196,591 research outputs found
Nuclear peroxisome proliferator activated receptor-gamma (PPARγ) as a therapeutic target to treat neurodegeneration and dependence elicited by drugs of abuse
Get PDFPeroxisome proliferator activated receptors (PPARs) are ligand-activated transcription factors that are located in the cytoplasm. After activation by specific ligands, PPARs enter the nucleus and heterodimerize with the retinoid x receptor. This heterodimer binds to PPAR response element in DNA to regulate the transcription of genes that are involved in different physiological processes, including insulin sensitization inflammatory response, and neuroprotection (Kapadia et al., 2008). The PPAR receptor family is composed of three isoforms—PPARalpha, PPARgamma and PPARdelta—that are expressed in both peripheral tissues and the brain. Endogeneous ligands of PPAR include polyunsatured fatty acids (e.g., oleic acid and arachidonic acid), prostaglandins, and low-density lipoproteins. PPAR can also be targeted by specific synthetic agonists that belong to the class of thiazolidinediones (TZDs), including pioglitazone and rosiglitazone. Because of their ability to bind PPARgamma, TZDs are approved for the treatment of type 2 diabetes and insulin resistance, improving insulin sensitivity in muscle, liver, and adipose tissue
Il paesaggio vegetale delle Balze di Verghereto, Monte Fumaiolo, Ripa della Moia
No full textIl paesaggio vegetale delle Balze di Verghereto, Monte Fumaiolo, Ripa della Moia (730-1407 m), sito della rete Natura 2000 (Direttiva Habitat 92/43/EEC), viene messo in evidenza per mezzo di una carta fisionomica della vegetazione (1:10.000) costruita in ambiente GIS e basata su 93 rilievi fitosociologici. Il paesaggio è prevalentemente forestale ed occupa il 60% della superficie complessiva del sito. Alle quote più elevate dominano i boschi di Fagus sylvatica e le abieti-faggete (1000-1400 m), mentre a quote più basse le formazioni forestali sono dominate da Quercus cerris. Nella fascia altitudinale dei boschi di faggio sono inoltre presenti rimboschimenti ad Abies alba, mentre nella fascia dei querceti misti rimboschimenti a Pinus nigra. Prati e prati-pascolo variamente arbustati compongono la maggior parte del restante paesaggio vegetale. Ciascun tipo di vegetazione è stato descritto nella sua composizione specifica. Si fanno inoltre alcune osservazioni di confronto con la vegetazione di due territori circonvicini, l’Alpe della Luna e il Parco del Sasso Simone e Simoncello
Probing dark matter with active galactic nuclei jets
No full textWe study the possibility of detecting a signature of particle dark matter in the spectrum of gamma-ray photons from active galactic nuclei (AGNs) resulting from the scattering of high-energy particles in the AGN jet off of dark matter particles. We consider particle dark matter models in the context of both supersymmetry and universal extra dimensions, and we present the complete lowest-order calculation for processes where a photon is emitted in dark matter-electron and/or dark matter-proton scattering, where electrons and protons belong to the AGN jet. We find that the process is dominated by a resonance whose energy is dictated by the particle spectrum in the dark matter sector (neutralino and selectron for the case of supersymmetry, Kaluza-Klein photon and electron for universal extra dimensions). The resulting gamma-ray spectrum exhibits a very characteristic spectral feature, consisting of a sharp break to a hard power-law behavior. Although the normalization of the gamma-ray flux depends strongly on assumptions on both the AGN jet geometry, composition and particle spectrum as well as on the particle dark matter model and density distribution, we show that for realistic parameters choices, and for two prominent nearby AGNs (Centaurus A and M87), the detection of this effect is in principle possible. Finally, we compare our predictions and results with recent gamma-ray observations from the Fermi, H.E.S.S., and VERITAS telescopes. © 2010 The American Physical Society
Sperm DNA fragmentation to predict embryo development, implantation, and miscarriage: still an open question
No full textRuolo della flora e della vegetazione di siepi e prati per la conservazione della fauna negli agroecosistemi della pianura emiliana
No full textE' presentato uno studio floristico-vegetazionale svolto sulle siepi e le banchine erbose della campagna modenese-reggiana (Novi e Rolo). E' stata valutata a) la ricchezza e la vulnerabilità floristica (specie rare e uniloche), b) la complessità vegetazionale in termini di struttura e di ricchezza in tipi, c) la naturalità-artificialità della vegetazione. Sono state poi analizzate le correlazioni tra i parametri floristici, vegetazionali e territoriali (complessità dell'area), al fine di fornire indirizzi utili alla gestione degli spazi naturali di questi agroecosistemi
Strategie di monitoraggio ecografico della induzione della crescita follicolare multipla
No full textAnalyse expérimentale de l'écoulement dans la zone axiale des canaux adducteurs des turbines-Hélices
No full textThe paper presents sorne results of the measurements carried out, in water, in the axial region of a propeller turbine admission duct (Hy), without runner, and, in air, in an annular section cylindrical duct fed by a radial distributor (1MB) (see Fig. 2). The measurements have been performed with different wicket-gate openings a and the attention has been drawn on the small openings where different phenomena have been observed (see Fig. 1) : a variation of the radial distribution of the tangential velocity near the hub, associated with the arising of a quite forced vortex ; the decrease and sometimes the inversion of the axial velocity; the presence of radial flows directed towards the hub; the drop of the total pressure, due to the viscous dissipation, These phenomena mainly develop in the axial region of the two ducts, rapidly extend their influence and finally settle on a practically constant area (see Fig. II). The distribution of axial and tangential velocity components change almost similarly in the two ducts according to the decrease of the wicket-gate opening, as it can be observed in figures 3 and 4. These figures show the distribution of axial and tangential velocity components divided by the average axial velocity, as a function of the ratio between the radius of the measurement points and the external one in the closest sections of the two ducts (1MB 2 and HyG). The similarity of the flow evolution in the two ducts is even more underlined by the comparison (see Fig. 5-8) of the velocity distributions for comparable values of the m parameter, called swirl rate, defined by the equation (1) and usually utilized in technical literature for the evaluation of the flow vortex intensity. In the diagram of figure 9 the radius limiting the central core, which is characterized by the decrease of axial velocity (ri) and the radius of the core characterized by the quite forced vortex distribution of tangential velocities (rf) have been associated to mparameter values, calculated by means of the geometric data of the duct according to the equation (2). The mand m values have been compared in the diagram of figure 10 versus a. Some experimental tests carried out on the Hy model with runner showed that, at small openings, a central core similar to the one previously described in the case without runner is developed (see Fig. 12). In axial turbines this phenomenon causes efficiency drop and cavitating vortexes which, as it happens without the runner (see Fig. 14), detach near the hub and pass through the runner (see Fig. 15) in a helix spiral form, thus causing vibrations and noise at low operation loads. The operation areas concerned by this phenomenon are indicated in figure 13 on the hill diagrams of a propeller and a Kaplan turbine with medium specific speed
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