110 research outputs found
The Feasibility of Soft Chemical Routes in the Processing of Hierarchically Organized Functional Nanoparticles
Global warming, climate change and natural resources depletion forces tremendous technological and scientifical research activities for the development of next generation of material able to address both the energy and environmental problems. This implies an exciting progress in the field of nanoscience and nanotechnology, particularly regarding the control synthesis of hierarchically organised nanoscaled particles that might have a great potential for use in solid-state functional materials and devices, like phosphors, sensors, photovoltaics, catalysts, drug delivery carriers, etc.
Among the diversity of the soft chemical approaches for nanomaterials processing, synthesis through dispersion phase (aerosol) enables generation of ultrafme, either single or complex powders with controlled stoichiometry, chemical and phase content provided by high heating and cooling rates, short residence time and high surface reaction and is here demonstrated for the synthesis of spherical three-dimensional (3D), hierarchically organized nanostructured particles with uniformly distributed components and phases. The particles composite inner structure, representing an assembly of nanosized primary particles, opens the possibility for particle surface modification and functionalization emphasizing their application in photovoltaics, energy transfer and bioimaging.
When one-dimensional (1D) nanomaterials are considered, the hydrothermal method (HT) is shown to be one of the simplest techniques for their obtaining. With the help of various analyzing technique like XRPD, SEMIEDS, FE-SEM, TEM, HR-TEM, STEM, nanotomography, UV-Vis diffusive reflectance (UV-Vis DRS), Fourier transform infrared (FTIR) spectroscopy and luminescence measurements, the opportunities of both methods for the synthesis of novel functional materials based on Gd20 3:Eu, Y203:Eu,Yb,Er,Ho,Tm, (Y1-xGdx)203:Eu, Y3Als012:Ce, NaYF4, Ti02 etc. for solving energy/environmental problems will be reviewed. The obtained results offer a general route for the synthesis of hierarchical nanomaterials with tunable structure, morphology and optical properties
Hydrothermal synthesis of optically active rare earth fluorides
Hydrothermal method has great interest in recent years for synthesis of nano- and micro- crystals of upconverting rare earth (RE) fluorides, with controlled morphology and high purity, under high temperatures and pressures. Some surfactants (ethylenediaminetetraacetic acid (EDTA), polyvinylpyrrolidone (PVP), oleic acid (OA)) along with different type of solvents are added in order to control size, morphology and crystalline phases of particles. In this work Yb3+/Er3+ co-doped YF3 and NaYF4 fine powders were synthesized using the hydro/solvo thermal method in the present of EDTA as a complexing agent. Effect of the processing parameters on the particles crystal structure, morphology and optical properties were estimated on the basis of X-ray diffractometry (XRPD), scanning electron microscopy (SEM) and photoluminescence measurement. It was shown that in terms of increased concentration of RE ions in aqueous solvent media the hexagonal β-NaYF4:Yb3+/Er3+ phase with the most efficient green emission were synthesized. On the other side, the occurrence of cubic α-NaYF4:Yb3+/Er3+ and orthorhombic YF3:Yb3+/Er3+ were observed with a decrease of the RE ions when ethanol is used as a solvent. All of the samples provide intense green emission after been excited with infrared light (λ = 978 nm), which is assigned to the Er3+ (2H11/2, 4S3/2) → 4I15/2 electronic transitions
Bortezomib “off label” to treat humoral rejection in kidney transplantation: case report
En Argentina, no hay suficiente información sobre el uso“off label” y mucho menos sobre promoción adecuadadirigida en ese sentido; por lo tanto, el farmacéutico enlos entornos de atención de salud organizados tiene unaresponsabilidad significativa para asegurar resultadosóptimos en la farmacoterapia.Bortezomib es un inhibidor selectivo del proteosoma 26Sdesarrollado para el tratamiento del mieloma múltiple, yha sido utilizado por su actividad anti-células plasmáticasen pacientes trasplantados.Se presenta nuestra experiencia entre enero y diciembrede 2011, un paciente tratado con bortezomib quepresentó Rechazo Mediado por Anticuerpos refractario ala terapia convencional anti-rechazo (inmunoglobulina Gintravenosa humana, plasmaferesis, rituximab,inmunoglobulina antitimocítica). El equipo de salud de laClínica Privada Vélez Sarsfield de Córdoba, Argentinadecidió utilizar en forma “off label” bortezomib comotratamiento a un paciente trasplantado luego de quefallara la terapia estándar para AMR y estuviera en riesgode perder el injerto.La terapia con bortezomib mejoró la función renal. Laterapia tradicional y “off label” fue, en general, bientolerada por el paciente. La inmunoglobulinaantitimocítica tuvo que ser suspendida en la cuarta dosisdel primer ciclo, debido a que el paciente presentóleucopenia severa. El segundo ciclo de 5 dosis deinmunoglobulina antitimocítica (Tymo) fue bien tolerado.Luego de bortezomib, el paciente presentó síntomas deneuropatía periférica, efecto adverso bien documentadodel medicamento. Se propuso la implementación de unprograma de Farmacovigilancia que fue aceptada por elequipo médico.In Argentina, there is insufficient information "off label" useand even less on adequate promotion aimed in thatdirection; therefore, pharmacists in organized health-caresettings bear a significant responsibility for ensuring optimaloutcomes from all drug therapy. Bortezomib is a selectiveinhibitor of the 26S proteasome developed to treat multiplemyeloma, and has been used for its anti - plasma cell activityin transplant patients. This is our experience betweenJanuary and December 2011 in one patient with bortezomibtherapy for Antibody-Mediated Rejection who was refractoryto traditional therapies (intravenous humanimmunoglobulin, plasmapheresis, rituximab, Antithymocyteimmunoglobulin preparations). The Clínica Privada VélezSarsfield de Córdoba, Argentina team decided to usebortezomib at the labeled dose therapy in an “off-label”fashion for one renal transplant recipient who had failedstandard therapy for AMR and who was at risk of losing hisrenal allograft.In this experience, bortezomib therapy providedimprovements in renal function. The traditional and “offlabel” therapy was generally well tolerated by the patient.Antithymocyte immunoglobulin had to be suspended in thefirst cycle, because the patient had severe leucopenia. Thesecond cycle of 5 Antithymocyte immunoglobulin (Tymo)doses was tolerated. After bortezomib, the patient developedsymptoms of peripheral neuropathy, adverse effect welldocumented. A pharmacovigilance program was proposedby the Pharmacist and it was accepted by the medical team.Fil: Rivero, Roxana Nicolasa. Clínica Privada Vélez Sarsfield; ArgentinaFil: Olivera, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Investigación y Desarrollo en Tecnología Farmacéutica. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Unidad de Investigación y Desarrollo en Tecnología Farmacéutica; ArgentinaFil: Maldonado, Rafael Alberto. Clínica Privada Vélez Sarsfield; Argentin
The feasibility of aerosol route in the optically active nanoparticles processing
Among the diversity of the soft chemical approaches for nanomaterials processing, synthesis through dispersion phase (aerosol) enables generation of ultrafine, either single or complex powders with controlled stoichiometry, chemical and phase content provided by high heating and cooling rates, short residence time and high surface reaction. This may favors to the formation of either amorphous, nanocrystalline or metastable phases that might have a huge impact in the processing of advanced functional materials having novel and unique structures and properties. Particularly, the opportunities of the hot wall aerosol processing, provided by high heating and cooling rates, short residence time and high surface reaction, is demonstrated for the synthesis of spherical three-dimensional (3D), hierarchically organized nanostructured particles with uniformly distributed components and phases. The particles composite inner structure, representing an assembly of nanosized primary particles, opens the possibility for particle surface modification and functionalization emphasizing their application in photovoltaics, energy transfer and bioimaging. The diverse levels of structural, morphological and functional complexity are explored by means of appropriate selection of different precursor solutions, either true or colloid, surface modification and proper selection of rare-earth based dopants for the generation of either photocatalytic titanium (IV) oxide or a range of up-conversion phosphor particles. With the help of various analyzing techniques like XRPD, SEM/EDS, FE-SEM, TEM, HR-TEM, STEM, nanotomography, UV-Vis diffusive reflectance (UV-Vis DRS), Fourier transform infrared (FTIR) spectroscopy and luminescence measurements, the synthesis of novel functional materials based on Y2O3:Eu,Yb,Er, NaYF4 and TiO2 for solving energy/environmental problems will be presented. The obtained results offer a general route for the synthesis of nanomaterials with tunable structure, morphology and optical properties
Optical Properties of Nanostructured Particles Synthesized by Spray Pyrolysis Route
Poster presented at the International Symposium on Advanced Complex Inorganic Nanomaterials (ACIN 2011), September 11-14, 2011 - Namur, Belgiu
Nanostructured Y2O3 Particles Doped with Europium Synthesized by Aerosol Route
Y2O3 doped with europium is a well known red phosphor material employed in modern high-resolution display devices such as plasma display panels (PDP) and field emission displays (FED). The incorporation of gadolinium in the yttria matrix may significantly contribute to the luminescent properties and x-ray absorption coefficient thus increasing the field of application in optoelectronic devices such as ceramic scintillators for computed tomography. In this work, the nanostructured particles of Y 2 O 3 doped with Eu 3+ were processed through the spray pyrolysis method. Synthesis was carried out with an ultrasonic aerosol device operating at 1.3 MHz in air atmosphere connected with a triple-zone tubular flow reactor (473-973-1173K). Particles were submitted t o post- thermal treatments at temperatures among 1273 and 1 573K for 12 hours in order to increase the crystallinity and uniform distribution of doped centers. Morphology, structure, crystallinity and chemical characteristics were studied by XRD, SEM-EDS, TEM-HRTEM and SAED. The particles obtained are spherical, having narrow size distributions, high compositional homogeneity and are in unagglomerated state. The effects of synthesis parameters were followed and discussed in terms of particle structure and morphology
Dense spherical rare earth oxide particles synthesis via spray pyrolysis of polimeric precursor solution
Poster presented at 12th Annual Conference of the Materials Research Society of Serbia - YUCOMAT 2010, Herceg Novi, Montenegro, September 6–10, 2010
The morphology, structure and luminescent properties of Gd2O3:Eu synthesized by aerosol route and high energy ball milling
Poster presented at the Seventh International Conference on Mechanochemistry and Mechanical Alloying - INCOME 2011, Herceg Novi, Montenegro, August 31 – September 3, 201
Dense spherical rare oxide particles synthesis via spray pyrolysis of polymeric precursor solution
Europium-doped (Y0.5Gd0.5)2O3 phosphor powder is synthesized via spray pyrolysis of polymeric precursor solution obtained by dissolving the stoichiometric amount of corresponding metal nitrates in ethylenediaminetetraacetic acid (EDTA) - ethylene glycol (EG) mixture. The 0.1M true stable solution is obtained after pH correction with NH4OH (final pH=8.7). Ultrasonically (1.3MHz) generated aerosol droplets are decomposed at 550 oC in argon atmosphere. Following the initial attempt for obtaining dense, nanostructured spherical particles of pure (Y0.5Gd0.5)2O3:Eu3+ phase, as-prepared dark-gray powder is additionally thermally treated for 12 h in air up to 1100 oC. The particle morphology is analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Phase identification is performed by X-ray powder diffraction (XRPD) based on which the structural refinement through Rietveld method was done. Particle chemical purity is confirmed through EDS analysis, while laser particle sizer is used for determination of the particle size distribution.Poster: [https://hdl.handle.net/21.15107/rcub_dais_220
Aerosol assisted processing of hierarchically organized functional nanoparticles
Global warming, climate change and natural resources depletion forces tremendous technological and scientific research activities for the development of next generation of materials able to address both the energy and environmental problems. This implies an exciting progress in the field of nanoscience and nanotechnology, particularly regarding the control synthesis of nanoscaled materials that might have a great potential for use in solid-state functional materials and devices, like phosphors, sensors, photovoltaics, catalysts, drug delivery carriers etc. The feasibility of the dispersion phase-aerosol route for the generation of innovative nanomaterials having advanced optical properties for solving energy/environmental problems is here presented. Particularly, the opportunities of the hot wall aerosol processing, provided by high heating and cooling rates, short residence time and high surface reaction, is demonstrated for the synthesis of spherical three-dimensional (3D), hierarchically organized nanostructured particles with uniformly distributed components and phases. The particles composite inner structure, representing an assembly of nanosized primary particles, opens the possibility for particle surface modification and functionalization emphasizing their application in photovoltaics, energy transfer and bioimaging. The diverse levels of structural, morphological and timctional complexity are explored by means of appropriate selection of different precursor solutions, either true or colloid, surface modification and proper selection of rare-earth based dopants for the generation of either photocatalytic titanium (IV) oxide or Yb3+, Er3+, codoped yttrium(III) oxide-based phosphor particles. Their advanced optical properties as the consequence of the particle nanostructure uature are proved by using various characterization techniques like x-ray powder diffraction (XRPD), scanning electron microscopy (SEM, FE-SEM), analytical and high-resolution transmission electron microscopy (TEMIHR-TEM) in combination with energy dispersive x-ray analysis (EDAX), selected area electron diffraction (SAED) and nanotomography. The optical properties and surface structure were analyzed by UV-Vis diffusive reflectance (UV-Vis DRS), Fourier transform infrared (FTIR) spectroscopy and by fluorescence measurements in the near infrared region. The obtained results offer ageneral route for the synthesis of nanomaterials with tunable structure, morphology and optical properties
- …