The hydrogen and helium lines of the symbiotic binary Z And during its brightening at the end of 2002

High resolution observations in the region of the lines Halpha, He II 4686 and Hgamma of the spectrum of the symbiotic binary Z And were performed during its small-amplitude brightening at the end of 2002. The profiles of the hydrogen lines were double-peaked. These profiles give a reason to suppose that the lines can be emitted mainly by an optically thin accretion disc. The Halpha line is strongly contaminated by the emission of the envelope, therefore for consideration of accretion disc properties we use the Hgamma line. The Halpha line had broad wings which are supposed to be determined mostly from radiation damping but high velocity stellar wind from the compact object in the system can also contribute to their appearance. The Hgamma line had a broad emission component which is assumed to be emitted mainly from the inner part of the accretion disc. The line He II 4686 had a broad emission component too, but it is supposed to appear in a region of a high velocity stellar wind. The outer radius of the accretion disc can be calculated from the shift between the peaks. Assuming, that the orbit inclination can ranges from 47$^\circ$ to 76$^\circ$, we estimate the outer radius as 20 - 50 R_sun. The behaviour of the observed lines can be considered in the framework of the model proposed for interpretation of the line spectrum during the major 2000 - 2002 brightening of this binary.Comment: 19 pages, 5 figures. Accepted for publication in Astronomy Report

The Continuing Slow Decline of AG Pegasi

We analyze optical and ultraviolet observations of the symbiotic binary AG Pegasi acquired during 1992-97. The bolometric luminosity of the hot component declined by a factor of 2-3 from 1980-1985 to 1997. Since 1992, the effective temperature of the hot component may have declined by 10%-20%, but this decline is comparable to the measurement errors. Optical observations of H-beta and He I emission show a clear illumination effect, where high energy photons from the hot component ionize the outer atmosphere of the red giant. Simple illumination models generally account for the magnitude of the optical and ultraviolet emission line fluxes. High ionization emission lines - [Ne V], [Mg V], and [Fe VII] - suggest mechanical heating in the outer portions of the photoionized red giant wind. This emission probably originates in a low density region $\sim$ 30-300 AU from the central binary.Comment: 17 pages, 7 pages, 5 tables; to be published in the Astronomical Journal, July 200

HIDDEN SD/WD STARS AMONG THE FAUST UV SOURCES TOWARD OPHIUCHUS

No white dwarf or hot subdwarf stars are found as optical counterparts of the 228 UV sources detected in a UV image toward Ophiuchus (Formiggini et al. 2002). The image was obtained at 1600 ˚A, with the FAUST instrument on board of the space shuttle Atlantis. Hot subluminous stars are numerous among blue objects, and dominate the population of blue stars down to B=16.5. To search for such stars, we cross-identified the UV sources positions with objects in the Main Part of the Tycho catalog, finding a significant parallax value for 46 entries. A significant number of objects have MV values as expected for WD or subdwarf stars (Fig. 1a), while their spectral classification spans types from B to early F. For all these stars the parallax errors are very large, hence their classification as subluminous stars on the basis of the parallax data is rather unreliable. Numbe

“Adiponectin is involved in the control of human lung epithelial A549 cell viability”

Adiponectin (Acrp30) is an insulin-sensitizing fat hormone that has enormous potential as a therapeutic target for obesity-related diseases, including diabetes, atherosclerosis and cancer. More- over, it displays anti-inflammatory actions and attenuates inflam- matory responses in several tissues and cell cultures. It has been reported elevated serum levels of Acrp30 in Chronic Obstructive Pulmonary disease (COPD) patients but the role of the increased levels are not yet clarified. Since COPD patients are characterized by increased serum and sputum concentrations of several cyto- kines (TNFa, IL-6, IL-1b), in this study we analyzed the effects of Acrp30 treatment in A549 cells (human lung adenocarcinoma) selected as a in vitro model of lung epithelia. Furthermore, we investigated the role of Acrp30 at two concentrations (5 and 50 lg/ml) in A549 cells treated with TNFa. We performed a via- bility assay (MTT test) and demonstrated that Acrp30 reduces cell viability in a dose and time dependent manner; interestingly in pre-treated cells with pro-inflammatory cytokine TNFa, Acrp30 treatment (48 and 72 hours) is able to ameliorate the pro- liferation rate. We found also that the reduction of cell viability induced by Acrp30 is linked to the inhibition in ERK1/2 phos- phorylation and that the beneficial effects induced in co-treat- ment with cytokines is mediated by activation in ERK1/2 phosphorylation. Our data show that Acrp30 could play a central role in the con- trol of local lung inflammatory state and epithelial cell degenera- tion in lung of COPD patients, thus Acrp30 may represent a target for the development of new therapeutic approaches also in inflammatory diseases as COPD, an increasing global health proble

Adiponectin is involved in the control of human lung epithelial A549 cell viability

Adiponectin (Acrp30) is an insulin-sensitizing fat hormone that has enormous potential as a therapeutic target for obesity-related diseases, including diabetes, atherosclerosis and cancer. More- over, it displays anti-inflammatory actions and attenuates inflam-\ud matory responses in several tissues and cell cultures. It has been reported elevated serum levels of Acrp30 in Chronic Obstructive Pulmonary disease (COPD) patients but the role of the increased levels are not yet clarified. Since COPD patients are characterized by increased serum and sputum concentrations of several cyto- kines (TNFa, IL-6, IL-1b), in this study we analyzed the effects of Acrp30 treatment in A549 cells (human lung adenocarcinoma) selected as a in vitro model of lung epithelia. Furthermore, we investigated the role of Acrp30 at two concentrations (5 and 50 lg/ml) in A549 cells treated with TNFa. We performed a via- bility assay (MTT test) and demonstrated that Acrp30 reduces cell viability in a dose and time dependent manner; interestingly in pre-treated cells with pro-inflammatory cytokine TNFa, Acrp30 treatment (48 and 72 hours) is able to ameliorate the pro- liferation rate. We found also that the reduction of cell viability induced by Acrp30 is linked to the inhibition in ERK1/2 phos- phorylation and that the beneficial effects induced in co-treat- ment with cytokines is mediated by activation in ERK1/2 phosphorylation. Our data show that Acrp30 could play a central role in the con- trol of local lung inflammatory state and epithelial cell degenera- tion in lung of COPD patients, thus Acrp30 may represent a target for the development of new therapeutic approaches also in inflammatory diseases as COPD, an increasing global health proble

Xenopus laevis come modello per lo studio degli effetti tossici da nanoparticelle

Nuovi nanomateriali (NM) vengono continuamente prodotti e prontamente utilizzati per varie applicazioni, tra cui: cosmesi, cura personale, elettronica e sistemi di drug delivery. In particolare, in medicina, le nanoparticelle (NP) offrono un'opportunità unica per superare le barriere fisiologiche e fornire agenti bioattivi alle cellule. Attualmente, la comunità scientifica dedica molti sforzi allo sviluppo sostenibile di questa tecnologia. Tuttavia, l'uso di NM potrebbe essere pericoloso per cui si presta molta attenzione ai loro potenziali effetti tossici sugli organismi viventi. Evidenze sperimentali mostrano che le NP possono essere associate a un aumento del rischio di alcune malattie per l???uomo a causa della loro tossicità e il rischio aumenta con la riduzione della loro dimensione. Questa nuova forma di inquinamento presenta un grave problema per la comunità data la mancanza di procedure standard volte a certificare la loro attività nelle complesse interazioni che si verificano tra NM e sistemi viventi. È ben noto che gli ambienti acquatici sono certamente a rischio di esposizione a questi inquinanti, in quanto, rappresentano un sito di concentrazione per la maggior parte dei contaminanti ambientali. Il nostro lavoro sfrutta la possibilità di utilizzare Xenopus laevis come modello affidabile e robusto per la valutazione della nanotossicità in organismi acquatici utilizzando nanoparticelle di polistirene (PSNPs), di Fe3O4 (nanoFe) e di SiO2 (nanoSi). Abbiamo utilizzato due procedure di somministrazione: microiniezione allo stadio di 2 cellule e diluizione nel mezzo di coltura. Abbiamo rilevato malformazioni della testa, dell???intestino e della coda in tutti gli embrioni trattati; edema nella zona ventrale anteriore e una lunghezza del corpo inferiore rispetto ai wt. Solo gli embrioni microiniettati mostrano un alto tasso di mortalità. La microscopia confocale ci ha permesso di localizzare le PSNPs nel citoplasma, nel nucleo e nella periferia cellulare. Mentre la microscopia elettronica ha mostrato quadri di sofferenza dell???intestino sia in trattati con nanoSi che con nanoFe. Queste ultime si localizzano a livello dei villi intestinali. Lo studio dell'espressione di geni coinvolti nelle prime fasi dello sviluppo embrionale ha mostrato una distribuzione anomala del marcatore precoce del mesoderma bra, del marcatore del mesoderma parassiale myod1, e di sox9, marcatore delle creste neurali. I nostri dati suggeriscono che la tossicità delle nanoparticelle dipende dalla loro concentrazione nel mezzo e dalla capacità di penetrare in profondità nel tessuto. Inoltre, dimostrano che Xenopus laevis potrebbe essere un potenziale modello per valutare la tossicità delle nanoparticelle a livello quantitativo e qualitativo