79 research outputs found
Cepheids with giant companions. I. Revealing a numerous population of double-lined binary Cepheids
Masses of classical Cepheids of 3 to 11 M are predicted by theory but
those measured, clump between 3.6 and 5 M. As a result, their
mass-luminosity relation is poorly constrained, impeding our understanding of
basic stellar physics and the Leavitt Law. All Cepheid masses come from the
analysis of 11 binary systems, including only 5 double-lined and well-suited
for accurate dynamical mass determination. We present a project to analyze a
new, numerous group of Cepheids in double-lined binary (SB2) systems to provide
mass determinations in a wide mass interval and study their evolution. We
analyze a sample of 41 candidate binary LMC Cepheids spread along the P-L
relation, that are likely accompanied by luminous red giants, and present
indirect and direct indicators of their binarity. In a spectroscopic study of a
subsample of 18 brightest candidates, for 16 we detected lines of two
components in the spectra, already quadrupling the number of Cepheids in SB2
systems. Observations of the whole sample may thus lead to quadrupling all the
Cepheid mass estimates available now. For the majority of our candidates,
erratic intrinsic period changes dominate over the light travel-time effect due
to binarity. However, the latter may explain the periodic phase modulation for
4 Cepheids. Our project paves the way for future accurate dynamical mass
determinations of Cepheids in the LMC, Milky Way, and other galaxies, which
will potentially increase the number of known Cepheid masses even 10-fold,
hugely improving our knowledge about these important stars.Comment: 12 pages, 7 figures, 3 tables, accepted for publication in Ap
A novel oncogenic BTK isoform is overexpressed in colon cancers and required for RAS-mediated transformation
20siBruton's tyrosine kinase (BTK) is essential for B-cell proliferation/differentiation and it is generally believed that its expression and function are limited to bone marrow-derived cells. Here, we report the identification and characterization of p65BTK, a novel isoform abundantly expressed in colon carcinoma cell lines and tumour tissue samples. p65BTK protein is expressed, through heterogeneous nuclear ribonucleoprotein K (hnRNPK)-dependent and internal ribosome entry site-driven translation, from a transcript containing an alternative first exon in the 5'-untranslated region, and is post-transcriptionally regulated, via hnRNPK, by the mitogen-activated protein kinase (MAPK) pathway. p65BTK is endowed with strong transforming activity that depends on active signal-regulated protein kinases-1/2 (ERK1/2) and its inhibition abolishes RAS transforming activity. Accordingly, p65BTK overexpression in colon cancer tissues correlates with ERK1/2 activation. Moreover, p65BTK inhibition affects growth and survival of colon cancer cells. Our data reveal that BTK, via p65BTK expression, is a novel and powerful oncogene acting downstream of the RAS/MAPK pathway and suggest that its targeting may be a promising therapeutic approach.openopenGrassilli, Emanuela; Pisano, Fabio; Cialdella, Annamaria; Bonomo, Sara; Missaglia, Carola; Cerrito, Maria Grazia; Masiero, Laura; Ianzano, Leonarda; Giordano, Federica; Cicirelli, Vittoria; Narloch, Robert; D'Amato, Filomena; Noli, Barbara; Ferri, Gian Luca; Leone, Biagio; Stanta, Giorgio; Bonin, Serena; Helin, Kristian; Giovannoni, Roberto; Lavitrano, MarialuisaGrassilli, Emanuela; Pisano, Fabio; Cialdella, Annamaria; Bonomo, Sara; Missaglia, Carola; Cerrito, Maria Grazia; Masiero, Laura; Ianzano, Leonarda; Giordano, Federica; Cicirelli, Vittoria; Narloch, Robert; D'Amato, Filomena; Noli, Barbara; Ferri, Gian Luca; Leone, Biagio; Stanta, Giorgio; Bonin, Serena; Helin, Kristian; Giovannoni, Roberto; Lavitrano, Marialuis
Oxygen adsorption on the Ru (10 bar 1 0) surface: Anomalous coverage dependence
Oxygen adsorption onto Ru (10 bar 1 0) results in the formation of two
ordered overlayers, i.e. a c(2 times 4)-2O and a (2 times 1)pg-2O phase, which
were analyzed by low-energy electron diffraction (LEED) and density functional
theory (DFT) calculation. In addition, the vibrational properties of these
overlayers were studied by high-resolution electron loss spectroscopy. In both
phases, oxygen occupies the threefold coordinated hcp site along the densely
packed rows on an otherwise unreconstructed surface, i.e. the O atoms are
attached to two atoms in the first Ru layer Ru(1) and to one Ru atom in the
second layer Ru(2), forming zigzag chains along the troughs. While in the
low-coverage c(2 times 4)-O phase, the bond lengths of O to Ru(1) and Ru(2) are
2.08 A and 2.03 A, respectively, corresponding bond lengths in the
high-coverage (2 times 1)-2O phase are 2.01 A and 2.04 A (LEED). Although the
adsorption energy decreases by 220 meV with O coverage (DFT calculations), we
observe experimentally a shortening of the Ru(1)-O bond length with O coverage.
This effect could not be reconciled with the present DFT-GGA calculations. The
nu(Ru-O) stretch mode is found at 67 meV [c(2 times 4)-2O] and 64 meV [(2 times
1)pg-2O].Comment: 10 pages, figures are available as hardcopies on request by mailing
[email protected], submitted to Phys. Rev. B (8. Aug. 97), other related
publications can be found at http://www.rz-berlin.mpg.de/th/paper.htm
The Araucaria Project: Improving the cosmic distance scale
The book consists of a number of short articles that present achievements of
the Araucaria members, collaborators, and friends, in various aspects of
distance determinations and related topics. It celebrates the 20-year
anniversary of the Araucaria Project, acknowledges the people who worked for
its success, and popularises our methods and results among broader readership.
This book is a part of a project that has received funding from the European
Union's Horizon 2020 research and innovation programme under grant agreement No
695099.Comment: 114 pages, book published in 2021 on behalf of the Nicolaus
Copernicus Astronomical Center of the Polish Academy of Sciences, to
celebrate 20 years of the Arauria Projec
A novel oncogenic BTK isoform is overexpressed in colon cancers and required for RAS-mediated transformation
Bruton’s tyrosine kinase (BTK) is essential for B-cell proliferation/differentiation and it is generally believed that its expression and function are limited to bone marrow-derived cells. Here, we report the identification and characterization of p65BTK, a novel isoform abundantly expressed in colon carcinoma cell lines and tumor tissue samples. p65BTK protein is expressed, through hnRNPK-dependent and IRES-driven translation, from a transcript containing an alternative first exon in the 5’UTR, and is post-transcriptionally regulated, via hnRNPK, by the MAPK pathway. p65BTK is endowed with strong transforming activity that depends on active ERK1/2 and its inhibition abolishes RAS transforming activity. Accordingly, p65BTK overexpression in colon cancer tissues correlates with ERK1/2 activation. Moreover, p65BTK inhibition affects growth and survival of colon cancer cells. Our data reveal that BTK, via p65BTK expression, is a novel and powerful oncogene acting downstream of the RAS/MAPK pathway and suggest that its targeting may be a promising therapeutic approac
Learn before Lecture: A Strategy That Improves Learning Outcomes in a Large Introductory Biology Class
Actively engaging students in lecture has been shown to increase learning gains. To create time for active learning without displacing content we used two strategies for introducing material before class in a large introductory biology course. Four to five slides from 2007/8 were removed from each of three lectures in 2009 and the information introduced in preclass worksheets or narrated PowerPoint videos. In class, time created by shifting lecture material to learn before lecture (LBL) assignments was used to engage students in application of their new knowledge. Learning was evaluated by comparing student performance in 2009 versus 2007/8 on LBL-related question pairs, matched by level and format. The percentage of students who correctly answered five of six LBL-related exam questions was significantly higher (p < 0.001) in 2009 versus 2007/8. The mean increase in performance was 21% across the six LBL-related questions compared with <3% on all non-LBL exam questions. The worksheet and video LBL formats were equally effective based on a cross-over experimental design. These results demonstrate that LBLs combined with interactive exercises can be implemented incrementally and result in significant increases in learning gains in large introductory biology classes
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