Crystal structure, NIR luminescence and X-ray computed tomography of Nd3+:Ba0.3Lu0.7F2.7 nanospheres

Uniform, hydrophilic 50 nm diameter Nd3+-doped Ba0.3Lu0.7F2.7 nanospheres are synthesized at 120 °C using a singular one-pot method based on the use of ethylene glycol as solvent, in the absence of any additive. The composition and crystal structure of the undoped material are analyzed in detail using ICP and XRD, which reveals a BaF2 cubic crystal structure that is able to incorporate 70 mol% of Lu ions. This finding contrasts with the reported phase diagram of the system, where the maximum solubility is around 30 mol% Lu. XRD proves as well that the Ba0.3Lu0.7F2.7 structure is able to incorporate Nd3+ ions up to, at least 10 mol%, without altering the uniform particles morphology. The Nd-doped particles exhibit nearinfrared luminescence when excited at 810 nm. The maximum emission intensity with the minimum concentration quenching effect is obtained at 1.5% Nd doping level. X-ray computed tomography experiments are carried out on powder samples of the latter composition. The sample significantly absorbs X-ray photons, thus demonstrating that the Nd3+-doped Ba0.3Lu0.7F2.7 nanospheres are good candidates as contrast agents in computed tomography.Ministerio de Economía y Competitividad MAT2014-54852-R, MAT2012-34919Consejo Superior de Investigaciones Científicas 201560E056, 201460E00

Optical 3D-storage in sol-gel materials with a reading by Optical Coherence Tomography-technique

We report on the recording of 3D optical memories in sol-gel materials by using a non-linear absorption effect. This effect induces a local change of the optical properties of the material which is read and quantified with a high resolution full-field Optical Coherence Tomography setup. It is the first time that this technique is used for this purpose. Data recording was performed by focused picosecond (ps) single-pulse irradiation at 1064 nm with energy densities of 10 and 33 J/cm2 per pulse.Comment: 19 pages, 7 figure

A new transgenic mouse line to image chemically induced p53 activation in vivo

International audienceMonitoring p53 transcriptional activity to identify genotoxic damages induced by drugs has been proposed and validated in vitro. However, this methodology is by design limited to the cell line tested. In this study, we have fully validated a luciferase-based p53-reporter system in vitro and in vivo. We generated a mouse transgenic line to monitor non-invasively p53 activation in response to chemically induced DNA damage. Doxorubicin was used as a drug of known toxicity to validate our model. Reporter gene expression was measured using bioluminescence imaging. In females, a weak p53 luciferase activity driven by a p53-responsive promoter was detectable in the oral cavity region after doxorubicin treatment. In males, the signal increased in the lower abdominal region. Imaging of various organs revealed that the luciferase activity was mainly generated from the testes. Immunohistology demonstrated that the cells in the seminiferous tubules were damaged by the drug and confirmed that they were luciferase and p53 positive. Therefore, these transgenic mice could provide a powerful tool to predict, map and characterize at the organ and cellular levels the toxicity of compounds and help to develop new therapeutic agents in humans

Mesure de la sensibilite a l'insuline in vivo chez le rat avec un nouveau traceur du transport du glucose (le [125i]-6-deoxy-6-iodo-d-glucose (6dig))

La résistance à l'insuline est un défaut clef dans le développement du diabète de type 2. Il n'existe pas de technique simple pour la mesurer in vivo. L'objectif de ce travail est d'évaluer la capacité du 6DIG à mettre en évidence des altérations de ce transport chez le rat, par détection externe de la radioactivité. Une étude faisabilité a permis de mettre au point une méthodologie pour la mesure de l'insulinorésistance in vivo. Un modèle mathématique a été développé afin de fournir des indices chiffrés du transport du 6DIG. Ce protocole a té adapté pour l'imagerie nucléaire du petit animal. La réalisation d'images scintigraphiques permet de mettre en évidence un défaut de la stimulation par l'insuline du transport du glucose chez les rats insulinorésistants et une stimulation de cetransport chez leurs témoins. Le modèle a fournit un bon index de la sensibilité à l'insuline. Ces résultats permettent d'envisager l'utilisation du 6DIG chez l'homme en Médecine Nucléaire.GRENOBLE1-BU Médecine pharm. (385162101) / SudocPARIS-BIUM (751062103) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

The FRD3 Citrate Effluxer Promotes Iron Nutrition between Symplastically Disconnected Tissues throughout Arabidopsis Development[C][W]

This work examines the role of the citrate transporter FRD3 in iron homeostasis during plant development, finding key roles in pollen and embryo development, and in leaf, in addition to its known role in roots and in the apoplastic transport of iron

An iron-induced nitric oxide burst precedes ubiquitin-dependent protein degradation for Arabidopsis AtFer1 ferritin gene expression

Ferritins play an essential role in iron homeostasis by sequestering iron in a bioavailable and non-toxic form. In plants, ferritin mRNAs are highly and quickly accumulated in response to iron overload. Such accumulation leads to a subsequent ferritin protein synthesis and iron storage, thus avoiding oxidative stress to take place. By combining pharmacological and imaging approaches in an Arabidopsis cell culture system, we have identified several elements in the signal transduction pathway leading to the increase of AtFer1 transcript level after iron treatment. Nitric oxide quickly accumulates in the plastids after iron treatment. This compound acts downstream of iron and upstream of a PP2A-type phosphatase to promote an increase of AtFer1 mRNA level. The AtFer1 gene transcription has been previously shown to be repressed under low iron conditions with the involvement of the cis-acting element iron-dependent regulatory sequence identified within the AtFer1 promoter sequence. We show here that the repressor is unlikely a transcription factor directly bound to the iron-dependent regulatory sequence; such a repressor is ubiquitinated upon iron treatment and subsequently degraded through a 26 S proteasome-dependent pathway

New prospects on the regulation of AtFer1 expression

New prospects on the regulation of AtFer1 expression. XVII Iron Symposium on Iron Nutrition and Interactions in Plant

Arabidopsis ferritins as an integrative model linking iron metabolism to light, clock and oxidative stress signalings

Arabidopsis ferritins as an integrative model linking iron metabolism to light, clock and oxidative stress signalings. POSTECH International Conference on Plant Scienc

Modélisation multicompartimentale et stratégies expérimentales pour l’étude du transport du glucose chez le rat insulinorésistant

International audienc