Flutter analysis of a morphing wing technology demonstrator : numerical simulation and wind tunnel testing

As part of a morphing wing technology project, the flutter analysis of two finite element models and the experimental results of a morphing wing demonstrator equipped with aileron are presented. The finite element models are representing a wing section situated at the tip of the wing; the first model corresponds to a traditional aluminium upper surface skin of constant thickness and the second model corresponds to a composite optimized upper surface skin for morphing capabilities. The two models were analyzed for flutter occurrence and effects on the aeroelastic behaviour of the wing were studied by replacing the aluminium upper surface skin of the wing with a specially developed composite version. The morphing wing model with composite upper surface was manufactured and fitted with three accelerometers to record the amplitudes and frequencies during tests at the subsonic wind tunnel facility at the National Research Council. The results presented showed that no aeroelastic phenomenon occurred at the speeds, angles of attack and aileron deflections studied in the wind tunnel and confirmed the prediction of the flutter analysis on the frequencies and modal displacements

Regulation of Embryonic and Induced Pluripotency by Aurora Kinase-p53 Signaling

SummaryMany signals must be integrated to maintain self-renewal and pluripotency in embryonic stem cells (ESCs) and to enable induced pluripotent stem cell (iPSC) reprogramming. However, the exact molecular regulatory mechanisms remain elusive. To unravel the essential internal and external signals required for sustaining the ESC state, we conducted a short hairpin (sh) RNA screen of 104 ESC-associated phosphoregulators. Depletion of one such molecule, aurora kinase A (Aurka), resulted in compromised self-renewal and consequent differentiation. By integrating global gene expression and computational analyses, we discovered that loss of Aurka leads to upregulated p53 activity that triggers ESC differentiation. Specifically, Aurka regulates pluripotency through phosphorylation-mediated inhibition of p53-directed ectodermal and mesodermal gene expression. Phosphorylation of p53 not only impairs p53-induced ESC differentiation but also p53-mediated suppression of iPSC reprogramming. Our studies demonstrate an essential role for Aurka-p53 signaling in the regulation of self-renewal, differentiation, and somatic cell reprogramming

Re-HEDP : pharmacokinetic characterization, clinical and dosimetric evaluation in osseous metastatic patients with two levels of radiopharmaceutical dose

BACKGROUND: A study for pain relief therapy with (188)Re-HEDP was done in patients with bone metastases secondary to breast and prostate cancer. MATERIALS AND METHODS: Patients received 1.3 or 2.2 GBq, in single or multiple doses. Platelets, white and red cells were evaluated during 11 weeks. Pharmacokinetic characterization was done from blood and urine samples for 5 patients along 24 hours. Urinary excretion was evaluated in other 16 patients during 6 hours. Bone uptake was estimated as remaining activity in whole body. Scintigraphic images were acquired at 2 and 24 hs post-administration. Absorbed dose in bone marrow was estimated with Mirdose3. Analgesics intake and pain score were daily recorded. Tumour markers (PSA, and Tn-structure) were monitored in 9 patients during 4 to 6 months. Single doses of low activity (1.3 GBq) were given to twelve patients. Nine patients received multiple doses. RESULTS: All except one patient had normal levels of platelets, white and red cells. Remaining dose in blood at 2 hours was 9%. Urinary elimination was 58%. Bone uptake at 24 hours was 43% (mean value; n = 5). No changes of the haematological parameters were detected along follow-up period. Pain relief was evidenced by decrease or supression of opioid analgesic and by subjective index. PSA showed a decrease in prostate cancer patients (n = 4). Tn-structure showed a significant increase after 4 to 8 months. CONCLUSION: Single or multiple dose scheme could be safely used, with administered activity of (188)Re-HEDP up to 60 mCi, with low bone marrow absorbed doses

Interaction Triplet-Doublet dans les cristaux moléculaires. Cas de l'anthracène

Triplet-Doublet interaction is studied in crystalline anthracene from a static magnetic field effect on the triplet induced photodetrapping current. Experimental observations are interpreted in the frame of Johnson-Merrifield theory where Triplet-Doublet pair states are introduced. We were able to describe correctly the dependence of the effect both in function of the intensity of the applied magnetic field and of its orientation in the crystalline plane. The agreement of the best fit between experiment and theory permitted us to reach the rate constants for pair formation (10-10 cm3 s-1), separation (2.2 x 109 s-1) and reaction (3. 5 x 10 8 s-1) and to have a detailed information on the microscopic mechanism of the interaction.Nous avons étudié l'interaction Triplet-Doublet dans l'anthracène cristallin à partir de l'effet d'un champ magnétique statique sur le photocourant de dépiégeage induit par les triplets. Les observations expérimentales sont interprétées dans le cadre de la théorie de Johnson-Merrifield où on introduit l'existence d'états de paires Triplet-Doublet. On a pu ainsi rendre compte convenablement de la dépendance de l'effet aussi bien en fonction de l'intensité du champ magnétique appliqué que de son orientation dans le plan du cristal. La recherche du meilleur accord entre l'expérience et la théorie nous a permis d'atteindre les constantes de vitesse pour la formation des paires (10-10 cm3 s -1), de leur séparation (2,2 x 109 s-1) et de leur réaction (3,5 x 108 s-1) et d'avoir ainsi une information détaillée sur le mécanisme microscopique de l'interaction

Photoconductivity detected magnetic resonance (PDMR) in crystalline tetracene

A detailed experimental study of the modulation by a high power microwave of induced exciton photoconductivity in crystalline tetracene is presented. These experiments, so called PDMR (Photoconductivity Detected Magnetic Resonance) are supported by a theoretical model based on a matrix density formalism and taking into account the fission of singlet excitons, dimensionality of triplet excitons motions and singlet and triplet detrapping of charge carriers. The best agreement between the observed PDMR lines and calculated curves allows the determination of the pertinent parameters governing the different process involved in the description of the photoconductivity mechanism. Copyright Springer-Verlag Berlin/Heidelberg 2003

Saturation of the ODMR effect on singlet exciton induced emission in molecular crystals: Application to crystalline tetracene

We have studied the variation of the ODMR effect according to the intensity of a microwave field. We have highlighted a saturation effect of ODMR lines. This effect has been studied as part of the kinetic theory by developing the pilot equation while utilizing for the first time the formalism of a superoperator coupled with a time dependent sinusoidal perturbation. The agreement of the best fit between the experiment and the theory gives the mixing between singlet and quintuplet states, which seems to depend on the direction of the applied magnetic field