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Prieto Gonzalez E.A.,Interamerican Open University | Mudry M.D.,University of Buenos Aires | Palermo A.M.,CITEDEF
Journal of Environmental Pathology, Toxicology and Oncology | Year: 2014

The objective of the present work was to study the fine kinetics of DNA repair in xeroderma pigmentosum (XP) syndrome, a complex disorder linked to a deficiency in repair that increases cancer susceptibility. The repair process was evaluated by the comet assay (CA) in cells from 2 XP patients and 9 controls exposed to UVA/B (UVA 366/UVB 280 nm) and H2O2(150 μM) at temperatures of 4, 15, and 37°C. Samples were taken at 2-min intervals during the first 10 min to analyze the “fine kinetics” repair during the initial phase of the curve, and then at 15, 20, 25, 30, 45, 60, and 120 min. CA evaluation of DNA repair activity points to BER/NER initiation in the first 30 min with both inductors at 37°C and 15°C, but final comet length showed differences according to treatment. Repair kinetics during 120 min showed a good correlation with clinical features in both XP patients. Differences in final comet length were less pronounced in XP cells treated with H2O2than with UVA/B, probably because the peroxide produces mainly base oxidation but less bulky lesions; UVA/B generates a mixture of both. These findings reinforce the value of CA in testing in DNA repair ability or exposure monitoring. © 2014 Begell House, Inc.


Bianchetti M.F.,CITEDEF | Arrieta C.L.,Thin Films Laboratory | Walsoe De Reca N.E.,CITEDEF
Sensors and Actuators, B: Chemical | Year: 2015

Abstract Nanocrystalline pure and doped SnO2 have been intensively studied for a long time to build resistive gas sensors. However, it is still useful to synthesize nanopowders with the smallest crystallite size to build devices. A modified gel-combustion method and a novel reactive oxidation process are proposed for nanopowders synthesis and results are compared. Materials have been characterized by XRD, Scherrer equation to evaluate the crystallite size; BET absorption to determine specific area and HRTEM to observe the crystallites (evaluating their mean size and distribution); defects and effect of calcination treatments are also considered. Previous studies have shown that if nano-SnO2 replaces the conventional microcrystalline-SnO2 to build resistive gas sensors, sensitivity increases (>30%) and the operation temperature considerably decreases. A heating and measuring system has been designed for achieving low power consumption and uses pulsed heating operation. This method of electrical control and measurement is operated intermittently, with "heating" and "readout" cycles (readout: signal of sensitive film). © 2014 Elsevier B.V.


Acuna L.M.,CITEDEF | Acuna L.M.,CONICET | Fuentes R.O.,Comision Nacional de la Energia Atomica | Fuentes R.O.,CONICET | And 3 more authors.
Journal of Physical Chemistry C | Year: 2014

In the present work, the local order of Zr in ZrO2-CeO 2 nanopowders (with 50, 65, 70, and 90 mol % CeO2) was studied by extended X-ray absorption fine structure around the Zr K-edge. In the cases of ZrO2-50 and 65 mol % CeO2, we studied how the local order is affected by the phase transition at high temperature. In order to study the tetragonal-cubic phase transition as a function of temperature, high-temperature synchrotron radiation X-ray powder diffraction (SR-XPD) was employed. We explored different models of the local atomic structure and interpreted them as distortions of the accepted long-range order deduced by XPD analyses. The results suggested the existence of distortions in the oxygen sublattice, which can be accounted for as displacements of the oxygen atoms along the (110) direction of the pseudofluorite unit cell that cannot be observed by XPD because of the random nature of these displacements. © 2014 American Chemical Society.


Palermo A.M.,CITEDEF | Mudry M.D.,University of Buenos Aires
Current Drug Safety | Year: 2013

The standard version of the wing somatic mutation and recombination test (SMART) in Drosophila melanogaster was employed in order to evaluate the genotoxic potential of metronidazole (MTZ) as a function of exposure concentration. MTZ was administered by chronic feeding of 3-day-old larvae with the parenteral solution at 0, 500, 1000 and 2000 μg/ml until pupation. The marker-heterozygous progeny (mwh+/+flr3) with phenotypically wild-type wings was analyzed. Non significant differences were found between control and each MTZ concentration tested for single small spots (SSS) frequencies. Large single spots (LSS) and twin spots (TS) were significantly increased with the higher dose. MTZ treatments with 1000 and 2000 μg/ml also significantly increased the frequency of Total spots. These findings suggest that MTZ is genotoxic in the present experimental conditions and induces recombinagenesis and/or gene conversion, two major mechanisms that cause loss of heterocigosity and could play an important role in tumorigenesis and carcinogenesis processes. © 2013 Bentham Science Publishers.


Lacomi H.A.,CITEDEF | David De Lima D.M.,CITEDEF | Lavorato M.B.,CITEDEF | Arrieta C.L.,CITEDEF
IEEE Latin America Transactions | Year: 2016

The InGaAs PIN photodiodes are widely used in spectrometric and medical equipment. However, it is not widespread its use for atmospheric remote sensing phenomena studies. In the present work we shows the development and construction of a detector-amplifier based on an InGaAs PIN photodiode, with high gain (110dB), low bandwidth (10MHz) and low distortion. Such device is the detection unit used for a backscatter LIDAR (Light Detection And Ranging) operating in 1064 nm. The PIN photodiode responsivity was characterized for the specific wavelength (1064 nm), as well as its juncture capacitance for the bandwidth of device. The independently characterization of amplifier (gain and bandwidth) without sensor, let us improve its performances. These characterizations allowed obtain a detector-amplifier system with a remarkable performance for remote sensing applications. Finally, we present the preliminary results obtained with a backscatter LIDAR, where we shows the measurements of cirrus clouds observations with altitude between 8 and 12 kilometers. © 2016 IEEE.


Nicora M.G.,CONICET | Quel E.J.,CONICET | Bali J.L.,CITEDEF | Acquesta A.,CITEDEF | And 5 more authors.
2015 International Symposium on Lightning Protection, XIII SIPDA 2015 | Year: 2015

This work presents a lightning jump algorithm (LJA): 'GeoRayos' to detect severe weather; it is based on the algorithm presented by Schultz et al. (2011) [1]. The lightning data used in this study came from the World Wide Lightning Location Network which is a real-time, world-wide and ground network. In this study, the lightning activity occurred during spring and summer of 2013 on the region [20-50]S of latitude and [50'70]W of longitude was examined. The LJA was validated by using information of severe weather occurrence in the report 'Estudio de los Tornados en la Rep. Argentina' this unpublished report (M. L. Altinger de Schwarzkopf, personal communication) provides severe phenomena occurred since 1930 to the present, also we used information from the National Weather Service in Argentina, local argentinean media, and radar data. The spatial and time distributions of lightning jumps were analyzed by using different spatial and temporal scales. © 2015 IEEE.


Palermo A.M.,CITEDEF | Mudry M.D.,University of Buenos Aires | Mudry M.D.,CONICET
Mutation Research - Genetic Toxicology and Environmental Mutagenesis | Year: 2011

Isopropanol (isopropyl alcohol, 2-propanol, IPA) is a volatile solvent widely used in domestic or industrial environments and reported as innocuous in various test systems. The aim of this work was to search for in vivo genotoxic effects of IPA in Drosophila melanogaster, studying its ability to induce nondisjunction (ND) in females, sex linked recessive lethals (SLRL) in males, and somatic mutation and/or recombination (SMART) in larvae. Treatments were acute (60. min) and were administered via inhalation. IPA had low toxicity in adult flies (75% IPA mortality index, MI = 12.7% (females) and 2.6% (males)) and larvae (MI = 14.3%, 75% IPA). Female fertility was severely affected during the first 24 h (brood I, BI) after treatment, but, afterwards, control values were recovered. IPA induced a 50-fold increase of ND (%) in 24 h old females, and a six-fold rise in 4-5 d old BI offspring. Nondisjunction frequencies (%) in the offspring of broods II to V (24 h in each case) were similar to control values. IPA doses of 25% and 50% (v/v), tested in 24 h old females, showed a significant dose-dependent increase of ND(%)in BI only, with control values in subsequent broods. Flies gave normal offspring when kept in regular media for 24 h before mating. The eye spot test (SMART) showed a significant increase at 50% IPA (p<0.05, m = 2), but the response was not dose-dependent. IPA failed to induce SLRL in any of the spermatogenesis stages tested. These findings suggest that the main effect of IPA is to induce chromosomal malsegregation; IPA must be present at the resumption of M-phase I after fertilization, to exert these effects. The alcohol does not affect DNA directly, but perturbations of the nuclear membrane may be responsible for induction of ND. © 2011 Elsevier B.V.


PubMed | CITEDEF
Type: Journal Article | Journal: Mutation research | Year: 2011

Isopropanol (isopropyl alcohol, 2-propanol, IPA) is a volatile solvent widely used in domestic or industrial environments and reported as innocuous in various test systems. The aim of this work was to search for in vivo genotoxic effects of IPA in Drosophila melanogaster, studying its ability to induce nondisjunction (ND) in females, sex linked recessive lethals (SLRL) in males, and somatic mutation and/or recombination (SMART) in larvae. Treatments were acute (60min) and were administered via inhalation. IPA had low toxicity in adult flies (75% IPA mortality index, MI=12.7% (females) and 2.6% (males)) and larvae (MI=14.3%, 75% IPA). Female fertility was severely affected during the first 24h (brood I, BI) after treatment, but, afterwards, control values were recovered. IPA induced a 50-fold increase of ND (%) in 24h old females, and a six-fold rise in 4-5 d old BI offspring. Nondisjunction frequencies (%) in the offspring of broods II to V (24h in each case) were similar to control values. IPA doses of 25% and 50% (v/v), tested in 24h old females, showed a significant dose-dependent increase of ND(%)in BI only, with control values in subsequent broods. Flies gave normal offspring when kept in regular media for 24h before mating. The eye spot test (SMART) showed a significant increase at 50% IPA (p<0.05, m=2), but the response was not dose-dependent. IPA failed to induce SLRL in any of the spermatogenesis stages tested. These findings suggest that the main effect of IPA is to induce chromosomal malsegregation; IPA must be present at the resumption of M-phase I after fertilization, to exert these effects. The alcohol does not affect DNA directly, but perturbations of the nuclear membrane may be responsible for induction of ND.


PubMed | CITEDEF
Type: Journal Article | Journal: Current drug safety | Year: 2013

The standard version of the wing somatic mutation and recombination test (SMART) in Drosophila melanogaster was employed in order to evaluate the genotoxic potential of metronidazole (MTZ) as a function of exposure concentration. MTZ was administered by chronic feeding of 3-day-old larvae with the parenteral solution at 0, 500, 1000 and 2000 g/ml until pupation. The marker-heterozygous progeny (mwh+/+flr3) with phenotypically wild-type wings was analyzed. Non significant differences were found between control and each MTZ concentration tested for single small spots (SSS) frequencies. Large single spots (LSS) and twin spots (TS) were significantly increased with the higher dose. MTZ treatments with 1000 and 2000 g/ml also significantly increased the frequency of Total spots. These findings suggest that MTZ is genotoxic in the present experimental conditions and induces recombinagenesis and/or gene conversion, two major mechanisms that cause loss of heterocigosity and could play an important role in tumorigenesis and carcinogenesis processes.


PubMed | Interamerican Open University, University of Buenos Aires and CITEDEF
Type: Journal Article | Journal: Journal of environmental pathology, toxicology and oncology : official organ of the International Society for Environmental Toxicology and Cancer | Year: 2014

The objective of the present work was to study the fine kinetics of DNA repair in xeroderma pigmentosum (XP) syndrome, a complex disorder linked to a deficiency in repair that increases cancer susceptibility. The repair process was evaluated by the comet assay (CA) in cells from 2 XP patients and 9 controls exposed to UVA/B (UVA 366/UVB 280 nm) and H2O2 (150 M) at temperatures of 4, 15, and 37C. Samples were taken at 2-min intervals during the first 10 min to analyze the fine kinetics repair during the initial phase of the curve, and then at 15, 20, 25, 30, 45, 60, and 120 min. CA evaluation of DNA repair activity points to BER/NER initiation in the first 30 min with both inductors at 37C and 15C, but final comet length showed differences according to treatment. Repair kinetics during 120 min showed a good correlation with clinical features in both XP patients. Differences in final comet length were less pronounced in XP cells treated with H2O2 than with UVA/B, probably because the peroxide produces mainly base oxidation but less bulky lesions; UVA/B generates a mixture of both. These findings reinforce the value of CA in testing in DNA repair ability or exposure monitoring.

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