TiO2 nanorods doped with g-C3N4 – Polyethylene composite coating for self-cleaning applications

Visible-light-absorbing graphitic carbon nitride–TiO2 nanorod nanomaterials (g-C3N4@TiO2NR) were successfully immobilized using a one-step UVA-induced photocatalytic procedure on commercially obtained flexible low-density polyethylene (LDPE) films. Self-cleaning properties were evaluated in solid–liquid and solid–gas phases using malachite green as a model molecule under UV-A and visible light irradiation. For comparison purpose, LDPE films containing P25 TiO2 nanoparticles was prepared using the same synthetic strategy (P25/LDPE). Among the fabricated films, the g-C3N4@TiO2NR/LDPE films exhibited the highest photocatalytic activity both in solid–liquid and solid–gas phases after 120 min of visible light irradiation (λ > 455 nm) removing efficiently malachite green stains probably due to the attack of photoinduced reactive oxygen species (ROS) such as singlet oxygen (1O2), hydroxyl radical (•OH) and superoxide anion radical (O2−•). Furthermore, the g-C3N4@TiO2NR/LDPE films retained their visible-light-photoinduced photocatalytic properties after four reuse cycles. The g-C3N4@TiO2NR/LDPE films also exhibited significant visible-light-photoinduced hydrophilicity. The high visible-light-photoinduced photocatalytic capacity of g-C3N4@TiO2NR/LDPE films was found to be related to the textural and electronic properties, superior visible-light absorption, and surface roughness of the films.Fil: Osorio Vargas, Paula Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentina. Universidad del Bio Bio; ChileFil: 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; Argentina. Universidad Tecnológica de Pereira; ColombiaFil: Marín Silva, Diego Alejandro. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Pinotti, Adriana Noemi. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina. Universidad Nacional de La Plata. Facultad de Ingeniería; ArgentinaFil: Damonte, Laura Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Canneva, Antonela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. YPF - Tecnología; ArgentinaFil: Donadelli, Jorge Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. YPF - Tecnología; ArgentinaFil: Pereira da Costa, Luiz. Universidad Federal del Amazonas.; BrasilFil: Pizzio, Luis Rene. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Torres, Cecilia C.. Universidad Andrés Bello; ChileFil: Campos, Cristian H.. Universidad de Concepción; ChileFil: Rengifo Herrera, Julian Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentin

Synergistic Interactions between HDAC and Sirtuin Inhibitors in Human Leukemia Cells

Aberrant histone deacetylase (HDAC) activity is frequent in human leukemias. However, while classical, NAD+-independent HDACs are an established therapeutic target, the relevance of NAD+-dependent HDACs (sirtuins) in leukemia treatment remains unclear. Here, we assessed the antileukemic activity of sirtuin inhibitors and of the NAD+-lowering drug FK866, alone and in combination with traditional HDAC inhibitors. Primary leukemia cells, leukemia cell lines, healthy leukocytes and hematopoietic progenitors were treated with sirtuin inhibitors (sirtinol, cambinol, EX527) and with FK866, with or without addition of the HDAC inhibitors valproic acid, sodium butyrate, and vorinostat. Cell death was quantified by propidium iodide cell staining and subsequent flow-cytometry. Apoptosis induction was monitored by cell staining with FITC-Annexin-V/propidium iodide or with TMRE followed by flow-cytometric analysis, and by measuring caspase3/7 activity. Intracellular Bax was detected by flow-cytometry and western blotting. Cellular NAD+ levels were measured by enzymatic cycling assays. Bax was overexpressed by retroviral transduction. Bax and SIRT1 were silenced by RNA-interference. Sirtuin inhibitors and FK866 synergistically enhanced HDAC inhibitor activity in leukemia cells, but not in healthy leukocytes and hematopoietic progenitors. In leukemia cells, HDAC inhibitors were found to induce upregulation of Bax, a pro-apoptotic Bcl2 family-member whose translocation to mitochondria is normally prevented by SIRT1. As a result, leukemia cells become sensitized to sirtuin inhibitor-induced apoptosis. In conclusion, NAD+-independent HDACs and sirtuins cooperate in leukemia cells to avoid apoptosis. Combining sirtuin with HDAC inhibitors results in synergistic antileukemic activity that could be therapeutically exploited

Nucleant layer effect on nanocolumnar ZnO films grown by electrodeposition

Different ZnO nanostructured films were electrochemically grown, using an aqueous solution based on ZnCl2, on three types of transparent conductive oxides grow on commercial ITO (In2O3:Sn)-covered glass substrates: (1) ZnO prepared by spin coating, (2) ZnO prepared by direct current magnetron sputtering, and (3) commercial ITO-covered glass substrates. Although thin, these primary oxide layers play an important role on the properties of the nanostructured films grown on top of them. Additionally, these primary oxide layers prevent direct hole combination when used in optoelectronic devices. Structural and optical characterizations were carried out by scanning electron microscopy, atomic force microscopy, and optical transmission spectroscopy. We show that the properties of the ZnO nanostructured films depend strongly on the type of primary oxide-covered substrate used. Previous studies on different electrodeposition methods for nucleation and growth are considered in the final discussion.We thank Prof. A. Segura of the Universitat de Valencia for the facilities with the sputtering equipment. This work was supported by the project PROMETEO/2009/074 from the Generalitat Valenciana.Reyes Tolosa, MD.; Damonte, LC.; Brine, H.; Bolink, HJ.; Hernández Fenollosa, MDLÁ. (2013). Nucleant layer effect on nanocolumnar ZnO films grown by electrodeposition. Nanoscale Research Letters. 8:135-144. https://doi.org/10.1186/1556-276X-8-135S1351448Franklin JB, Zou B, Petrov P, McComb DW, Ryanand MP, McLachlan MA,J: Optimised pulsed laser deposition of ZnO thin films on transparent conducting substrates. Mater Chem 2011, 21: 8178–8182. 10.1039/c1jm10658aJaroslav B, Andrej V, Marie N, Šuttab P, Miroslav M, František U: Cryogenic pulsed laser deposition of ZnO. Vacuum 2012, 86(6):684–688. 10.1016/j.vacuum.2011.07.033Jae Bin L, Hyeong Joon K, Soo Gil K, Cheol Seong H, Seong-Hyeon H, Young Hwa S, Neung Hun L: Deposition of ZnO thin films by magnetron sputtering for a film bulk acoustic resonator. Thin Solid Films 2003, 435: 179–185. 10.1016/S0040-6090(03)00347-XXionga DP, Tanga XG, Zhaoa WR, Liua QX, Wanga YH, Zhoub SL: Deposition of ZnO and MgZnO films by magnetron sputtering. Vacuum 2013, 89: 254–256.Reyes Tolosa MD, Orozco-Messana J, Lima ANC, Camaratta R, Pascual M, Hernandez-Fenollosa MA: Electrochemical deposition mechanism for ZnO nanorods: diffusion coefficient and growth models. J Electrochem Soc 2011, 158(11):E107-E110.Ming F, Ji Z: Mechanism of the electrodeposition of ZnO nanosheets below room temperature. J Electrochem Soc 2010, 157(8):D450-D453. 10.1149/1.3447738Pullini D, Pruna A, Zanin S, Busquets Mataix D: High-efficiency electrodeposition of large scale ZnO nanorod arrays for thin transparent electrodes. J Electrochem Soc 2012, 159: E45-E51. 10.1149/2.093202jesPruna A, Pullini D, Busquets Mataix D: Influence of deposition potential on structure of ZnO nanowires synthesized in track-etched membranes. J Electrochem Soc 2012, 159: E92-E98. 10.1149/2.003205jesMarotti RE, Giorgi P, Machado G, Dalchiele EA: Crystallite size dependence of band gap energy for electrodeposited ZnO grown at different temperatures. Solar Energy Materials and Solar Cells 2009, 90(15):2356–2361.Yeong Hwan K, Myung Sub K, Jae Su Y: Structural and optical properties of ZnO nanorods by electrochemical growth using multi-walled carbon nanotube-composed seed layers. Nanoscale Res Lett 2012, 7: 13. 10.1186/1556-276X-7-13Elias J, Tena-Zaera R, Lévy-Clément C: Electrodeposition of ZnO nanowires with controlled dimensions for photovoltaic applications: role of buffer layer. Thin Solid Films 2007, 515(24):8553–8557. 10.1016/j.tsf.2007.04.027Zhai Y, Zhai S, Chen G, Zhang K, Yue Q, Wang L, Liu J, Jia J: Effects of morphology of nanostructured ZnO on direct electrochemistry and biosensing properties of glucose oxidase. J Electroanal Chem 2011, 656: 198–205. 10.1016/j.jelechem.2010.11.020Reyes Tolosa MD, Orozco-Messana J, Damonte LC, Hernandez-Fenollosa MA: ZnO nanoestructured layers processing with morphology control by pulsed electrodeposition. J Electrochem Soc 2011, 158(7):D452-D455. 10.1149/1.3593004Gouxa A, Pauporté T, Chivot J, Lincot D: Temperature effects on ZnO electrodeposition. Electrochim Acta 2005, 50(11):2239–2248. 10.1016/j.electacta.2004.10.007Kwok WM, Djurisic , Aleksandra B, Leung , Yu H, Li D, Tam KH, Phillips DL, Chan WK: Influence of annealing on stimulated emission in ZnO nanorods. Appl Phys Lett 2006, 89(18):183112. 183112–3 183112–3 10.1063/1.2378560Donderis V, Hernández-Fenollosa MA, Damonte LC, Marí B, Cembrero J: Enhancement of surface morphology and optical properties of nanocolumnar ZnO films. Superlattices and Microstructures 2007, 42: 461–467. 10.1016/j.spmi.2007.04.068Ghayour H, Rezaie HR, Mirdamadi S, Nourbakhsh AA: The effect of seed layer thickness on alignment and morphology of ZnO nanorods. Vacuum 2011, 86: 101–105. 10.1016/j.vacuum.2011.04.025Michael B, Mohammad Bagher R, Sayyed-Hossein K, Wojtek W, Kourosh K-z: Aqueous synthesis of interconnected ZnO nanowires using spray pyrolysis deposited seed layers. Mater Lett 2010, 64: 291–294. 10.1016/j.matlet.2009.10.065Jang Bo S, Hyuk C, Sung-O K: Rapid hydrothermal synthesis of zinc oxide nanowires by annealing methods on seed layers. J Nanomater 2011, 2011: 6.Peiro AM, Punniamoorthy R, Kuveshni G, Boyle DS, Paul O’B, Donal DC, Bradley , Jenny N, Durrant JR: Hybrid polymer/metal oxide solar cells based on ZnO columnar structures. J Mater Chem 2006, 16(21):2088–2096. 10.1039/b602084dVallet-Regí M, Salinas AJ, Arcos D: From the bioactive glasses to the star gels. J Mater Sci Mater Med 2006, 17: 1011–1017.Peulon S, Lincot D: Mechanistic study of cathodic electrodeposition of zinc oxide and zinc hydroxychloride films from oxygenated aqueous zinc chloride solutions. J Electrochem Soc 1998, 145: 864. 10.1149/1.1838359Dalchiele EA, Giorgi P, Marotti RE, Martín F, Ramos-Barrado JR, Ayouci R, Leinen D: Electrodeposition of ZnO thin films on n-Si(100). Sol. Energy Mater. Sol. Cells 2001, 70: 245. 10.1016/S0927-0248(01)00065-4Courtney IA, Dahn JR: Electrochemical and in situ X‐ray diffraction studies of the reaction of lithium with tin oxide composites. J Electrochem Soc 1997, 144(6):2045–2052. 10.1149/1.183774

Optical and Electrical Properties of TiO2/Co/TiO2 Multilayer Films Grown by DC Magnetron Sputtering

Transparent oxide multilayer films of TiO2/Co/TiO2 were grown on glass substrate by DC magnetron sputtering technique. The optical and electrical properties of these films were analyzed with the aim of substituting ITO substrate in optoelectronic devices. The samples were characterized by UV-visible spectroscopy, atomic force microscopy (AFM), and Kelvin probe force microscopy (KPFM). The effect of Co interlayer thickness (4, 8, and 12 nm) on the transmittance spectra yielded an optical absorption edge shift. The work function of these films was determined by KPFM technique allowing us to predict the Fermi level shift by extending the model for pure materials to our multilayer system. The Fermi level and optical absorption edge seem to be correlated and shifted toward lower energies when Co interlayer thickness is increased

Low temperature rolling of AZ91 alloy for hydrogen storage

The hydrogen storage properties of a commercial AZ91 magnesium alloy were investigated after processing by cold rolling in two different conditions: (a) extensive cold rolling at room temperature (CR); (b) rolling with the immersion of the alloy in liquid nitrogen bath after 05 rolling passes. This second condition is named as low temperature rolling (LTR). A full microstructural characterization including scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction (XRD), X-ray photoelectron and positron annihilation life time spectroscopy (XPS and PALS) were performed in the processed alloys. The hydrogen storage properties were measured using a Sievert-type apparatus. The AZ91-alloy is composed by the β-Mg and Mg17Al12 phases, and after processing by CR, an intense peak broadening and strong [002] texture were observed in the alloys. The LTR processing resulted in a more fragile material containing more microcracks and exposed interfaces than the conventionally cold rolled one. The LTR sample also presented a more refined microstructure in comparison with CR sample. These features resulted in superior hydrogen storage properties for the LTR sample in comparison with the CR sample. In addition, the effect of surface contamination was also studied in detail and it was found to play a significant role during the activation kinetics.Fil: Floriano, R.. Universidade Estadual de Campinas; BrasilFil: Leiva, D. R.. Universidade Federal do São Carlos; BrasilFil: Melo, G. C.. Universidade Federal do São Carlos; BrasilFil: Ishikawa, T. T.. Universidade Federal do São Carlos; BrasilFil: Huot, J.. Universite Du Quebec A Trois-rivieres; CanadáFil: Kaufman, M.. Department of Metallurgical and Materials Engineering; Estados UnidosFil: Figueroa, S.J.A.. Centro Nacional de Pesquisa Em Energia E Materiais; BrasilFil: Mendoza Zélis, Luis Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Damonte, Laura Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Botta, W.J.. Universidade Federal do São Carlos; Brasi

The plant hormone abscisic acid stimulates the proliferation of human hemopoietic progenitors through the second messenger cyclic ADP-ribose

Abscisic acid (ABA) is a hormone involved in pivotal physiological functions in higher plants, such as response to abiotic stress and control of seed dormancy and germination. Recently, ABA was demonstrated to be autocrinally produced by human granulocytes, beta pancreatic cells, and mesenchymal stem cells (MSC) and to stimulate cell-specific functions through a signaling pathway involving the second messenger cyclic ADP-ribose (cADPR). Here we show that ABA expands human uncommitted hemopoietic progenitors (HP) in vitro, through a cADPR-mediated increase of the intracellular calcium concentration ([Ca(2+)](i)). Incubation of CD34(+) cells with micromolar ABA also induces transcriptional effects, which include NF-kappaB nuclear translocation and transcription of genes encoding for several cytokines. Human MSC stimulated with a lymphocyte-conditioned medium produce and release ABA at concentrations sufficient to exert growth-stimulatory effects on co-cultured CD34(+) cells, as demonstrated by the inhibition of colony growth in the presence of an anti-ABA monoclonal antibody. These results provide a remarkable example of conservation of a stress hormone and of its second messenger from plants to humans and identify ABA as a new hemopoietic growth factor involved in the cross-talk between HP and MSC