Pecorelli M.,National Institute of Industrial Technology
18th IMEKO TC4 Symposium on Measurement of Electrical Quantities 2011, Part of Metrologia 2011 | Year: 2011
A new PD (partial discharge) measuring system calibrator is described. The device, battery operated, may be used either grounded or in a floating position, and generates securely mains-synchronized impulses by capacitive coupling. It allows the determination of the scale factor k and resolution time Tr in PD measuring systems, and it fulfils the requirements of International Standard IEC 60270. PD measuring instruments have mains-synchronized sweeps. Hence, in order to have stationary calibration impulses in the PD measuring instrument, the calibrator must generate mains-synchronized impulses. Usually, PD calibrators synchronize to mains frequency by a photodiode. In case of insufficient pick-up of power frequency light, these calibrators automatically select an internal quartz oscillator. When the internal oscillator is on, there is usually a slight difference between the oscillator frequency (fixed) and the mains frequency (variable), and consequently the impulses generated by the internal oscillator are not stationary in the PD measuring instrument (detector screen). This new calibrator avoids that problem because it generates securely mains-synchronized impulses by capacitive coupling, making unnecessary an internal quartz oscillator. Copyright © 2011 by the International Measurement Confederation (IMEKO) All rights reserved.
Rodriguez C.E.,University of Buenos Aires |
Reidel S.I.,National Institute of Industrial Technology |
De Kier Joffe E.D.B.,University of Buenos Aires |
Jasnis M.A.,University of Buenos Aires |
And 2 more authors.
PLoS ONE | Year: 2015
Multicellular tumor spheroids represent a 3D in vitro model that mimics solid tumor essential properties including assembly and development of extracellular matrix and nutrient, oxygen and proliferation gradients. In the present study, we analyze the impact of 3D spatial organization of HER2-overexpressing breast cancer cells on the response to Trastuzumab. We cultured human mammary adenocarcinoma cell lines as spheroids with the hanging drop method and we observed a gradient of proliferating, quiescent, hypoxic, apoptotic and autophagic cells towards the inner core. This 3D organization decreased Trastuzumab sensitivity of HER2 over-expressing cells compared to monolayer cell cultures. We did not observe apoptosis induced by Trastuzumab but found cell arrest in G0/G1 phase. Moreover, the treatment downregulated the basal apoptosis only found in tumor spheroids, by eliciting protective autophagy. We were able to increase sensitivity to Trastuzumab by autophagy inhibition, thus exposing the interaction between apoptosis and autophagy. We confirmed this result by developing a resistant cell line that was more sensitive to autophagy inhibition than the parental BT474 cells. In summary, the development of Trastuzumab resistance relies on the balance between death and survival mechanisms, characteristic of 3D cell organization. We propose the use of spheroids to further improve the understanding of Trastuzumab antitumor activity and overcome resistance. © 2015 Rodríguez et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Gallego A.,University of Buenos Aires |
Gemini V.L.,University of Buenos Aires |
Gemini V.L.,National Institute of Industrial Technology |
Rossen A.A.,University of Buenos Aires |
And 5 more authors.
World Journal of Microbiology and Biotechnology | Year: 2012
An indigenous strain of Pseudomonas putida capable of degrading 3-chlorobenzoic acid as the sole carbon source was isolated from the Riachuelo, a polluted river in Buenos Aires. Aerobic biodegradation assays were performed using a 2-l microfermentor. Biodegradation was evaluated by spectrophotometry, chloride release, gas chromatography and microbial growth. Detoxification was evaluated by using Vibrio fischeri, Pseudokirchneriellasubcapitata and Lactuca sativa as test organisms. The indigenous bacterial strain degrades 100 mg l-1 3-chlorobenzoic acid in 14 h with a removal efficiency of 92. 0 and 86. 1% expressed as compound and chemical oxygen demand removal, respectively. The strain was capable of degrading up to 1,000 mg of the compound l-1. Toxicity was not detected at the end of the biodegradation process. Besides initial concentration, the effect of different factors, such as initial pH, initial inoculum, adaptation to the compound and presence of other substrates and toxic related compounds, was studied. © 2011 Springer Science+Business Media B.V.
Gomez G.,National Institute of Industrial Technology
MeMeA 2013 - IEEE International Symposium on Medical Measurements and Applications, Proceedings | Year: 2013
The present paper describe a proposal scheme of calibration of electrosurgery equipment. This work also discuss the operation of electrosurgical equipment, analyzers of electrosurgical equipment and equipment and methods necesary to make the calibrations. © 2013 IEEE.
Monnier S.L.D.,National Institute of Industrial Technology |
Mendez A.M.,National Institute of Industrial Technology
Proceedings - 10th Annual IEEE Symposium on Product Compliance Engineering, ISPCE 2013 | Year: 2013
This paper describes the different stages that were necessary in testing microwave ovens for product comparison on the safety laboratory of National Institute of Industrial Technology. Although several departments of the Institute were involved in the comparison, this work will focus only on the work of one of those departments, the safety laboratory. The necessary stages were technical organization, realization and obtained results. The technical organization included the definition of the type of microwave oven used in comparison, selection of microwave power range, capacity and functionality. After that, a selection of test included in comparison was made, taking into account the critical points, the potential interests of users and the capacity of the laboratory. Then the work will explain the criteria used during the realization of tests and the challenges that laboratory should face. Finally, the obtained results were published in a final report and in a brochure friendly to consumers. © 2013 IEEE.