Key Production Parameters to Obtain Transparent Nanocellular PMMA

Transparent nanocellular polymethylmethacrylate (PMMA) with relative density around 0.4 is produced for the first time by using the gas dissolution foaming technique. The processing conditions and the typical characteristics of the cellular structure needed to manufacture this novel material are discovered. It is proved that low saturation temperatures (−32 °C) combined with high saturation pressures (6, 10, 20 MPa) allow increasing the solubility of PMMA up to values not reached before. In particular, the highest CO2 uptake ever reported for PMMA, (i.e., 48 wt%) is found for a saturation pressure of 20 MPa and a saturation temperature of −32 °C. Due to these processing conditions, cell nucleation densities of 1016 nuclei cm−3 and cell sizes clearly below 50 nm are achieved. The nanocellular polymers obtained, with cell sizes ten times smaller than the wavelength of visible light and very homogeneous cellular structures, show a significant transparency

Efecto de la estructura del mercado y eficiencia sobre el desempeño de las casas de bolsa en México

La competencia es un elemento fundamental para el buen funcionamiento de un sistema económico de mercado. Con competencia se mejoran las condiciones de precio y calidad de los productos y servicios, se mejora la productividad e incentiva la innovación dirigiéndose hacia un mayor bienestar de la sociedad (Navarro Zermeño, 2014). En ocasiones, la competencia se ve perjudicada debido a prácticas anticompetitivas por parte de las empresas con incentivos a generar mayores beneficios propios, lo cual puede llegar a tener un impacto negativo en el mercado relevante que se trate. Existen leyes que fomentan el derecho a la competencia y prohíben dichas prácticas anticompetitivas

Datacab: a geographical‐information‐system‐based expert system for the design of cable networks

Telecommunication networks have evolved over time as a result of technological advances, and network topologies and equipment have become increasingly complex. Expert systems are being successfully applied to the management of telecommunication networks. However, applying expert systems to network design is another especially beneficial yet still not very common approach. In this paper we propose a rule‐based expert system called Datacab. Datacab was developed at Enditel Endesa in collaboration with the Electronic Technology Department of the University of Seville, for the automatic design of hybrid fibre coax (HFC) cable networks. Using data from a geographical information system as input, it automatically generates viable HFC network designs

A Precise Electrical Disturbance Generator for Neural Network Training with Real Level Output

Power Quality is defined as the study of the quality of electric power lines. The detection and classification of the different disturbances which cause power quality problems is a difficult task which requires a high level of engineering expertise. Thus, neural networks are usually a good choice for the detection and classification of these disturbances. This paper describes a powerful tool, developed by the Institute for Natural Resources and Agrobiology at the Scientific Research Council (CSIC) and the Electronic Technology Department at the University of Seville, which generates electrical patterns of disturbances for the training of neural networks for PQ tasks. This system has been expanded to other applications (as comparative test between PQ meters, or test of effects of power-line disturbances on equipment) through the addition of a specifically developed high fidelity power amplifier, which allows the generation of disturbed signals at real levels.Ministerio de Ciencia y Tecnología DPI2006-15467-C02-0

Evaluation of warning signs in autism spectrum disorders at the age of 9 to 16 months

Se presenta un estudio ideográfico de seguimiento de un bebé con riesgo de alteración en el desarrollo. Entre los 9 y los 16 meses de edad se ha registrado en vídeo la conducta espontánea del sujeto en el entorno del hogar en situaciones de interacción diádica (sujeto-sujeto) y triádica (sujeto-objeto-sujeto). Para el análisis de datos se establecieron 14 categorías observacionales, basadas en la literatura sobre desarrollo típico y desarrollo alterado en los Trastornos del Espectro Autista. Los resultados obtenidos muestran signos de alarma en el desarrollo en todas las edades en las que ha sido estudiado en: seguimiento de mirada, uso de gestos y conductas de atención (y acción) conjunta. Sería muy aconsejable, introducir la categoría de Usos de Objetos –usos no convencionales, convencionales, y atípicos– en los instrumentos para la identificación de los Trastornos del Espectro Autista. Las conclusiones principales señalan la necesidad de seguir ahondando en el conocimiento de conductas discriminativas desde el primer año de vida, capaces de alertar sobre un desarrollo alteradoAn ideographic study is presented based on the follow-up of a baby at high risk of impaired development. The spontaneous behavior of the child was video recorded, in the home environment in situations of dyadic (subject-subject) and triadic interactions (subject-object-subject). For data analysis, 14 observational categories were established, based on a theoretical review of typical development and altered development in Autism Spectrum Disorder. Results show warning signs at all ages that were studied, based on the following aspects: Eye tracking, use of gestures and join attention and action behaviors. The need to include the category of uses –non-conventional, conventional and atypical uses– of objects in the instruments and guidelines for the identification of Autism Spectrum Disorders was considered. The main finding indicates the need to deepen knowledge of discriminative behavior in the first year of life, useful to identify warning signs of impaired developmentParte de esta investigación ha sido financiada por el Ministerio de Ciencia e Innovación. Referencia: EDU2011-2784

Changes in P-glycoprotein activity are mediated by the growth of a tumour cell line as multicellular spheroids

BACKGROUND: Expression of P-glycoprotein (P-gp), the multidrug resistance (MDR) 1 gene product, can lead to multidrug resistance in tumours. However, the physiological role of P-gp in tumours growing as multicellular spheroids is not well understood. Recent evidence suggests that P-gp activity may be modulated by cellular components such as membrane proteins, membrane-anchoring proteins or membrane-lipid composition. Since, multicellular spheroids studies have evidenced alterations in numerous cellular components, including those related to the plasma membrane function, result plausible that some of these changes might modulate P-gp function and be responsible for the acquisition of multicellular drug resistance. In the present study, we asked if a human lung cancer cell line (INER-51) grown as multicellular spheroids can modify the P-gp activity to decrease the levels of doxorubicin (DXR) retained and increase their drug resistance. RESULTS: Our results showed that INER-51 spheroids retain 3-folds lower doxorubicin than the same cells as monolayers however; differences in retention were not observed when the P-gp substrate Rho-123 was used. Interestingly, neither the use of the P-gp-modulating agent cyclosporin-A (Cs-A) nor a decrease in ATP-pools were able to increase DXR retention in the multicellular spheroids. Only the lack of P-gp expression throughout the pharmacological selection of a P-gp negative (P-gp(neg)) mutant clone (PSC-1) derived from INER-51 cells, allow increase of DXR retention in spheroids. CONCLUSION: Thus, multicellular arrangement appears to alter the P-gp activity to maintain lower levels of DXR. However, the non expression of P-gp by cells forming multicellular spheroids has only a minor impact in the resistance to chemotherapeutic agents