Ignacio Hernández

Efficient oxide phosphors for light upconversion; green emission from Yb3+ and Ho3+ co-doped Ln2BaZnO5 (Ln = Y, Gd)

The optical properties of Yb3+ and Ho3+ co-doped Y2BaZnO5, synthesized by solid-state reactions, are investigated in detail. Under 977 nm excitation (∼25 × 10−3 W mm−2), bright green upconversion emission is observed. Concentration dependence studies at room temperature show that relatively high infrared to visible upconversion efficiencies are obtained with values up to ∼2.6%. The results of power dependence studies and temperature-dependent lifetime measurements allow us to determine the dominant upconversion mechanisms in Yb3+:Ho3+ co-doped Y2BaZnO5oxides. The materials presented in this article constitute new and efficient upconversion phosphors which may find utility in a variety of applications.

Oxide phosphors for efficient light upconversion: Yb3+ and Er3+ co-doped Ln2BaZnO5 (Ln = Y, Gd)

The optical properties of Yb3+ and Er3+ co-doped Ln2BaZnO5 (Ln = Y or Gd), synthesized by solid-state reaction, are investigated in detail. Two main emission bands centered around 548 nm (green) and 673 nm (red) are observed under 977 nm laser excitation via an upconversion process. Studies of the behavior as a function of dopant concentration are described and relatively high infrared to visible upconversion efficiencies of ∼5% are obtained at room temperature. Under modulated 977 nm excitation and for fixed dopant concentrations, the upconverted emission chromaticity can be varied by changing the excitation duration. The results of power dependence studies and lifetime measurements are presented. This detailed study of the upconversion processes allows us to identify the dominant upconversion mechanisms in Yb3+,Er3+ co-doped Ln2BaZnO5 oxides.

Estudio multicéntrico epidemiológico-clínico de cáncer de pulmón en España (estudio EpicliCP-2003)

Objetivo La mortalidad por cancer de pulmon en Espana aumenta ininterrumpidamente. El objetivo del presente estudio ha sido conocer su incidencia hospitalaria, asi como otros datos de manejo clinico, en varias regiones espanolas. Material y metodos Se ha realizado un estudio prospective observacional de los pacientes diagnosticados de cancer de pulmon en 2003 en 13 centros de 9 comunidades autonomas. Se evaluaron variables epidemiologicas, clinicas, diagnosticas y terapeuticas. Resultados Se han registrado 1.064 varones y 125 mujeres correspondientes a una poblacion total de 2.726.601 habitantes (1.346.483 varones y 1.380.118 mujeres). Las tasas estandarizadas segun poblacion mundial variaron entre 42,4 y 61,8/100.000 en varones y entre 1,5 y 8,6/100.000 en mujeres. El 51% tenia mas de 70 anos. El 97,5% de los varones y el 32% de las mujeres eran fumadores o ex fumadores. Se obtuvo confirmacion citohistologica en el 93,1% de los casos (un 20,8% microciticos y un 79,2% no microciticos). Los sintomas iniciales predominantes fueron tos, dolor toracico y perdida de peso. En el 13,7% el diagnostico se sospecho solo por anormalidad radiologica. La proporcion de estadios TNM clinicos I y II vario entre el 6,3 y el 26,9%. El estadio IV fue el mas comun en todos los centros. La tasa de intervenciones vario entre el 2,5 y el 20,6%; el promedio fue del 14,8% (un 19,9% del total de no microciticos). El 27,0% solo recibio medidas paliativas. Conclusiones Entre los casos de cancer de pulmon aumenta la proporcion de mujeres con respecto a estudios previos, con notables diferencias interregionales. Pese a las mejoras diagnosticas, la tasa de intervenciones, muy variable entre diferentes centros, es muy baja.

Efficient white light emission by upconversion in Yb3+-, Er3+- and Tm3+-doped Y2BaZnO5

We report efficient white upconversion luminescence in Yb(3+)-, Er(3+)- and Tm(3+)-doped monophasic and biphasic Y(2)BaZnO(5) phosphors under 977 nm near-infrared excitation and at low excitation power densities (down to ∼25 mW mm(-2)).

Oxide phosphors for light upconversion; Yb3+ and Tm3+ co-doped Y2BaZnO5

The optical properties of Yb3+ and Tm3+ co-doped Y2BaZnO5, synthesized by solid-state reaction, are investigated in detail. Three main emission bands centered around 479 nm (blue), 654 nm (red), and 796 nm (near-infrared) are observed under near-infrared laser excitation via an upconversion process. Detailed studies of the upconversion properties as a function of dopant concentrations are described and upconversion efficiencies quantified precisely. Maximum efficiencies of ∼ 1.53% in the 730-870 nm near-infrared emission range and of ∼ 0.09% in the 420-530 nm blue range are obtained. The results of power dependence studies and concentration dependent lifetime measurements are presented. This in-depth spectroscopic study allows us, for the first time, to identify the dominant processes involved in the upconversion mechanism of Yb3+, Tm3+ co-doped Y2BaZnO5 oxides.

Influence of high hydrostatic pressure on Alq3, Gaq3, and Inq3 (q = 8-hydroxyquinoline).

We have studied the spectroscopic properties of OLED materials Alq(3), Gaq(3) and Inq(3) (q = 8-hydroxyquinoline) under pressure. We discuss the results in terms of the influence of structural modifications, the isomeric state and the enhancement of the intermolecular interaction. As-grown Alq(3), Gaq(3), Inq(3) containing meridional (mer) isomer experience a red shift of nearly 90 nm (2400 cm(-1)) in the 0-8 GPa range. Abrupt changes in the photoluminescence occur during compression at intermediate pressures for all materials. We assign them to a phase transition, its critical pressure depending on the central cation. All three samples experience an amorphization at P approximately 6 GPa, with associated changes in the spectroscopic properties. The pressure-induced phase transitions present hysteresis to ambient conditions. Photoluminescence lifetime decreases in all cases in the explored pressure range. In the case of facial isomer containing polymorphs of Alq(3), luminescence does not change its energy significantly. The most significant spectroscopic change observed in fac-isomer containing materials corresponds to gamma-Alq(3), which presents a low energy component that gains relative importance when pressure is increased. We ascribe this phenomenon to the presence of sensitized mer isomer impurities.

Cooperative Infrared to Visible Up Conversion in Tb3+, Eu3+, and Yb3+ Containing Polymers

The conversion of IR photons to higher energies is widely employed in lasers, imaging, and biology. Mechanisms based on nonlinear properties of the interaction between matter and radiation [ 1 ] are longstanding techniques to achieve this, but usually require very high excitation powers. Up-conversion (UC) processes, which occur when IR-excited centers populate a higher-energy emitting state, [ 2 ] represent a promising linear Hamiltonian alternative. This process can be extremely effi cient and allows a number of photonic and solar cell applications, [ 3 ] all of them currently based on inorganic materials. Consequently there are diffi culties with their processability, which, together with the low concentration of emitters required to avoid inter-ion quenching of the luminescence, [ 4 ] present serious operational limits. Here, we present and analyze the design rules for the observation of intense cooperative UC [ 5 ]

Luminescent zinc(II) complexes of fluorinated benzothiazol-2-yl substituted phenoxide and enolate ligands.

Zn(II) complexes of the following new, fluorine-containing, benzothiazole-derived ligands have been synthesized and characterized crystallographically: 2-(3,3,3-trifluoro-2-oxopropyl)benzothiazole (3), 4,5,6,7-tetrafluoro-2-(3,3,3-trifluoro-2-oxopropyl)benzothiazole (4), 4,5,6,7-tetrafluoro-2-(2-hydroxyphenyl)benzothiazole (12), 2-(3,4,5,6-tetrafluoro-2-hydroxyphenyl)-4,5,6,7-tetrafluorobenzothiazole (13), and 2-(3,4,5,6-tetrafluoro-2-hydroxyphenyl)benzothiazole (16); the Cu(II) complex of ligand 4 is also reported. These are analogs of the important photo- and electroluminescent material [Zn(BTZ)(2)](2), where H-BTZ = 2-(2-hydroxyphenyl)benzothiazole. DFT calculations indicate that HOMO and LUMO energy levels in these materials are substantially lowered by fluorination. The fluorinated ZnL(2) complexes are mononuclear (in contrast to the dinuclear, nonfluorinated material [Zn(BTZ)(2)](2)). They easily sublime and show broad visible photoluminescence. A common crystallographic feature is the existence of pairs of fluorinated ZnL(2) molecules related by inversion centers, with their π systems facing one another.

Synthesis, Characterization, and Application of Core–Shell Co0.16Fe2.84O4@NaYF4(Yb, Er) and Fe3O4@NaYF4(Yb, Tm) Nanoparticle as Trimodal (MRI, PET/SPECT, and Optical) Imaging Agents

Multimodal nanoparticulate materials are described, offering magnetic, radionuclide, and fluorescent imaging capabilities to exploit the complementary advantages of magnetic resonance imaging (MRI), positron emission tomography/single-photon emission commuted tomography (PET/SPECT), and optical imaging. They comprise Fe3O4@NaYF4 core/shell nanoparticles (NPs) with different cation dopants in the shell or core, including Co0.16Fe2.84O4@NaYF4(Yb, Er) and Fe3O4@NaYF4(Yb, Tm). These NPs are stabilized by bisphosphonate polyethylene glycol conjugates (BP-PEG), and then show a high transverse relaxivity (r2) up to 326 mM(-1) s(-1) at 3T, a high affinity to [(18)F]-fluoride or radiometal-bisphosphonate conjugates (e.g., (64)Cu and (99m)Tc), and fluorescent emissions from 500 to 800 nm under excitation at 980 nm. The biodistribution of intravenously administered particles determined by PET/MR imaging suggests that negatively charged Co0.16Fe2.84O4@NaYF4(Yb, Er)-BP-PEG (10K) NPs cleared from the blood pool more slowly than positively charged NPs Fe3O4@NaYF4(Yb, Tm)-BP-PEG (2K). Preliminary results in sentinel lymph node imaging in mice indicate the advantages of multimodal imaging.

Epidemiology of lung cancer in Spain and forecast for the future

Lung cancer, a steadily growing problem, ranks as the first cause of tumor-related deaths in developed countries. The relation between lung cancer and smoking makes it a potentially avoidable disease. Found mainly in men, it has made alarming gains among women. The main prognostic factor is the possibility of receiving curative surgery; however, in real practice the diagnosis usually comes when the disease has reached an advanced stage, when only 20% can be treated surgically. Nonsurgical treatments based on chemo- and radiotherapy have not advanced appreciably in recent years, and 5-year survival is poor, estimated at only around 7% to 12% in Spain. Attempts must be made to improve preventive measures and early diagnosis in order to improve the prognosis for lung cancer patients.