Biological effects of brachytherapy using a 32P-patch on the skin of Sencar mice Salgueiro, María Jimena; Collia, Nicolas; Duran, Hebe Alicia; Palmieri, Mónica Alejandra; Medina, Vanina Araceli; Ughetti, Ricardo; Nicolini, Jorge Osvaldo; Zubillaga, Marcela Beatriz In recent years, specially designed patches containing beta emitters have been developed for contact brachytherapy of skin lesions. The aim of the present work was to evaluate the biological effects of the 32P-patch on the skin of Sencar mice as a result of a brachytherapy treatment. For this purpose, a 32Ppatch was prepared with Chromic 32P-phosphate and silicone and the classical model of two-stage skin carcinogenesis was reproduced in Sencar mice. Animals were divided in six groups. Four groups received the contact brachytherapy treatments using a scheme of a single session of 40 and 60 Gy (SD40 and SD60) and a scheme of two sessions of 40 and 60 Gy each (FD40 and FD60). The other two groups were used as controls of the single (CSD) and the fractionated (CFD) treatments. Radiation doses were estimated with equations derived from the MIRD DOSE scheme, and biologically effective doses (BED) were calculated according to equations derived from the linear-quadratic model. The endpoint to evaluate the treatments effects was tumor size after a follow-up period of 44 days. Finally, animals were sacrificed in order to get samples of all tumors for histological analysis and PCNA staining. Erythema, dermatitis and skin ulceration developed in almost all treated animals, but they gradually healed with regeneration of tissue during the follow-up period. Radiation effects on the skin of SD40, SD60, FD40 and FD60 showed a significant reduction of the tumor size with regard to controls, independently of the scheme and the radiation dose considered. PCNA staining scores of control groups were higher than for treated groups, independently of the scheme and the radiation dose considered. This radioactive 32Psilicone-patch which is easy to prepare and use in the treatment of skin diseases, seems promising as a radioactive device for clinical use.

Fiebre de archivo Gerbaudo, Analía Isabel En el II Workshop Internacional de Investigadores Jóvenes ‘La gravitación de la memoria: testimonios literarios, sociales e institucionales de las dictaduras en el Cono Sur’ recientemente realizado en Tucumán con el auspicio de la Universidad Nacional de Tucumán y The Swedish Foundation for International Cooperation in Research and Higher Education, Rossana Nofal plantea en el panel de cierre una pregunta que interroga los rumbos de la investigación en el campo literario en Argentina: ¨¿cómo salir del canon-Sarlo?¨. Este trabajo inscribe una posible respuesta exhumando viejos textos y revisando el modo en que se han armado las tradiciones literarias.

Transient transformation of sunflower leaf discs via an Agrobacterium-mediated method: applications for gene expression and silencing studies Manavella, Pablo Andrés; Chan, Raquel Lia The sunflower belongs to the Compositae family and is an economically important crop because of the quality of its oil. Unfortunately, molecular analyses are limited due to the lack of genomic information, mutant libraries and efficient and rapid transformation protocols. In a wide variety of species, Agrobacterium-mediated transient transformation is a useful tool that can provide valuable insight into many biological processes. However, this technology has not been routinely applied to the sunflower because of difficulties with infiltration. Here, we present an optimized protocol for Agrobacterium-mediated transient transformation of leaf discs. Using this procedure, we were able to quickly overexpress or silence a given gene, enabling us to study several biochemical processes and characterize sunflower regulatory sequences. One of the major advantages of this approach is that in only 1 work-week it is possible to acquire considerable molecular information while avoiding the use of controversial heterologous systems. Transforming heterologous species is frequently unacceptable, as the conservation of molecular events in many cases is not well documented.

Theoretical explanation of the regioselectivity of polar cycloaddition reactions between furan derivatives and Danishefsky’s diene Brasca, Romina; Kneeteman, Maria Nelida; Mancini, Pedro Maximo Emilio; Fabian, Walter M.F. The regioselectivity for a series of experimentally studied Diels–Alder reactions between furan derivatives and Danishefsky’s diene has been rationalized within the framework of local DFT-based descriptors (i.e. electrophilicity and nucleophilicity indexes). The importance of the solvent in the calculations has been studied. It has been shown that the relative trend of an atomic center to behave as an electrophile is affected by the medium (gas phase or benzene solution) and the basis set used in the calculation of the reactivity descriptors. The local electrophilicity (xk) and nucleophilicity (Nk) indexes properly account for the observed regioselectivity only when B3LYP/LANL2DZ and HF/LANL2DZ levels of theory have been used.

Assessing Interannual Water Balance of La Plata River Basin Krepper, Carlos Maria; Venturini, Virginia The Paraná River is the most important component of the La Plata River, sustaining regional economies in four Countries. In the last decades, significant regional changes such as deforestation and crop substitution have been taken place in the Paraná basin. Thus, the basin response in terms of the Paraná streamflow could have been modified.  The main objective of this paper is to analyse the structure of the evapotranspiration (ET(t)) time series of the upper Paraná basin.  We analyzed the relationship between the variables in the water balance equation then, we applied a SSA analysis to learn more about the temporal structure of the ET(t) time series. The correlation study shows that ET(t) is correlated with precipitations in the northern sub-basins but it is not correlated at all in the Southern basin. The time structure of ET(t)1, ET(t)3 and ET(t)4 exhibit low-frequency signals while the ENSO-range signals are statistically significant in ET(t)1 and ET(t)4 although it also appears in ET(t)2 and ET(t)3 as a weak signals. Looking at the whole basin, ET(t) would be affected either by changes in the basin physical properties or by the ENSO-range signals present in the precipitation.

Suspension-Vero cell cultures as a platform for viral vaccine production Paillet, Cristian; Forno, Angela Guillermina; Kratje, Ricardo Bertoldo; Etcheverrigaray, Marina Since Vero cells are currently considered as an acceptable cell substrate to produce a wide range of viruses, we developed a virus production platform using Vero cells adapted to grow in suspension in serum-free media. After adapting anchorage-dependent Vero cells to grow as a free-cell suspension, vesicular stomatitis virus, herpes simplex virus 1 and polio virus 1 production rates were evaluated in batch cultures using spinner flasks and perfused cultures in a bioreactor. The achieved results constitute valuable information for the development of a low-cost high-productivity process using a suspension culture of Vero cells to produce viral vaccines.

Sperm morphology of two marine neogastropods from the southwestern Atlantic Ocean (Caenogastropoda: Volutidae and Olividae) Giménez, Juliana; Arrighetti, Florencia; Teso, Silvia Valeria; Hermida, Gladys Noemí; Zabala, Maria Soledad; Penchaszadeh, Pablo Enrique The testes of Caenogastropoda typically produce two types of spermatozoa, euspermatozoa and paraspermatozoa. The structures of both morphological forms of sperm contribute to our understanding of reproductive biology, and also have been useful to elucidate taxonomic and phylogenetic relationships among gastropods. The following account describes the ultrastructure and the possible systematic importance of euspermatozoa in two species, Adelomelon beckii from the family Volutidae and Olivancillaria deshayesiana from the family Olividae. The euspermatozoa of these species are characterized by: the presence of an acrosomal vesicle with an apical bleb and accessory membrane; a nucleus that is long and tubular with the axoneme penetrating the nucleus; a midpiece with mitochondrial elements coiled helically around the axoneme; a glycogen piece; and a short end piece.  A constriction in the acrosomal vesicle and mitochondrial elements that appear U-shaped and electron dense in cross section are features that are present in the studied taxa, but have not been reported outside of the Neogastropoda.

The hydrogen effect in the electronic structure and bonding of the B2 FeAl alloy with a Fe vacancy Jasen, Paula Verónica; Gonzalez, Estela Andrea; Luna, Carla Romina; Brizuela, Graciela Petra; Juan, Alfredo A study of H absorption near a Fe vacancy in a B2 FeAl alloy is performed using density functional calculations. The H locates in an octahedral site (Al capped) where one of the Fe atoms in its base is replaced by a vacancy. The computed Fe-H equilibrium distance is 2.065 Å and the H becomes negatively charged. The overlap population analysis reveals metal-metal bond breaking being the intermetallic bond the more affected.

New ferromagnetic La3Co2TaO9 double perovskite: Structural and magnetic properties Fuertes, Valeria Cintia; Blanco, Marìa Cecilia; Franco, Diego Gaspar; de Paoli, Juan Martin; Pannunzio Miner, Elisa Victoria; Sanchez, Rodolfo Daniel; Fernández Díaz, M. T.; Carbonio, Raul Ernesto The new double perovskite La3Co2TaO9 has been prepared by a solid-state procedure. The crystal and magnetic structures have been studied from X-ray powder diffraction (XRPD) and neutron powder diffraction (NPD) data. Rietveld refinements were performed in the monoclinic space group P21/n. The structure consists of an ordered array of alternating B′O6 and B″O6 octahedra sharing corners, tilted along the three pseudocubic axes according to the Glazer notation a-b-c+. Rietveld refinements show that at RT the cell parameters are a=5.6005(7) Å, b=5.6931(7) Å, c=7.9429(9) Å and β=89.9539(7)°, and the refined crystallographic formula of this "double perovskite" can be written as La2(Co)2d(Co1/3Ta2/3)2cO6. Magnetization measurements and low-temperature NPD data show that the perovskite is a ferromagnet with TC=72 K. At high T it follows the Curie-Weiss law with an effective magnetic moment of 3.82μB per Co ion which is very close to spin only Co2+ (HS).

Antifungal activity of selected indigenous Pseudomonas and Bacillus from the soybean rhizosphere León, Mariana; Yaryura, Pablo Marcelo; Montecchia, Marcela Susana; Hernandez, Alejandra Ines; Correa, Olga Susana; Pucheu, Norma Lucrecia; Kerber, Norma Lucia; Garcia, Augusto Fernando The purpose of this study was to isolate and select indigenous soil Pseudomonas and Bacillus bacteria capable of developing multiple mechanisms of action related to the biocontrol of phytopathogenic fungi affecting soybean crops. The screening procedure consisted of antagonism tests against a panel of phytopathogenic fungi, taxonomic identification, detection by PCR of several genes related to antifungal activity, in vitro detection of the antifungal products, and root colonization assays. Two isolates, identified and designated as Pseudomonas fluorescens BNM296 and Bacillus amyloliquefaciens BNM340, were selected for further studies. These isolates protected plants against the damping-off caused by Pythium ultimum and were able to increase the seedling emergence rate after inoculation of soybean seeds with each bacterium. Also, the shoot nitrogen content was higher in plants when seeds were inoculated with BNM296. The polyphasic approach of this work allowed us to select two indigenous bacterial strains that promoted the early development of soybean plants.

Resonancias mediáticas de transformaciones urbanas en Posadas, Misiones Maidana, Elena Silvia; Millán, María del Rosario En este artículo reseñamos brevemente los procesos de urbanización de la ciudad de Posadas, Misiones, Argentina y caracterizamos sintéticamente la dinámica socio espacial que presenta actualmente. En este marco, describimos el tratamiento mediático que reciben ciertas obras públicas de intervención sobre el espacio costero, en contraste con el otorgado a la situación generada por políticas de vivienda que tienden a la formación de periferia periurbana y a la relocalización compulsiva de pobres urbanos. Asimismo, se exponen los resultados de varios encuentros realizados con vecinos en los que, a partir de la lectura de la Carta Orgánica Municipal, se discutió y debatió acerca de la situación de la ciudad y, específicamente, sobre espacio público y participación ciudadana; In this article we briefly reviewed the processes of urbanization of the city of Posadas, Misiones, Argentina, and synthetically characterize the social and spatial dynamic the city exhibits at this moment. We describe the media’s treatment of certain projects and public policies being implemented on the riparian side of the city, and contrast it with the treatment of the situation generated by housing policies that tend to develop a new urban periphery and the compulsive relocation of urban poor. We also reproduce the results of meetings held with neighbors in which, on the basis of Municipal Ordinances, the city’s actual situation and, specifically, its public space and citizen participation were discussed and debated

Obra del tiempo Sanchez Negrette, Angela La reseña del libro Obra del tiempo. Introduccón a la reoria y la Práctica de la Gestión Integral del Patrimonio Urbano Arquitectónico  del Dr Roberto Fernández (2007) importa en la medida que el tema de la Gestión especificamente para la proteccion del Patrimonio Arquitectónico y Urbano es un desafío ante el crecimiento de las ciudades en un mercado inmobiliario cada vez más especulativo. En el caso de América Latina la gestión implica poseer una serie de herramientas en particular debido a la presión inmobiliaria justamente de un mercado aun más especulativo y con gobiernos locales que poco o nada pueden imponer políticas de defensa del patrimonio construido. Por ello se considera de sumo interés el analizar e informar el contenido del libro que resume la larga experiencia de estudios realizados por el Dr Roberto Fernández, tanto en Argentina como en América Latina

Catalytic Combustion of Diesel Soot: Experimental Design for Laboratory Testing Peralta, María Ariela; Gross, Martin Sebastian; Sanchez, Barbara Sabrina; Querini, Carlos Alberto In order to abate diesel soot particles many catalysts have been studied at several industrial and academic laboratories. However, the comparison of kinetic data obtained with such catalysts is not straightforward, due to the different experimental conditions used in the activity measurement carried out by each research group. Temperature-programmed analysis is the most common technique used to determine catalytic activity for soot oxidation. For a given catalyst, the temperature-programmed oxidation profile depends on variables such as heating rate, oxygen partial pressure, gas flow rate, catalyst:soot weight ratio, type of contact between the catalyst and the soot, and existence of energy and/or mass transfer limitations during the analysis. This work presents a systematic study of the influence of all these testing variables on the TPO profile, and the optimum testing conditions to obtain good reproducibility during the kinetic study. Both experimental and computer simulation results are included to assist researchers in the comparison of results obtained under different experimental conditions.

AFLP characterization in pathogenic and coprophilous fungi Cinto, Isabel Esther; Gottlieb, Alexandra Marina; Gally, Marcela Edith; Ranalli, Maria Esther; Ramos, Araceli Marcela The objective of this study was to ascertain the usefulness of the AFLP technique in assessing genetic diversity among 47 strains belonging to three Ascomycota genera and as a tool for solving taxonomic problems in related morphological species. Four MseI +1 primers were assayed in combination with two EcoRI +2 and four EcoRI +3 primers. In the present study both +2 and +3 EcoRI primers were informative, but EcoRI +2 produced profiles with high complexity. The addition of the extra selective nucleotide reduced the complexity of the banding patterns generating easily readable patterns to evaluate genetic diversity within and among species. Of the three ascomycetous genera assessed in this study, Colletotrichum (Glomerellaceae) presented the highest proportion of polymorphic AFLP loci, followed in order by Iodophanus (Pezizaceae) and Saccobolus (Ascobolaceae).

Taxonomic and nomenclatural aspects of Hypoxylon taxa from southern South America proposed by Spegazzini Hladki, Adriana Ines; Romero, Andrea Irene The holotypes and isotypes of 20 Hypoxylon taxa described by Spegazzini have been examined and their taxonomic positions and nomenclatural problems are discussed. Two new combinations, Annulohypoxylon apiahynum comb. nov. and A. subeffusum comb. nov., are proposed. H. goliath is considered a synonym of Rosellinia bunodes. H. albostigmatosum and H. guarapiense are synonyms of H. anthochroum, H. anthracoderma of H. monticulosum, H. mbaiense of H. notatum, H. paulistanum of H. diatrypeoides, H. plumbeum and H. rubiginosum var. microcarpum of H. perforatum. H. porteri and H. intermedium belong in Biscogniauxia capnodes, H. puiggarii in Annulophypoxylon subeffusum, H. subvinosum. in H. lenormandii, H. turbinatum var. guaraniticum in Phylacia turbinata and H. valsarioides in Creosphaeria sassafras. H. leptascum is transferred to A. leptascum, H. circostomum to Nemania circostoma and H. latissimum to N. latissima. The holotype of H. albostigmatosum has been recovered, thus the lectotypification by Shear no longer is needed. H. subnigricans and H. umbilicatum are confirmed as good taxa. H. anthochroum and H. lenormandii are reported as first records from Argentina (Tucumán).

Gene flow between cultivated sunflower and Helianthus petiolaris (Asteraceae) Gutierrez, Agustina; Carrera, Alicia Delia; Basualdo, Jessica; Rodríguez, R.; Cantamutto, Miguel Ángel; Poverene, María Mónica Helianthus petiolaris (Asteraceae) native to North America has naturalized in Argentina. The extensive overlapping with sunflower crop regions, the coincidence of life cycles and the common pollinators facilitate interspecific crosses with sun- flower, H. annuus var. macrocarpus. To estimate the occurrence of crop-to-wild and wild-to-crop gene flow, off-type plants in progenies of pure stands of both species flowering in coincidence and the presence of crop alleles in H. petiolaris populations were investigated in 26 wild populations and nine crop fields. Morphological traits and RAPD markers were used to attempt hybrid characterization. Off-type individuals were found in frequencies of 0.5 and 0.3% among crop progenies and wild populations, respectively. Off-type plants showed intermediate values for metric morphological traits and low fertility traits. Some off-type plants proved to carry crop alleles based on molecular analysis. The average frequency of cultivar-marker introgression across the wild populations was very low (0.02). Although observed hybridization rates seem to be low, the extension of crop-wild overlapping in Argentina make hybrid formation a noticeable process. Therefore, the new sunflower varieties and eventually GM varieties would transfer their traits through pollen flow and they would persist in H. petiolaris populations.

Global environmental effects versus galaxy interactions Perez, Maria Josefa; Tissera, Patricia Beatriz; Padilla, Nelson David; Alonso Giraldes, Maria Sol; Garcia Lambas, Diego Rodolfo We explore properties of close galaxy pairs and merging systems selected from the Sloan Digital Sky Survey Data Release 4 in different environments with the aim to assess the relative importance of the role of interactions over global environmental processes. For this purpose, we perform a comparative study of galaxies with and without close companions as a function of local density and host halo mass, carefully removing sources of possible biases. We find that at low- and high-local-density environments, colours and concentration indices of close galaxy pairs are very similar to those of isolated galaxies. At intermediate densities, we detect significant differences, indicating that close pairs could have experienced a more rapid transition on to the red sequence than isolated galaxies. The presence of a correlation between concentration index and colours indicates that the physical mechanism responsible for the colour transformation also operates in the transformation of the luminous matter distribution. At fixed local densities, we find a dependence of the red galaxy fraction on dark matter halo mass for galaxies with or without a close companion. This suggests the action of host halo mass related effects. Regardless of dark matter halo mass, we show that the percentage of red galaxies in close pairs and in the control sample are comparable at low- and high-local-density environments. However, at intermediate local densities, the gap in the red fraction between close pairs and the control galaxies increases from ∼10 per cent in low-mass haloes up to ∼50 per cent in the most massive ones. Interestingly, we also detect that 50 per cent of merging systems populate the intermediate local environments, with a large fraction of them being extremely red and bulge dominated. Our findings suggest that in intermediate-density environments galaxies are efficiently pre-processed by close encounters and mergers before entering higher local density regions.

Chemical composition of four essential oils from Eupatorium spp. Biological activities toward Tribolium castaneum (Coleoptera: Tenebrionidae) Lancelle, Hugo Guillermo Ramon; Giordano, Oscar Santiago; Sosa, Marta Edit; Tonn, Carlos Eugenio Toxic and repellent properties of whole essential oils from four Eupatorium (Asteraceae) species (E. buniifolium Hook. et Arn, E. inulaefolium Kunth, E. arnottii Baker, and E. viscidum Hook. & Arn) were investigated in different concentrations toward Tribolium castaneum Herbst adults. The essential oils were isolated by hydrodistillation techniques from the aerial parts. The analysis was performed by GC-FID and GC-MS methods. Contact toxicity assays showed that all the evaluated essential oils were toxic. Furthermore, in all the cases mortality was dose dependent. The main repellency was observed for the essential oil recovered from E. buniifolium.

IRI 2001/90 TEC predictions over a low latitude station Scida, Luis Alberto; Ezquer, Rodolfo Gerardo; Cabrera, Miguel Angel; Mosert, Marta Estela Total electron content (TEC) over Tucumán (26.9°S, 294.6°W) measured with Faraday technique during the high solar activity year 1982, is used to check IRI 2001 TEC predictions at the southern crest of the equatorial anomaly region. Comparisons with IRI 90 are also made. The results show that in general IRI overestimates TEC values around the daily minimum and underestimates it the remaining hours. Better predictions are obtained using ground ionosonde measurements as input coefficients in the IRI model. The results suggest that for hours of maximum TEC values the electron density profile is broader than that assumed by the model. The main reason for the disagreement would be the IRI shape of the electron density profile. In a previous work using TEC measurements over Tucumán, obtained from GPS satellite signals during the high solar activity year 1999, a better agreement between IRI predictions and measurements has been observed. That better agreement was produced by the fact that 1999 GPS TEC measurements are 50% lower than those obtained by Faraday rotation technique during 1982. An equator ward movement of the southern peak of the EA plus the minor ionization level in 1999 could produce this reduction in TEC values. Moreover, it can be seen that in most of cases IRI TEC values around daily minimum show an hour displacement with respect to the experimental data.

A parametric representation of totally mixed Nash equilibria Jeronimo, Gabriela Tali; Perrucci, Daniel Roberto; Sabia, Juan Vicente Rafael We present an algorithm to compute a parametric description of the totally mixed Nash equilibria of a generic game in normal form with a fixed structure. Using this representation, we also show an algorithm to compute polynomial inequality conditions under which a game has the maximum possible number of this kind of equilibria. Then, we present symbolic procedures to describe the set of isolated totally mixed Nash equilibria of an arbitrary game and to compute, under certain general assumptions, the exact number of these equilibria. The complexity of all these algorithms is polynomial in the number of players, the number of each player´s strategies and the generic number of totally mixed Nash equilibria of a game with the considered structure.