The trypanocidal activity of the alkaloid oliverine involves inhibition of DNA synthesis

The Trypanosoma cruzi parasite is an etiologic agent of the American trypanosomiasis called Chagas disease. This pathology affects more than 24 million persons and represents one of the most important public health problems in Latin America. Taking into account this, it is necessary the search of new antitrypanosomal agents that show a major level of efficacy and minor indexes of toxicity in affected patients. Vast source of them are the natural products from plants with enormous structural diversity. A particular type of these compounds is represented by aporphinoid alkaloids. In our experiments, anonaine (2), oliverine (3) and guatterine (5) displayed antitrypanosomal activity. The compound 3 showed the most important activity with an IC50 = 12.00 ± 0.36 μM. Its mechanism of action may include inhibition of DNA synthesis.Fil: Garro, Hugo Alejandro. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Química. Area de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Investigaciones en Tecnología Química; ArgentinaFil: Juri Ayub, Maximiliano. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas; Argentina. Fundación Instituto Leloir; ArgentinaFil: Nieto, M.. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Química. Area de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Investigaciones en Tecnología Química; ArgentinaFil: Lucero Estrada, Cecilia Stella Marys. Universidad Nacional de San Luis. Facultad de Quimica, Bioquimica y Farmacia. Area Microbiologia; ArgentinaFil: Pungitore, Carlos Rodolfo. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Química. Area de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Investigaciones en Tecnología Química; ArgentinaFil: Tonn, Carlos Eugenio. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Química. Area de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Investigaciones en Tecnología Química; Argentin

Variability of 137Cs and 40K soil-to-fruit transfer factor in tropical lemon trees during the fruit development period

In this investigation we evaluate the soil uptake of 137Cs and 40K by tropical plants and their consequent translocation to fruits, by calculating the soil-to-fruit transfer factors defined as Fv = [concentration of radionuclide in fruit (Bq kg-1 dry mass)/concentration of radionuclide in soil (Bq kg-1 dry mass in upper 20 cm)]. In order to obtain Fv values, the accumulation of these radionuclides in fruits of lemon trees (Citrus limon B.) during the fruit growth was measured. A mathematical model was calibrated from the experimental data allowing simulating the incorporation process of these radionuclides by fruits. Although the fruit incorporates a lot more potassium than cesium, both radionuclides present similar absorption patterns during the entire growth period. Fv ranged from 0.54 to 1.02 for 40K and from 0.02 to 0.06 for 137Cs. Maximum Fv values are reached at the initial time of fruit growth and decrease as the fruit develops, being lowest at the maturation period. As a result of applying the model a decreasing exponential function is derived for Fv as time increases. The agreement between the theoretical approach and the experimental values is satisfactory.Fil: Velasco, Ricardo Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Cid, A. S.. Universidade Federal Fluminense; BrasilFil: Anjos, R. M.. Universidade Federal Fluminense; BrasilFil: Zamboni, C. B.. Comissao Nacional de Energia Nuclear. Centro de Lasers e Aplicacoes. Instituto de Pesquisas Energéticas e Nucleares; BrasilFil: Rizzotto, Marcos Gregorio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Valladares, Diego Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Juri Ayub, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina. Universidade Federal Fluminense; Brasi

Chopping and Changing: the Evolution of the Flavin-dependent Monooxygenases.

Flavin-dependent monooxygenases play a variety of key physiological roles and are also very powerful biotechnological tools. These enzymes have been classified into eight different classes (A-H) based on their sequences and biochemical features. By combining structural and sequence analysis, and phylogenetic inference, we have explored the evolutionary history of classes A, B, E, F, and G and demonstrate that their multidomain architectures reflect their phylogenetic relationships, suggesting that the main evolutionary steps in their divergence are likely to have arisen from the recruitment of different domains. Additionally, the functional divergence within in each class appears to have been the result of other mechanisms such as a complex set of single-point mutations. Our results reinforce the idea that a main constraint on the evolution of cofactor-dependent enzymes is the functional binding of the cofactor. Additionally, a remarkable feature of this family is that the sequence of the key flavin adenine dinucleotide-binding domain is split into at least two parts in all classes studied here. We propose a complex set of evolutionary events that gave rise to the origin of the different classes within this family

Atmospheric deposition of beryllium-7 in soil

El Berilio-7 es un radionucleido natural (Eγ = 477.6 keV; t1/2 = 53.3 d) que se origina a partir de la interacción de los rayos cósmicos con la atmósfera terrestre, e ingresa al suelo principalmente por deposición húmeda (lluvias). Es ampliamente utilizado para la estimación de la redistribución del suelo (erosión/sedimentación), ocasionada por las precipitaciones en cortos periodos de tiempo. En este trabajo se analizó el contenido de 7 Be en lluvia y en suelo, en una región semiárida de la provincia de San Luis, para el período húmedo (Noviembre a Abril). El contenido en lluvias de 7 Be varió entre (0.7 ± 0.3) Bq l-1 y (3.2 ± 0.7) Bq l-1 y la magnitud de la precipitación entre 1 mm y 57 mm. El depósito atmosférico de 7 Be mostró una alta correlación lineal con la magnitud de la precipitación. En base al contenido de 7 Be en lluvias y al régimen de precipitaciones, se estimó la densidad superficial de actividad (DSA) de 7 Be en suelo, para el período húmedo, utilizando un modelo simple de iteración. En suelo, 7 Be fue detectado en el primer centímetro del perfil; y la concentración de actividad varió entre (83 ± 17) Bq kg-1 y (168 ± 26) Bq kg-1, lo cual corresponde a un rango de DSA, entre (263 ± 53) Bq m-2 y (488 ± 98) Bq m-2. Los valores experimentales de DSA obtenidos para cada mes fueron contrastados con los valores predichos, encontrándose un buen acuerdo entre ambos. Los resultados confirman que son las precipitaciones el principal factor que determina el contenido de 7 Be en suelo, pudiendo el sitio evaluado ser utilizado como sitio de referencia a los efectos de la aplicación de la técnica de 7 Be para documentar redistribución de suelo.Beryllium-7 is a natural radionuclide (Eγ = 477.6 keV; t1/2 = 53.3 d) originating from the interaction of cosmic rays with terrestrial atmosphere, entering to soil mainly by wet deposition (rain). It is widely used in estimating the soil redistribution (erosion/sedimentation) produced by rains in short periods of time. In this work 7 Be content in rain and soil was analyzed, in a semiarid region of San Luis Province, for the wet period of the region (November to April). The 7 Be content in rain ranged between (0.7 ± 0.3) Bq l-1 and (3.2 ± 0.7) Bq l-1 while the precipitation regime between 1 mm and 57 mm. The 7 Be atmospheric deposit showed a high linear correlation with precipitation. 7 Be areal activity density (AAD) in soil was estimated from 7 Be content in rains and the precipitations regime, for the wet period, using a simple iteration model. 7 Be in soil was measured for the first centimeter of soil profile; and the mass activity density ranged between (83 ± 17) Bq kg-1 and (168 ± 26) Bq kg-1, which corresponds to a range of AAD between (263 ± 53) Bq m-2 and (488 ± 98) Bq m-2. The experimental AAD values obtained for each month were compared with predicted values, finding a good agreement. The results confirm that precipitations are the main factor in determining 7 Be soil content, thus making possible to use the studied site as a reference one in applying the 7 Be technique to document soil redistribution.Fil: Lohaiza, Flavia Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Juri Ayub, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Velasco, Ricardo Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Rizzotto, M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Di Gregorio, D.. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Huck, H.. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Valladares, D.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentin

Production of recombinant enzymes of wide use for research

For biotechnological purposes, protein expression refers to the directed synthesis of large amounts of desired proteins. The aim of the present work was to produce reverse transcriptase Moloney murine Leukaemia Virus retro-transcriptase and Taq DNA polymerase, as bioactive products. In the present paper, we report the preparation of recombinant enzymes, expressed in E. coli strains. The enzymes produced exhibited quite good activity, compared with commercial enzymes, allowing us to replace the last ones for several lab applications. We are reporting changes and modifications to standard protocols described. The standard protocols were modified, i.e. for the purification step of Taq, a temperature dependent procedure was designed. The enzymes produced were used in different applications, such as PCR, RT-PCR, PCR Multiplex and RAPDs molecular markers

Production of recombinant enzymes of wide use for research

For biotechnological purposes, protein expression refers to the directed synthesis of large amounts of desired proteins. The aim of the present work was to produce reverse transcriptase Moloney murine Leukaemia Virus retro-transcriptase and Taq DNA polymerase, as bioactive products. In the present paper, we report the preparation of recombinant enzymes, expressed in E. coli strains. The enzymes produced exhibited quite good activity, compared with commercial enzymes, allowing us to replace the last ones for several lab applications. We are reporting changes and modifications to standard protocols described. The standard protocols were modified, i.e. for the purification step of Taq, a temperature dependent procedure was designed. The enzymes produced were used in different applications, such as PCR, RT-PCR, PCR Multiplex and RAPDs molecular markers

Cytokine Production but Lack of Proliferation in Peripheral Blood Mononuclear Cells from Chronic Chagas' Disease Cardiomyopathy Patients in Response to T. cruzi Ribosomal P Proteins

Background:Trypanosoma cruzi ribosomal P proteins, P2β and P0, induce high levels of antibodies in patients with chronic Chagas' disease Cardiomyopathy (CCC). It is well known that these antibodies alter the beating rate of cardiomyocytes and provoke apoptosis by their interaction with β1-adrenergic and M2-muscarinic cardiac receptors. Based on these findings, we decided to study the cellular immune response to these proteins in CCC patients compared to non-infected individuals.Methodology/Principal findings:We evaluated proliferation, presence of surface activation markers and cytokine production in peripheral blood mononuclear cells (PBMC) stimulated with P2β, the C-terminal portion of P0 (CP0) proteins and T. cruzi lysate from CCC patients predominantly infected with TcVI lineage. PBMC from CCC patients cultured with P2β or CP0 proteins, failed to proliferate and express CD25 and HLA-DR on T cell populations. However, multiplex cytokine assays showed that these antigens triggered higher secretion of IL-10, TNF-α and GM-CSF by PBMC as well as both CD4+ and CD8+ T cells subsets of CCC subjects. Upon T. cruzi lysate stimulation, PBMC from CCC patients not only proliferated but also became activated within the context of Th1 response. Interestingly, T. cruzi lysate was also able to induce the secretion of GM-CSF by CD4+ or CD8+ T cells.Conclusions/Significance:Our results showed that although the lack of PBMC proliferation in CCC patients in response to ribosomal P proteins, the detection of IL-10, TNF-α and GM-CSF suggests that specific T cells could have both immunoregulatory and pro-inflammatory potential, which might modulate the immune response in Chagas' disease. Furthermore, it was possible to demonstrate for the first time that GM-CSF was produced by PBMC of CCC patients in response not only to recombinant ribosomal P proteins but also to parasite lysate, suggesting the value of this cytokine to evaluate T cells responses in T. cruzi infection.Fil: Longhi, Silvia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Atienza, Augusto. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Ramos Mejía"; ArgentinaFil: Perez Prados, Graciela. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Juan A. Fernández"; ArgentinaFil: Buying, Alcinette. Torrey Pines Institute for Molecular Studies; Estados UnidosFil: Balouz, Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Buscaglia, Carlos Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Santos, Radleigh. Torrey Pines Institute for Molecular Studies; Estados UnidosFil: Tasso, Laura Mónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Bonato, Ricardo. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Ramos Mejía"; ArgentinaFil: Chiale, Pablo. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Ramos Mejía"; ArgentinaFil: Pinilla, Clemencia. Torrey Pines Institute for Molecular Studies; Estados UnidosFil: Judkowski, Valeria A.. Torrey Pines Institute for Molecular Studies; Estados UnidosFil: Gomez, Karina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentin

Reconstructing the evolutionary history of F420-dependent dehydrogenases

Abstract During the last decade the number of characterized F420-dependent enzymes has significantly increased. Many of these deazaflavoproteins share a TIM-barrel fold and are structurally related to FMN-dependent luciferases and monooxygenases. In this work, we traced the origin and evolutionary history of the F420-dependent enzymes within the luciferase-like superfamily. By a thorough phylogenetic analysis we inferred that the F420-dependent enzymes emerged from a FMN-dependent common ancestor. Furthermore, the data show that during evolution, the family of deazaflavoproteins split into two well-defined groups of enzymes: the F420-dependent dehydrogenases and the F420-dependent reductases. By such event, the dehydrogenases specialized in generating the reduced deazaflavin cofactor, while the reductases employ the reduced F420 for catalysis. Particularly, we focused on investigating the dehydrogenase subfamily and demonstrated that this group diversified into three types of dehydrogenases: the already known F420-dependent glucose-6-phosphate dehydrogenases, the F420-dependent alcohol dehydrogenases, and the sugar-6-phosphate dehydrogenases that were identified in this study. By reconstructing and experimentally characterizing ancestral and extant representatives of F420-dependent dehydrogenases, their biochemical properties were investigated and compared. We propose an evolutionary path for the emergence and diversification of the TIM-barrel fold F420-dependent dehydrogenases subfamily

Methology for reuising yeast in a craft brewery

Beer is one of the most widely consumed alcoholic beverages in the world, which reaches all social status and is an industrial sector that generates millions of dollars a year The craft breweries are in Argentina an innovative industrial sector that has experienced a explosive growth in the last fifteen years, particularly high in the San Luis Province (Argentina).. The growing demand for quality craft beers has driven significant technological development, process optimization and cost reduction by the breweries. The yeast is critical to beer, that involves much more than converting sugars into alcohol, it contribute to flavor and aroma to beer too. The reusing of the yeasts is a wanted process that is being by brewers, as it generates significant savings in the production of new batches of beer. This reusing imply the collection of the yeast after the fermentation process from the bottom of the fermentation tank. The handling and collection of healthy yeast, avoiding biological contamination, is a crucial to achieving a good beer quality. With the aim to generate a technological transfer to the craft breweries, we developed a procedure of handling and collection of yeast for reuse in breweries. The work was carried out in the Kerze brewery, located at San Luis Province. Yeast samples were daily taken from the bottom of fermentation tank during all the fermentation process (7 days). In the yeast samples viability was measured using standard methodogy. The results indicated that the time optimal to the yeasts collection for reuse is from 3 to 5 days of fermentation, when the total number of yeast cell is higher (1.43 x109) and the best viability is recorded (90%). After the collection the yeast were stored 24 hours in a refrigerator at 4°C and its viability measured, showing a viability minor than 50%. The results indicate that for yeast reusing, it must be harvested the fifth day of fermentation and reuse for a new batch within 24 hours and stored at 4°C. The implementation of this operative procedure for yeast collection generates an optimal process for resusing beer yeast (quantity of cells and viability necessary) and avoiding losses to craft breweries. Future studies are need in order to increase the storage time of recovered yeast.Fil: Aguirre, V.. Universidad Nacional de San Luis; ArgentinaFil: Caballer, G.. Universidad Nacional de San Luis; ArgentinaFil: Juri Ayub, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Sanz Ferramola, M. I.. Universidad Nacional de San Luis; ArgentinaFil: Fernández, Jorge Gastón. Universidad Nacional de San Luis; ArgentinaXXXVII Reunión Anual de la Sociedad de Biología de CuyoSan LuisArgentinaSociedad de Biología de Cuy

An alternative methodology to determine 210Pb activity soil profiles

Unsupported 210Pb (Pbexc) is generated in air and is subsequently deposited on soil surface. The Pbexc can be used for sediment dating, soil erosion/sedimentation and air mass studies.In many cases, 210Pb activity determination (gamma ray 46.5 keV) cannot be performed due to the lack of efficiency calibration curve, especially when radioactive patron source is not available.This work presents an alternative methodology to obtain the 210Pb activity values, based on the activity definition and the attenuation coefficient determinations and assuming that soil samples coming from depth higher than 25 cm only contain 210Pb generated in the soil (Pbexc free, i.e., for those soil layers the 210Pb activity is equal to the 226Ra activity, at secular equilibrium).The proposed methodology was evaluated using soils from La Plata region, Argentina. The same soil samples were also analyzed in a second laboratory by the conventional methodology. The obtained results indicated that the proposed procedure can be used as a good alternative in cases where a calibration sample is not available.Fil: Montes, María Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; ArgentinaFil: Rizzoto, M. G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Juri Ayub, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; Argentina. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; ArgentinaFil: Torres Astorga, Romina Vanesa. Universidad Nacional de San Luis. Facultad de Ciencias Físico- Matemáticas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Taylor, Marcela Andrea. Universidad Nacional de La Plata. Facultad de Ingeniería. Departamento de Ciencias Básicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin