oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 282 )

2018 ( 518 )

2017 ( 535 )

2016 ( 764 )

Custom range...

Search Results: 1 - 10 of 325141 matches for " S Fulle "
All listed articles are free for downloading (OA Articles)
Page 1 /325141
Display every page Item
Functional assay, expression of growth factors and proteins modulating bone-arrangement in human osteoblasts seeded on an anorganic bovine bone biomaterial
O Trubiani,S Fulle,T Traini,M Paludi
European Cells and Materials (ECM) , 2010,
Abstract: The basic aspects of bone tissue engineering include chemical composition and geometry of the scaffold design, because it is very important to improve not only cell attachment and growth but especially osteodifferentiation, bone tissue formation, and vascularization. Geistlich Bio-Oss (GBO) is a xenograft consisting of deproteinized, sterilized bovine bone, chemically and physically identical to the mineral phase of human bone.In this study, we investigated the growth behaviour and the ability to form focal adhesions on the substrate, using vinculin, a cytoskeletal protein, as a marker. Moreover, the expression of bone specific proteins and growth factors such as type I collagen, osteopontin, bone sialoprotein, bone morphogenetic protein-2 (BMP-2), BMP-7 and de novo synthesis of osteocalcin in normal human osteoblasts (NHOst) seeded on xenogenic GBO were evaluated. Our observations suggest that after four weeks of culture in differentiation medium, the NHOst showed a high affinity for the three dimensional biomaterial; in fact, cellular proliferation, migration and colonization were clearly evident. The osteogenic differentiation process, as demonstrated by morphological, histochemical, energy dispersive X-ray microanalysis and biochemical analysis was mostly obvious in the NHOst grown on three-dimensional inorganic bovine bone biomaterial. Functional studies displayed a clear and significant response to calcitonin when the cells were differentiated. In addition, the presence of the biomaterial improved the response, suggesting that it could drive the differentiation of these cells towards a more differentiated osteogenic phenotype. These results encourage us to consider GBO an adequate biocompatible three-dimensional biomaterial, indicating its potential use for the development of tissue-engineering techniques.
Retrospective study of histological types of esophageal cancer prevalent in the Metropolitan Region of Santiago, Chile
Juan Carlos Acu?a Hinojosa,Felipe Hernández Sotomayor,Nicolás Flores Moltedo,Angelo Fulle Caro
Medwave , 2010,
Abstract: This study tries to determine the statistical relation between the most frequent histological types of oesophageal carcinoma in the Metropolitan region of Santiago, Chile. For it there were obtained clinical samples of different laboratories of Pathological Anatomy of the Metropolitan region corresponding to the south and east sector of Santiago, gathering a total of 348 cases, which were diagnosed by means of endoscopic biopsy, using as parameters the morphologic characteristics of neoplastic tissue evaluated by light microscopy with hematoxylin-eosin dye. The obtained information was submitted to a model of logistic multiple regression, in order to determine the associations between the most frequent histological types of oesophageal cancer (adenocarcinoma and squamous carcinoma), topographic location compromised to the moment of the diagnosis, age and sex of the patients in study. The proportion between the histological types of cancer of esophagus did not present significant differences, which contrasts with the results of international publications. The analyses demonstrated that the low third is the only parameter that is subject to variation, which relates to the metaplasia of Barrett and the development of oesophageal adenocarcinoma.
Multicolor Photometry of the Uranus Irregular Satellites Sycorax and Caliban
Michele Maris,Giovanni Carraro,Gabriele Cremonese,Marco Fulle
Physics , 2001, DOI: 10.1086/320378
Abstract: We report on accurate BVRI photometry for the two Uranus irregular satellites Sycorax and Caliban. We derive colours, showing that Sycorax is bluer than Caliban. Our data allows us to detect a significant variability in the Caliban's light-curve, which suggests an estimated period of about 3 hours. Despite it is the brighter of the two bodies, Sycorax does not display a strong statistically significant variability. However our data seem to suggest a period of about 4 hours
Potassium detection and Lithium depletion in comets C/2011 L4 (Panstarrs) and C/1965 S1 (Ikeya-Seki)
M. Fulle,P. Molaro,L. Buzzi,P. Valisa
Physics , 2013, DOI: 10.1088/2041-8205/771/2/L21
Abstract: On 21 March 2013 high-resolution slit spectrographs of comet C/2011 L4 (Panstarrs), at the heliocentric distance r = 0.46 Astronomical Units (AU), were obtained at the Osservatorio Astronomico Campo dei Fiori, Italy. Emission lines of sodium were the strongest in the spectrum as is common in comets, but also potassium lines were detected. These have been rarely observed in comets since the apparition of brightest comet C/1965 S1 (Ikeya-Seki). Lithium was not detected, and stringent upper limits of its abundance compared to other alkali were derived. We obtain abundance ratios Na/K = 54 +/-14 and Na/Li > 8000. As well as in Mercury exosphere (Leblanc & Douressoundiram 2011)}, we show that photoionization at the beginning of the alkali tails may increase the solar ratio Na/K = 15.5 (Asplund et al 2009) by a factor 3, close to that required to match the observed value. In the same tail position the Na/Li ratio increases by a factor 2 only, very far from the factor > 8 required to match an original meteoritic ratio. We apply the same model to similar alkali data (Preston 1967) of comet C/1965 S1 (Ikeya-Seki), obtaining consistent results. An original solar Na/K ratio fits the observed value at the beginning of the alkali tails within the slit size, whereas Li is depleted by a factor > 8.
A Potent (R)-alpha-bis-lipoyl Derivative Containing 8-Hydroxyquinoline Scaffold: Synthesis and Biological Evaluation of Its Neuroprotective Capabilities in SH-SY5Y Human Neuroblastoma Cells
Ivana Cacciatore,Erika Fornasari,Leonardo Baldassarre,Catia Cornacchia,Stefania Fulle,Ester Sara Di Filippo,Tiziana Pietrangelo,Francesco Pinnen
Pharmaceuticals , 2013, DOI: 10.3390/ph6010054
Abstract: A novel bis-lipoyl derivative containing 8-hydroxyquinoline scaffold (LA-HQ-LA, 5) was synthesized as a new multifunctional drug candidate with antioxidant, chelant, and neuroprotective properties for the treatment of neurodegenerative diseases. We have investigated the potential effectiveness of LA-HQ-LA against the cytotoxicity induced by 6-OHDA and H2O2 on human neuroblastoma SH-SY5Y cell line. Our outcomes showed that LA-HQ-LA resulted in significant neuroprotective and antioxidant effects against H2O2- and 6-OHDA-induced neurotoxicity in human neuroblastoma SH-SY5Y cells, as assessed by MTT assay. In particular, it showed potent neuroprotective effects against 6-OHDA in RA/PMA differentiated cells at all the tested concentrations.
Neutral sodium from comet Hale-Bopp: a third type of tail
G. Cremonese,H. Boehnhardt,J. Crovisier,A. Fitzsimmons,M. Fulle,J. Licandro,D. Pollacco,H. Rauer,G. P. Tozzi,R. M. West
Physics , 1997, DOI: 10.1086/311040
Abstract: We report on the discovery and analysis of a striking neutral sodium gas tail associated with comet C/1995 O1 Hale-Bopp. Sodium D-line emission has been observed at heliocentric distance r<1.4 AU in some long-period comets and the presence of neutral sodium in the tailward direction of a few bright comets has been noted, but the extent, and in particular the source, has never been clear. Here we describe the first observations and analysis of a neutral sodium gas tail in comet Hale-Bopp, entirely different from the previously known ion and dust tails. We show that the observed characteristics of this third type of tail are consistent with itbeing produced by radiation pressure due to resonance fluorescence of sodium atoms and that the lifetime for photoionization is consistent with recent theoretical calculation.
Are fractured cliffs the source of cometary dust jets ? Insights from OSIRIS/Rosetta at 67P
J. -B. Vincent,N. Oklay,M. Pajola,S. H?fner,H. Sierks,X. Hu,C. Barbieri,P. L. Lamy,R. Rodrigo,D. Koschny,H. Rickman,H. U. Keller,M. F. A'Hearn,M. A. Barucci,J. -L. Bertaux,I. Bertini,S. Besse,D. Bodewits,G. Cremonese,V. Da Deppo,B. Davidsson,S. Debei,M. De Cecco,M. R. El-Maarry,S. Fornasier,M. Fulle,O. Groussin,P. J. Gutiérrez,P. Gutiérrez-Marquez,C. Güttler,M. Hofmann,S. F. Hviid,W. -H. Ip,L. Jorda,J. Knollenberg,G. Kovacs,J. -R. Kramm,E. Kührt,M. Küppers,L. M. Lara,M. Lazzarin,Z. -Y. Lin,J. J. Lopez Moreno,S. Lowry,F. Marzari,M. Massironi,F. Moreno,S. Mottola,G. Naletto,F. Preusker,F. Scholten,X. Shi,N. Thomas,I. Toth,C. Tubiana
Physics , 2015,
Abstract: Dust jets, i.e. fuzzy collimated streams of cometary material arising from the nucleus, have been observed in-situ on all comets since the Giotto mission flew by comet 1P/Halley in 1986. Yet their formation mechanism remains unknown. Several solutions have been proposed, from localized physical mechanisms on the surface/sub-surface (see review in Belton (2010)) to purely dynamical processes involving the focusing of gas flows by the local topography (Crifo et al. 2002). While the latter seems to be responsible for the larger features, high resolution imagery has shown that broad streams are composed of many smaller features (a few meters wide) that connect directly to the nucleus surface. We monitored these jets at high resolution and over several months to understand what are the physical processes driving their formation, and how this affects the surface. Using many images of the same areas with different viewing angles, we performed a 3-dimensional reconstruction of collimated jets, and linked them precisely to their sources on the nucleus. Results.We show here observational evidence that the Northern hemisphere jets of comet 67P arise from areas with sharp topographic changes and describe the physical processes involved. We propose a model in which active cliffs are the main source of jet-like features, and therefore the regions eroding the fastest on comets. We suggest that this is a common mechanism taking place on all comets.
Temporal morphological changes in the Imhotep region of comet 67P/Churyumov-Gerasimenko
O. Groussin,H. Sierks,C. Barbieri,P. Lamy,R. Rodrigo,D. Koschny,H. Rickman,H. U. Keller,M. F. A Hearn,A. -T. Auger,M. A. Barucci,J. -L. Bertaux,I. Bertini,S. Besse,G. Cremonese,V. Da Deppo,B. Davidsson,S. Debei,M. De Cecco,M. R. El-Maarry,S. Fornasier,M. Fulle,P. J. Gutiérrez,C. Güttler,S. Hviid,W. -H Ip,L. Jorda,J. Knollenberg,G. Kovacs,J. R. Kramm,E. Kührt,M. Küppers,L. M. Lara,M. Lazzarin,J. J. Lopez Moreno,S. Lowry,S. Marchi,F. Marzari,M. Massironi,S. Mottola,G. Naletto,N. Oklay,M. Pajola,A. Pommerol,N. Thomas,I. Toth,C. Tubiana,J. -B. Vincent
Physics , 2015, DOI: 10.1051/0004-6361/201527020
Abstract: We report on the first major temporal morphological changes observed on the surface of the nucleus of comet 67P/Churyumov-Gerasimenko, in the smooth terrains of the Imhotep region. We use images of the OSIRIS cameras onboard Rosetta to follow the temporal changes from 24 May 2015 to 11 July 2015. The morphological changes observed on the surface are visible in the form of roundish features, which are growing in size from a given location in a preferential direction, at a rate of 5.6 - 8.1$\times$10$^{-5}$ m s$^{-1}$ during the observational period. The location where changes started and the contours of the expanding features are bluer than the surroundings, suggesting the presence of ices (H$_2$O and/or CO$_2$) exposed on the surface. However, sublimation of ices alone is not sufficient to explain the observed expanding features. No significant variations in the dust activity pattern are observed during the period of changes.
Spectrophotometric properties of the nucleus of comet 67P/Churyumov-Gerasimenko from the OSIRIS instrument onboard the ROSETTA spacecraft
S. Fornasier,P. H. Hasselmann,M. A. Barucci,C. Feller,S. Besse,C. Leyrat,L. Lara,P. J. Gutierrez,N. Oklay,C. Tubiana,F. Scholten,H. Sierks,C. Barbieri,P. L. Lamy,R. Rodrigo,D. Koschny,H. Rickman,H. U. Keller,J. Agarwal,M. F. A'Hearn,J. -L. Bertaux,I. Bertini,G. Cremonese,V. Da Deppo,B. Davidsson,S. Debei,M. De Cecco,M. Fulle,O. Groussin,C. Güttler,S. F. Hviid,W. Ip,L. Jorda,J. Knollenberg,G. Kovacs,R. Kramm,E. Kührt,M. Küppers,F. La Forgia,M. Lazzarin,J. J. Lopez Moreno,F. Marzari,K. -D. Matz,H. Michalik,F. Moreno,S. Mottola,G. Naletto,M. Pajola,A. Pommerol,F. Preusker,X. Shi,C. Snodgrass,N. Thomas,J. -B. Vincent
Physics , 2015, DOI: 10.1051/0004-6361/201525901
Abstract: The Rosetta mission of the European Space Agency has been orbiting the comet 67P/Churyumov-Gerasimenko (67P) since August 2014 and is now in its escort phase. A large complement of scientific experiments designed to complete the most detailed study of a comet ever attempted are onboard Rosetta. We present results for the photometric and spectrophotometric properties of the nucleus of 67P derived from the OSIRIS imaging system, which consists of a Wide Angle Camera (WAC) and a Narrow Angle Camera (NAC). The disk-averaged phase function of the nucleus of 67P shows a strong opposition surge with a G parameter value of -0.13$\pm$0.01 in the HG system formalism and an absolute magnitude $H_v(1,1,0)$ = 15.74$\pm$0.02 mag. The integrated spectrophotometry in 20 filters covering the 250-1000 nm wavelength range shows a red spectral behavior, without clear absorption bands except for a potential absorption centered at $\sim$ 290 nm that is possibly due to SO$_2$ ice. The nucleus shows strong phase reddening, with disk-averaged spectral slopes increasing from 11\%/(100 nm) to 16\%/(100 nm) in the 1.3$^{\circ}$--54$^{\circ}$ phase angle range. The geometric albedo of the comet is 6.5$\pm$0.2\% at 649 nm, with local variations of up to $\sim$ 16\% in the Hapi region. From the disk-resolved images we computed the spectral slope together with local spectrophotometry and identified three distinct groups of regions (blue, moderately red, and red). The Hapi region is the brightest, the bluest in term of spectral slope, and the most active surface on the comet. Local spectrophotometry shows an enhancement of the flux in the 700-750 nm that is associated with coma emissions.
Gravitational slopes, geomorphology, and material strengths of the nucleus of comet 67P/Churyumov-Gerasimenko from OSIRIS observations
O. Groussin,L. Jorda,A. -T. Auger,E. Kührt,R. Gaskell,C. Capanna,F. Scholten,F. Preusker,P. Lamy,S. Hviid,J. Knollenberg,U. Keller,C. Huettig,H. Sierks,C. Barbieri,R. Rodrigo,D. Koschny,H. Rickman,M. F. A Hearn,J. Agarwal,M. A. Barucci,J. -L. Bertaux,I. Bertini,S. Boudreault,G. Cremonese,V. Da Deppo,B. Davidsson,S. Debei,M. De Cecco,M. R. El-Maarry,S. Fornasier,M. Fulle,P. J. Gutiérrez,C. Güttler,W. -H Ip,J. -R. Kramm,M. Küppers,M. Lazzarin,L. M. Lara,J. J. Lopez Moreno,S. Marchi,F. Marzari,M. Massironi,H. Michalik,G. Naletto,N. Oklay,A. Pommerol,M. Pajola,N. Thomas,I. Toth,C. Tubiana,J. -B. Vincent
Physics , 2015, DOI: 10.1051/0004-6361/201526379
Abstract: We study the link between gravitational slopes and the surface morphology on the nucleus of comet 67P/Churyumov-Gerasimenko and provide constraints on the mechanical properties of the cometary material. We computed the gravitational slopes for five regions on the nucleus that are representative of the different morphologies observed on the surface, using two shape models computed from OSIRIS images by the stereo-photoclinometry (SPC) and stereo-photogrammetry (SPG) techniques. We estimated the tensile, shear, and compressive strengths using different surface morphologies and mechanical considerations. The different regions show a similar general pattern in terms of the relation between gravitational slopes and terrain morphology: i) low-slope terrains (0-20 deg) are covered by a fine material and contain a few large ($>$10 m) and isolated boulders, ii) intermediate-slope terrains (20-45 deg) are mainly fallen consolidated materials and debris fields, with numerous intermediate-size boulders from $<$1 m to 10 m for the majority of them, and iii) high-slope terrains (45-90 deg) are cliffs that expose a consolidated material and do not show boulders or fine materials. The best range for the tensile strength of overhangs is 3-15 Pa (upper limit of 150 Pa), 4-30 Pa for the shear strength of fine surface materials and boulders, and 30-150 Pa for the compressive strength of overhangs (upper limit of 1500 Pa). The strength-to-gravity ratio is similar for 67P and weak rocks on Earth. As a result of the low compressive strength, the interior of the nucleus may have been compressed sufficiently to initiate diagenesis, which could have contributed to the formation of layers. Our value for the tensile strength is comparable to that of dust aggregates formed by gravitational instability and tends to favor a formation of comets by the accrection of pebbles at low velocities.
Page 1 /325141
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.