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In order to clarify the polymorphism in the lithium sulfate family, LiRE x (NH4)1 − x SO4 (0.5 ≤ x ≤ 4.0 mol%, nominal value; RE = Er3+, Yb3+ and Dy3+) crystals were grown from aqueous solution by slow evaporation between 298 and 313 K. The doping of the samples allowed us to obtain two polymorphic forms, α and β, of LiNH4SO4 (LAS). By means of X-ray diffraction (XRD) in single crystals, we determined the crystal structures of two new α-polytypes, which we have named α1- and α2-LAS. They present the same space group P21/c and the following relation among their lattice parameters: a 2 = −c 1, b 2 = −b 1, c 2 = −2a 1 − c 1. In order to evaluate the stability of the new α-polytypes, we performed thermal analysis, X-ray diffraction and dielectric spectroscopy on single crystals and polycrystalline samples over the cyclic temperature range: 190 → 575 → 190 K. The results obtained by all the techniques used in this study demonstrate that α-polytypes are stable across a wide range of temperatures and they show an irreversible phase transition to the paraelectric β-phase above 500 K. In addition, a comparative study of α- and β-polytypes shows that both polymorphic structures have a common axis, with a possible intergrowth that facilitates their coexistence and promotes the reconstructive α → β transition. This intergrowth was related to small anomalies detected between 240 and 260 K, in crystals with an α-habit.

Grupo de Física de Materiales, Universidad La Laguna RE-doped (Eu3+, Sm3+, Dy3+ or Tb3+) nano-glass-ceramics containing BaGdF5 nanocrystals, have been successfully obtained under thermal treatment of precursor sol-gel glasses. X-ray diffraction, high-resolution transmission electron microscope images and energy dispersive X-ray spectroscopy measurements confirmed the precipitation and distribution of cubic BaGdF5 nanocrystals (around 10 nm in size) in the glass matrix. The luminescent properties, via excitation and emission spectra along with decay curves, were studied. In order to complete the structural analysis, the luminescent features of Eu3+ and Sm3+ ions were also used as sensitive probes, confirming the distribution of a significant fraction of dopant ions into the fluoride nanocrystalline environment. Intense visible emissions were obtained through efficient energy transfer from Gd3+ to RE ions, which leads to consider these materials as potential emitting phosphors for colour converted UV LEDs. Ministerio de Economía y Competitividad (MAT2014-57551-R (LUNALEDs)

Transparent nano-glass–ceramics comprising Yb 3+ , Er 3+ and Tm 3+ co-doped KYF 4 nanocrystals have been developed from sol–gel method. A structural analysis by means of X-ray diffraction confirmed the precipitation of cubic KYF 4 nanocrystals into a silica matrix. Visible luminescence has been analyzed as function of treatment temperature of precursor sol–gel glasses. Highly efficient up-conversion emissions have been obtained under 980 nm excitation and studied by varying the doping level, processing temperature and pump power. Color tuneability has been quantified in terms of CIE diagram and in particular, a white-balanced overall emission has been achieved for a certain doping level and thermal treatment.

The mechanisms of the few known molecular nitrogen-fixing systems, including nitrogenase enzymes, are of much interest but are not fully understood. We recently reported that Fe–N_2 complexes of tetradentate P_3^E ligands (E = B, C) generate catalytic yields of NH_3 under an atmosphere of N_2 with acid and reductant at low temperatures. Here we show that these Fe catalysts are unexpectedly robust and retain activity after multiple reloadings. Nearly an order of magnitude improvement in yield of NH_3 for each Fe catalyst has been realized (up to 64 equiv of NH_3 produced per Fe for P_3^B and up to 47 equiv for P_3^C) by increasing acid/reductant loading with highly purified acid. Cyclic voltammetry shows the apparent onset of catalysis at the P_3^BFe–N_2/P_3^BFe–N_2– couple and controlled-potential electrolysis of P_3^BFe^+ at −45 °C demonstrates that electrolytic N_2 reduction to NH_3 is feasible. Kinetic studies reveal first-order rate dependence on Fe catalyst concentration (P_3^B), consistent with a single-site catalyst model. An isostructural system (P_3^(Si)) is shown to be appreciably more selective for hydrogen evolution. In situ freeze-quench Mössbauer spectroscopy during turnover reveals an iron–borohydrido–hydride complex as a likely resting state of the P_3^BFe catalyst system. We postulate that hydrogen-evolving reaction activity may prevent iron hydride formation from poisoning the P_3^BFe system. This idea may be important to consider in the design of synthetic nitrogenases and may also have broader significance given that intermediate metal hydrides and hydrogen evolution may play a key role in biological nitrogen fixation.

95SiO 2 –5LaF 3 sol–gel derived nano-glass–ceramics single doped with Ce 3+ or Tb 3+ and co-doped with Ce 3+ –Tb 3+ were synthesized by thermal treatment of precursor glasses. Precipitation of LaF 3 nanocrystals during ceramming process was confirmed by X-ray diffraction with mean size ranging from 12 to 15 nm. An exhaustive spectroscopic analysis has been carried out. As a result, it was found that the green emission of Tb 3+ ions was greatly enhanced through down shifting process, due to efficient energy transfer from Ce 3+ to Tb 3+ ions in the glass–ceramics, which is favored by the reduction of the interionic distances when the dopant ions are partitioned into LaF 3 nanocrystals. These results suggest the use of these materials to improve the efficiency of solar cells.

Er 3+ –Yb 3+ co-doped transparent glass-ceramics with varying Er/Yb content and ratio have been prepared. High quantum yields for up- and down-conversion luminescence by energy transfer from Yb 3+ to Er 3+ and from Er 3+ to Yb 3+ , respectively, have been detected and optimized with respect to the Er/Yb content and ratio, and proposed in particular for up- and down-conversion of solar spectrum for enhancement of the efficiency of solar cells. The rise and decay kinetics for the population of the excited levels of Er 3+ and Yb 3+ have been studied and fit. Based on these experimental data, the mechanisms for the energy transfers have been suggested with emphasis on the optimized Er/Yb content and ratio for enhancement of the efficiency of the Er 3+ ↔Yb 3+ energy transfers.

95SiO2–5LaF3 sol-gel derived nano-glass-ceramics single doped with Eu3+ or Sm3+ and codoped with both of them were successfully obtained. XRD measurements confirm the precipitation of LaF3 nanocrystals after the ceramming process, with mean size ranging from 10 to 20 nm which increases with the thermal treatment temperature. The incorporation of rare-earth ions into precipitated LaF3 nanocrystals was confirmed from luminescence spectra. Intense yellow-red emissions were detected under UV and blue light excitation in single and codoped samples. The effect of codoping with Eu3+ and Sm3+ ions and the energy transfer mechanism between them have been analyzed in order to increase the yellow-red emissions.

Resumen: Objetivo: Valorar si un espirómetro puede medir el volumen corriente en ventilación de alta frecuencia oscilatoria (VAFO) y por jet (VAFJ) y analizar el efecto de los cambios en los parámetros del respirador. Métodos: Se realizó un estudio con pulmones de prueba pediátricos y en cerdos. Para la VAFO se utilizó el respirador Sensormedics 3100BR y para la VAFJ el respirador Paravent PateR. La medición del volumen corriente (VC) se realizó con un espirómetro D-Fend. Se realizaron cambios en la frecuencia, amplitud y presión media en la vía aérea (PMVA), registrándose los cambios en el VC y las presiones. Resultados: El espirómetro midió el VC en los pulmones de prueba y en los cerdos, pero no pudo medir VC menores de 8 ml, cuando la amplitud era mayor de 55 cmH2O o la PMVA mayor de 30 cmH2O. En la VAFO existió una correlación entre la amplitud y el VC y en la VAFJ entre la presión y el VC. En ambos respiradores existió una correlación negativa entre la frecuencia y el VC. Conclusiones: El espirómetro D-Fend puede medir el volumen corriente durante la VAFO y la VAFJ, pero no es capaz de medir VC menores de 8 o cuando se utilizan amplitudes o presiones elevadas. Abstract: Objective: To ascertain whether a spirometer can measure tidal volume (TV) during high frequency oscillatory ventilation (HFOV) and high frequency jet ventilation (HFJV), and to analyse the effect of changes in ventilator settings. Methods: The study was performed with paediatric porcine lung models submitted to HFOV with a Sensormedics 3100 ventilator and HFJV with a Paravent PateR ventilator connected to a D-Fend spirometer. Programmed frequency, amplitude, and mean airway pressure (MAP) were changed in the ventilator, and TV and pressures were recorded using the spirometer. Results: The spirometer measured TV in the paediatric lung models and piglets, but could not measure TV less than 8 ml, when the pressure amplitude was higher than 55 cmH2O or the MAP was higher than 30 cmH2O. With HFOV there was a correlation between amplitude and tidal volume, and a positive correlation between pressure and TV with HFJV. With both respirators there was a negative correlation between frequency and TV. Conclusions: The D-Fend spirometer can measure tidal volume and pressure during HFOV and HFJV. However, it does not work with volumes lower than 8 ml, and high amplitude or mean airway pressure.

We report a novel class of nanostructured glass-ceramics comprising two co-existing rare-earth doped nanocrystalline phases, SnO2 semiconductor nanocrystal (quantum dot), and LaF3, presenting sizes at around 4.6 and 9.8 nm, respectively, embedded into a silica glass matrix for an efficient simultaneous UV and IR to visible photon conversion. On one hand, the wide and strong UV absorption by SnO2 quantum dot and subsequent efficient energy transfer to Eu3+ and, on the other hand, the also very efficient IR to visible up-conversion with the pair Yb3+–Er3+ partitioned into low phonon LaF3 nanocrystalline environment, yield to visible emissions with application in improving the spectral response of photovoltaic solar cells. We report a novel class of nanostructured glass-ceramics comprising two co-existing rare-earth doped nanocrystalline phases, SnO2 semiconductor nanocrystal (quantum dot) and LaF3, presenting sizes at around 4.6 and 9.8 nm, respectively, embedded into a silica glass matrix for an efficient simultaneous UV and IR to visible photon conversion. On one hand, the wide and strong UV absorption by SnO2 quantum dot and subsequent efficient energy transfer to Eu3+ and, on the other hand, the also very efficient IR to visible up-conversion with the pair Yb3+–Er3+ partitioned into low phonon LaF3 nanocrystalline environment, yield to visible emissions with application in improving the spectral response of photovoltaic solar cells.

Up-conversion emission processes have been studied in a transparent oxyfluoride nano-structured glass–ceramic co-doped with Yb 3+ and Tm 3+ ions. The decay and rise times, and pump power dependence of the different emission peaks have been analysed. The aim was to achieve a complete picture of the dynamics in this multiphoton excitation system. A method based on balance equations for the involved energy levels has been proposed in order to evaluate the up-conversion and decay rates from these levels. The results are analysed from the point of view of potential application to photovoltaic cells.

Sol–gel derived glass–ceramics containing CeF3 nanocrystals have been developed for the first time, to the best of our knowledge, by adequate heat treatments of precursor bulk glasses with composition 95SiO2–5CeF3 doped with 0.1 Eu3+ or 0.1 Sm3+ and co-doped with 0.3 Yb3+ and 0.1 Er3+ ions (in mol%). X-Ray Diffraction and High Resolution Transmission Electron Microscopy confirm the precipitation of CeF3 nanocrystals. Moreover, this structural analysis is completed using Eu3+ and Sm3+ as probe ions of the different local environments for rare-earth ions in the nano-structured glass–ceramics. Luminescence measurements led us to discern the final environments for the ions, revealing the partition of a large fraction of these ions into like-crystalline environment of the precipitated CeF3 nanocrystals. Near infrared emission at 1.5 μm was observed after excitation at 980 nm in Yb3+–Er3+ co-doped samples for potential applications in telecommunications.

Transparent glass-ceramics containing Ln3+-doped YF3 nanocrystals are successfully obtained under adequate thermal treatment of precursor sol-gel glasses for the first time, to the best of our knowledge. Precipitation of YF3 nanocrystals is confirmed by X-ray diffraction and high-resolution transmission electron microscopy images. An exhaustive structural analysis is carried out using Eu3+ and Sm3+ as probe ions of the final local environment in the nano-structured glass-ceramic. Noticeable changes in luminescence spectra, related to relative intensity and Stark structure of band components, along with remarkably different lifetime values, allow us to discern between ions residing in precipitated YF3 nanocrystals and those remaining in a glassy environment. A large fraction of optically active ions is efficiently partitioned into nanocrystals of small size, around 11 nm. Moreover, bright and efficient up-conversion, including very intense high-energy emissions in the UV range, due to 4- and 5-infrared photon processes, are achieved in Yb3+-Tm3+ co-doped samples. Up-conversion mechanisms are analysed in depth by means of intensity dependence on sensitiser Yb3+ concentration and pump power. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly transparent sol–gel derived nano-glass-ceramics containing YF3 nanocrystals doped with Dy3+ or Tb3+ and co-doped with Dy3+–Tb3+ have been successfully developed. A structural analysis and luminescence spectra features confirmed the incorporation of rare-earth ions into precipitated YF3 nanocrystals, where efficient energy transfer from Dy3+ to Tb3+ takes place. Higher efficiency is obtained with increasing Tb3+ concentration, and no quenching effects are observed. Observed luminescence features leads the way to enhance solar cell spectral response by down-shifting of the incident solar spectrum, with an extended absorption range from 300 to 500 nm, yielding to a predominant green emission by co-doping with Dy3+ and Tb3+ ions.

YF 3 nanocrystals triply-doped with Yb 3+ , Ho 3+ and Tm 3+ ions embedded in amorphous silica matrix have been successfully obtained by heat treatment of precursor sol–gel glasses for the first time to our knowledge and confirmed by X-ray diffraction and luminescence measurements. Simultaneous UV and visible efficient up-conversion emissions, with well-resolved Stark structure, under 980 nm infrared pump are observed, indicating the effective partition of rare-earth ions into a crystalline-like environment of the YF 3 nanocrystals. Corresponding energy transfer mechanisms have been analyzed and overall colour emission has been quantified in terms of standard chromaticity diagram. By an adequate doping level and heat treatment temperature of precursor sol–gel glasses, a bright white colour has been accomplished, close to the standard equal energy white light illumination point, with potential applications in photo-electronic devices and information processing.

Sol-gel glasses with composition (100−x)SiO2–xSnO2 doped with 0.4 mol% of Sm3+, with x ranging from 1 to 10, have been successfully synthesized. Transparent doped nano-glass-ceramics were prepared by thermal treatment of the precursor glasses at 900°C during 4 hours, leading to nanocomposites comprising SnO2 nanocrystals embedded into an amorphous SiO2 phase. A structural analysis in terms of X-ray Diffraction and High Resolution Transmission Electron Microscopy confirms the precipitation of SnO2 nanocrystals within the glassy matrix. The mean radius of the obtained SnO2 nanocrystals, ranging from 2.1 to 4.7 nm calculated by the Scherrer and Brus equations, similar to the Bohr’s exciton radius, constitutes a wide band-gap semiconductor quantum-dot system. Energy transfer from SnO2 nanocrystal host to Sm3+ ions is confirmed by luminescence spectra and analyzed as a function of SnO2 concentration, showing an evolution that could be ascribed to selective excitation of nanocrystal sets with predetermined size. Besides, a study of the luminescence as a function of temperature helps to clarify the involved energy transfer mechanisms.

NaYF 4 is an excellent host material for rare-earth ions presenting very high efficiencies in up-conversion processes. Thus, nano-glass–ceramics containing NaYF 4 nano-crystals emerge as promising candidates for general lighting appliances and integrated optical devices. Here we report highly transparent sol–gel derived nano-glass–ceramics comprising Yb 3+ –Ho 3+ and Yb 3+ –Ho 3+ –Tm 3+ co-doped NaYF 4 nano-crystals. A structural analysis by means of X-ray diffraction measurements confirmed the formation of NaYF 4 nano-crystals during thermal treatment. Luminescence features have been related to the crystallinity degree of the samples. Violet, blue, green and red up-conversion emissions were obtained under infrared excitation at 980 nm and corresponding mechanisms involved have been analysed. Additionally, the total visible up-conversion emission has been quantified in terms of the standard chromaticity coordinates. In particular, an overall colour emission, very close to the standard equal energy white-light illumination point of the chromaticity diagram, was obtained in the Yb 3+ –Ho 3+ –Tm 3+ triply-doped samples.

The up-conversion of near infrared photons into the visible range is of major interest for lighting appliances and photonic integrated devices. Here we report up-conversion luminescence in transparent nano-glass-ceramics with composition of 95SiO2–5LaF3 co-doped with 0.1 mol% of Pr3+ and 0.3 mol% of Yb3+, which were synthesized by different thermal treatments of precursor sol–gel glasses. Precipitation of LaF3 nanocrystals during ceramming process was confirmed by means of X-ray diffraction and the partition of rare-earth ions into them has been analyzed. The effect of increasing thermal treatment temperature and adding Yb3+ ions in the degree of crystallinity of the samples has been discussed. Efficient up-conversion emissions were observed under infrared excitation of the Yb3+ ions in the co-doped Yb3+–Pr3+ samples, while it was hardly detected in single Pr3+-doped samples.

Las fístulas arteriovenosas en la cabeza y el cuello son entidades poco frecuentes. La mayoría es secundaria a heridas penetrantes por arma blanca. Se describe el tratamiento exitoso mediante cirugía endovascular de una fístula postraumática tras una herida penetrante entre la arteria maxilar interna izquierda y la vena yugular externa. A través de este caso clínico y la revisión de la literatura se ilustran las causas, manifestaciones, estudio radiológico y tratamiento de una fístula postraumática entre la arteria maxilar interna y la vena yugular externa. A través de este caso clínico se demuestra la utilidad de los procedimientos endovasculares en el tratamiento de estas complicaciones.Traumatic arteriovenous fistulas of the head and neck region are uncommon. The majority are due to penetration of blunt injury. We describe a successful endovascular treatment of a posttraumatic fistula between the left maxillary artery and the external jugular vein due to a penetration injury. This case and a review of the literature illustrate the causes, manifestations, image studies and treatment for a posttraumatic fistula between the maxillary artery and the external jugular vein. This case demonstrate the utility of endovascular treatment of head and neck injuries complications.

A spectroscopic study has been carried out in transparent nano-glass–ceramics containing Eu3+-doped NaYF4 nanocrystals, successfully developed for the first time by thermal treatment of precursor sol–gel derived glasses. X-ray diffraction and high-resolution transmission electron microscopy measurements confirmed the precipitation of NaYF4 nanocrystals during heat treatment and their corresponding sizes have been calculated by using Scherrer’s equation and from electron microscopy measurements. Changes in the luminescence spectra with the temperature of the heat treatment have been analyzed and correlated with the crystallinity degree of the samples. In addition, emission spectra have been obtained for selected excitation wavelengths, observing large excitation selectivity among the fraction of the rare-earth ions located in near crystalline environments and those remaining in the silica glassy phase.

White light can be obtained by up-conversion processes in a cheap and efficient way, being of great interest for lighting, displays, and photonic integrated devices. Here we report a generation of white light under 980 nm laser infrared excitation in Y(b3+)-Er(3+)-Tm3+ triply doped sol-gel derived nano-glass-ceramics containing NaYF4 nanocrystals where co-dopants ions are partitioned. Efficient simultaneous blue, green, and red up-conversion emissions give rise to a balanced white overall emission and corresponding up-conversion mechanisms have been analyzed. Changes in pump power intensity or heat treatment temperature widely vary the ratio of emission bands, resulting in a colour tuneability which has been analyzed and quantified in terms of CIE standard chromaticity diagram.

Transparent oxyfluoride nano-glass–ceramics 90(SiO2)10(PbF2) co-doped with 0.3 Yb3+ and 0.1 Er3+ (mol%) have been prepared by thermal treatment of precursor sol–gel glasses. X-ray diffraction and high resolution transmission electron microscopy analysis pointed out a precipitation of cubic β-PbF2 nanocrystals of certain diameter in nano-glass–ceramics varying from 10 to 20 nm depending on heat treatment conditions. The incorporation of Yb3+ and Er3+ dopants in these nanocrystals has been confirmed by signatures of luminescence spectroscopy. Up-conversion luminescence pumped at 980 nm has been detected. Colour tuneability of up-conversion luminescence varying pump power has been analyzed in terms of standard chromaticity diagram. This tuneability opens applications for up-conversion phosphors and three-dimensional optical recording.

Transparent nano-glass-ceramics containing rare-earth-doped NaYF 4 nanocrystals (Eu 3+ single-doped and Yb 3+ ―Er 3+ co-doped) have been successfully developed for the first time by thermal treatment of precursor bulk glasses obtained by sol―gel technique. X-ray diffraction and high-resolution transmission electron microscopy measurements reveal the precipitation of NaYF 4 nanocrystals during the heat treatment and their corresponding sizes have been calculated. Luminescence measurements confirm the partition of rare-earth ions in NaYF 4 nanocrystals. In Eu 3+ -doped samples, changes in the local environment of these rare-earth ions have been investigated by site-selective emission and excitation spectra. In Yb 3+ ―Er 3+ co-doped samples, efficient visible up-conversion luminescence has been obtained under infrared excitation at 980 nm. The red to green up-conversion emission ratio can be varied as a function of temperature of heat treatment, resulting in colour tuneable up-conversion phosphors with applications in optical integrated devices. Colour tuneability has been analysed and quantified in terms of Comission Internationale d'Eclairage standard chromaticity diagram.

Transparent nano-glass-ceramics containing Yb 3+ –Er 3+ co-doped NaYF 4 nanocrystals have been successfully developed for the first time by thermal treatment of precursor bulk glasses obtained by sol–gel technique. Precipitation of NaYF 4 nanocrystals has been confirmed by X-ray diffraction measurements and their sizes have been determined by Scherrer's equation. Luminescence measurements confirm the partition of rare-earth ions in NaYF 4 nanocrystals. Visible up-conversion luminescence has been obtained under infrared excitation at 980 nm. Up-conversion mechanisms have been discussed and the ratio between red and green up-conversion emission bands can be varied as a function of temperature of heat treatment and pump power resulting in colour tuneable up-conversion phosphors with applications in optical integrated devices. Colour tuneability has been also analyzed and quantified in terms of CIE standard chromaticity diagram.

The present work is devoted to the preparation of transparent nano-glass-ceramics (nGC) with composition 30SiO 2 –15AlO 1.5 –29CdF 2 –22PbF 2 –1.5YF 3 co-doped with 1.5YbF 3 , 0.5ErF 3 and 0.5TmF 3 (in mol%). The co-dopant ions mostly dissolve in the fluoride PbF 2 -based nano-crystals precipitated during thermal treatment of precursor glasses. Visible up-conversion luminescence, obtained under 980 nm infrared excitation, have been discussed and compared in glasses and daughter nGCs. Specifically, the ratio between red, green and blue up-conversion emissions can be varied with nano-ceramming of the precursor glass resulting in large colour tuneability, which has been quantified in terms of CIE standard chromaticity diagram, with applications in optical integrated devices and tuneable up-conversion phosphors.

Transparent nano-glass–ceramics of composition 95SiO 2 –5SnO 2 mol%, single doped with 0.4 mol% of Tb 3+ and co-doped with 0.4 mol% of Eu 3+ and Tb 3+ have been obtained by thermal treatment of precursor sol–gel glasses. The segregated SnO 2 nanocrystals, precipitated in the insulator SiO 2 glass matrix during heat treatment, constitute a wide band gap quantum-dot system with mean radius of nanocrystals around 2.2–2.8 nm, comparable to the bulk exciton Bohr radius. A fraction of the rare earth ions is incorporated to the SnO 2 nanocrystals and can be excited by energy transfer from the semiconductor host. The efficiency of this energy transfer process is strongly dependent on the nanocrystal radius in the case of the Tb 3+ ions, whereas the dependence is not appreciable in the case of Eu 3+ ions. These results can be explained taking into account the variations of the overlap of the SnO 2 broad visible emission due to oxygen vacancies with the rare earth excitation spectra.

Nanostructured transparent glass-ceramics with composition of 95SiO2–5LaF3 co-doped with 0.3Yb3+, 0.1Ho3+ and 0.1Tm3+ (mol%) were synthesized by thermal treatment of precursor sol–gel derived glasses. X-ray diffraction and transmission electron microscopy analysis point out the precipitation of hexagonal LaF3 nanocrystals with diameter ranging from 11 to 20 nm in these nano-glass-ceramics. White light generation by means of efficient blue, green and red up-conversion luminescence under infrared excitation at 980 nm was observed and involved mechanisms were analyzed. Colour tuneability is achieved by varying the up-conversion emission ratios as a function of pump power.

A measurement of quantum yield of up-conversion luminescence has been done for the Er(3+)-doped transparent oxyfluoride glass-ceramics 32(SiO,)9(AlO1.5)31.5(CdF2)18.5(PbF2)5.5(ZnF2): 3.5(ErF3) mol%, where most of Er3+ dopants partition in 8 nm diameter nano-crystals Er10Pb25F65. The yield was found by newly proposed method using the pump power dependence of the resonant luminescence. The result of the measurement points out that a theoretical maximum of 50% may be reached for the up-conversion luminescence yield in this material. This high yield is shown to be due to low phonon energy and short inter-dopant distances in the nano-crystals.

Targeting of numerous transmembrane proteins to the cell surface is thought to depend on their recognition by cargo receptors that interact with the adaptor machinery for anterograde traffic at the distal end of the Golgi complex. We report here on consortin, a novel integral membrane protein that is predicted to be intrinsically disordered, i.e. that contains large segments whose native state is unstructured. We identified consortin as a binding partner of connexins, the building blocks of gap junctions. Consortin is located at the trans-Golgi network (TGN), in tubulovesicular transport organelles, and at the plasma membrane. It directly interacts with the TGN clathrin adaptors GGA1 and GGA2, and disruption of this interaction by expression of a consortin mutant lacking the acidic cluster-dileucine (DXXLL) GGA interaction motif causes an intracellular accumulation of several connexins. RNA interference-mediated silencing of consortin expression in HeLa cells blocks the cell surface targeting of these connexins, which accumulate intracellularly, whereas partial depletion and redistribution of the consortin pool slows down the intracellular degradation of gap junction plaques. Altogether, our results show that, by studying connexin trafficking, we have identified the first TGN cargo receptor for the targeting of transmembrane proteins to the plasma membrane. The identification of consortin provides in addition a potential target for therapies aimed at diseases in which connexin traffic is altered, including cardiac ischemia, peripheral neuropathies, cataracts and hearing impairment. Sequence accession numbers. GenBank: Human CNST cDNA, NM_152609; mouse Cnst cDNA, NM_146105.

The generation of a wide colour gamut, based on up-conversion of cheap near-infrared photons into the visible range, is of great importance for general lighting appliances and integrated optical devices. Here, we report for the first time on up-conversion luminescence under infrared excitation at 980 nm in Yb3+–Er3+–Tm3+ triply doped sol–gel derived SiO2–LaF3 based nano-glass–ceramics (SOL-YET), containing LaF3 nanocrystals with a size about 13 nm. Efficient simultaneous up-conversion emission of the three primary colours (blue, green and red) gives rise to a balanced white overall emission. The ratio between up-conversion emission bands can be varied by changing pump power intensity resulting in colour tuneable up-conversion phosphor.

Transparent Yb 3+ -Er 3+ -Tm 3+ co-doped nano-glass-ceramics have been prepared, 32(SiO2) 9(AlO1.5) 31.5(CdF2) 18.5(PbF2 )5 .5(ZnF 2): 3.5(Yb-Er-TmF3) mol%, where the co-dopants partition mostly to the fluoride PbF2-based nano-crystals. A comparative study of the up-conversion luminescence in nano-glass-ceramics and its precursor glass indicates that these materials can be used as blue/green/red tuneable up-conversion phosphor, in particular for white light generation. A ratio between blue, green and red emission bands of the Tm 3+ and Er 3+ can be widely varied with nano-ceramming of the precursor glass and with changing a pump power of luminescence. The change in the ratio between the blue, green and red emission bands is explained to be due to substantial lowering phonon energy and shortening of inter-dopant distances with nano-ceramming of the precursor glass and due to change in the ratio of 2- and 3-photon up-conversion processes with pump power.

Objetivo: Analizar las modificaciones de los parámetros en el respirador Servoi con distintas concentraciones de héliox. Material y métodos: Estudio experimental en el que se utilizó un respirador Servoi (Maquet) en modalidades de volumen control (VC), presión control (PC) y volumen controlado regulado por presión (VCRP) conectado a un pulmón de artificial. El héliox se administró mediante una bombona con el 70 % de helio y el 30 % de oxígeno conectada a la entrada de aire del respirador. Se programó el respirador en VC con volúmenes corrientes de 30, 50, 100, 250 y 500 ml, en PC con presión de 20 y 30 cmH2O, y en VCRP con volumen corriente de 150 ml. En cada modalidad se programó una FiO2 de 21, 30, 40, 50, 60, 70, 80, 90 y 100 % y se comparó el volumen corriente inspirado, el espirado y la presión inspiratoria pico medidas por el respirador y por un espirómetro colocado entre la tubuladura y el pulmón de prueba y conectado a un monitor Datex_S5. Resultados: En modalidad de VC y VCRP el aumento de la concentración de helio produjo una disminución progresiva del pico de presión necesario para administrar el volumen programado y una disminución en el volumen corriente medido por el espirómetro y el volumen espirado medido por el respirador. En modalidad de PC el héliox produjo un aumento progresivo del volumen corriente inspirado con incremento en las diferencias entre el volumen corriente inspirado y el espirado. Conclusiones: La administración de héliox en el respirador Servoi produce una disminución de las presiones inspiratorias en las modalidades de VC y VCRP y un aumento del volumen corriente inspirado en la modalidad de PC. En todas las modalidades produce una falsa disminución en el volumen corriente espirado medido por el respirador y el espirómetro. Es necesario tener en cuenta estas alteraciones si se utiliza héliox con este respirador. : Objective: To analyze the changes in respiratory parameters in a Servoi ventilator with heliox. Material and methods: In vitro study with a Servoi (Maquet) ventilator in volume controlled (VC), pressure controlled (PC) and volume control regulated by pressure (VCPR) modes connected to an artificial lung. A heliox tank with a fixed concentration of helium 70 % and oxygen 30 % was connected to the air inlet of the ventilator.The ventilator was set in VC mode with tidal volumes of 30, 50, 100, 250 and 500 ml; in PC mode with pressure of 20 and 30 cmH2O and in VCPR mode with tidal volume of 150 ml. In each case FiO2 of 21, 30, 40, 50, 60, 70, 80, 90 and 100 % was used. The FiO2, inspired and expired tidal volume and inspiratory pressure measured by the ventilator and a pitot spirometer (Datex_S5) were compared. Results: In VC and VCPR modes the increase in helium produced a progressive decrease in the pressure needed to administrate the set volume. Heliox also produced a decrease in the tidal volume measured by the spirometer and the tidal expired volume measured by the respirator. In PC mode, heliox produced a progressive increase in the inspired tidal volume, increasing the differences between inspired and expired tidal volumes. Conclusions: Heliox used with Servoi ventilator produces a decrease in inspiratory pressures in VC and VCPR modes, and an increase in inspiratory tidal volume in PC mode. In all modes heliox reduced the expired tidal volume measured by the ventilator and the spirometer. These changes should be borne in mind if heliox is used with this ventilator.

The room temperature near-infrared emission at 1.06 μm corresponding to the 4 F 3/2 → 4 I 11/2 laser transition in Nd 3+ -doped SiO 2 –LaF 3 transparent glass–ceramics prepared by sol–gel method has been characterized in terms of the product of emission cross-section and fluorescence lifetime. Stimulated emission cross-sections have been calculated from experimental emission spectra using the Fuchtbauer–Ladenburg equation. The precipitation of LaF 3 nanocrystals after heat-treatment, confirmed by X-ray diffraction, induces a significant increment of the 1.06 μm near-infrared emission compared with the as made sample. An enhancement of emission cross-section of about 10% has been achieved with increasing temperature of heat-treatment of the nano-ceramming process from 800 to 1000 °C, which is related to the growth of LaF 3 nanocrystals.

Ultrafiltration (UF) and microfiltration (MF) are theoretically the best pre-treatment upstream reverse osmosis, removing from the feed water most of the potential elements responsible of desalinating membranes fouling such as particles, turbidity, bacteria and large molecular weight organic maters. Those clarification membranes reduce also significantly the silt density index below 3 (100%) [1–6] and generally below 2. Many papers present results about the efficiency of UF/MF regarding clarification efficiency. UF/MF can be an economical option for RO pre-treatment. Several evaluations of the cost of UF/MF upstream RO demonstrate the interest of this pre-treatment technology on average to bad water qualities, compared to a double filtration steps conventional pre-treatment. In that case, and on a long-term operation basis, the treatment line is economically viable [7]. However, UF/MF remains more costly than a single filtration on mono or multimedia filter: UF/MF is not economically applicable on the best water quality to pre-treat. Nevertheless, UF/MF technology has some limits. If this technology is economically viable on average to bad water qualities, UF/MF direct filtration can overpass the technical limits of the process, generating the need of frequent cleanings. In that case, the RO fouling is moved upstream to the pre-treatment stage. Moreover, the clarification membranes, with cut off generally higher than 100,000 kd, do not remove the smaller organic matter molecules responsible of the biofouling development on RO membranes. In this situation, it is very difficult to demonstrate the real technical advantage of UF/MF on the RO operation, since this demonstration needs a long-term study (more than one year depending on the application) with side-by-side technologies to compare, and the results appear to be site specific. Solution of this double problem, UF/MF fouling on average to bad surface seawater and biodegradable organic matters removal, can be found in the treatment line, enhancing the UF/MF treatment by adding a pre-coagulation/settling of flotation. The benefits of this association of technologies are multiples, as it was developed for the treatment on surface water one decade ago for drinking water production. Moreover, the benefit of the coagulation/separation on the design (filtration flux) and operation (frequency of cleaning, membrane life duration) can significantly improve the economical balance of the process. It also allows a definitive advantage concerning RO membrane fouling and its related impact on cleaning frequency, RO membrane replacement and plant availability.

Nanostructured transparent glass-ceramics with composition of 95SiO2–5LaF3 doped with 0.1 mol% of Tm3+ or co-doped with 0.1 mol% of Tm3+ and 0.3 mol% of Yb3+ were synthesized by thermal treatment of precursor sol–gel derived glasses. A comparative luminescence analysis in terms of different temperatures of thermal treatments has been carried out. Segregation of LaF3 nanocrystals in the matrix was con- firmed by X-ray diffraction. Blue and red efficient up-conversion emissions were observed under 980 nm excitation at room temperature. These results indicate partition of a significant fraction of co-dopants into the precipitated LaF3 nanocrystals. The mechanisms involved in the up-conversion emissions have been analyzed and can be ascribed to processes with two, three and four photons. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Undoped and Er3+-doped glass–ceramics of composition (100−x)SiO2–xSnO2, with x = 5 or 10 and with 0.4 or 0.8 mol% of Er3+ ions, were synthesised by thermal treatment of precursor sol–gel glasses. Structural studies were developed by X-Ray Diffraction. Wide band gap SnO2 semiconductor quantum-dots embedded in the insulator SiO2 glass are obtained. The mean radius of the SnO2 nanocrystals, ranging from 2 to 3.2 nm, is comparable to the exciton Bohr radius. The luminescence properties have been analysed as a function of sample composition and thermal treatment. The results show that Er3+ ions are partially partitioned into the nanocrystalline phase. An efficient UV excitation of the Er3+ ions by energy transfer from the SnO2 nanocrystal host is observed. The Er3+ ions located in the SnO2 nanocrystals are selectively excited by this energy transfer mechanism. On the other hand, emission from the Er3+ ions remaining in the silica glassy phase is obtained by direct excitation of these ions.

Transparent glass-ceramics with composition of 95SiO 2 -5LaF 3 doped with 0.1 mol% of Ho 3+ or co-doped with 0.1 mol% of Ho 3+ and 0.3 mol% of Yb 3+ were synthesized by thermal treatment of precursor sol-gel glasses. Segregation of LaF 3 nanocrystals in the matrix was confirmed from a structural analysis by means of X-ray diffraction. Blue, green and red efficient up-conversion emissions were observed under 980 nm excitation at room temperature. These results could be attributed to the partition of a fraction of Ho 3+ ions into the precipitated LaF 3 nanocrystals. Moreover, near infrared down-conversion at 1.2 μm is also observed. The mechanisms involved in the up-conversion emissions could be ascribed to a two- and three-photon process.

Glass–ceramics with composition of 89.9SiO 2 –10LaF 3 –0.1EuF 3 (mol%) were prepared by sol–gel method. LaF 3 nanocrystals, precipitated by heat-treatments, were identified by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Besides the well-known red emission of Eu 3+ ions, higher energy emissions coming from upper-lying levels 5 D 1 and 5 D 2 can be observed at room temperature due to the very low phonon energies of the LaF 3 matrix. Moreover, from site selective excitation and emission spectra in the temperature range from 13 to 300 K, it is concluded that the fraction of Eu 3+ ions partitioned into LaF 3 nanocrystals, substituting La 3+ ions, is comparable to the one staying in the SiO 2 glassy phase.

Antibiotics may appear in the environment when manure, sewage sludge, and other organic amendments are added to soils. There is concern that the presence of antibiotics in soils may lead to the development of antibiotic-resistant bacteria which may spread to the rest of the environment. This paper aims at evaluating the sorption kinetics of two antibiotics frequently used in pig production. The results indicate that sorption of chlortetracycline (CTC) and tylosin (TYL) in sandy loam and clay occurs very fast. More than 95% of the CTC adsorption is completed within 10 min on both soils and of TYL within 3 h. These results suggest that 24-h soil and antibiotic solution mixtures is enough for sorption studies. Also, there is less likelihood that these antibiotics will leach through soil and appear in the ground water since their sorption on soils is very high unless they are carried by soil particles through preferential flow. There was also no effect of soil sterilization on sorption kinetics of these antibiotics thus suggesting that there is minimal probability of the antibiotics degrading by microorganisms during 24- to 48-h adsorption studies.

Auditory neuropathy is a particular type of hearing impairment in which neural transmission of the auditory signal is impaired, while cochlear outer hair cells remain functional. Here we report on DFNB59, a newly identified gene on chromosome 2q31.1-q31.3 mutated in four families segregating autosomal recessive auditory neuropathy. DFNB59 encodes pejvakin, a 352-residue protein. Pejvakin is a paralog of DFNA5, a protein of unknown function also involved in deafness. By immunohistofluorescence, pejvakin is detected in the cell bodies of neurons of the afferent auditory pathway. Furthermore, Dfnb59 knock-in mice, homozygous for the R183W variant identified in one DFNB59 family, show abnormal auditory brainstem responses indicative of neuronal dysfunction along the auditory pathway. Unlike previously described sensorineural deafness genes, all of which underlie cochlear cell pathologies, DFNB59 is the first human gene implicated in nonsyndromic deafness due to a neuronal defect.

Hearing impairment is a common and highly heterogeneous sensory disorder. Genetic causes are thought to be responsible for more than 60% of the cases in developed countries.1 In the majority of cases, non-syndromic hearing impairment is inherited in an autosomal recessive pattern.2 Thirty eight different loci and 20 genes for autosomal recessive non-syndromic hearing impairment (ARNSHI) have been identified to date.3 In many populations, up to 50% of all cases of ARNSHI are caused by mutations in the DFNB1 locus (MIM 220290) on 13q12.4 This locus contains the GJB2 gene (MIM 121011), encoding connexin-26 (Cx26),5 which belongs to a family of transmembrane proteins with about 20 members in humans. Hexamers of connexins (connexons) are displayed in the plasma membrane. Docking of connexons on the surfaces of two adjacent cells results in the formation of intercellular gap junction channels.6 Several different connexins, including Cx26, have been shown to participate in the complex gap junction networks of the cochlea.7,8 It has been postulated that these networks play a key role in potassium homeostasis, which is essential for the sound transduction mechanism.9 Given the high prevalence of DFNB1 deafness, molecular testing for GJB2 mutations has become the standard of care for the diagnosis of patients with non-syndromic hearing impairment of unknown cause.10 However, the finding of a large number of affected subjects with only one GJB2 mutant allele complicates the molecular diagnosis of DFNB1 deafness. In different studies, these have accounted for 10–50% of deaf subjects with GJB2 mutations.4 It was hypothesised that there could be other mutations in the DFNB1 locus but outside the GJB2 gene. This hypothesis gained support by the finding of a deletion in the DFNB1 locus outside GJB2 but truncating the neighbouring GJB6 gene (MIM 604418), which …

Nanostructured silica based ceramic samples of composition (100− x)SiO2–xSnO2, doped with 0.4 mol% of Eu3+ and with x from 1 to 10, have been developed after a thermal treatment of precursor sol–gel glasses. A structural analysis has been performed by x-ray diffraction and high resolution transmission electron microscopy. The mean radius of the obtained SnO2 nanocrystals, ranging from 2 to 5 nm, is comparable to the exciton Bohr radius, corresponding to wide bandgap semiconductor quantum dots in an insulator SiO2 glass. A spectroscopy study in terms of emission and excitation spectra has been carried out as a function of SnO2 concentration. Moreover, time-resolved fluorescence measurements have also been performed in order to discern the emission of ions in glassy and nanocrystalline environments. The nanocrystal sizes have been obtained and compared by using the Brus and Scherrer equations.

Mutations in GJB2, the gene encoding connexin-26 at the DFNB1 locus on 13q12, are found in as many as 50% of subjects with autosomal recessive, nonsyndromic prelingual hearing impairment. However, genetic diagnosis is complicated by the fact that 10%-50% of affected subjects with GJB2 mutations carry only one mutant allele. Recently, a deletion truncating the GJB6 gene (encoding connexin-30), near GJB2 on 13q12, was shown to be the accompanying mutation in approximately 50% of these deaf GJB2 heterozygotes in a cohort of Spanish patients, thus becoming second only to 35delG at GJB2 as the most frequent mutation causing prelingual hearing impairment in Spain. Here, we present data from a multicenter study in nine countries that shows that the deletion is present in most of the screened populations, with higher frequencies in France, Spain, and Israel, where the percentages of unexplained GJB2 heterozygotes fell to 16.0%-20.9% after screening for the del(GJB6-D13S1830) mutation. Our results also suggest that additional mutations remain to be identified, either in DFNB1 or in other unlinked genes involved in epistatic interactions with GJB2. Analysis of haplotypes associated with the deletion revealed a founder effect in Ashkenazi Jews and also suggested a common founder for countries in Western Europe. These results have important implications for the diagnosis and counseling of families with DFNB1 deafness.

Inherited hearing impairment affects one in 2,000 newborns. Nonsyndromic prelingual forms are inherited mainly as autosomal recessive traits, for which 16 genes are currently known. Mutations in the genes encoding connexins 26 and 30 account for up to 50% of these cases. However, the individual contribution of the remaining genes to the whole remains undetermined. In addition, for most of the genes there is a need for studies on genotype–phenotype correlations, to identify distinctive clinical features which may direct the molecular diagnosis to specific genes. Here we present a mutation analysis and a genotype–phenotype correlation study on the gene encoding otoferlin (OTOF), responsible for the DFNB9 subtype of prelingual hearing impairment. Four novel mutations were identified: c.2122C>T (p.Arg708Ter), c.4275G>A (p.Trp1425Ter), c.4362+2T>G, and c.5860_5862delATC (p.Ile1954del). A total of 37 subjects with muta-tions in OTOF were studied clinically. They were phenotypically homogeneous, having profound hearing impairment with very early onset, as shown by pure-tone audiometry and auditory brainstem responses. Magnetic resonance imaging and computed tomography did not reveal any inner ear malformation. Unexpectedly, transient evoked otoacoustic emissions (TEOAEs) were present, either bilaterally or unilaterally in 11 subjects. Altogether, clinical data of these subjects met the diagnostic criteria of auditory neuropathy. A total of 10 subjects had been successfully provided with cochlear implants. The results of our study indicate that genetic diagnosis of subjects with auditory neuropathy and profound hearing impairment should be directed to the otoferlin gene. Our data are of concern to universal screening programs which use TEOAEs as the first detection test for hearing impairment in newborns, since this technique may overlook a nonnegligible proportion of cases. Hum Mutat 22:451–456, 2003. © 2003 Wiley-Liss, Inc.

Hearing impairment is the most prevalent sensory disorder and genetic causes are thought to be responsible for over 60% of the cases in developed countries.1 Inherited hearing impairment is highly heterogeneous from both the clinical and genetic points of view.1,2 It varies in age of onset, severity, and audiological characteristics, and it can be associated or not with other clinical features (syndromic or non-syndromic hearing impairment). Genetic transmission includes autosomal (dominant and recessive), X linked, and maternal inheritance patterns. This unparalleled heterogeneity is well illustrated by the fact that over 70 loci in the nuclear genome have been reported to be involved in non-syndromic hearing impairment, and about 30 genes have been isolated from their critical intervals.3 Furthermore, a number of different mutations in several genes of the mitochondrial genome are responsible for syndromic and non-syndromic forms of hearing loss.4,5 Mutations responsible for maternally inherited non-syndromic hearing loss are so far confined to only two genes in the mitochondrial genome. These include mutations 7510T>C6 and 7511T>C7 in the tRNASer(UCN) gene, and 1095T>C8 and 1555A>G9 in the gene for the 12S rRNA. This last mutation is responsible for a dual phenotype, since it also confers increased susceptibility to the ototoxic action of aminoglycoside antibiotics.9 Most of these mutations have been reported in a small number of families from several countries, with the exception of 1555A>G, which seems to be more frequent than the others,10–13 although its real prevalence remains to be determined in most populations. Remarkably, in Spain it accounts for about 15–20% of all familial cases of non-syndromic hearing loss, irrespective of their mode of inheritance and age of onset14,15 (our unpublished results). In a majority of these patients, the hearing loss is not …

A crystallization study of Er3+/Yb3+-doped NaYF4-based nano-glass-ceramics and their optical characterisation is presented. NaYF4 nano-crystals were precipitated from heat treatments close to the glass transition temperature. The crystallization process occurs from a constant number of nuclei. The increase of dopant ions has a nucleating effect. Crystal growth is limited with the length of the heat treatment, keeping the crystal size to the nanometric scale. Er3+-single doped samples show a predominant green up-conversion emission under near infrared excitation at 980 nm, while a predominant red emission is observed in the Er3+/Yb3+ co-doped samples. The efficiency of the up-conversion emission is higher in the glass-ceramics than in the parent glasses.

Trivalent rare-earth (RE = Eu, Sm) doped transparent nano-glass–ceramics comprising BaYF 5 nanocrystals were successfully obtained by appropriate heat-treatment of the corresponding precursor sol–gel glasses. Their structural and spectroscopic properties were investigated and compared with those for Eu 3+ -doped-BaYF 5 nanocrystals prepared by a solvothermal method. X-ray Diffraction, Transmission Electron Microscopy and Energy Dispersive X-ray Spectroscopy measurements confirmed the distribution of BaYF 5 nanocrystals in the glass matrix, presenting a cubic phase structure with space group Fm - 3m . In order to achieve a further structural characterization, the luminescence properties of the Eu 3+ and Sm 3+ dopants were also used as sensitive probes. The reduction in the emission intensities of hypersensitive transitions 5 D 0 → 7 F 2 and 4 G 5/2 → 6 H 9/2 for Eu 3+ and Sm 3+ ions respectively, along with time-resolved measurements, confirm the distribution of a significant fraction of RE ions into the fluoride nanocrystal environment. These results suggest that BaYF 5 nano-glass–ceramics doped with Eu 3+ or Sm 3+ can be considered as potential red-emitting phosphors for the development of white LEDs under near UV excitation.

Inherited hearing impairment affects about 1 in 2000 newborns. Up to 50 percent of all patients with autosomal recessive nonsyndromic prelingual deafness in different populations have mutations in the gene encoding the gap-junction protein connexin 26 (GJB2) at locus DFNB1 on chromosome 13q12. However, a large fraction (10 to 42 percent) of patients with GJB2 mutations have only one mutant allele; the accompanying mutation has not been identified. DFNB1-linked familial cases with no mutation in GJB2 have also been reported.We evaluated 33 unrelated probands with nonsyndromic prelingual deafness who had only one GJB2 mutant allele. Nine subjects had evidence of linkage to DFNB1. We used haplotype analysis for markers on 13q12 to search for mutations other than the one involving GJB2.We identified a 342-kb deletion in the gene encoding connexin 30 (GJB6), a protein that is reported to be expressed with connexin 26 in the inner ear. The deletion extended distally to GJB2, which remained intact. The break-point junction of the deletion was isolated and sequenced, and a specific diagnostic test was developed for this common mutation. Twenty-two of the 33 subjects were heterozygous for both the GJB6 and GJB2 mutations, including all 9 with evidence of linkage to DFNB1. Two subjects were homozygous for the GJB6 mutation.A 342-kb deletion in GJB6 is the second most frequent mutation causing prelingual deafness in the Spanish population. Our data suggest that mutations in the complex locus DFNB1, which contains two genes (GJB2 and GJB6), can result in a monogenic or a digenic pattern of inheritance of prelingual deafness.