Prenatal Diagnosis of WAGR Syndrome.

Wilm's tumour, aniridia, genitourinary abnormalities, and mental retardation (WAGR) syndrome is a rare genetic disorder with an estimated prevalence of 1 in 500,000 to 1 million. It is a contiguous gene syndrome due to deletion at chromosome 11p13 in a region containing WT1 and PAX6 genes. Children with WAGR syndrome mostly present in the newborn/infancy period with sporadic aniridia. The genotypic defects in WAGR syndrome have been well established. However, antenatal ultrasonographic presentation of this syndrome has never been reported. Prenatal diagnosis of this condition is possible in some cases with careful ultrasound examination of classical and nonclassical manifestations of this syndrome. The key point for this rare diagnosis was the decision to perform chromosomal microarray analysis after antenatal diagnosis of absent corpus callosum and absent cavum septum pellucidum, as this finding mandates search for potentially associated genetic disorders. We report a case of WAGR syndrome diagnosed prenatally at 29-week gestation. The diagnosis of the anomaly was based on two- and three-dimensional ultrasound as well as fetal MRI scan and microarray analysis. The ultrasonographic findings included borderline ventriculomegaly, absent corpus callosum, and absent cavum septum pellucidum. Cytogenetic results from the amniotic fluid confirmed WAGR syndrome. Parental karyotype was normal, with no evidence of copy number change, deletion, or rearrangement of this region of chromosome 11

An Empirical Measure of the Rate of White Dwarf Cooling in 47 Tucanae

We present an empirical determination of the white dwarf cooling sequence in the globular cluster 47 Tucanae. Using spectral models, we determine temperatures for 887 objects from Wide Field Camera 3 data, as well as 292 objects from data taken with the Advanced Camera for Surveys. We make the assumption that the rate of white dwarf formation in the cluster is constant. Stellar evolution models are then used to determine the rate at which objects are leaving the main sequence, which must be the same as the rate at which objects are arriving on the white dwarf sequence in our field. The result is an empirically derived relation between temperature ($T_{eff}$) and time ($t$) on the white dwarf cooling sequence. Comparing this result to theoretical cooling models, we find general agreement with the expected slopes between 20,000K and 30,000K and between 6,000K and 20,000K, but the transition to the Mestel cooling rate of $T_{eff} \propto t^{-0.4}$ is found to occur at hotter temperatures, and more abruptly than is predicted by any of these models.Comment: 10 pages, 16 figures, accepted for publication in Ap

Proper motions in Terzan 5: membership of the multi-iron sub-populations and first constrain to the orbit

By exploiting two sets of high-resolution images obtained with HST ACS/WFC over a baseline of ~10 years we have measured relative proper motions of ~70,000 stars in the stellar system Terzan 5. The results confirm the membership of the three sub-populations with different iron abudances discovered in the system. The orbit of the system has been derived from a first estimate of its absolute proper motion, obtained by using bulge stars as reference. The results of the integration of this orbit within an axisymmetric Galactic model exclude any external accretion origin for this cluster. Terzan 5 is known to have chemistry similar to the Galactic bulge; our findings support a kinematic link between the cluster and the bulge, further strengthening the possibility that Terzan 5 is the fossil remnant of one of the pristine clumps that originated the bulge.Comment: 25 pages, 14 figures, accepted for publication by Ap

FTIR spectroscopic imaging and mapping with correcting lenses for studies of biological cells and tissues

Histopathology of tissue samples is used to determine the progression of cancer usually by staining and visual analysis. It is recognised that disease progression from healthy tissue to cancerous is accompanied by spectral signature changes in the mid-infrared range. In this work, FTIR spectroscopic imaging in transmission mode using a focal plane array (96 × 96 pixels) has been applied to the characterisation of Barrett's oesophageal adenocarcinoma. To correct optical aberrations, infrared transparent lenses were used of the same material (CaF2) as the slide on which biopsies were fixed. The lenses acted as an immersion objective, reducing scattering and improving spatial resolution. A novel mapping approach using a sliding lens is presented where spectral images obtained with added lenses are stitched together such that the dataset contained a representative section of the oesophageal tissue. Images were also acquired in transmission mode using high-magnification optics for enhanced spatial resolution, as well as with a germanium micro-ATR objective. The reduction of scattering was assessed using k-means clustering. The same tissue section map, which contained a region of high grade dysplasia, was analysed using hierarchical clustering analysis. A reduction of the trough at 1077 cm−1 in the second derivative spectra was identified as an indicator of high grade dysplasia. In addition, the spatial resolution obtained with the lens using high-magnification optics was assessed by measurements of a sharp interface of polymer laminate, which was also compared with that achieved with micro ATR-FTIR imaging. In transmission mode using the lens, it was determined to be 8.5 μm and using micro-ATR imaging, the resolution was 3 μm for the band at a wavelength of ca. 3 μm. The spatial resolution was also assessed with and without the added lens, in normal and high-magnification modes using a USAF target. Spectroscopic images of cells in transmission mode using two lenses are also presented, which are necessary for correcting chromatic aberration and refraction in both the condenser and objective. The use of lenses is shown to be necessary for obtaining high-quality spectroscopic images of cells in transmission mode and proves the applicability of the pseudo hemisphere approach for this and other microfluidic systems

An Age Difference of 2 Gyr between a Metal-Rich and a Metal-Poor Globular Cluster

Globular clusters trace the formation history of the spheroidal components of both our Galaxy and others, which represent the bulk of star formation over the history of the universe. They also exhibit a range of metallicities, with metal-poor clusters dominating the stellar halo of the Galaxy, and higher metallicity clusters found within the inner Galaxy, associated with the stellar bulge, or the thick disk. Age differences between these clusters can indicate the sequence in which the components of the Galaxy formed, and in particular which clusters were formed outside the Galaxy and later swallowed along with their original host galaxies, and which were formed in situ. Here we present an age determination of the metal-rich globular cluster 47 Tucanae by fitting the properties of the cluster white dwarf population, which implies an absolute age of 9.9 (0.7) Gyr at 95% confidence. This is about 2.0 Gyr younger than inferred for the metal-poor cluster NGC 6397 from the same models, and provides quantitative evidence that metal-rich clusters like 47 Tucanae formed later than the metal-poor halo clusters like NGC 6397.Comment: Main Article: 10 pages, 4 figures; Supplementary Info 15 pages, 5 figures. Nature, Aug 1, 201

Effects of neutrino oscillations and neutrino magnetic moments on elastic neutrino-electron scattering

We consider elastic antineutrino-electron scattering taking into account possible effects of neutrino masses and mixing and of neutrino magnetic moments and electric dipole moments. Having in mind antineutrinos produced in a nuclear reactor we compute, in particular, the weak-electromagnetic interference terms which are linear in the magnetic (electric dipole) moments and also in the neutrino masses. We show that these terms are, however, suppressed compared to the pure weak and electromagnetic cross section. We also comment upon the possibility of using the electromagnetic cross section to investigate neutrino oscillations.Comment: 12 pages, REVTEX file, no figures, submitted to Phys.Rev.

Deep Photometry in a Remote M31 Major Axis Field Near G1

We present photometry from Hubble Space Telescope (HST)/Wide Field Planetary Camera 2 parallel imagery of a remote M31 field at a projected distance of about 34 kpc from the nucleus near the SW major axis. This field is near the globular cluster G1, and near one of the candidate tidal plumes identified by Ferguson et al. (2002). The F606W (V) and F814W (I) images were obtained in parallel with Space Telescope Imaging Spectrograph spectroscopy of G1 (GO-9099) and total 7.11 hours of integration time -- the deepest HST field in the outer disk of M31 to date, reaching to V ~ 28. The color-magnitude diagram of the field shows a clearly-defined red clump at V = 25.25 and a red giant branch consistent with [Fe/H] ~ -0.7. The lack of a blue horizontal branch contrasts with other M31 halo fields, the Andromeda dwarf spheroidals, and with the nearby globular cluster G1. Comparing the observed luminosity function to the Padova models, we find that at least some of the stellar population must be younger than 6 - 8 Gyr. The outermost detected neutral hydrogen gas disk of M31 lies only 2 kpc in projection from our field. The finding that some giants in the field have radial velocities close to that of the neutral hydrogen gas (Reitzel, Guhathakurta, & Rich 2003) leads us to conclude that our field samples the old, low-surface-brightness disk rather than the true Population II spheroid.Comment: 15 pages, 3 figures. accepted for publication in the A