Upconversion thermometry: a new tool to measure the thermal resistance of nanoparticles.

The rapid evolution in luminescence thermometry in the last few years gradually shifted the research from the fabrication of more sensitive nanoarchitectures towards the use of the technique as a tool for thermal bioimaging and for the unveiling of properties of the thermometers themselves and of their local surroundings, for example to evaluate heat transport at unprecedented small scales. In this work, we demonstrated that KLu(WO4)2:Ho3+,Tm3+ nanoparticles are able to combine controllable heat release and upconversion thermometry permitting to estimate its thermal resistance (in air), a key parameter to model the heat transfer at the nanoscale.

Diversity of Anopheles spp. (Diptera: Culicidae) in an Amazonian Urban Area.

The genus Anopheles encompasses several species considered as vectors of human infecting Plasmodium. Environmental changes are responsible for behavior changes in these vectors and therefore the pattern of malaria transmission. To better understand the dynamics of malaria transmission, this study aimed at identify the species of adult anophelines found in a malaria endemic urban area of the Amazon region, Mâncio Lima, located in the Acre State Brazil. Using Shannon-type light traps installed at 11 collection points near fish ponds, a total of 116 anophelines were collected belonging to nine species. Anopheles darlingi Root 1926 and An. albitarsis s.l. Lynch-Arribalzaga 1878 were the most abundant and predominant species. Despite the low number of captured adult anophelines, the occurrence of An. darlingi throughout all urban area and the presence of secondary vectors reinforce the need of a permanent and continuous entomological surveillance.

Anisotropic enhancement of Yb3+ luminescence by disordered plasmonic networks self-assembled on RbTiOPO4 ferroelectric crystals.

Increasing Yb3+ absorption efficiency is currently desired in a number of applications including bio-imaging, photovoltaics, near infrared driven photocatalysis or ultra-short pulsed solid-state lasers. In this work, silver nanoparticles, which are connected forming disordered networks, have been self-assembled on Yb3+ doped RbTiOPO4 crystals to produce a remarkable enhancement of Yb3+ absorption, and hence in the photoluminescence of this ion. The results are interpreted taking into account the near-field response of the plasmonic networks, which display strong amplification of the electric field at the maximum of Yb3+ excitation at around 900 nm, together with the anisotropic character of the Yb3+ transitions in RbTiOPO4. We show that in the near field regime, the scattering of the plasmonic networks produces additional polarization field components to those of the incident field, which allows access to the largest transition dipolar moment of Yb3+ ions in RbTiOPO4. As a result, a much more efficient route for Yb3+ excitation takes place at the immediacy of the plasmonic networks. This work provides fundamental insights for improving the optical properties of rare earth ions by the suitable design of metallic nanoparticle arrangements, and constitutes a promising step towards the development of new multifunctional solid-state lasers.

Er:Yb:NaY2F5O up-converting nanoparticles for sub-tissue fluorescence lifetime thermal sensing.

Non-contact thermometry is essential in biomedical studies requiring thermal sensing and imaging with high thermal and spatial resolutions. In this work, we report the potential use of Er:Yb:NaYF4 and Er:Yb:NaY2F5O up-conversion nanoparticles as thermal sensors by means of lifetime based luminescent thermometry. We demonstrate how Er:Yb:NaY2F5O nanocrystals present a higher thermal sensitivity than the Er:Yb:NaYF4 ones and that their lifetime thermal coefficient is comparable to those corresponding to other nano-sized luminescent systems already used for high resolution lifetime fluorescence thermal sensing. We evaluate the potential use of Er:Yb:NaY2F5O nanoparticles as lifetime based thermal probes by providing the first experimental evidence on sub-tissue lifetime fluorescence thermal sensing by using up-conversion nanoparticles in an ex vivo experiment.

White light upconversion in Yb-sensitized (Tm, Ho)-doped KLu(WO4)2 nanocrystals: the effect of Eu incorporation.

Monoclinic Yb-sensitized (Tm, Ho)-doped KLu(WO4)2 nanocrystals of ~100 nm size have been synthesized by the modified Pechini sol-gel method. Their diode laser near-infrared (~980 nm) excited upconversion emission properties have been characterized at power densities in the range 30-355 W cm(-2). Bright white light composed of blue ~475 nm, green ~540 nm, and red ~650 nm emissions, corresponding to Tm(3+ 1)G4 → (3)H6, Ho(3+ 5)S2, (5)F4 → (5)I8, and Ho(3+ 5)F5 → (5)I8 electronic transitions, respectively, was generated by adjusting the Yb, Tm, and Ho contents in KLu(WO4)2 nanocrystalline samples. Chromaticity coordinates of the emitted white light can be tuned by modifying the excitation power density. The effect of Tm and Ho on the luminescence dynamics has been described by analyzing the upconverted emission intensity dependence on the excitation power, as well as from Stokes and decay time measurements. The effect on upconversion properties of further codoping with Eu in these (Tm, Ho, Yb)-doped KLu(WO4)2 nanocrystals has also been studied.

Channel waveguides on RbTiOPO4 by Cs+ ion exchange.

In this Letter we report Cs(+) ion exchange channel waveguides on RbTiOPO(4) (RTP) for what we believe is the first time. A Ti channel mask was fabricated on an RTP substrate by conventional photolithography. The ion exchange process was carried out in a CsNO(3) melt, and the channels produced ranged from 6 to 11 µm in width. The near-field pattern of the modes was recorded, and type II second harmonic generation in waveguide regime was obtained, producing 512.5 nm green light. The optical characterization shows optical losses of 3.8 dB/cm.

Efficient Type II phase-matching second-harmonic generation in Ba:Yb:Nb:RbTiOPO4/RbTiOPO4 waveguides.

Efficient Type II phase-matching second-harmonic generation of a 1125 nm fundamental beam has been obtained using Ba:Yb:Nb:RbTiOPO(4)/RbTiOPO(4) waveguides grown by liquid phase epitaxy. The refractive indices of the epitaxial layer have been measured at different wavelengths, and the Sellmeier coefficients of the chromatic dispersion curves have been obtained. The phase-matching curve shows that the Ba(2+) doping in RbTiOPO(4) contributes to increase the phase-matching range until 900 nm. The measured effective refractive indices of the propagation modes agree well with the theoretical calculations.

Broad emission band of Yb3+ in the nonlinear Nb:RbTiOPO4 crystal: origin and applications.

By means of micro-structural and optical characterization of the Yb:Nb:RbTiOPO(4) crystal, we demonstrated that the broad emission band of Yb(3+) in these crystals is due to the large splitting of the ytterbium ground state only, and not to a complex multisite occupation by the ytterbium ions in the crystals. We used this broad emission band to demonstrate wide laser tuning range and generation of femtosecond laser pulses. Passive mode-locked laser operation has been realized by using a semiconductor saturable absorber mirror, generating ultra short laser pulses of 155 fs, which were very stable in time, under Ti:sapphire laser pumping at 1053 nm.

Synthesis and characterization of KTiOPO4 nanocrystals and their PMMA nanocomposites.

KTiOPO(4) (KTP) nanocrystals have been synthesized by the modified Pechini method using ethylenediaminetetraacetic acid (EDTA) and ethylene glycol (EG) as chelating and sterification agents, respectively. Orthorhombic KTP has been obtained by calcination at 1073 K for several hours. Differential thermal and thermogravimetric (DTA-TG) analyses have been used to study the optimized heat treatment used on the precursor powder to obtain KTP nanocrystals. X-ray powder diffraction (XRD) studies on the thermally treated precursor powders indicated that nanocrystals began to crystallize at 923 K. Nanocrystals with a size dispersion distribution that fit to a lognormal function centered at 25 nm were observed by electronic microscopy. KTP nanocomposites were prepared by embedding nanocrystals in poly(methyl methacrylate) (PMMA). The photoinduced second-order susceptibility parameter and the piezo-optical coefficient were measured for the KTP nanocomposites. The optimal conditions for the generation of the frequency-doubled second harmonic generation were recorded at 391 K, and at a fundamental laser wavelength of 1064 nm and under additional treatment by polarized UV light, provided the maximum value obtained of 3.23 pm V(-1). The piezo-optical coefficients were recorded at room temperature under photoinduced treatment by a UV laser beam; the maximum value achieved was 0.673 x 10(-14) m(2) N(-1) at a pump-probe delaying time of 160 s.

Scanning probe microscopies applied to the study of the domain wall in a ferroelectric crystal.

Scanning near-field optical microscopy is capable of measuring the topography and optical signals at the same time. This fact makes this technique a valuable tool in the study of materials at nanometric scale and, in particular, of ferroelectric materials, as it permits the study of their domains structure without the need of chemical etching and, therefore, not damaging the surface (as will be demonstrated later). We have measured the scanning near-field optical microscopy transmission, as well as the topography, of an RbTiOPO(4) single crystalline slab, which exhibits two different of macroscopic ferroelectric domains. A chemical selective etching has been performed to distinguish between them, obtaining areas with a noticeable roughness (C(-) domain) in comparison with the original flat aspect of the other ones (C(+) domain). The effects of the selective chemical etching have been quantified in topographic images obtained by means of our fibre tip probe, and have been compared to topographic images obtained by Atomic Force Microscopy, with a better resolution. The near-field optical transmission images recorded have been obtained under different excitation wavelengths. These images are modulated by the light scattering due to the grains at the rough surface, which depends on the excitation wavelength used. In addition, they show a significant optical contrast due to the variations of the dielectric constant on the proximity of the ferroelectric domain wall.

Neoplasia pulmonar múltiple primaria

La neoplasia primaria múltiple de pulmón es una forma de presentación poco común entre las neoformaciones pulmonares. Acontece entre el 1,5 y el 3 per cent del total de las neoplasias de pulmón. Los criterios que la definen fueron establecidos en 1975 por Martini y Melamed, y aún son la referencia. La neoplasia primaria múltiple pulmonar puede manifestarse de forma sincrónica (aparición simultánea) o metacrónica (diferencia de aparición de más de 2 años entre ambos tumores). Se da una mayor incidencia en grandes fumadores y desde el punto de vista anatomopatológico suele tratarse de uncarcinoma epidermoide. Se considera que la supervivencia de este tipo de neoplasia pulmonar es menor que la de presentación única (AU)

[Lemièrre's syndrome. Report of 2 new cases and review of the literature]. / Síndrome de Lemièrre. Descripción de dos nuevos casos y revisión de la literatura.

Septic thrombophlebitis of internal jugular vein following oropharyngeal infections, referred to as postanginal sepsis, was first described at the beginning of the century by Lemièrre. For diagnostic of Lemièrre's syndrome, distant metastatic abscesses from septic embolization are required. These are placed most frequently in the lungs, but also occurred in soft tissues. Two cases of this unusual syndrome seen in a year period, are reported in this brief communication. We described the first liver metastatic infection, in the syndrome. Successful result was observed when we use a low molecular weight heparin as treatment in the septic thrombophlebitis of internal jugular vein.

Mujer joven con múltiples lesiones ocupantes de espacio en el sistema nervioso central / Young woman with multiple space-occupying lesions in the central nervous system

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Gota tofácea: ¿indisciplina o desconocimiento? / Tophic gout: indiscipline or ignorance?

La gota es una enfermedad con una etiopatogenia clara, diagnóstico preciso y tratamiento eficaz. A pesar de ello, un porcentaje no despreciable de pacientes desarrollan gota tofácea crónica. Su presencia se correlaciona con el tiempo de evolución de la enfermedad y con el grado de elevación de los niveles de ácido úrico. Realizando desde nuestro ámbito un diagnóstico precoz y un tratamiento adecuado conseguiremos disminuir los ataques agudos, prevenir la artropatía crónica y reducir las complicaciones extraarticulares de los pacientes con hiperuricemia (AU)

Síndrome de Lemièrre. Descripción de dos nuevos casos y revisión de la literatura / Lemièrre's syndrome. Description of two new cases and bibliographyc review

La tromboflebitis séptica de la vena yugular interna como complicación de las infecciones orofaríngeas, tras un cuadro de sepsis postangina, fue descrita por primera vez a principios de siglo por Lemièrre. Para el diagnóstico de este síndrome, se requiere la existencia de abscesos metastásicos a distancia. Estos se localizan más frecuentemente a nivel pulmonar, pero también se han descrito en tejidos blandos. En este trabajo presentamos dos nuevos casos de este infrecuente síndrome, observados en el período de un año. En nuestro conocimiento, no han sido descritos anteriormente abscesos metastásicos hepáticos en este cuadro, que observamos en uno de nuestros pacientes. También aportamos nuestra experiencia en el tratamiento con heparina de bajo peso molecular de la tromboflebitis venosa yugular, que forma parte de este síndrome (AU)

Septic thrombophlebitis of internal jugular vein following oropharyngeal infections, referred to as postanginal sepsis, was first described at the begining of the century by Lemièrre. For diagnostic of Lemièrre`s syndrome, distant metastatic abscesses from septic embolization are required. These are placed most frequently in the lungs, but also ocurred in soft tissues. Two cases of this inusual syndrome seen in a year period, are reported in this brief communication. We described the first liver metastatic infection, in the syndrome. Successful result was observed when we use a low molecular weight heparin as treatment in the septic thrombophlebitis of internal jugular vein (AU)