Increased AT 1 receptor expression and mRNA in kidney glomeruli of AT 2 receptor gene-disrupted mice Saavedra, Juan M.; Häuser, Walter; Ciuffo, Gladys Maria; Egidy, Giorgia; Hoe, Kwang Lae; Jöhren, Olaf; Sembonmatsu, Takaaki; Inagami, Tadashi; Armando, Inés The proposed feedback between angiotensin II AT2 and AT1 receptors prompted us to study AT1 receptor expression in kidneys of male AT2 receptor-gene disrupted mice (agtr2 −/y). In wild-type (agtr2 +/y) mice, AT1 receptor binding and mRNA is abundant in glomeruli, and AT1 receptor binding is also high in the inner stripe of the outer medulla. AT2 receptors are scarce, primarily associated to cortical vascular structures. In agtr2 −/y mice, AT1 receptor binding and mRNA were increased in the kidney glomeruli, and AT1 receptor binding was higher in the rest of the cortex and outer stripe of the outer medulla, but not in its inner stripe, indicating different cellular regulation. Although AT2 receptor expression is very low in male agtr 2 +/y mice, their gene disruption alters AT1 receptor expression. AT1 upregulation alone may explain the AT2 gene-disrupted mice phenotype such as increased blood pressure, higher sensitivity to angiotensin II, and altered renal function. The indirect AT1/AT2 receptor feedback could have clinical significance because AT1antagonists are widely used in medical practice.

Influence of lysine content and PH on the stability of alanine based copolypeptides Vila, Jorge Alberto; Ripoll, Daniel R.; Scheraga, Harold A. To account for the relative contributions of lysine and alanine residues to the stability of α‐helices of copolymers of these two residues, conformational energy calculations were carried out for several hexadecapeptides at several pHs. All the calculations considered explicitly the coupling between the conformation of the molecule and the ionization equilibria as a function of pH. The total free energy function used in these calculations included terms that account for the solvation free energy and free energy of ionization. These terms were evaluated by means of a fast multigrid boundary element method. Reasonable agreement with experimental values was obtained for the helix contents and vicinal coupling constants (3JHNα). The helix contents were found to depend strongly on the lysine content, in agreement with recent experimental results of Williams et al. (Journal of the American Chemical Society, 1998, Vol. 120, pp. 11033–11043) In the lowest energy conformation computed for a hexadecapeptide containing 3 lysine residues at pH 6, the lysine side chains are preferentially hydrated; this decreases the hydration of the backbone CO and NH groups, thereby forcing the latter to form hydrogen bonds with each other in the helical conformation. The lowest energy conformation computed for a hexadecapeptide containing 6 lysine residues at pH 6 shows a close proximity between the NHurn:x-wiley:00063525:media:BIP1001:tex2gif-stack-1 groups of the lysine side chains, a feature that was previously observed in calculations of short alanine‐based oligopeptides. The calculation on a blocked 16‐mer of alanine shows a 7% helix content based on the Boltzmann averaged vicinal coupling constants computed from the dihedral angles ϕ, consistent with previous experimental evidence on triblock copolymers containing a central block of alanines, and with earlier theoretical calculations.

Metasomatism and Melting in Carbonated Peridotite Xenoliths from the Mantle Wedge: The Gobernador Gregores Case (Southern Patagonia) Laurora, Angela; Mazzucchelli, Maurizio; Rivalenti, Giorgio; Vannucci, Riccardo; Zanetti, Alberto; Barbieri, María Adelaide; Cingolani, Carlos Alberto Spinel-facies mantle xenoliths occur in a diatreme cutting through the Neogene Southern Patagonia Plateau at Gobernador Gregores (Santa Cruz Province, Argentina). This plateau is in a back-arc position with respect to the Chile trench. Xenoliths differ in their whole-rock composition from other South America occurrences, having higher CaO/Al2O3 ratios and, in some samples, TiO2 enrichment, whereas the Na2O/Al2O3 variation range is similar. Three assemblages can be distinguished. Assemblage 1, in anhydrous protogranular lherzolites and harzburgites, contains clinopyroxene with a depleted major and trace element composition, indicating pre-metasomatic depletion processes. This assemblage fully recrystallized to Assemblage 2 (amphibole ± phlogopite ± Cl-apatite-bearing) during a metasomatic episode. This causes clinopyroxene to acquire geochemical characteristics often attributed to carbonate-melt metasomatism. Noticeably, amphibole is markedly enriched in Nb (up to 298 ppm), especially when depleted in Ti. A further event, related to decompression during xenolith uplift to the surface, induces closed-system (perhaps with the exception of CO2 addition) disequilibrium melting of Assemblage 2, dominantly of amphibole. It is found in pockets (where amphibole is a residual phase) consisting of Na–Si-rich glass and carbonate (Mg-rich calcite) drops, and in veins originating from the pockets (Assemblage 3). Euhedral olivine, clinopyroxene and spinel crystallize only in the silicate glass. So do new, euhedral apatite crystals when glass is in contact with previous Assemblage 2 apatite. Textural evidence and comparison with experimental work suggest that silicate glass and carbonates are the result of unmixing of a former homogeneous melt. Because of the different flow rates of carbonate and silicate melt, the xenoliths become enriched in carbonate, which is found in the veins during their migration. Thus, the high CaO/Al2O3 ratio of whole rocks provides inconclusive evidence of carbonatite metasomatism. This factor, and other minor deviations from the expected results of carbonatite metasomatism, lead us to hypothesize an aqueous, Cl-rich fluid, possibly slab derived, as an alternative agent. Amphibole, resulting from reactive porous flow of this agent in the mantle, could fully explain the observed geochemical features, as indicated by estimates of its partition coefficients.

Single strand mRNA differential display (SSDD) applied to the identification of serine/threonine phosphatases regulated during cerebellar development Vilá Ortiz, Guillermo J.; Radrizzzani, Martín; Carminatti, Hector; Idoyaga Vargas, Victor Pastor; Santa Coloma, Tomás Antonio Differential display is a used widely and useful technique for the study of differentially expressed genes. However, very poor results have been obtained in the past when particular gene families were studied. Initially, we attempted to study the mRNA expression of catalytic subunits of serine/threonine phosphatases, using two primers specific to consensus sequences of these phosphatases. When differential display was applied, two wide, unresolved bands were isolated that contained cDNA of several phosphatases, together with that of many other unrelated transcripts. To overcome this problem, we used an alternative strategy, referred to as single strand differential display (SSDD), which is a combination of differential display and single strand conformation polymorphism (SSCP). After initial PCR amplification with specific primers, we ran a polyacrylamide (or agarose) gel, pre-selecting the region that contained fragments of the size expected for the consensus region (250-350 bp). The DNA eluted from this zone was then separated on a non-denaturing (SSCP) gel. Using this approach, we were able to characterize the expression of five ser/thr phosphatases, and a previously unreported splice variant of one of them, PP1γ. All these phosphatases show varying levels of expression during development, indicating a very complex regulation of protein phosphorylation-dephosphorylation during the period of synaptogenesis in the mouse cerebellum.

From direct to inverse GMR: Introduction of Cr in Fe/Cu superlattices Milano, Julian; Llois, Ana Maria It is well known that layered systems can present giant magnetoresistance (GMR). Particularly, the multilayers FeN/Cu8/Fe M/Cr/ FeM/Cu8 show inverse GMR. That is, the electrical conductivity decreases with the applied magnetic field. In the most common multilayers the conductivity increases with the applied field and this kind of GMR is called direct. In general the GMR is attributed to spin-dependent scattering in the bulk and mainly at interfaces. In this work we calculate the electronic band contribution to the GMR for Fe3/Cu 4/Fe/Cr/Fe/Cu4 and Fe3/Cu4 multilayers within the semiclassical approximation. The electrical conductivity is obtained in the ballistic and diffusive regimes. The results show a large change in the GMR behavior when one layer of Cr is introduced within the Fe layers. The GMR calculated in the CPP configuration (current flowing perpendicular to layers) of Fe3/Cu4 is of the direct type, with a value of about 40% while that obtained for Fe3/Cu 4/Fe/Cr/Fe/Cu4 is inverse and of the order of 45%. In the CIP configuration (current flowing parallel to the layers) the calculated GMR is direct with a value of about 35% for the system without Cr while, by the introduction of Cr, we obtain also a direct GMR but of about 3%. © 2001 Published by Elsevier Science B.V.

Structure sensitivity and in-situ activation of benzene combustion on Pt/Al2O3 catalysts Garetto, Teresita Francisca; Apesteguia, Carlos Rodolfo The structure sensitivity and in situ activation of benzene combustion on Pt/Al2O3 catalysts of different platinum and chlorine loadings were studied. The catalyst activities were evaluated through both conversion versus temperature (light-off curves) and conversion versus time catalytic tests. The light-off curves shifted to lower temperature with increasing Pt particle size, thereby suggesting that benzene combustion is a structure sensitive reaction. Kinetically-controlled catalytic tests confirmed that benzene oxidation turnover rates are preferentially promoted by larger Pt crystallites. Kinetic studies showed that the reaction orders and the apparent activation energy are not changed by changing the metallic dispersion. Results are explained by considering that benzene oxidation proceeds via a Langmuir–Hinshelwood mechanism which involves the rapid and strong adsorption of benzene on metallic platinum and assumes that the rate constant of oxygen adsorption is very low compared to the rate constant of the surface reaction. The number of PtO bonds of lower binding energy, i.e. the site density of more reactive surface oxygen, increases on larger Pt particles. Low-conversion catalytic tests performed at constant temperature showed that on well-dispersed Pt/Al2O3 catalysts the benzene conversion increases with time, irrespective of the chlorine content on the sample. TEM examination and hydrogen chemisorption measurements suggested that the activity increase parallels a concomitant increase in the platinum particle size. In contrast, sintered samples (platinum dispersions lower than 10%) did not exhibit initial activation periods. It is proposed that the initial in situ activation of well-dispersed Pt catalysts is caused by the sintering of the metallic phase. Hot-spots on the metallic particles together with the presence of gaseous water cause the formation of larger Pt crystallites, even at mild reaction conditions. As a result, the benzene conversion increases with time until the formation of larger steady state Pt particles is completed.

A boundary value problem of a semilinear second order ODE Amster, Pablo Gustavo; Mariani, Maria Cristina; Sabia, Juan Vicente Rafael We solve by topological methods a Dirichlet problem for the genera.l scmilinear second order ODE. We also prove the uniqueness of the solutions. Moreover, we develop an iterative method in order to find a solution in certain cases, for which the usual Picard iteration is riot appliable.

Fórmulas de tratamiento y cortesía en las relaciones amorosas de la novela de caballería (siglo XVI) Rígano, Mariela Elizabeth El objetivo de este trabajo es analizar la evolución de las fórmulas de tratamiento de uso vocativo empleadas para manifestar cortesía en el marco del vínculo amoroso en la novela de caballería del siglo XVI. En tal sentido, empleamos como fuentes dos de las obras más importantes de este género en la literatura española: el Amadís de Gaula y Palmerín de Oliva. El análisis se encuadra en el enfoque de la sociolingüística histórica y el material se analiza, siempre que sea posible, empleando la metodología propuesta por la etnografía del habla (véase Rigatuso, 1986, 1992 a y b, 1993 y 1995). Asimismo, en el procesamiento de los datos, trabajamos con un enfoque sociolingüístico e interaccional. Consideramos también las dimensiones de poder y solidaridad, según lo propuesto por Roger Brown y Albert Gilman para los estudios sobre tratamientos (1960). Por otra parte, en los aspectos contemplados en el análisis de los tratamientos, seguimos la propuesta de Elizabeth M. Rigatuso en su estudio sobre las fórmulas de tratamiento en la relación amorosa del español bonaerense entre 1830 y 1930, considerando la evolución en el uso de los tratamientos a lo largo de las distintas instancias de una relación de pareja: primer encuentro, declaración, noviazgo, después del matrimonio.

Analysis of a styrene-divinylester copolymerization: Reaction heats, double bond conversions and average sequence lengths Auad, Maria Lujan; Aranguren, Mirta Ines; Borrajo Fernandez, Julio A simple model, based on the free radical copolymerization theory of Mayo and Lewis, is developed to predict reaction heats, calorimetric and molar conversions and average sequence lengths, during the crosslinking reaction between a monounsaturated monomer (M1) and a multiunsaturated comonomer (M2). The M2-double bonds are assumed to react independently with equal initial reactivities. The input variables of the model are the initial reactivity ratios (r10, r20) and their variation with the global molar conversion, the initial composition of the reactive mixture (f10) and the molar heat of formation of the different bonds formed during the copolymerization (ΔH11, ΔH22, ΔH12). The application of this model allows to calculate the overall molar and calorimetric double bond conversions (P(m) and P(c)), the heat developed during the reaction (ΔH(T)), the conversions corresponding to each type of unsaturations (P(c1), P(c2), P(m1), P(m2)), and the average sequence lengths of the reacted bonds ( and ). Published data of experimental comonomers conversions in the system styrene-divinylester (SDVER) were satisfactorily reproduced by including a functionality of both reactivity ratios with the overall conversion. Finally, it was shown that the assumption implicitly made in most published kinetic studies from the differential scanning calorimetric (DSC) data, that P(c) and P(m) are equivalent, is not general and this feature must be investigated in order to perform correct kinetic calculations.

Efectos de sustratos competitivos y de la insulina sobre la captación y el destino metabólico de la glucosa en corazón perfundido de ratas dislipémicas Chicco, Adriana Graciela; Montes, Monica; D'alessandro, Maria Eugenia Guadalupe; Pighín, Darío Gabriel; Lombardo, Yolanda La utilización de sustratos energéticos por el músculo cardíaco depende no sólo de la disponibilidad de los mismos sino del entorno metabólico y hormonal. En el presente trabajo nos propusimos analizar la captación y el destino metabólico de la glucosa en los corazones perfundidos de ratas en un modelo experimental de hipertrigliceridemia, elevados niveles de ácidos grasos circulantes y resistencia insulínica global. Los corazones de ratas alimentadas durante 15 semanas con una dieta rica en sacarosa (DRS) (63% p/p) fueron perfundidos durante 30 min con un medio adicionado de glucosa y ácido palmítico en concentraciones semejantes a las del entorno de los animales in vivo, en presencia o ausencia de insulina. Los resultados muestran: i) Una alterada captación y reducida utilización de la glucosa, ii) Una menor oxidación de la glucosa (estimada como la actividad del complejo PDH) principalmente debido a mayor actividad enzimática PDH quinasa y menor actividad del complejo PDH, iii) La adición de insulina in vitro incrementa la captación sin lograr normalizarla, pero no muestra un efecto significativo sobre la oxidación de la glucosa durante el período de perfusión. Estos resultados nos señalan que en los corazones de ratas alimentadas con DRS perfundidos con ácidos grasos y glucosa a niveles semejantes a los del plasma del animal in vivo, al menos dos mecanismos podrían contribuir al alterado metabolismo de la glucosa: 1) una menor captación y utilización de la glucosa a nivel basal y frente al estímulo de la insulina y 2) una incrementada disponibilidad y oxidación de lípidos (menor actividad PDHc y mayor actividad PDH quinasa) que a su turno disminuirían la captación de la glucosa y su utilización. Finalmente cabe señalar que este modelo animal experimental inducido nutricionalmente podría ser de gran utilidad para el estudio de algunos mecanismos fisiopatológicos involucrados en lesiones cardíacas tales como las observadas en individuos dislipémicos y en diabetes mellitus no insulino dependiente.

Determinación de las Concentraciones Letales de Diazinón para Haematobia Irritans (Diptera: Muscidae) Susceptibles a los Organo-Fosforados y su Aplicación para el Diagnóstico de Resistencia Castellino, Marta Elena; Volpogni, M.M.; Mangold, Atilio Jose; Guglielmone, Alberto Alejandro Se usaron papeles de filLro y frascos de vidrio lrarados con dislintas cooceutracio nes de diazinón para obtener la conc.cntración letal 50 (CL50) y 90 (Cl.90) de una población de Haenllltobio irrilnns susceptible a los órgano fosforados.

Bifurcation control: Theories, methods, and applications Chen, Guanrong; Moiola, Jorge Luis; Wang, Hua O. Bifurcation control deals with modification of bifurcation characteristics of a parameterized nonlinear system by a designed control input. Typical bifurcation control objectives include delaying the onset of an inherent bifurcation, stabilizing a bifurcated solution or branch, changing the parameter value of an existing bifurcation point, modifying the shape or type of a bifurcation chain, introducing a new bifurcation at a preferable parameter value, monitoring the multiplicity, amplitude, and/or frequency of some limit cycles emerging from bifurcation, optimizing the system performance near a bifurcation point, or a combination of some of these objectives. This article offers an overview of this emerging, challenging, stimulating, and yet promising field of research, putting the main subject of bifurcation control into perspective.

Screening for and characterization of phospholipase A1 hypersecretory mutants of Tetrahymena thermophila Hartmann, M.; Guberman, Alejandra Sonia; Florin-Christensen, M.; Tiedtke, A. We have described a procedure for the isolation of mutants of Tetrahymena thermophila with hyperscretion of phospholipase A1 (PLA1). Using random chemical mutagenesis, uniparental cytogamy, genetic crossing and a new, fast and effective screening procedure, four PLA1-hypersecretory mutants were isolated. The screening procedure is based on the formation of a halo appearing around cylindrical holes in a lecithin-containing agar plate filled with cell-free supernatants. About 3,940 clones were tested with this procedure in primary screening for hypersecretory features, of which 60 putative hypersecretory mutants were isolated, subcloned and tested in a secondary screening. Of these, four selected mutants showed 1.8-2.2 more PLA1 activity in the cell-free supernatants compared to the wild-type strain CU 438.1. Hypersecretion was only observable for PLA1; no increased activity for two other lysosomal enzymes could be detected. These hypersecretory mutants of T. thermophila can be very useful for increasing the yield of PLA1 in fermentation processes. This is particularly relevant because, in contrast to other phospholipases, PLA1 is not available on the commercial market for fine chemicals and little is known about the role of PLA1 in cell signaling and metabolism.

Relaciones fronterizas en la Cordillera Chubutense: Actividades productivas y circuitos de comercialización (1900-1920) Gavirati, Jorge Marcelo; Finkelstein, Débora; Novella, María Marta En este trabajo se obtienen explicaciones relacionadas con los antecedentes y conformación de las unidades económicas minifundistas –cuyos titulares eran en su mayoría migrantes chilenos– de una sección catastral del noroeste del Territorio Nacional del Chubut, en el período 1900-1920. A partir del análisis de datos referidos a las mismas, se describen las características productivas y los circuitos de comercialización en los que participaban los bienes producidos. Estos circuitos tienen antecedentes en las prácticas aborígenes y, a comienzos del período considerado, se volcaban mayoritariamente hacia los mercados chilenos. Estas prácticas comerciales deben vincularse con la procedencia de los productores, las relaciones establecidas con los centros de intercambio ubicados en Neuquén –región por la que muchos de ellos habían realizado su ingreso al país y residido durante algún tiempo–, la transitabilidad de los pasos cordilleranos utilizados y la inexistencia de trabas aduaneras. Por otra parte, era la práctica comercial implementada también por la unidad económica latifundista más importante de la región. Los pobladores, provenientes del Oeste no percibían en una primera etapa las posibilidades de comerciar con el área atlántica con la que no se encontraban relacionados. No obstante, se perfilaban ya algunas problemáticas que irían paulatinamente inclinando los flujos comerciales hacia ese sector. Entre otras, la presencia más notoria del Estado argentino y de sus representantes en el territorio, la implementación de distinto tipo de restricciones aduaneras por parte de los dos estados, el trazado de caminos y líneas y vías férreas que vinculan la zona cordillerana con la costa atlántica, y la presencia a partir de la década del 20 de flujos poblacionales provenientes de ese sector y con relaciones comerciales con él.

Nutritional requirements and nitrogen-dependent regulation of proteinase activity of Lactobacillus helveticus CRL 1062 Hebert, Elvira Maria; Raya, Raul Ricardo; Savoy, Graciela The nutritional requirements of Lactobacillus helveticus CRL 1062 were determined with a simplified chemically defined medium (SCDM) and compared with those of L. helveticus CRL 974 (ATCC 15009). Both strains were found to be prototrophic for alanine, glycine, asparagine, glutamine, and cysteine. In addition, CRL 1062 also showed prototrophy for lysine and serine. The microorganisms also required riboflavin, calcium pantothenate, pyridoxal, nicotinic acid, and uracil for growth in liquid SCDM. The growth rate and the synthesis of their cell membrane-bound serine proteinases, but not of their intracellular leucyl-aminopeptidases, were influenced by the peptide content of the medium. The highest proteinase levels were found during cell growth in basal SCDM, while the synthesis of this enzyme was inhibited in SCDM supplemented with Casitone, Casamino Acids, or β-casein. Low-molecular-mass peptides (<3,000 Da), extracted from Casitone, and the dipeptide leucylproline (final concentration, 5 mM) play important roles in the medium-dependent regulation of proteinase activity. The addition of the dipeptide leucylproline (5 mM) to SCDM reduced proteinase activity by 25%.

Acid-base properties and active site requirements for elimination reactions on alkali-promoted MgO catalysts Diez, Veronica Karina; Apesteguia, Carlos Rodolfo; Di Cosimo, Juana Isabel Base-catalyzed elimination reactions were studied on MgO and alkali-modified MgO catalysts using 2-propanol as a probe reactant. The effect of the acid–base properties on the catalyst activity and selectivity was investigated by modifying the surface properties of MgO with 1 mol% of alkaline metals. Group IA metals promote the formation of medium- and high-strength basic sites, thereby increasing the basic site density and strength. The addition of alkaline promoters improves the MgO activity for 2-propanol conversion reactions. The selectivity toward dehydration or dehydrogenation products depends on the base site nature, so that intermediate-strength base sites promote acetone formation, whereas high-strength base sites selectively yield propylene. 2-Ppropanol decomposition to acetone and propylene is proposed to take place via an E1cB mechanism in two parallel pathways sharing a common 2-propoxy intermediate.

An inquiry into the nature of the gamma-ray source 3EG J1828+0142 Punsly, Brian; Romero, Gustavo Esteban; Torres, Diego F.; Combi, Jorge Ariel The unidentified, low-latitude, gamma -ray source 3EG J1828+0142 presents high levels of variability and a steep spectral index Gamma ~ 2.7. Here we propose a model for this source where the high-energy emission is produced by a galactic Kerr-Newman black hole. The model takes into account electron-positron annihilation losses in the calculation of the expected spectral energy distribution and can reproduce the observational features, including the absence of a strong radio counterpart. We also report the discovery of a nearby supernova remnant that could be associated with the original supernova explosion that created the black hole. Several faint radio sources were also detected in the radio field within the inner gamma -ray confidence contour and their spectral index estimated. Some of these sources could be the expected weak radio counterpart.

Geomorfología de estuarios: una visión diferente Piccolo, Maria Cintia; Perillo, Gerardo Miguel E. Los estuarios son una de las mas importantes caracteristicas de las zonas costeras sujetas a fuertes procesos de interaccion mar-continente en un amplio rango de escalas espacio-temporales. En general, estos ambientes ocupan las areas costeras menos expuestas ala accion marina, permitiendo el desarrollo de puertos, facilidades recreacionales 0 apropiados emprendimientos de acuicultura, Sin embargo, dentro de los estuarios los procesos dinamicos son significativos imponiendo un marc ado stress sobrela biota, ya sea pennanente 0 temporaria, la morfologia y las construccione.

Integración, fronteras y movilidad espacial de la población Meichtry, Norma Cristina Se analizan los posibles argumentos que pudieran respaldar los procesos de cambios que se vienen registrando en la frontera entre Argentina y Paraguay, desde el punto de vista de la teoría de la nueva división del trabajo en el marco de un sistema mundial o de la teoría de la generalización de las crisis socioeconnómicas a partir de los procesos de reestructuración de la economía.

Análisis empírico de algoritmos de inversión de matrices, aplicados al cálculo de propiedades moleculares. Godoy, María Viviana; Provasi, Patricio Federico; Aucar, Gustavo Adolfo En este articulo se evahia la performance en cuanto a tiempos de ejecuci6n de dos algoritmos de inversi6n de matrices: uno tradicionalmente utilizado en calculos de propiedades moleculares y uno nuevo implementado en nuestro grupo de investigaci6n y que utiliza un desarrollo en sene de potencias de los elementos matriciales. Se probaron distintas plataformas, sistemas operativos, compiladores y subrutinas de algebra lineal (BLAS). Se realizaron calculos para compuestos modelo que requieren el tratamiento de matrices conteniendo entre 80.000 y 4.000.000 de elementos. Se obtuvieron los tiempos de ejecuci6n de dichos algoritmos a traves de la evaluaci6n con el metodo de propagadores de polarizaci6n de propiedades moleculares tipo triplete y singulete. Se observ6 que el rendimiento del algoritmo de la serie aumenta al crecer la dimensi6n de la matriz a invertir. Para todas las plataformas utilizadas se obtuvo una performance ganancioso de la serie con respecto al algoritmo tradicional.; In this article, the performance of two algorithms for matrix inversion are evaluated considering as a parameter the times of execution: one traditionally used in the calculations of molecular properties and a new one implemented in our research group, that makes use of a series development of matrix elements. Different platforms, operating sistems, compilers and subroutines of lineal algebra (BLAS) were investigated. Calculations for model compounds that require the treatment of matrix containing a number of elements between 80.000 and 4.000.000 was carried out. The calculation of molecular properties of both, singlet and triplet type was used to evaluate the execution time of these algorithms. It was observed that the performance of the series algorithm increases when the dimension of the given matrix grows. For all plataforms, a gainful performance of the series was obtained, compared to the tradicional algorithm.