3.1 Estancias en cooperación internacional

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https://hdl.handle.net/20.500.12390/3674

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Recent Submissions

Now showing 1 - 5 of 39
  • Publication
    Morphological Characterization of Mycobacterium tuberculosis in a MODS Culture for an Automatic Diagnostics through Pattern Recognition
    (PLOS, 2013)
    Alva, A
    ;
    Aquino, F
    ;
    Gilman, RH
    ;
    Olivares, C
    ;
    Requena, D
    ;
    Gutierrez, AH
    ;
    Caviedes, L
    ;
    Coronel, J
    ;
    Larson, S
    ;
    Sheen, P
    ;
    Moore, DAJ
    ;
    Zimic, M
    Tuberculosis control efforts are hampered by a mismatch in diagnostic technology: modern optimal diagnostic tests are least available in poor areas where they are needed most. Lack of adequate early diagnostics and MDR detection is a critical problem in control efforts. The Microscopic Observation Drug Susceptibility (MODS) assay uses visual recognition of cording patterns from Mycobacterium tuberculosis (MTB) to diagnose tuberculosis infection and drug susceptibility directly from a sputum sample in 7–10 days with a low cost. An important limitation that laboratories in the developing world face in MODS implementation is the presence of permanent technical staff with expertise in reading MODS.
  • Publication
    Theoretical and experimental study of solar cells based on nanostructured films of TiO2 sensitized with natural dyes extracted from Zea mays and Bixa orellana
    (Royal Society of Chemistry, 2021)
    Huamán Aguirre, Arnold Anthony
    ;
    Celestino, Michael R.
    ;
    Quintana Cáceda, María Esther
    Natural dyes were extracted from Zea mays and Bixa orellana, products from Peru, for the sensitization of nanoporous titanium dioxide (TiO2) films. The manufactured DSSCs were studied from the theoretical and experimental point of view in two main stages. In the first, the computational simulation of the dye molecules was carried out using the DFT and TD-DFT method. The analysis was complemented with UV-visible characterization. In the second stage, the transport and recombination processes that occur in the solar cell were studied.
  • Publication
    Vacancy ordered gamma-Fe2O3 nanoparticles functionalized with nanohydroxyapatite: XRD, FTIR, TEM, XPS and Mossbauer studies
    (Elsevier B.V., 2016)
    Guivar, JAR
    ;
    Sanches, EA
    ;
    Bruns, F
    ;
    Sadrollahi, E
    ;
    Morales, MA
    ;
    Lopez, EO
    ;
    Litterst, FJ
    Vacancy ordered maghemite (γ-Fe2O3) nanoparticles functionalized with nanohydroxyapatite (HAp – Ca10(PO4) 6(OH)2) have been successfully synthesized using an inexpensive co-precipitation chemical route. Evidence for the presence of vacancy order in maghemite was shown by the superstructure lines observed in X-ray diffraction. The adsorption of carboxyl groups of citric acid (C6H8O7) onto γ-Fe2O3 nanoparticles was investigated by FTIR, XPS and Mössbauer spectroscopy.
  • Publication
    Molecular interaction of natural dye based on Zea mays and Bixa orellana with nanocrystalline TiO2 in dye sensitized solar cells
    (International Association of Physical Chemists, 2021)
    Huamán Aguirre, Arnold Anthony
    ;
    Quintana Cáceda, María Esther
    ;
    Salazar Salinas, Karim
    This work studies the interaction between natural dyes obtained from Peruvian Zea mays and Bixa orellana seeds and nanostructured titanium dioxide, in order to evaluate their function as sensitizers into solar cell devices. The effective attachment of dyes to the TiO2 layer is corroborated by the comparison of UV-Visible absorption and FT-IR spectra of the extracted dye solutions and sensitized TiO2 electrodes. The principal compounds from the seed extraction of Zea mays and Bixa orellana are cyanidin-3-glucoside (C3G) and bixin respectively, which were analyzed in an isolated dye/cluster TiO2 system by molecular dynamic simulation. The results showed that chemisorption is carried out through a consecutive deprotonation process, and Ti-O bond formation by the monodentate OH and COOH anchoring groups, for C3G and bixin respectively. Finally, we tested the effect of the dye - TiO2 interaction on the charge transfer by the comparison of the current-voltage curves and incident photon-to-current conversion efficiency (IPCE) of the cells. We found that dye agglomeration in films with Bixa orellana and high charge recombination of films with Zea mays are critical points to be solved. For this reason, we propose the pretreatment of the TiO2 film before sensitization with Bixa orellana and analyze the effects of pH in Zea mays solution, in order to obtain better device efficiencies.
  • Publication
    Optical characterization and bandgap engineering of flat and wrinkle-textured FA0.83Cs0.17Pb(I1-xBrx)3 perovskite thin films
    (American Institute of Physics Inc., 2018)
    Tejada A.
    ;
    Braunger S.
    ;
    Korte L.
    ;
    Albrecht S.
    ;
    Rech B.
    ;
    Guerra J.A.
    The complex refractive indices of formamidinium cesium lead mixed-halide [FA0.83Cs0.17Pb(I1– xBrx)3] perovskite thin films of compositions ranging from x = 0 to 0.4, with both flat and wrinkle-textured surface topographies, are reported. The films are characterized using a combination of variable angle spectroscopic ellipsometry and spectral transmittance in the wavelength range of 190 nm to 850 nm.