186 research outputs found
Spectral changes during six years of Scorpius X-1 monitoring with BeppoSAX Wide Field Cameras
We analyse a sample of fifty-five observations of Scorpius X-1 available in
the BeppoSAX Wide Field Camera public archive and spanning over the six years
of BeppoSAX mission life. Spectral changes are initially analysed by inspection
of colour-colour and colour-intensity diagrams, we also discuss the shift of
the Z tracks in these diagrams. Then we select two long observations for
spectral fitting analysis, a secular shift is evident between the tracks in
these observations. We finally extract spectra along the tracks and discuss the
best fit model, the parameter variations along the track and between tracks,
and their link to the accretion rate.Comment: 6 pages, 11 postscrpt figures.To appear in the conference proceedings
of `Interacting Binaries: Accretion, Evolution & Outcomes' (Cefalu', July
4-10 2004
Dibutyltin(IV) and Tributyltin(IV) Derivatives of meso-Tetra(4-sulfonatophenyl)porphine Inhibit the Growth and the Migration of Human Melanoma Cells
Melanoma is the most aggressive and deadly form of skin cancer, which is largely due to its propensity to metastasize. Therefore, with the aim to inhibit the growth and the metastatic dissemination of melanoma cells and to provide a novel treatment option, we studied the eects of the melanoma treatment with two organotin(IV) complexes of the meso-tetra(4-sulfonato-phenyl)porphine, namely (Bu2Sn)2TPPS and (Bu3Sn)4TPPS. In particular, we showed that nanomolar concentrations of (Bu2Sn)2TPPS and (Bu3Sn)4TPPS are sucient to inhibit melanoma cell growth, to increase the expression of the full-length poly (ADP-ribose) polymerase (PARP-1), to induce the cell cycle arrest respectively at G2/M and G0/G1 through the inhibition of the Cyclin D1 expression and to inhibit cell colony formation. Nanomolar concentrations of (Bu2Sn)2TPPS and (Bu3Sn)4TPPS are also sucient to inhibit the melanoma cell migration and the expression of some adhesion receptors. Moreover, we report that (Bu2Sn)2TPPS and (Bu3Sn)4TPPS act downstream of BRAF, mainly bypassing its functions, but targeting the STAT3 signalling protein. Finally, these results suggest that (Bu2Sn)2TPPS and (Bu3Sn)4TPPS may be eective therapeutic strategies for their role in the inhibition of melanoma growth and migration
Dibutyltin(IV) and Tributyltin(IV) Derivatives of meso-Tetra(4-sulfonatophenyl)porphine Inhibit the Growth and the Migration of Human Melanoma Cells
Melanoma is the most aggressive and deadly form of skin cancer, which is largely due to its propensity to metastasize. Therefore, with the aim to inhibit the growth and the metastatic dissemination of melanoma cells and to provide a novel treatment option, we studied the eects of the melanoma treatment with two organotin(IV) complexes of the meso-tetra(4-sulfonato-phenyl)porphine, namely (Bu2Sn)2TPPS and (Bu3Sn)4TPPS. In particular, we showed that nanomolar concentrations of (Bu2Sn)2TPPS and (Bu3Sn)4TPPS are sucient to inhibit melanoma cell growth, to increase the expression of the full-length poly (ADP-ribose) polymerase (PARP-1), to induce the cell cycle arrest respectively at G2/M and G0/G1 through the inhibition of the Cyclin D1 expression and to inhibit cell colony formation. Nanomolar concentrations of (Bu2Sn)2TPPS and (Bu3Sn)4TPPS are also sucient to inhibit the melanoma cell migration and the expression of some adhesion receptors. Moreover, we report that (Bu2Sn)2TPPS and (Bu3Sn)4TPPS act downstream of BRAF, mainly bypassing its functions, but targeting the STAT3 signalling protein. Finally, these results suggest that (Bu2Sn)2TPPS and (Bu3Sn)4TPPS may be eective therapeutic strategies for their role in the inhibition of melanoma growth and migration
New Biocide Based on Tributyltin(IV) Ferulate-Loaded Halloysite Nanotubes for Preserving Historical Paper Artworks
Combining biologically active compounds with nanocarriers is an emerging and promising
strategy for enhancing the activities of molecules while reducing their levels of toxicity. Green
nanomaterials have recently gained momentum in developing protocols for treating and preserving
artifacts. In this study, we designed a functional biohybrid material by incorporating tributyltin(IV)
ferulate (TBT-F) into halloysite nanotubes (HNTs), generating a new formulation called HNT/TBTF.
The primary objective was to develop a formulation with robust antimicrobial properties and
reinforcing features for treating paper with artistic and historical value. To characterize HNT/TBT-F,
assess the HNT’s loading capacity, and investigate the TBT-F release kinetics from the nanotubes,
various analytical techniques, including UV-Vis and infrared spectroscopies, thermogravimetry, and
microscopy analysis, were employed. Furthermore, we evaluated the antimicrobial potential of TBT-F
and HNT/TBT-F against Kocuria rhizophila, a bacterial strain known for its opportunistic behavior and
a cause of artifact biodeterioration. HNT/TBT-F exhibited a significantly stronger bactericidal effect
than TBT-F alone against K. rhizophila cells growing planktonically or those forming a biofilm. This
enhanced performance could relate to the confinement of TBT-F within the nanotubes, which likely
improved its physical-chemical stability and increased the local concentration of TBT-F upon contact
with the bacterial cells. Additionally, we evaluated the mechanical properties of a paper treated with
HNT/TBT-F, assessing any potential alterations in its color. The findings of this study highlight the
favorable attributes of the HNT/TBT-F formulation and its potential for developing protocols aimed
at consolidating and preserving culturally significant paper objects
Studies on DNA interaction of organotin(IV) complexes of meso-tetra(4-sulfonatophenyl)porphine that show cellular activity
The interaction of the diorgano- and triorganotin(IV) derivatives of meso-tetra-(4-sulfonatophenyl)porphine (Me2Sn)2TPPS, (Bu2Sn)2TPPS, (Me3Sn)4TPPS and (Bu3Sn)4TPPS to natural DNA was analysed (together with free meso-tetra-(4-sulfonatophenyl)porphine (TPPS4-) for comparison purposes). Particular attention was paid to (Bu3Sn)4TPPS, a species that shows significant cellular action. Preliminary tests were done on the solution properties of the organotin(IV) compounds (pKA and possible self-aggregation). Spectrophotometric and spectrofluorometric experiments showed that all the investigated organotin(IV) derivatives strongly interact with DNA, the binding energy depending on the dye steric hindrance. In all cases experimental data concur in indicating that external binding mode prevails. Interestingly, fluorescence quenching and viscosity experiments show that the Bu-containing species, and in particular (Bu3Sn)4TPPS, are able to noticeably alter the DNA conformation
Boosting the Performance of One-Step Solution-Processed Perovskite Solar Cells Using a Natural Monoterpene Alcohol as a Green Solvent Additive
The perovskite film is the core of a perovskite solar cell (PSC), and its quality is crucial for the performance of such devices. The morphology, crystallinity, and surface coverage of the perovskite layer greatly affect the power conversion efficiency (PCE), hysteresis, and long-term stability of PSCs. The incorporation of appropriate solvent additives in the perovskite precursor solution is an effective strategy to control the film morphology and reduce the defects and grain boundaries. However, the commonly used solvent additives are environmentally harmful and highly toxic. In this work, α-terpineol (a nontoxic, eco-friendly, and low-cost monoterpene alcohol) is employed for the first time as an alternative green solvent additive to improve the quality of one-step solution-processed CH3NH3PbI3–xClx films and to restrain nonradiative recombination in the corresponding devices. An in-depth investigation of the physicochemical effects induced by such a high-boiling-point, polar protic solvent when incorporated into a conventional perovskite solvent system is provided. The collected data demonstrate that the addition of a precise amount of α-terpineol can generate uniform and highly crystalline perovskite films with improved photovoltaic performances. Through this approach, the PCE of planar n–i–p PSCs is boosted up to 17.5% (against 16.1% of the top control device) with reduced hysteresis and enhanced ambient stability
Apoptosis and cell growth arrest in A375 human melanoma cells by diorganotin(IV) and triorganotin(IV) complexes of [meso-Tetra(4-sulfonatophenyl)porphine]manganese(III)chloride
In previous studies we have demonstrated that two derivatives of meso-Tetra(4-sulfonatophenyl)porphine (TPPS), (Bu2Sn)2TPPS and (Bu3Sn)4TPPS, cause apoptotic death of A375 melanoma cells and, at lower concentrations, arrest of cell proliferation. In the present study, we examined if the manganese metal inside the porphyrin cavity could improve the efficacy of this class of compounds. Thus, [meso-
Tetra(4-sulfonatophenyl)porphine]Mn(III)Cl (=MnTPPS) derivatives, namely (Me2Sn)2MnTPPS, (Bu2Sn)2MnTPPS, (Me3Sn)4MnTPPS and (Bu3Sn)4MnTPPS, were tested on the A375 human melanoma cell line. A cytotoxicity assay showed that (Bu2Sn)2MnTPPS and (Bu3Sn)4MnTPPS were
highly cytotoxic by inducing apoptosis in melanoma cells, as shown by DNA fragmentation analysis and by apoptotic
nuclei fluorescence, and when used at lower concentrations, they affected only cellular proliferation. An arrest of cell proliferation was also observed with (Me3Sn)4MnTPPS, but at the highest concentrations used. Moreover, the lower
concentration of (Bu3Sn)4MnTPPS induced a change in cell morphology, from a polygonal to an elongated and spindle-shaped phenotype, likewise to its cognate (Bu3Sn)4TPPS, previously tested. Western blotting analysis showed indeed
that both tributyltin compounds, i.e. (Bu3Sn)4MnTPPS and (Bu3Sn)4TPPS, lowered levels of the major proteins involved
in tumorigenesis: ß-catenin, c-myc and snail. We also demonstrated that all compounds entered the cells and localized in
the nuclei. In conclusion, our results show that, in spite of the Mn(III) metal introduction, the butyl derivatives always have a higher efficacy than methyl derivatives, and the tributyltin
compounds in particular have an interesting effect in vitro on A375 cell proliferation
Trattamento funerario differenziale di neonati di epoca tardo-romana. Le deposizioni di infanti e cani a Peltuinum.
È indubbio che la ricostruzione delle caratteristiche demografiche delle popolazioni antiche trovi il suo maggiore ostacolo nella sottostima degli scheletri infantili recuperati dai contesti cimiteriali. Mentre i modelli di riferimento
prevedono, infatti, una mortalità nei primi anni di vita superiore al 30% dei decessi totali nelle popolazioni pre-industriali, gli scavi di necropoli raramente restituiscono tali proporzioni. Fattori casuali, quali il minor grado di mineralizzazione dello scheletro in accrescimento, processi post-deposizionali, scavi e recuperi parziali del materiale scheletrico, sono oggi ritenuti marginali; molto più credito viene attribuito invece a scelte culturali che implicano trattamenti differenziali - sia nelle modalità che nei luoghi - degli infanti rispetto al resto della popolazione. Nell' ambito della ricerca sulla città romana di Peltuinum
(AQ), i recenti scavi del teatro forniscono nuove ed interessanti indicazioni in tale senso. I pozzetti antistanti il muro del pulpitum
, connessi al sistema di funzionamento del sipario, hanno restituito numerosi resti di feti e neonati umani, in associazione a resti di cani e di altra fauna.The symbolic value of water as a vector to the prenatal life or deities drives the choice to bury the bodies in underground environments. It can therefore be assumed that the disused wells of the theater have been considered the most suitable place for infants burial in a rural area.
Thus, the particularity of the deposition and the high concentration of perinatal deaths, are likely connected to cultural practices, involving a differential treatment of infants, in association with an high risk of mortality at birt
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