Selective absorbers based on carbon nanotube coating from Electrophoretic Deposition

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Metastability effects on the photoluminescence of ZnO nano-micro structures grown at low temperature and influence of the precursors on their morphology and structure

Nanocrystalline ZnO films were grown on silicon substrate by hydrothermal synthesis at 125 °C, using diethanolamine as stabilizer. A powder containing ZnO spheres, with diameters between 100 to 200 nm and formed by aggregation of ZnO nanoparticles, was also obtained as a secondary reaction product. The samples were studied by scanning electron microscopy, X-ray diffraction and photoluminescence (PL) spectroscopy. The effects of the [diethanolamine]/[Zn+2] molar ratio on morphological, structural and optical properties were studied, as well as the effect of laser illumination (=325 nm) and annealing treatment on photoluminescence properties. The film samples exhibited a compact columnar structure, with thickness between 180 to 210 nm, which were not strongly affected by the diethanolamine concentration. The X-ray diffraction patterns from the films evidenced preferred orientation along the c-axis of the ZnO wurzite structure; while the nanospheres did not show any preferential crystalline direction. The PL spectra from the films showed large initial UV emission and a weak defect band centered in the yellow. A PL evolution while the samples were UV illuminated, attributed to oxygen vacancy generation following the photoinduced equilibration of metastable structures, was observed.Fil: Gonzalez, Vanessa. Instituto de Física del Noroeste Argentino, INFINOA (CONICET-UNT); Argentina. NanoProject - LNPD, Facultad de Ciencias Exactas y Tecnología, Universidad Nacional de Tucumán; ArgentinaFil: Marín Ramírez, Oscar Alonso. Instituto de Física del Noroeste Argentino, INFINOA (CONICET-UNT); Argentina. NanoProject - LAFISO, Facultad de Ciencias Exactas y Tecnología, Universidad Nacional de Tucumán; ArgentinaFil: Tirado, Monica Cecilia. Instituto de Física del Noroeste Argentino, INFINOA (CONICET-UNT); Argentina. NanoProject - LNPD, Facultad de Ciencias Exactas y Tecnología, Universidad Nacional de Tucumán; ArgentinaFil: Comedi, David Mario. NanoProject - LAFISO, Facultad de Ciencias Exactas y Tecnología, Universidad Nacional de Tucumán; Argentina. Instituto de Física del Noroeste Argentino, INFINOA (CONICET-UNT); Argentin

Effects of methanol on morphology and photoluminescence in solvothermal grown ZnO powders and ZnO on Si

ZnO nano and microstructures were obtained by solvothermal synthesis using hexamethylenetetramine (HMTA) as alkaline agent, and water, water/methanol and methanol as solvents. Two types of samples were obtained: a ZnO powder that grew at the bulk solution and ZnO on silicon substrates. The effect of the solvent on the morphology and optical emission was studied, as well as the influence of the growth zone. With increasing methanol content, the morphology changed from nanorods to nanoparticles powders, and from oriented arrangement of nanorods to thin film on silicon substrates. Important changes in photoluminescence induced by the methanol content and depending on the growth zone were also observed.Fil: Marín Ramírez, Oscar Alonso. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: González, Vanessa. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Tirado, Monica Cecilia. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Comedi, David Mario. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; Argentina. Universidad Nacional de Tucumán; Argentin

GENECODIS: a web-based tool for finding significant concurrent annotations in gene lists

We present GENECODIS, a web-based tool that integrates different sources of information to search for annotations that frequently co-occur in a set of genes and rank them by statistical significance. The analysis of concurrent annotations provides significant information for the biologic interpretation of high-throughput experiments and may outperform the results of standard methods for the functional analysis of gene lists. GENECODIS is publicly available at

Non-linear excitation of polariton cavity modes in ZnO single nanocombs

Tunable second harmonic (SH) polaritons have been efficiently generated in ZnO nanocombs, when the material is excited close to half of the band-gap. The nonlinear signal couples to the nanocavity modes, and, as a result, Fabry-Pérot resonances with high Q factors of about 500 are detected. Due to the low effective volume of the confined modes, matter-light interaction is very much enhanced. This effect lowers the velocity of the SH polariton in the material by 50 times, and increases the SH confinement inside the nanocavity due to this higher refractive index. We also show that the SH phase-matching condition is achieved through LO-phonon mediation. Finally, birrefringence of the crystal produces a strong SH intensity dependence on the input polarization, with a high polarization contrast, which could be used as a mechanism for light switching in the nanoscale.Fil: Capeluto, Maria Gabriela. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires; ArgentinaFil: Grinblat, Gustavo Sergio. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; ArgentinaFil: Tirado, Monica Cecilia. Universidad Nacional de Tucuman. Facultad de Ciencias Exactas y Tecnologia. Departamento de Fisica. Departamento de Nanomateriales y Propiedades Dielectricas; ArgentinaFil: Comedi, David Mario. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; ArgentinaFil: Bragas, Andrea Veronica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires; Argentin

Brucelosis, revisión bibliográfica

Brucellosis is a common infection between humans and animals with a worldwide distribution, acquired mainly by direct contact or with fluids from domestic and wild animals, depending mainly on the causative agent, it manifests itself in different ways, from asymptomatic to chronic pictures, causing focal manifestations with multisystemic complications that can be recurrent, the diagnosis is based on serological methods and culture, the antibiotic of choice is dicloxacillin and in more serious cases streptomycin. A systematic search of recent research was carried out in the databases of PubMed, Scielo, Science direct, Medline, Elsevier, New England Journal of Medicine, Google Scholar and other relevant search engines for articles published between 2017 and 2022, in English and Spanish. .La brucelosis es una infección común entre humanos y animales con una distribución a nivel mundial, adquirida principalmente por contacto directo o con fluidos de animales domésticos y salvajes, dependiendo principalmente del agente causal, se manifiesta de diferentes formas, desde asintomática a cuadros crónicos, provocando manifestaciones focales con complicaciones multisistémicas que pueden ser recurrentes,el diagnóstico se basa en métodos serológicos y cultivo, el  antibiotico de elección es la  dicloxacilina y en casos más graves estreptomicina. Se realizó una búsqueda   sistemática   de   investigaciones recientes  en  bases  de  datos  de PubMed,  Scielo,  Science  direct, Medline, Elsevier, New England Journal of Medicine, Google Académico  y  otros  buscadores  relevantes de artículos publicados entre el 2017 al 2022, de idioma inglés y español

ZnO nanowire sensitization with Ru polypyridyl complexes: charge-transfer probed by spectral and relaxation photocurrent measurements

Dye-sensitized ZnO nanowire (NW) electrodes were fabricated using Ru polypyridyl complexes that use nitrile instead of carboxylic group as anchoring unit to the NW surfaces. The complexes formula is [Ru(bpy)3−x(Mebpy-CN)x]2+ (x = 1−3, bpy = 2,2'-bipyridine, Mebpy-CN = 4-methyl-2,2'-bipyridine-4'-carbonitrile). The ZnO NWs were grown by a vapor transport method on insulating SiO2/Si substrates. The sensitized ZnO NW electrodes were studied by electron microscopy, Raman and PL spectroscopies, and spectral and relaxation photocurrent measurements. The Raman spectra confirm that the complexes were effectively anchored to the ZnO NWs through one of the pendant nitrile groups of the bipyridyl ligands. The nanostructured morphology of the NW electrodes was maintained so that their light trapping characteristics were preserved. The Ru complexes were found to be excellent sensitizers of the ZnO NWs, improving by orders of magnitude their photocurrent in the visible region. The Fe-based complex of formula [Fe(Mebpy-CN)3](PF6)2 was also tested; however it did not show any sensitizing effect. An order of magnitude shortening of the persistent photocurrent relaxation times (after the illumination is interrupted) was found to occur upon successful sensitization of the ZnO NWs with the Ru complexes. This effect is interpreted in terms of hole traps at ~1 eV above the ZnO valence band edge, which are lowered by ~50–60 meV in the soaked samples due to screening of the trap centers provided by the extra photoexcited charge carriers transferred from the sensitizing complex to the NWs.Fil: Vega, Nadia Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Instituto de Física del Noroeste Argentino, INFINOA. Universidad Nacional de Tucumán, Facultad de Ciencias Exactas y Tecnología, Argentina; ArgentinaFil: Mecchia Ortiz, Juan Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; ArgentinaFil: Tirado, Monica Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Instituto de Física del Noroeste Argentino, INFINOA. Universidad Nacional de Tucumán, Facultad de Ciencias Exactas y Tecnología, Argentina; Argentina; ArgentinaFil: Katz, Néstor Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; ArgentinaFil: Comedi, David Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Instituto de Física del Noroeste Argentino, INFINOA. Universidad Nacional de Tucumán, Facultad de Ciencias Exactas y Tecnología, Argentina; Argentina; Argentin

ZnO Nanostructures Synthesized by Vapor Transport and Liquid Phase Synthesis Techniques: Growth and Properties

In this review, we briefly describe work devoted in recent years towards the effective control of morphology, structure and optical properties of ZnO nanostructures, with particular focus on cost effective and simple methods for ZnO nanowires (NWs) fabrication. For the vapor transport technique, we describe in detail mechanisms for growth precursors generation, their transport in inert and forming gas, as well as their reactions on different pretreated substrates and corresponding growth mechanisms. As for low temperature synthesis methods, three techniques are outlined: sol-gel, solvothermal and electrophoretic deposition, with emphasis on effective morphology, structure and optical properties control. In this context, we discuss recent attempts to understand the role of solvent and alkaline agents used during solvothermal synthesis of ZnO nanostructures on their morphology and photoluminescence properties. Recent success of electrophoretic deposition of ZnO nanoparticles on pre-patterned silicon substrates in the form of NWs and NW bunches is highlighted over many previous attempts to fabricate ZnO NWs with inconvenient sacrificial templates. Finally, we present a critical discussion on the current understanding of passivation mechanisms of ZnO NW surfaces by MgO shells.Fil: Marín Ramírez, Oscar Alonso. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Real, Silvina Claudia. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Vega, Nadia Celeste. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Tirado, Monica Cecilia. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Comedi, David Mario. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; Argentin

Luminescence and electrical properties of single ZnO/MgO core/shell nanowires

To neutralise the influence of the surface of ZnO nanowires for photonics and optoelectronic applications, we have covered them with insulating MgO film and individually contacted them for electrical characterisation. We show that such a metal-insulator-semiconductor-type nanodevice exhibits a high diode ideality factor of 3.4 below 1 V. MgO shell passivates ZnO surface states and provides confining barriers to electrons and holes within the ZnO core, favouring excitonic ultraviolet radiative recombination, while suppressing defect-related luminescence in the visible and improving electrical conductivity. The results indicate the potential use of ZnO/MgO nanowires as a convenient building block for nano-optoelectronic devices.Fil: Grinblat, Gustavo Sergio. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bern, Francis. University of Leipzig; AlemaniaFil: Barzola Quiquia, José. University of Leipzig; AlemaniaFil: Tirado, Monica Cecilia. Universidad Nacional de Tucuman. Facultad de Ciencias Exactas y Tecnologia. Departamento de Fisica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Comedi, David Mario. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Esquinazi, Pablo. University of Leipzig; Alemani

On the properties of NiO powders obtained by different wet chemical methods and calcination

NiO powders were synthesized using coprecipitation, sol-gel, and hydrothermal synthesis methods. The powders were subjected to calcination in atmospheric air, followed by recalcination in an O2-rich atmosphere at 800°C for 2 h each. Characterization techniques, such as scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, and microRaman spectroscopy, were utilized. The coprecipitation and hydrothermal methods resulted in disaggregated submicrometric particles. The average size of particles obtained by the coprecipitation method after calcination in atmospheric air and recalcination in an O2-rich atmosphere was 360 ± 140 nm and 400 ± 130 nm, respectively. Regarding the particles obtained by the hydrothermal method, the average size was 190 ± 50 and 220 ± 80 nm for calcined in atmospheric air and recalcined in O2-rich atmosphere, respectively. Conversely, the sol-gel method produced particle aggregates with an average size of 430 ± 150 nm after calcination in atmospheric air and 500 ± 200 nm for calcination in an O2-rich atmosphere. X-ray diffraction analysis revealed that only the hydrothermal method yielded pure NiO without additional Ni-related phases, irrespective of the calcination procedure. In contrast, the coprecipitation sample exhibited a Ni2O3 phase after calcination in atmospheric air, which disappeared after recalcination in an O2-rich atmosphere. The sol-gel-derived sample maintained a Ni phase after both calcination processes. Analysis of the crystallite size demonstrated an increase after recalcination in an O2-rich atmosphere for the hydrothermal and sol-gel-derived samples, while a decrease was observed for the coprecipitation-derived sample. Raman spectra exhibited defect-enabled first-order forbidden phonon modes that were sensitive to the synthesis route. The two magnon phonon modes also demonstrated dependency on the route, indicating variations in defect structures. Photocatalytic evaluation using methylene blue degradation in aqueous solutions indicated better performance for the powders recalcined in an O2-rich atmosphere.Fil: Alastuey, Patricio. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Pais Ospina, Daniel Humberto. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Comedi, David Mario. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Tirado, Monica Cecilia. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Marín Ramírez, Oscar Alonso. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; Argentin