturas típicas de diferentes profundidades de formación, sugiere un proceso de tipo telescópico producido por la propagación, en profundidad, del frente de ebullición y por lo tanto de la zona de depositación de metales preciosos.; Hydrothermal quartz textural analysis from El Pantanito epithermal ore deposit, province of Mendoza: New contributions on its genesis. Hydrothermal quartz textural analysis from El Pantanito ore deposit, provide new information about the genesis of this low sulphidation Au epithermal mineralization. It is located in the San Rafael Massif, province of Mendoza, Argentina, and is hosted by a permo-triassic volcanic sequence with geochemical characteristics transitional between subduction and continental intraplate settings. The combined occurrence of calcite pseudomorphically replaced by quartz, crustiform-colloform silica and adularia, reflect that the erosion level is within the paleozone of boiling upflow. Overprinting of textures generated at different depths within the deposit, suggests telescoping produced by downward propagation of the boiling front and therefore the domain of precious metal deposition.

Mass transfer studies at rotating cylinder electrodes of expanded metal Grau, Javier Mario; Bisang, Jose Maria Mass transfer has been studied at rotating cylinder electrodes of expanded metal using the reduction of ferricyanide as test reaction. The experimental data are well correlated by an empirical expression between the Sherwood number and the Reynolds number both in terms of the hydraulic diameter as characteristic length and including two additional dimensionless parameters in order to characterize the geometry of the expanded metal. Comparisons of the mass-transfer performance of the expanded metal electrodes with other three-dimensional structures are made.

Neuronal and astroglial alterations in the hippocampus of a mouse model for type 1 diabetes Revsin, Yanina; Saravia, Flavia Eugenia; Roig, Paulina; Lima, Analia Ethel; de Kloet, E. Ronald; Homo Delarche, Francoise; de Nicola, Alejandro Federico The influence of diabetes mellitus on brain pathology is increasingly recognized. Previous contributions of our laboratory demonstrated in models of type 1 diabetes (nonobese diabetic and streptozotocin (STZ)-treated mice), a marked astrogliosis and neurogenesis deficit in hippocampus and increased expression of hypothalamic neuropeptides. In the present investigation, we further analyzed alterations of astroglia and neurons in the hippocampus of mice 1 month after STZ-induced diabetes. Results showed that these STZ-diabetic mice presented: (a) increased number of astrocytes positive for apolipoprotein-E (Apo-E), a marker of ongoing neuronal dysfunction; (b) abnormal expression of early gene products associated with neuronal activation, including a high number of Jun + neurons in CA1 and CA3 layers and dentate gyrus, and of Fos-expressing neurons in CA3 layer; (c) augmented activity of NADPH-diaphorase, linked to oxidative stress, in CA3 region. These data support the concept that uncontrolled diabetes leads to hippocampal pathology, which adjoin to changes in other brain structures such as hypothalamus and cerebral cortex.

Vibrational spectra of Hg3TeO6 and Hg2TeO5 Baran, Enrique José; Weil, Matthias The infrared and Raman spectra of the crystalline hexaoxotellurates Hg3TeO6 and Hg2TeO5 were recorded and discussed on the basis of a site symmetry analysis derived from known structural data. Approximate values for the Tesingle bondO bond force constants are reported and some comparisons with related species are made.

Arsenic concentration in water and bovine milk in Cordoba, Argentina. Preliminary results Pérez Carrera, Alejo Leopoldo; Fernandez Cirelli, Alicia The Chaco Pampean Plain of central Argentina constitutes one of the largest regions of high arsenic (As) groundwaters known, covering around 1r106 km2 (Smedley & Kinniburg, 2002; Farı´as et al. 2004). The high-As groundwaters are from Quaternary deposits of loess (mainly silt) with intermixed rhyolitic or dacitic volcanic ash (Nicolli et al. 1989, Smedley et al. 1998, 2002). Early in the last century an endemic disease due to contamination of drinking water with arsenic was recognised. This disease is called HACRE (Hidroarsenicismo Crónico Regional Endémico, Chronic Endemic Regional Hydroarsenism) and is connected with a particular type of skin cancer (Astolfi et al. 1981)

Pharmacokinetics and synovial fluid concentrations of flurbiprofen enantiomers in horses: chiral inversion Soraci, Alejandro Luis; Tapia, Maria Ofelia; Garcia, Jorge Flurbirpofen (FBP), a member of the 2-aryl propionate nonsteroidal anti-inflammatory drug class, has potent anti-inflammatory and analgesic properties. The commercial preparation is a racemic mixture of the R(−) and S(+) enantiomers of FBP. In this study, R(−) and S(+) FBP were used to investigate the metabolic chiral inversion. Each enantiomer was administered separately (0.25 mg/kg) and in a racemic mixture (0.5 mg/kg) intravenously to horses. Plasma and synovial concentration of each enantiomer was determined and the disposition of each was analyzed. After intravenous administration of R(−) FBP and S(+) FBP to horses no chiral inversion was detected. After the administration of the FBP racemate and individual enantiomers no differences were observed between pharmacokinetic parameters [t1/2â (h), Cl (L/h·kg), AUC (ìg·h/mL), Vss (L/kg) and MRT (h)] for R(−) and S(+) FBF. Synovial fluid concentrations of both FBP enantiomers were lower than plasma concentrations and no stereoselective differences were detected. These data indicate that the disposition of FBF in horses is not enantioselective and demonstrate a difference in the pharmacokinetic behavior of the enantiomers as compared with other 2-aryl-propionic acids, such as carprofen, ketoprofen and vedaprofen in the horse.

Primates fósiles en la Patagonia : elementos para una filogenia de los Platirrinos Tejedor, Marcelo Fabian Los primates fósiles de la Patagonia tienen enorme relevancia para comprender la sistemática y filogenia de los platirrinos neotropicales. En las provincias argentinas de Neuquén, Chubut y Santa Cruz, se han descubierto al menos 8 especies incluidas en 6 géneros de platirrinos fósiles del Mioceno inferior a medio. Estos son representantes de las subfmilias Cebinae, Pitheciinae y posiblemente Atelinae, y fueron datados entre 20 y 15.8 millones de años.