On the Geometry of Sculpting-like Gauging Processes

Recently, a new gauging procedure called Sculpting mechanism was proposed to obtain the M-theory origin of type II gauged Supergravity theories in 9D. We study this procedurein detail and give a better understanding of the different deformations and changes in fiber bundles, that are able to generate new relevant physical gauge symmetries in the theory. We discuss the geometry involved in the standard approach (Noether-like) and in the new Scultping-like one and comment on possible new applications.Comment: 9 pages, latex, Notation and typos reviewed, more clear explanations, results unchange

Prediction of non-genotoxic carcinogenicity based on genetic profiles of short term exposure assays

Non-genotoxic carcinogens are substances that induce tumorigenesis by non-mutagenic mechanisms and long term rodent bioassays are required to identify them. Recent studies have shown that transcription profiling can be applied to develop early identifiers for long term phenotypes. In this study, we used rat liver expression profiles from the NTP (National Toxicology Program, Research Triangle Park, USA) DrugMatrix Database to construct a gene classifier that can distinguish between non-genotoxic carcinogens and other chemicals. The model was based on short term exposure assays (3 days) and the training was limited to oxidative stressors, peroxisome proliferators and hormone modulators. Validation of the predictor was performed on independent toxicogenomic data (TG-GATEs, Toxicogenomics Project-Genomics Assisted Toxicity Evaluation System, Osaka, Japan). To build our model we performed Random Forests together with a recursive elimination algorithm (VarSelRF). Gene set enrichment analysis was employed for functional interpretation. A total of 770 microarrays comprising 96 different compounds were analyzed and a predictor of 54 genes was built. Prediction accuracy was 0.85 in the training set, 0.87 in the test set and increased with increasing concentration in the validation set: 0.6 at low dose, 0.7 at medium doses and 0.81 at high doses. Pathway analysis revealed gene prominence of cellular respiration, energy production and lipoprotein metabolism. The biggest target of toxicogenomics is accurately predict the toxicity of unknown drugs. In this analysis, we presented a classifier that can predict non-genotoxic carcinogenicity by using short term exposure assays. In this approach, dose level is critical when evaluating chemicals at early time points.Fil: Perez, Luis Orlando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: González José, Rolando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Peral Garcia, Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria ; Argentin

In vitro approach to the study of chronic exposure to low doses of x-rays

El presente trabajo fue realizado con el fin de estudiar el efecto de dosis bajas y repetidas de radiación sobre dos líneas celulares de la misma especie. Se desarrolló un modelo in vitro para evitar la influencia de los factores de confusión que afectan a los estudios epidemiológicos y para simular una exposición crónica. Las técnicas utilizadas fueron el ensayo cometa y el análisis de apoptosis temprana; estas se llevaron a cabo inmediatamente después de la exposición y luego de la irradiación crónica. La irradiación secuencial indujo un aumento de células con daño en el ADN. El índice de daño fue mayor que el de los controles en ambas líneas celulares, tanto inmediatamente después de la exposición como luego de la irradiación crónica. Este aumento fue estadísticamente significativo solamente para la línea celular transformada luego de la irradiación crónica (p<0,001). El análisis de apoptosis arrojó niveles significativamente mayores al control para ambas líneas celulares luego de la exposición crónica (p<0.001). Se demostró que la exposición crónica a radiación ionizante de dosis bajas indujo daño en el ADN y apoptosis en células de hámster chino cultivadas in vitro. Las respuestas de ambos tipos celulares fueron algo diferentes. Evidentemente, el tipo celular debe ser tenido en cuenta a la hora de diseñar experimentos in vitro para entender los efectos de la radiación crónica de dosis baja en las poblaciones celulares.The present research was undertaken in order to study the effect of repeated low doses of radiation on two different cell lines from the same species. An in vitro model test was developed to avoid the influence of the confounding factors affecting epidemiological studies and to simulate a chronic exposure (50 mSv of x-rays during ten consecutive days). Comet assay and early apoptosis were analyzed immediately after exposure and after chronic irradiation. Sequential irradiation induced an increase of cells showing DNA damage. Index Damage was higher than that of the controls in both cell lines immediately after exposure and after chronic irradiation; these differences between exposed and control cells were statistically significant only for the transformed cell line after chronic irradiation (p<0.001). Significantly higher levels of apoptosis were scored after chronic exposure in both cells lines (p<0.001). The induction of DNA damage and apoptosis in hamster cells by chronic exposure to low dose ionizing radiation was demonstrated. Cell types reacted differently to chronic exposure; though further investigation is needed to understand the mechanisms of radiation effects on chronic low-dose-exposed cell populations, cellular type should be taken into account in the design of in vitro experiments to understand low-dose-irradiation effects.Fil: Ponzinibbio, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Peral Garcia, Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; ArgentinaFil: Seoane, Analia Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET- La Plata. Instituto de Genética Veterinaria "Ing. Fernando Noel Dulout". Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Genética Veterinaria; Argentin