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[en] The whole crystallisation process of three Fe-rich FeZr metallic glasses has been studied using in situ neutron thermo-diffraction. While the beginning of the transformation occurs at the same temperature, the further evolution is strongly compositional dependent. Metastable BCC-Fe phase appears at intermediate temperatures only in Fe75Zr25 alloy. From this study a clear evidence of the existence of an FCC-Fe3+xZr is shown
Journal
[en] To investigate whether past exposure to Hepatitis B virus (HBV) and Hepatitis C Virus (HCV) were risk factors for the development of Hepatocellular Carcinoma (HCC) in Peru, a case-control study of 136 patients with HCC and 136 age-matched and sex-matched control subjects was performed. Past exposure to HBV and HCV were assessed respectively by antibody to hepatitis B core antigen (Anti-HBc) and HbsAg and Anti-HCV. Of the HCC cases, 63,2% were positive for HbsAg and 0,73% for anti-HCV. Of the control patients, 4,4% were positive to HbsAg and 0,73% to anti-HCV. The mean age of patients with HCC negative for HbsAg was significantly greater than that of patients HCC positive for HbsAg (35,4 versus 29,4 years, p less than 0,001). The HbsAg patients are 36,26 times more prone to developing HCC than those with HbsAg negative (95% confidence interval: 15.31-90.7). Infection with HCV does not pose a risk for the development of HCC (RR 1, 95% confidence interval: 0.062-16.152). A causal relation between HBV infection in children HCC was observed. These results indicate that HbsAg carriage is a risk factor for HCC in Peru. The importance of vertical or perinatal transmission of HBV and the prophylactic role of passive immunization plus vaccination during childhood is emphasized as well as the selective vaccination of high risk groups. (authors)
Journal
Revista de Gastroenterologia del Peru; ISSN 1022-5129; 
; v. 18(3); p. 199-211
; v. 18(3); p. 199-211
[en] The ohmic drop in the bulk of the electrolytic solution and at the surgace layers of corrosion products, RΩ, can be the source of errors on estimating the corrosion rates, icorr, by the polarization resistance technique, Rp, if their effect is not compensated, for which nowadays use can be made of convenient and effective proceedings. In this paper some experimental results with Al, Cu, Fe and Zn in sulphuric acid solutions are included. These results prove that very important errors can appear even in high conductivity media, whenever the corrosion rates would be high (low Rp), because the relative error magnitude is expressed by the RΩ/Rp ratio, between the resistance offered by the media to the current flow and the polarization resistance value. (author)
Journal
[en] Fourteen years ago, studies on bacteria growing in clean water were made in order to assess the hazard imposed by a possible expansion of bacteria population in the water tanks of the Pierre Auger Observatory Cherenkov detectors. In 1999 TANGO Array, a reduced-size unitary cell, composed of four water Cherenkov detectors, was constructed at the TANDAR campus of the Atomic Energy Commission, in Buenos Aires, to be used as a working model of the proposed surface array. TANGO Array ran for one year observing energy, intensity, and arrival directions of cosmic rays at sea level. Nine years after it was decommissioned, the water tanks configuring the Cherenkov detectors are still kept closed. In May 2009 water and liner samples from these tanks were collected to determine eventual long term bacteria growth in the internal detector environment, which is very similar to those of the detectors installed in the Malargüe Site. In the present note we report the results of the bacteriological study performed on the samples obtained from the TANGO Array detector tanks. Cultivable, long time surviving, bacterial species were identified, both in the water mass and on the liner surface, and the light transmission in water at the relevant Cherenkov wavelength was studied. An upper limit of possible interferences caused by bacteria is estimated.
Journal
Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment; ISSN 0168-9002; ; CODEN NIMAER; v. 659(1); p. 169-174
; CODEN NIMAER; v. 659(1); p. 169-174
[en] The crystallization of the Fe75Zr25 as-milled amorphous alloy has been studied by Moessbauer spectroscopy. The process begins at around 880 K with the complete and fast crystallization of the amorphous phase into the crystalline α-Fe and Fe2Zr ones but, from around 915 K, there is a sudden phase transformation into the Fe23Zr6 phase, which remains stable after cooling. A fitting for the Moessbauer contribution of the Fe23Zr6 phase, consistent with its crystalline structural features, has been obtained.
Journal
[en] Detection of hepatitis C virus in sera samples by specific amplification of the 5' non-coding conserved region of HCV. 8 anti-HCV EIAs positive blood donors sera were evaluated, 5 from the Hospital Nacional Cayetano Heredia (HNCH) and 3 from the Instituto de Enfermedades Neoplasicas (INEN). RNA was extracted from sera using trizol and reverse transcripted with primer 209. Nested PCR amplification was carried out with primers 209-939 in a first round and 211-940 primers during the second round of amplification. Visualization of amplification products was done after electrophoresis in 2% agarose gel and ethidium bromide staining
Source
Gayoso C, C.; Ezpinoza Z, M.; Prado C, A.; Robles N, A. (eds.); Instituto Peruano de Energia Nuclear (IPEN), Lima (Peru); 512 p; ISSN 1684-1662; ; 2002; p. 200; Also available from the Library of the Peruvian Institute of Nuclear Energy in electronic format (pdf)
; 2002; p. 200; Also available from the Library of the Peruvian Institute of Nuclear Energy in electronic format (pdf)
[en] The amorphous system Fe-Zr has been extensively studied due to its particular magnetic behaviour, especially in the concentration range around 90 at.% Fe, only accessible by rapid quenching. We have extended the study to lower Fe content alloys, by using mechanical alloying to synthesize FexZr100-x amorphous powders with x = 65, 70, 75. Moessbauer spectra and magnetization measurements have been performed as a function of temperature. Different magnetic measurements were performed to characterize the Curie temperatures of these multiphase samples and hyperfine field (Bhf) distributions, P (Bhf), were used to fit Moessbauer spectra below the Curie temperature (TC) and quadrupole splitting distributions, P (Δ), above TC, in agreement with the amorphous structures. The hyperfine field distributions of as-milled samples are characterized by two maxima and are fitted with two Gaussian curves that evolve with temperature in position, intensity and width. This bimodal behaviour has been also found in higher Fe content FeZr alloys as well as in ternary alloys with boron, and with nickel, and can be interpreted as arising from different neighbourhood Fe sites. The rather uncommon P (Δ) are also interpreted in the same terms. (author)
Journal
Journal of Physics. Condensed Matter; ISSN 0953-8984; ; v. 12(13); p. 3101-3112
; v. 12(13); p. 3101-3112
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