Generación de mallas de elementos finitos para arterias coronarias a partir de imágenes Ivus
Jonas, Ignacio; Romero, Luis J.; del Fresno, Mirta Mariana; D'amato, Juan Pablo; Venere, Marcelo Javier
El interés por el desarrollo de algoritmos para el procesamiento de imágenes médicas orientadas al estudio del funcionamiento del sistema cardiovascular ha crecido ampliamente en los últimos años. En especial, el ultrasonido intravascular (Intra Vascular Ultra Sound - IVUS) constituye una opción mínimamente invasiva basada en el uso de un catéter que recorre la arteria. Este tipo de imágenes permite obtener información volumétrica con alta resolución temporal y espacial, que puede ser utilizada para diagnóstico y desarrollo de aplicaciones avanzadas de análisis. En este trabajo se presenta una herramienta computacional para la detección de las paredes de arterias coronarias a partir de series de imágenes tomadas por un sensor de IVUS. Debido a las características de los datos analizados, previamente a la segmentación se aplica un algoritmo de filtrado espacial que permite la reducción de ruido. Para la detección del contorno de la arteria, se requiere la ubicación manual de algunos puntos en uno de los cortes transversales para determinar un contorno inicial interior, el cual luego se deforma automáticamente para ajustarlo a la pared arterial. Dada la similitud entre las imágenes consecutivas de la secuencia, la información de la segmentación en un corte se considera en el siguiente, para llevar a cabo la deformación del contorno estimado en forma iterativa. Finalmente, en base a los contornos individuales detectados es posible reconstruir una serie de mallas de superficie que describen la estructura arterial en los diferentes ciclos cardiacos de sístole y diástole. Para asegurar la calidad de las geometrías se aplica un algoritmo iterativo basado en cambios de topología, suavizado y proyección sobre la malla original. Dicho algoritmo logra mejorar la calidad de los elementos con pérdida de volumen despreciable o nula, en tiempos razonables. Las pruebas experimentales realizadas muestran que el algoritmo permite obtener mallas de calidad superior a la que se puede generar a partir de otros tipos de imágenes, con una excelente definición de la sección arterial. Resta explorar la combinación de información de IVUS y otras modalidades como angiografías o resonancias magnéticas, a fin de lograr la reconstrucción tridimensional completa de las arterias teniendo en cuenta su disposición espacial, lo que contribuirá ampliamente a la representación virtual de procedimientos diagnósticos o quirúrgicos.
Sin puerto para el sueño americano. Políticas de exclusión, inmigración y tracoma en Argentina (1908-1930); Without port of entry for the American dream. Politics of exclusion, immigration and trachoma in Argentina (1908-1930)
Di Liscia, María Silvia; Fernández Marrón, Melisa
Este trabajo plantea el estudio del tracoma, patología ocular que podía llevar a la ceguera, considerando especialmente las políticas inmigratorias desarrolladas en la República Argentina. La detección de la conjuntivitis granulosa, como también fue llamada, fue causa de rechazo a partir de 1908 y hasta mediados de los años cuarenta, pero su número disminuyó en los años treinta. La enfermedad fue también utilizada como argumento para impedir el ingreso de rusos y polacos (judíos) y sirio-libaneses, entre otros grupos excluidos. Nuestra intención es examinar las prácticas utilizadas por las agencias (Departamento Nacional de Migración y Departamento Nacional de Higiene) a cargo de instalar tal sistema de exclusión en el momento crítico del ingreso de los inmigrantes al país, a partir de la reglamentación sancionada en 1908. También se analizarán las estrategias elaboradas por los sujetos para resistir a tal violencia, en un país cuya publicitada modernidad requería el ingreso de población inmigrante. Las fuentes seleccionadas son, fundamentalmente, las Memorias de la Dirección General de Migración (serie: 1890-1945, incompleta, Archivo y Biblioteca del Centro de Estudios Migratorios) y los Partes Consulares y Expedientes de la inspección médica en los buques. Dicha información se complementa con otras publicaciones de referencia médica.; Ce travail analyse le trachome, pathologie de l’œil qui peut provoquer la cécité, à la lumière des politiques de migration développées en Argentine. La détection de la conjonctivite granulaire, autre nom du trachome, fut une cause de rejet, à partir de 1908 et jusqu’au milieu des années quarante. Le nombre de personnes atteintes diminua dans les années trente. La maladie fut aussi une cause d’empêchement pour les candidats à l’immigration russes, polonais (juifs) et syriens-libanais, entre autres groupes d’exclus. Nous examinerons les pratiques employées par les agences telles le Departamento Nacional de Migración et le Departamento Nacional de Higiene, qui ont mis en place ce système d’exclusion à un moment critique de l’entrée des migrants dans le pays, depuis la réglementation qui est en lien avec les processus de discrimination et de xénophobie. Seront aussi analysées les stratégies élaborées par les sujets pour résister à cette violence, dans un pays dont la modernité appelait l’entrée de populations migrantes.; This paper studies trachoma, an ocular pathology that may cause blindness, in the context of the migratory politics developed in the Argentinean Republic. The detection of the granular conjunctivitis was a reason for rejection from the 1908 until the mid-1940s, despite its decrease started one decade before. The disease was also presented as an argument to prevent the entrance of groups of Russian, Polish (Jewish) and Syrian-Lebanese, amongst others. Our aim is to examine the practice used by the agencies that established that system of exclusion, such as the National Department of Migrations and the National Department of Hygiene, based on a regulation which was related to processes of discrimination and xenophobia. Additionally, this article will analyze the strategies elaborated by individuals in order to resist violence, in a country in which the advertised modernity called for the massive entrance of immigrant population.
Análisis de una praxeología matemática universitaria en torno al límite de funciones y la producción de los estudiantes en el momento de evaluación; Analysis of a College Mathematics Praxeology with Respect to the Limit of Functions and Students' Productions at the Moment of Assessment
Corica, Ana Rosa; Otero, Maria Rita
Este artículo presenta los resultados parciales de una investigación cuyo propósito es describir y comprender las organizaciones matemáticas en torno al límite de funciones que se estudian en una institución universitaria, así como la producción de los estudiantes en el momento de la evaluación. Se adopta como sustento teórico a la Teoría Antropológica de lo Didáctico. Dicho estudio se realizó en un curso de Cálculo, al que asistían 283 estudiantes, y correspondía al primer año del ciclo básico que llevaban todas las carreras de Ciencias Básicas y Aplicadas en una Facultad de Ciencias Exactas. Las conclusiones parciales indicarían que en esta universidad se estudian organizaciones matemáticas puntuales y rígidas que sólo conducen a la revisión de algoritmos algebraicos.; This article presents the partial results of an investigation which aim is to describe and understand mathematical organizations concerning the limit of functions that are studied in a university institution and the students' production at the time of an evaluation. The work is upheld by the Anthropological Theory of Didactics. This study was carried out in a calculus course attended by 283 students and which corresponded to the first year of the basic cycle common to all Basic and Applied Sciences degree courses in an Exact Sciences faculty. The partial conclusions would indicate that in this university precise and rigid mathematical organizations are studied that only lead to the revision of algebraic algorithms.
La ciencia y los científicos & la religión y los religiosos
Mateo, Jose Antonio
La llamada revolución científica del siglo XVII se asocia a las figuras de Newton y Descartes y en algunos casos se la ubica en una posición de ruptura entre la fe y la razón o entre el orden feudal y el capitalismo. En el presente trabajo pretendemos argumentar cómo la supuesta separación entre ciencia y religión en este proceso ha resultado ser el nacimiento de un nuevo tipo de conocimiento, el conocimiento científico, diferenciado aunque no opuesto a la filosofía y a la teología. También cómo, en paralelo a la ciencia nacida dentro del entorno puritano se desarrolló otra con alcances similares dentro de la orden jesuítica, aunque alcanzando menor trascendencia histórica que aquella.
Scheduling Hard Real-Time Tasks in Multicore General Purpose/ Special Purpose Processors Systems-on-a-Chip: An Energy-Aware Approach
Santos, Rodrigo Martin; Santos, Jorge; Orozco, Javier Dario; Donari Acquaroli, David Raul; Ordinez, Leonardo Damian
In this paper an energy-aware scheduling algorithm for heterogeneous multicore general purpose/special purpose processors systems-on-a-chip is presented. The load consists in chains of precedence-related tasks. A systematic search method to find an optimal set of reduced frequencies that diminish the energy consumption is proposed. Evaluations were conducted by means of extensive simulations.
Factores virales de riesgo para la transmisión madre-hijo del VIH-1
Dolcini, Guillermina Laura
Entre los principales factores de riesgo para la transmisión madre-hijo (TMH) del VIH-1 se encuentran la carga viral y el estado clínico e inmunológico de la madre. La presente revisión bibliográfica se aboca exclusivamente a los factores virales de riesgo: la carga viral (CV) y las características del virus. La CV plasmática tiene un fuerte valor predictivo para el riesgo de TMH; los distintos tratamientos con antirretrovirales en embarazadas tienden a disminuir la CV plasmática. Se analiza además la relación entre presencia viral y TMH a nivel local (placenta, secreciones cérvico-vaginales y leche). Existe una selección de variantes virales que se transmiten de madre a hijo; se discute el rol de la heterogeneidad viral y de los diferentes subtipos del VIH en la TMH. Si bien pueden transmitirse virus con diferentes tropismos, se destaca la preferencia de virus de fenotipo R5 en la TMH.
The effect of the sixth sulfur ligand in the catalytic mechanism of periplasmic nitrate reductase
Cerqueira, N.M.F.S.A.; Gonzalez, P.J.; Brondino, Carlos Dante; Romão, M.J.; Romão, C.C.; Moura, I.; Moura, J.J.G.
The catalytic mechanism of nitrate reduction by periplasmic nitrate reductases has been investigated using theoretical and computational means. We have found that the nitrate molecule binds to the active site with the Mo ion in the +6 oxidation state. Electron transfer to the active site occurs only in the proton-electron transfer stage, where the MoV species plays an important role in catalysis. The presence of the sulfur atom in the molybdenum coordination sphere creates a pseudo-dithiolene ligand that protects it from any direct attack from the solvent. Upon the nitrate binding there is a conformational rearrangement of this ring that allows the direct contact of the nitrate with MoVI ion. This rearrangement is stabilized by the conserved methionines Met141 and Met308. The reduction of nitrate into nitrite occurs in the second step of the mechanism where the two dimethyl-dithiolene ligands have a key role in spreading the excess of negative charge near the Mo atom to make it available for the chemical reaction. The reaction involves the oxidation of the sulfur atoms and not of the molybdenum as previously suggested. The mechanism involves a molybdenum and sulfur-based redox chemistry instead of the currently accepted redox chemistry based only on the Mo ion. The second part of the mechanism involves two protonation steps that are promoted by the presence of MoV species. MoVI intermediates might also be present in this stage depending on the availability of protons and electrons. Once the water molecule is generated only the MoVI species allow water molecule dissociation, and, the concomitant enzymatic turnover.
Design and evaluation of a fast Fourier transform-based nonlinear dielectric spectrometer
Treo, Ernesto Federico; Felice, Carmelo Jose
Nonlinear dielectric spectroscopy of micro-organism is carried out by applying a moderate electrical field to an aqueous sample through two metal electrodes. Several ad hoc nonlinear spectrometers were proposed in the literature. However, these designs barely compensated the nonlinear distortion derived from the electrode-electrolyte interfaces (EEI). Moreover, the contribution of the suspension is masked by the effect of the nonlinearity introduced by the electrode contacts. Conversely, the nonlinear capability of a commercial tetrapolar analyzer has not been fully investigated. In this paper a new nonlinear tetrapolar spectrometer is proposed based on a commercial linear apparatus and ad hoc control and signal processing software. The system was evaluated with discrete electronic phantoms and showed that it can measure nonlinear properties of aqueous suspension independently of the presence of EEI (ANOVA test, p0.001). It was also tested with real aqueous samples. The harmonics observed in the current that circulates through the sample reveals useful information about the transfer function of the sample. The total harmonic distortion was computed for linear mediums. Values lower than -60 dB suggest that the system has enough capability to perform nonlinear microbiological analysis. Design specifications, sources of interference, and equipment's limitations are discussed.
Los estudios sobre medicina y farmacopea vernácula en el gran Chaco
Arenas Rodriguez, Pastor
Se evalúa la situación del conocimiento referido a la medicina y la farmacopea vernácula entre grupos humanos del Gran Chaco. El análisis y reseña se basa en la revisión de aportes bibliográficos correspondientes a diversas disciplinas. Se eligieron las contribuciones más significativas y específicas sobre el tema, excluyéndose como fin la exhaustividad. Se hace una semblanza sobre los grupos humanos tratados, así como de los tópicos resaltantes de la etnomedicina indígena y criolla y la farmacopea propia de ambos colectivos. Se discuten los logros alcanzados y las carencias que aún persisten. Se proponen líneas y orientaciones para fortalecer las investigaciones en temáticas poco tratadas o aún no encaradas.; The scientific knowledge about the medicine and folk pharmacopoeia from ethnic groups of the Gran Chaco region is evaluated. This analysis and review is referred on bibliographical contributions from diverse disciplines. Only those most significant papers about each item are included, thus avoiding repetitive enumerations. A sketch of the ethnic groups under study, as well as important issues on indigenous and creole ethnomedicine and pharmacopoeias are provided. The successes and persistent deficiencies about these data are also discussed. Novel research on little-known subjects is suggested.
Efecto terapéutico de la melatonina en la uveítis experimental
Sande, Pablo Horacio; Fernández, Diego Carlos; Chianelli, Mónica Silvia; Silberman, Dafne Magalí; de Zavalía, Nuria María Asunción; Belforte, Nicolás Adalberto; Salido, Ezequiel Martín; Franco, Pablo Javier; Dorfman, Damián; Lanzani, María Florencia; Bordone, Melina Paula; Keller Sarmiento, María Inés; Saenz, Daniel Alberto; Rosenstein, Ruth Estela
Objetivos: Analizar el efecto de la melatonina en la uveítis inducida por una inyección intravítrea de lipopolisacárido bacteriano (LPS) en el hámster dorado. Métodos: Se implantó un pellet de melatonin dos horas antes de la inyección de LPS. La respuesta inflamatoria se evaluó en términos de: i) integridad de la barrera hemato-ocular, ii) signos clínicos, iii) estudios histopatológicos, y iv) función retiniana. Resultados: La melatonina disminuyó los signos clínicos y la infiltración de proteínas y células en el segmento anterior, protegió la ultraestructura de las barreras hemato-oculares y los fotorreceptores, previno la disfunción electrorretinográfica, y el aumento de la actividad retiniana de NOS y de TNF inducidos por LPS. La melatonina disminuyó el efecto del LPS sobre los niveles nucleares de las subunidades p50 y p65 del factor nuclear B. Conclusiones: La melatonina podría constituir una nueva estrategia terapéutica para el tratamiento de la uveítis.; Objective: To analyze the therapeutic effect of melatonin on uveitis induced by an intravitreal injection of bacterial lipopolysaccharide (LPS) in the golden hamster. Methods: A pellet of melatonin was implanted subcutaneously two hours before the injection of LPS. One and eight days after injections, the inflammatory response was evaluated in terms of: i) integrity of blood-ocular barrier, ii) clinical signs, iii) histopathological studies, and iv) retinal function. Results: Melatonin reduced the leakage of proteins and cells in the anterior segment of LPS-injected eyes, decreased clinical signs and protected the ultrastructure of blood-ocular barriers, and photoreceptors. Melatonin prevented the decrease in the electroretinographic activity induced by LPS. Melatonin significantly abrogated the LPS-induced increase in retinal NOS activity, tumor necrosis factor (TNF), and nuclear factor B (NFB) p50 and p65 subunits levels. Conclusions: These results support the use of melatonin as a new therapeutic strategy for the treatment of uveitis.
Germination of stored and scarified seeds of Passiflora caerulea L. (Passifloraceae)
Mendiondo, Guillermina M.; Amela Garcia, Maria Teresa
This work evaluates the influence of storage and scarification in the germination of Passiflora caerulea L., in order to acquire the necessary knowledge to cultivate this economically important species. Seeds stored one month under different conditions (no storage, fermentation, desiccation) were submitted to various pre‐treatments (aril removal, mechanical and chemical scarification or combinations of these). Emergence was recorded periodically for 11 months in a greenhouse. Germination time, germination percentage and germination speed were calculated. Histochemical tests were applied to seeds maintained under the three storage conditions, for observing possible changes in the integument and storage tissue. Viability was maintained at least for the storage period tested, as germination occurred after that time. Because the seeds stored under desiccation germinated, the species is orthodox. Chemical scarification prevented germination in most cases. Although germination levels were low, they were higher in stored seeds (fermented and desiccated) than in fresh ones. Fermented seeds (which exhibited no storage tissue and less lignin in the integument) devoid of the aril germinated earlier, faster and in greater quantity. The type of dormancy of this species is discussed.
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.
