La poética de Olga Orozco o el rehuso del último dios en su paso fugaz

Para comprender la motivación y expectativa que nos embarga sería oportuno hacer un recuento de nuestro diálogo con la obra de la poeta argentina. Lo más importante3 es que en el año 2003 le dediqué mi tesis de licenciatura en filosofía bajo la dirección de María Gabriela Rebok. Fue titulada Vida y obra poética de Olga Orozco, y sus subtítulos correspondieron a las dos monografías que la constituyeron: una, de carácter especulativo ensayó Una hermenéutica filosófica a partir de una poética esencial; la otra, de carácter histórico investigó unas contribuciones de la poética de Orozco para la aclaración del fenómeno óntico del sacrificio como posible hilo conductor de una interpretación de la historia del ser.

Física de la medicina nuclear : Introducción al control y verificación de los equipos. Una guía práctica

La Medicina Nuclear (MN), según la definición establecida en el año 1972 en Ginebra, por la Organización Mundial de la Salud y la OIEA, “es la especialidad que se ocupa del diagnóstico, tratamiento e investigación médica, mediante el uso de radioisótopos como fuentes abiertas”. Cuando son utilizados con un propósito diagnóstico, se aprovecha la propiedad emisora de los radioisótopos para detectarlos a distancia; cuando la intención es terapéutica, se usufructúa el efecto deletéreo que la radiación puede tener sobre un tejido. El procedimiento para generar imágenes en MN requiere la administración (intravenosa, subdérmica, oral, inhalación, etc.) de una dosis trazadora de una sustancia radioactiva o radiofármaco; una dosis trazadora es una cantidad mínima, capaz de “marcar”, pero sin perturbar la fisiología del blanco en cuestión. El radiofármaco consiste en la combinación de un ligando que determina su biodistribución y una radioisótopo responsable de generar una señal detectable. Un estudio diagnóstico basado en la detección de un radiofármaco, no se reduce a una mera detección. Si así fuera, nos bastaría un simple contador Geiger, o más aún, un sencillo film monitor, que sin duda son capaces de detectar la radioactividad procedente del radiofármaco que está siendo emitida por el paciente (que funciona como una fuente no sellada). En un estudio diagnóstico pretendemos obtener con la detección una representación lo más exacta posible de la distribución de la actividad (y del radiofármaco) dentro del organismo. Muchas veces esa detección tiene como resultado la elaboración de una imagen donde verificamos esa distribución. Y si es posible, muchas veces también intentamos medir, (cuantificar) esa distribución.Facultad de Ciencias Exacta

A vanadium/aspirin complex controlled release using a poly(ß-propiolactone) film : Effects on osteosarcoma cells

A delivery system for vanadium was developed using poly(ß-propiolactone)(PßPL) films. The release kinetics of a complex of vanadium (IV) with aspirin (VOAspi) was evaluated with lms prepared from polymers of different molecular weights, as well as with variable drug load. A sustained release of vanadium over 7 days was achieved. The drug release kinetics depends on contributions from two factors: (a) diffusion of the drug; and (b) erosion of the PßPL lm. The experimental data at an early stage of release were tted with a diffusion model, which allowed determination of the diffusion coef cient of the drug. VOAspi does not show strong interaction with the polymer, as demonstrated by the low apparent partition coef cient (approximately 10-2). UMR106 osteosarcoma cells were used as a model to evaluate the anticarcinogenic effects of the VOAspi released from the PßPL lm. VOAspi–PßPL lm inhibited cell proliferation in a dose-response manner and induced formation of approximately half of the thiobarbituric acid reactive substances (TBARS), an index of lipid peroxidation, compared to that with free VOAspi in solution. The unloaded PßPL lm did not generate cytotoxicity, as evaluated by cell growth and TBARS. Thus, the polymer-embedded VOAspi retained the antiproliferative effects showing lower cytotoxicity than the free drug. Results with VOAspi–PßPL lms suggest that this delivery system may have promising biomedical and therapeutic applications.Facultad de Ciencias Exacta

A vanadium/aspirin complex controlled release using a poly(ß-propiolactone) film : Effects on osteosarcoma cells

A delivery system for vanadium was developed using poly(ß-propiolactone)(PßPL) films. The release kinetics of a complex of vanadium (IV) with aspirin (VOAspi) was evaluated with lms prepared from polymers of different molecular weights, as well as with variable drug load. A sustained release of vanadium over 7 days was achieved. The drug release kinetics depends on contributions from two factors: (a) diffusion of the drug; and (b) erosion of the PßPL lm. The experimental data at an early stage of release were tted with a diffusion model, which allowed determination of the diffusion coef cient of the drug. VOAspi does not show strong interaction with the polymer, as demonstrated by the low apparent partition coef cient (approximately 10-2). UMR106 osteosarcoma cells were used as a model to evaluate the anticarcinogenic effects of the VOAspi released from the PßPL lm. VOAspi–PßPL lm inhibited cell proliferation in a dose-response manner and induced formation of approximately half of the thiobarbituric acid reactive substances (TBARS), an index of lipid peroxidation, compared to that with free VOAspi in solution. The unloaded PßPL lm did not generate cytotoxicity, as evaluated by cell growth and TBARS. Thus, the polymer-embedded VOAspi retained the antiproliferative effects showing lower cytotoxicity than the free drug. Results with VOAspi–PßPL lms suggest that this delivery system may have promising biomedical and therapeutic applications.Facultad de Ciencias Exacta

A vanadium/aspirin complex controlled release using a poly(ß-propiolactone) film : Effects on osteosarcoma cells

A delivery system for vanadium was developed using poly(ß-propiolactone)(PßPL) films. The release kinetics of a complex of vanadium (IV) with aspirin (VOAspi) was evaluated with lms prepared from polymers of different molecular weights, as well as with variable drug load. A sustained release of vanadium over 7 days was achieved. The drug release kinetics depends on contributions from two factors: (a) diffusion of the drug; and (b) erosion of the PßPL lm. The experimental data at an early stage of release were tted with a diffusion model, which allowed determination of the diffusion coef cient of the drug. VOAspi does not show strong interaction with the polymer, as demonstrated by the low apparent partition coef cient (approximately 10-2). UMR106 osteosarcoma cells were used as a model to evaluate the anticarcinogenic effects of the VOAspi released from the PßPL lm. VOAspi–PßPL lm inhibited cell proliferation in a dose-response manner and induced formation of approximately half of the thiobarbituric acid reactive substances (TBARS), an index of lipid peroxidation, compared to that with free VOAspi in solution. The unloaded PßPL lm did not generate cytotoxicity, as evaluated by cell growth and TBARS. Thus, the polymer-embedded VOAspi retained the antiproliferative effects showing lower cytotoxicity than the free drug. Results with VOAspi–PßPL lms suggest that this delivery system may have promising biomedical and therapeutic applications.Facultad de Ciencias Exacta

Estudio de arenas de trituración para el reemplazo de arenas naturales en la elaboración de morteros y hormigones

En Argentina, el Reglamento Argentino de Estructuras de Hormigón, permite el empleo de hasta un 30% de arenas trituradas en el agregado fino del hormigón. El objetivo del presente trabajo, fue estudiar la forma, textura superficial y granulometría de arenas de trituración de explotaciones de rocas de aplicación, ubicadas en la provincia de Buenos Aires. Se estudiaron de manera preliminar, las arenas de trituración generadas en el 75% de los establecimientos mineros registrados en la Dirección Provincial de Minería de la provincia de Buenos Aires. La forma y textura, se analizó utilizando lupa binocular y microscopio para las fracciones menores a 250H. La distribución del tamaño de partículas, se llevó a cabo mediante tamizado en seco. Los resultados mostraron un buen ajuste a la curva óptima de distribución granulométrica, textura rugosa a cristalina, e índices de esfericidad y redondez que podrían condicionar la trabajabilidad.Instituto de Recursos MineralesFacultad de Arquitectura y Urbanism

Ecología – biopolítica: indagando el rol de la educación

The aim of this research paper consisted in generating a contribution to the concept of ecology from the point of view of an investigation of critical-creative nature which could benefit teacher training from the multidisciplinary observation of a line of research that linked the mainstreaming of education and values communication.The organism-environment relationship – as ecology itself is defined – has been established as a concern that exceeds public opinion setting in academic areas and integrating the curricula at different educational levels through tutorial policies or programs.Having this raised and on the basis of categories granted by the theoretical framework provided by authors such as Foucault, Baudrillard, Deleuze and Guattari, the object of research invited to wonder about the place education occupies in a present-future period; about the training of future guardians of this work in a photographic, static instant, frozen in the present for future generations, among other issues.The methodology was applied in “Green Schools”–an ecology project instituted in different institutions in the City of Buenos Aires–with the intention of implementing an urban environmental planning and management policy. “Green Schools” facilitates content development, training and generates environmental management actions. In its methodology, we have identified some hotspots by the lack of theoretical criterion and an excessive demand for students´ active participation in their community and involvement in setting values.The content of teaching material was analyzed and we found out it does not provide didactic and pedagogical resources enough to carry out the instructive transposition. When attempting this crossing with the analysis of the above mentioned materials, published in print and on the web, we noticed there is no specific theoretical framework to support the teaching-learning equation in relation to these topics.Then, we conclude asserting that if ecology is seen as a set of practices reduced to the produced waste and its processes, it is impossible to relieve them to a more complex analysis with cultural social-educational projection. When we mention “reduced”, we refer to its sense of uniqueness, generator of a loss in value or significance which leads to the impossibility of transforming thought, thus causing deep problematic in matter, what would result optimal for the educational aim.El objetivo de esta investigación consistió en generar un aporte al concepto de ecología desde una investigación de índole crítico-creativa, que contribuyera a la formación docente, a partir de la observación multidisciplinar de una línea de investigación que vincula la transversalidad de la educación y la comunicación de valores. La relación “organismo-entorno” –como se define la ecología a sí misma– se ha establecido como una preocupación que excede a la opinión pública, instalándose en ámbitos académicos e incorporándose a los currículos en diferentes niveles educativos a través de políticas o programas educativos.En este planteo y en base a las categorías que otorgó un marco teórico con autores como Foucault, Baudrillard, Deleuze y principalmente Guattari, el objeto de la investigación nos invitó a preguntarnos acerca del lugar que ocupa la educación en un presente-futuro; sobre la formación de futuros custodios de este mundo en un instante fotográfico, estático, congelado en un presente para generaciones futuras, entre otras cuestiones. La metodología fue aplicada en Escuelas Verdes –proyecto ecológico instituido en las escuelas en la Ciudad de Buenos Aires– con la intención de implementar una política de planeamiento y gestión del ambiente urbano. Escuelas Verdes facilita el desarrollo de contenidos, capacitación y genera acciones de gestión ambiental. En la metodología, hemos identificado puntos conflictivos por la carencia de criterio teórico, y una excesiva demanda a los estudiantes para que participen activamente en su comuna y con una puesta de valores. Se analizó el contenido del material para la formación docente y se observó que no brinda elementos didácticos y pedagógicos para la transposición didáctica. Al realizar este cruce con el análisis de los materiales publicados de forma impresa y digital, observamos que no hay un marco teórico específico que fundamente la ecuaciónen señanza-aprendizaje de estos temas. Concluimos, entonces, que si la ecología se observa como un conjunto de prácticas que se reducen a los residuos producidos y sus procesos, es imposible relevarlas a análisis más complejos con una proyección educativa-social-cultural. Cuando mencionamos “reducidas” nos referimos aque la univocidad de sentidos genera pérdida de valor o significancia, conduce a la imposibilidad de transformación de pensamiento, provocando una profunda problematización en la materia, que sería lo óptimo para el fin educativo

Estudio de arenas de trituración para el reemplazo de arenas naturales en la elaboración de morteros y hormigones

El hormigón es uno de los materiales de uso más difundido a nivel global. Su empleo, demanda grandes volúmenes de recursos naturales no renovables y elevados consumos de energía.

Role of oxidative stress in the antitumoral action of a new vanadyl(IV) complex with the flavonoid chrysin in two osteoblast cell lines: relationship with the radical scavenger activity

The new complex [VO(chrysin)₂EtOH]₂ (VOchrys) has been synthesized and thoroughly characterized. Fourier transform IR, UV-vis, diffuse reflectance, and EPR spectroscopies as well as elemental analysis and thermal measurements were performed. In solution, different species could be detected by EPR spectroscopy as a function of the ligand-to-metal ratio. The stoichiometry of the chelate complex formed at pH 5 was also determined by spectrophotometric titrations. Since flavonoids are natural antioxidant compounds, the antioxidant capacity of chrysin and its vanadyl(IV) complex was investigated using different radicals. Chrysin and its complex were not able to diminish the level of superoxide and 1,1-diphenyl-2-picrylhydrazyl radicals to a great extent. In contrast, they were strong scavengers for 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt radical cations and OH. radicals with a greater potency for VOchrys. Taking into account their selective antioxidant properties, we investigated the bioactivity of these compounds in two osteoblast-like cells in culture. Chrysin and VOchrys caused an inhibition of cell proliferation in MC3T3E1 normal osteoblasts and UMR106 tumor cells in a dose-response manner, with a greater effect in the latter cell line. The generation of reactive oxygen species (ROS) was evaluated in both cell lines and a correlation could be established between the antiproliferative effects of chrysin and the increase in the ROS levels. The complex did not generate types of ROS that can be detected by the dihydrorhodamine 123 technique so the antiproliferative effect may be attributed to the formation of other radicals such as superoxide, which is not detected by this probe. The morphological alterations were in agreement with these changes.Facultad de Ciencias ExactasCentro de Química Inorgánic

C3G, through its GEF activity, induces megakaryocytic differentiation and proplatelet formation

[Background]: Megakaryopoiesis allows platelet formation, which is necessary for coagulation, also playing an important role in different pathologies. However, this process remains to be fully characterized. C3G, an activator of Rap1 GTPases, is involved in platelet activation and regulates several differentiation processes. [Methods]: We evaluated C3G function in megakaryopoiesis using transgenic mouse models where C3G and C3GΔCat (mutant lacking the GEF domain) transgenes are expressed exclusively in megakaryocytes and platelets. In addition, we used different clones of K562, HEL and DAMI cell lines with overexpression or silencing of C3G or GATA-1. [Results]: We found that C3G participates in the differentiation of immature hematopoietic cells to megakaryocytes. Accordingly, bone marrow cells from transgenic C3G, but not those from transgenic C3GΔCat mice, showed increased expression of the differentiation markers CD41 and CD61, upon thrombopoietin treatment. Furthermore, C3G overexpression increased the number of CD41+ megakaryocytes with high DNA content. These results are supported by data obtained in the different models of megakaryocytic cell lines. In addition, it was uncovered GATA-1 as a positive regulator of C3G expression. Moreover, C3G transgenic megakaryocytes from fresh bone marrow explants showed increased migration from the osteoblastic to the vascular niche and an enhanced ability to form proplatelets. Although the transgenic expression of C3G in platelets did not alter basal platelet counts, it did increase slightly those induced by TPO injection in vivo. Moreover, platelet C3G induced adipogenesis in the bone marrow under pathological conditions. [Conclusions]: All these data indicate that C3G plays a significant role in different steps of megakaryopoiesis, acting through a mechanism dependent on its GEF activity.This work was supported by grants from the Spanish Ministry of Economy and Competitiveness [SAF2013–48210-C2–1-R and SAF2016–76588-C2–2-R to CG, SAF2013–48210-C2–2-R and SAF2016–76588-C2–1-R to AP], and by two grants from the Council of Education of Junta de Castilla y León, Spain [SA157A12–1 and SA017U16 to CG]. All funding was cosponsored by the European FEDER Program