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In the present work the classification of dairies additives in a rapid and simple way, is proposed. Measurements were made by means of an Electronic Nose developed in our laboratories, which we named 'Patagonia E-Nose.' This E-Nose is composed of SnO2 sensors located in a thermally stabilized chamber which improves the repeatability of the measurements. Samples of various hydrolyzed dairies were measured using air as a reference gas. Then, the integrals of the signals were analyzed using a combination of different multivariate chemometric methods such as linear discriminant analysis (LDA), principal components analysis (PCA), back-propagation neural network and different classifiers. Also, different algorithms were implemented and compared by calculating the number of correctly classified samples of each method. 99.4% of correct classifications were obtained by using cross-validation and selecting the most appropriate algorithms. The results indicate that the samples were correctly classified through the implementation of a simple and low cost measurement protocol. Fil: Vorobioff, Juan. Comisión Nacional de Energía Atómica; Argentina Fil: Adaro, Mauricio Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Boggio, Norberto Gabriel. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Magallanes, J.. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Boselli, A.. Comisión Nacional de Energía Atómica; Argentina Fil: Lamagna, Federico Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; Argentina Fil: Rinaldi, Carlos Alberto. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

The objective of this work is to improve the electronic nose (e-nose) response to detect the presence of Triatoma infestans, commonly named “vinchuca”, transmitters of Trypanosoma cruzi, agent of the Chagas disease (ECh). An electronic nose developed in our own laboratory, with 8 commercial MOX type SnO 2 sensors, was used. Different reference gases used in the purging of the e-nose sensors chamber were analyzed. The samples analyzed consisted of pieces of filter paper placed in contact with individuals of Triatoma infestans during 168 hours. After removing the insects, the samples were irradiated with UV laser to increase the intensity of the measured signals. Notable improvements in the amplitude of the sensors signals were obtained using N 2 as reference gas in combination with UV laser irradiation.

In this research work, DEXTRAN- and polyethyl- ene glycol (PEG)-coated iron-oxide superparamagnetic nano- particles were synthetized and their cytotoxicity and biodistribution assessed. Well-crystalline hydrophobic Fe3O4 SPIONs were formed by a thermal decomposition process with d 5 18 nm and r 5 2 nm; finally, the character of SPIONs was changed to hydrophilic by a post-synthesis pro- cedure with the functionalization of the SPIONs with PEG or DEXTRAN. The nanoparticles present high saturation mag- netization and superparamagnetic behavior at room tempera- ture, and the hydrodynamic diameters of DEXTRAN- and PEG-coated SPIONs were measured as 170 and 120 nm, respectively. PEG- and DEXTRAN-coated SPIONs have a Spe- cific Power Absorption SPA of 320 and 400 W/g, respectively, in an ac magnetic field with amplitude of 13 kA/m and fre- quency of 256 kHz. In vitro studies using VERO and MDCK cell lineages were performed to study the cytotoxicity and cell uptake of the SPIONs. For both cell lineages, PEG- and DEXTRAN-coated nanoparticles presented high cell viability for concentrations as high as 200 lg/mL. In vivo studies were conducted using BALB/c mice inoculating the SPIONs intrave- nously and exposing them to the presence of an external magnet located over the tumour. It was observed that the amount of PEG-coated SPIONs in the tumor increased by up to 160% when using the external permanent magnetic as opposed to those animals that were not exposed to the exter- nal magnetic field. V C

Throughout this investigation, experiments on laser ablation with silicon (Si) wafers have been performed using silicon nitride (Si 3 N 4 ) as a sacrificial layer to find the optimal fluence capable of removing the Si 3 N 4 , which allows the subsequent anisotropic etching in Si with potassium hydroxide. As a result, an alternative to the traditional micromachining techniques that require more steps and processing times has been introduced. The effect of the pulse numbers on Si wafers has been studied and it has been observed that when increasing the pulse numbers at the same fluence, the capacity of the pyramidal cavity formed was greater than using only one pulse at higher fluences. Microcavities were performed with a floating Si 3 N 4 layer. This happens to be very useful for the development of drug delivery systems and the manufacture of microarrays. Microcavities were also used as masters for the fabrication of microionizers in polydimethyl siloxane (PDMS).

Carbon nanotubes (CNT) are valuable for their application in nanotechnology, electrical properties and high surface area, and in our particular case, for the manufacture of nanosensors. In this work the technique of Plasma Enhanced Chemical Vapor Deposition (PECVD) was used for the manufacture of CNT. The process was conducted in a horizontal tube reactor using methane as precursor gas and an R.F. discharge of 1000w output power acting as ionizing medium. Having achieved the synthesis of CNT on copper (Cu) substrates, heated with an internal electrical resistance to a process temperature of 900°C, the substrates were coated with ferric nitrate Fe(NO 3 ) 3 , which served as a catalyst and nucleation center. The heating system used differs from traditional methods by its internal heating. Growth of CNT was achieved on vertical walls on Cu substrates and perpendicular to it; a prerequisite for the manufacture of nanosensors, which is the main objective of this work, as well as to reduce as much as possible the diameter of the CNT, being its main features 5 μm average length and 7 nm average diameter.

Propulsion pellets of different metal/salt (Zn/CaCO 3 ) composition have been prepared. The impulse imparted to the pellet by the laser has been measured using two different methods: a torsion pendulum and a piezoelectric sensor. The dependence of the coupling coefficient, C m , on the composition of the solid binary propellants in ablative laser propulsion has been investigated under different experimental conditions: in vacuum and at atmospheric pressure as well as with two different wavelengths, IR and UV. The composition of the Zn/CaCO 3 propellant mixture that optimizes the coupling coefficient, C m , has been determined.

SnO2 microrods exhibited an ultra-fast photo-response when light led 402-940 nm was switched on and off. SnO2 microrods films were prepared with SnCl4 as the starting material. We found that increasing light radiation flux decreases the resistance. The effect of radiation on the film will be discussed as function of chemiabsorbed oxygen.

In this article a method to increase the capability of an electronic nose to discriminate between a priori similar odours is presented. Olive oil is analyzed because it is well known that the characteristics of its aroma impair in many cases the discrimination between different kinds of olive oils especially when they are from similar geographic regions. In the present work the improvement of the electronic nose performance for the above-mentioned discrimination by a non-destructive method of IR laser vaporization of the sample is studied. Laser vaporization has also been performed at two different IR wavelengths to analyze the effect of laser radiation absorption of the sample on the electronic nose selectivity.

This work shows the integration of a sensor based on carbon nanotubes using CMOS technology. A chip sensor (CS) was designed and manufactured using a 0.30 μm CMOS process, leaving a free window on the passivation layer that allowed the deposition of SWCNTs over the electrodes. We successfully investigated with the CS the effect of humidity and temperature on the electrical transport properties of SWCNTs. The possibility of a large scale integration of SWCNTs with CMOS process opens a new route in the design of more efficient, low cost sensors with high reproducibility in their manufacture.

The Riachuelo–Matanza basin area (2.240 km 2 ) is located in Buenos Aires province, Argentina. This area is affected by intensive and extensive agricultural activities, and bears almost 3,000,000 inhabitants and more than 10,000 industries, that release their effluents to the main collector of the basin, the Riachuelo River. It is a highly polluted area and the quality of water, soil and air is severely impaired causing chronic health problems. As part of an interdisciplinary study undertaken by local institutions to reach an environmental quality diagnosis and analysis of the pollutants dynamics in the basin system we have measured, with an electronic nose, the air immediately above the water in several points at the Riachuelo River mouth where the painteresque La Boca district is located. Water quality parameters simultaneously collected at the same sites were analyzed and correlated with the electronic nose response. This study is only exploratory and focuses on the viability of using an electronic nose to locate conflictive emissions throughout a given zone.

A prototype of an electronic nose (e-nose), based on an array of six undoped and doped SnO2 gas sensors made by the rheotaxial growth and thermal oxidation (RGTO) technique, is applied to the analysis of a basic ingredient of beer, the hop. We address two main requirements from the local brewing industry: to detect departures from the hop’s quality due to aging processes or lousy storage and to obtain a quick discrimination of the various similar types of pellets usually employed. Different methods for the extraction of the features of each sensor response have been studied. A comparison between discrimination obtained with a linear dimensional reduction via principal component analysis and a nonlinear reduction obtained with self-organized maps has also been made. © 2004 Elsevier B.V. All rights reserved.

We propose a new method for determining the quantity of superparamagnetic iron oxide nanoparticles (Fe3O4, SPIONs) embedded in animal tissue using magnetization measurements. With this method, the smallest detectable quantity of magnetite nanoparticles in a tissue sample is ∼1 μg. We showed that this method has proved being efficient. In this study, we focused in determining the quantity of SPION confined in lung and liver tissue of mice injected with ∼13 nm magnetite superparamagnetic nanoparticles. Furthermore, the method allowed us to detect the magnetite nanoparticles present in animal tissues without letting the natural iron ions present in the tissue or blood interfere with the measurements. Fil: Zysler, Roberto Daniel. Comisión Nacional de Energía Atómica. Gerencia del Area de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Lima, Enio Junior. Comisión Nacional de Energía Atómica. Gerencia del Area de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Vasquez Mansilla, Marcelo. Comisión Nacional de Energía Atómica. Gerencia del Area de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Troiani, Horacio Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energia Atomica. Fundación Jose A. Balseiro; Argentina Fil: Mojica Pisciotti, Mary Luz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Energía Nuclear. Instituto Balseiro; Argentina Fil: Gurman, P.. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigación y Aplicaciones No Nucleares. Gerencia de Desarrollo Tecnológico y Proyectos Especiales. Departamento de Micro y Nanotecnología; Argentina Fil: Lamagna, Federico Agustín. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigación y Aplicaciones No Nucleares. Gerencia de Desarrollo Tecnológico y Proyectos Especiales. Departamento de Micro y Nanotecnología; Argentina Fil: Colombo, Lucas Luis. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina. Universidad Abierta Interamericana. Facultad de Medicina. Centro de Altos Estudios en Ciencias de la Salud; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

It is well know that the use of chambers with the sensors in the e‐nose improves the measurements, due to a constant gas flow and the controlled temperature sensors[1]. Normally, the chamber temperature is above room temperature due to the heat generated by the heater of sensors. Also, the chamber takes a long time to reach a stable equilibrium temperature and it depends on enviromental conditions. Besides, the temperature variations modify the humidity producing variations in resistance measurements[2]. In this work using a heater system that controls the temperature of the chamber, the desorption process on SnO2 sensor array was study[3]. Also, it was fitted the data signal sensors using a two exponential decay functions in order to determine the desorbing constant process. These constants were used to classify and identify different alcohols and their concentrations.

Epitaxial YBa2Cu3Ox superconducting films have been grown in-situ by XeCl excimer laser ablation of a sintered pellet. The films, 1000–1500 A thick, were deposited on monocrystalline SrTiO3, LaAlO3, MgO and YSZ substrates. X-ray diffraction and RBS-channeling techniques were used for the structural analysis of the substrates and of the films.