128 research outputs found
A NOVEL FUSION 5'AFF3/3'BCL2 ORIGINATED FROM A t(2;18)(Q11.2-Q21.33) TRANSLOCATION IN FOLLICULAR LYMPHOMA
Follicular lymphoma is the second most frequent type of non-Hodgkin's lymphoma in adults. The basic molecular defect consists of the t(14;18)(q32;q21) translocation, juxtaposing the B-cell lymphoma protein 2 gene BCL2 to the immunoglobulin heavy chain locus IGH@, and leading to the antiapoptotic BCL2 protein overproduction. Variations in the t(14;18) are rare and can be classified into two categories: (i) simple variants, involving chromosomes 18 and 2, or 22, in which the fusion partner of BCL2 is the light-chain IGK@ or IGL@; (ii) complex variant translocations occurring among chromosomes 14, 18 and other chromosomes. We report a follicular lymphoma case showing BCL2 overexpression, detected by immunohistochemistry and real-time quantitative PCR, consequently to the formation of a novel fusion gene between the 5' of the lymphoid nuclear transcriptional activator gene AFF3 at 2q11.2, and the 3' of BCL2. This case shows evidence, for the first time, of BCL2 overexpression consequently to the fusion of BCL2 to a non-IG partner locus
GIANO-TNG spectroscopy of red supergiants in the young star cluster RSGC3
The Scutum complex in the inner disk of the Galaxy has a number of young star
clusters dominated by red supergiants that are heavily obscured by dust
extinction and observable only at infrared wavelengths. These clusters are
important tracers of the recent star formation and chemical enrichment history
in the inner Galaxy. During the technical commissioning and as a first science
verification of the GIANO spectrograph at the Telescopio Nazionale Galileo, we
secured high-resolution (R=50,000) near-infrared spectra of five red
supergiants in the young Scutum cluster RSGC3. Taking advantage of the full
YJHK spectral coverage of GIANO in a single exposure, we were able to measure
several tens of atomic and molecular lines that were suitable for determining
chemical abundances. By means of spectral synthesis and line equivalent width
measurements, we obtained abundances of Fe and iron-peak elements such as Ni,
Cr, and Cu, alpha (O, Mg, Si, Ca, Ti), other light elements (C, N, F, Na, Al,
and Sc), and some s-process elements (Y, Sr). We found average half-solar iron
abundances and solar-scaled [X/Fe] abundance patterns for most of the elements,
consistent with a thin-disk chemistry. We found depletion of [C/Fe] and
enhancement of [N/Fe], consistent with standard CN burning, and low 12C/13C
abundance ratios (between 9 and 11), which require extra-mixing processes in
the stellar interiors during the post-main sequence evolution. We also found
local standard of rest V(LSR)=106 km/s and heliocentric V(HEL)=90 km/s radial
velocities with a dispersion of 2.3 km/s. The inferred radial velocities,
abundances, and abundance patterns of RSGC3 are very similar to those
previously measured in the other two young clusters of the Scutum complex,
RSGC1 and RSGC2, suggesting a common kinematics and chemistry within the Scutum
complex
Lines and continuum sky emission in the near infrared: observational constraints from deep high spectral resolution spectra with GIANO-TNG
Aims Determining the intensity of lines and continuum airglow emission in the
H-band is important for the design of faint-object infrared spectrographs.
Existing spectra at low/medium resolution cannot disentangle the true
sky-continuum from instrumental effects (e.g. diffuse light in the wings of
strong lines). We aim to obtain, for the first time, a high resolution infrared
spectrum deep enough to set significant constraints on the continuum emission
between the lines in the H-band. Methods During the second commissioning run of
the GIANO high-resolution infrared spectrograph at La Palma Observatory, we
pointed the instrument directly to the sky and obtained a deep spectrum that
extends from 0.97 to 2.4 micron. Results The spectrum shows about 1500 emission
lines, a factor of two more than in previous works. Of these, 80% are
identified as OH transitions; half of these are from highly excited molecules
(hot-OH component) that are not included in the OH airglow emission models
normally used for astronomical applications. The other lines are attributable
to O2 or unidentified. Several of the faint lines are in spectral regions that
were previously believed to be free of line emission. The continuum in the
H-band is marginally detected at a level of about 300
photons/m^2/s/arcsec^2/micron, equivalent to 20.1 AB-mag/arcsec^2. The observed
spectrum and the list of observed sky-lines are published in electronic format.
Conclusions Our measurements indicate that the sky continuum in the H-band
could be even darker than previously believed. However, the myriad of airglow
emission lines severely limits the spectral ranges where very low background
can be effectively achieved with low/medium resolution spectrographs. We
identify a few spectral bands that could still remain quite dark at the
resolving power foreseen for VLT-MOONS (R ~6,600).Comment: 7 pages, 4 figures, to be published in Astronomy & Astrophysic
The fiber-fed preslit of GIANO at T.N.G
Giano is a Cryogenic Spectrograph located in T.N.G. (Spain) and commisioned
in 2013. It works in the range 950-2500 nm with a resolving power of 50000.
This instrument was designed and built for direct feeding from the telescope
[2]. However, due to constraints imposed on the telescope interfacing during
the pre-commissioning phase, it had to be positioned on the rotating building,
far from the telescope focus. Therefore, a new interface to the telescope,
based on IR-transmitting ZBLAN fibers with 85\mu m core, was
developed.Originally designed to work directly at the nasmyth focus of
the telescope, in 2011 it has decided to use a fiber to feed it. The beam from
the telescope is focused on a double fiber boundle by a Preslit Optical Bench
attached to the Nasmith A interface of the telescope. This Optical Bench
contains the fiber feeding system and other important features as a guiding
system, a fiber viewer, a fiber feed calibration lamp and a nodding facility
between the two fibers. The use of two fibers allow us to have in the
echellogram two spectrograms side by side in the same acquisition: one of the
star and the other of the sky or simultaneously to have the star and a
calibration lamp. Before entering the cryostat the light from the fiber is
collectd by a second Preslit Optical Bench attached directly to the Giano
cryostat: on this bench the correct f-number to illuminate the cold stop is
generated and on the same bench is placed an image slicer to increase the
efficiency of the system.Comment: 21 pages, 24 figures, 3 tables. Presented at SPIE Astronomical
Telescope + Instrumentation 2014 (Ground-based and Airbone Instrumentation
for Astronomy 5, 9147-360). To be published in Proceeding of SPIE Volume 914
Multi-band high resolution spectroscopy rules out the hot Jupiter BD+20 1790b - First data from the GIARPS Commissioning
Context. Stellar activity is currently challenging the detection of young
planets via the radial velocity (RV) technique. Aims. We attempt to
definitively discriminate the nature of the RV variations for the young active
K5 star BD+20 1790, for which visible (VIS) RV measurements show divergent
results on the existence of a substellar companion. Methods. We compare VIS
data with high precision RVs in the near infrared (NIR) range by using the
GIANO - B and IGRINS spectrographs. In addition, we present for the first time
simultaneous VIS-NIR observations obtained with GIARPS (GIANO - B and HARPS -
N) at Telescopio Nazionale Galileo (TNG). Orbital RVs are achromatic, so the RV
amplitude does not change at different wavelengths, while stellar activity
induces wavelength-dependent RV variations, which are significantly reduced in
the NIR range with respect to the VIS. Results. The NIR radial velocity
measurements from GIANO - B and IGRINS show an average amplitude of about one
quarter with respect to previously published VIS data, as expected when the RV
jitter is due to stellar activity. Coeval multi-band photometry surprisingly
shows larger amplitudes in the NIR range, explainable with a mixture of cool
and hot spots in the same active region. Conclusions. In this work, the claimed
massive planet around BD+20 1790 is ruled out by our data. We exploited the
crucial role of multi- wavelength spectroscopy when observing young active
stars: thanks to facilities like GIARPS that provide simultaneous observations,
this method can reach its maximum potential.Comment: 12 pages, 7 figure
GIARPS: commissioning and first scientific results
GIARPS (GIAno \& haRPS) is a project devoted to have on the same focal
station of the Telescopio Nazionale Galileo (TNG) both high resolution
spectrographs, HARPS-N (VIS) and GIANO-B (NIR), working simultaneously. This
could be considered the first and unique worldwide instrument providing
cross-dispersed echelle spectroscopy at a resolution of 50,000 in the NIR range
and 115,000 in the VIS and over in a wide spectral range (m)
in a single exposure. The science case is very broad, given the versatility of
such an instrument and its large wavelength range. A number of outstanding
science cases encompassing mainly extra-solar planet science starting from
rocky planets search and hot Jupiters to atmosphere characterization can be
considered. Furthermore both instruments can measure high precision radial
velocities by means the simultaneous thorium technique (HARPS-N) and absorbing
cell technique (GIANO-B) in a single exposure. Other science cases are also
possible. GIARPS, as a brand new observing mode of the TNG started after the
moving of GIANO-A (fiber fed spectrograph) from Nasmyth-A to Nasmyth-B where it
was re-born as GIANO-B (no more fiber feed spectrograph). The official
Commissioning finished on March 2017 and then it was offered to the community.
Despite the work is not finished yet. In this paper we describe the preliminary
scientific results obtained with GIANO-B and GIARPS observing mode with data
taken during commissioning and first open time observations.Comment: 10 pages, 11 figures, Telescopes and Astronomical instrumentation,
SPIE Conf. 201
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