NGC 5694: another foster son of the Galactic Halo

We present the results of the analysis of high-resolution spectra obtained with UVES-FLAMES@VLT for six red giant branch stars in the outer-halo metal-poor ([Fe/H]I=-1.98 and [Fe/H]II=-1.83) Galactic globular cluster NGC 5694, which has been suggested as a possible incomer by Lee et al. (2006) based on the anomalous chemical composition of a single cluster giant. We obtain accurate abundances for a large number of elements and we find that: (a) the six target stars have the same chemical composition within the uncertainties, except for Na and Al; (b) the average cluster abundance of \alpha\ elements (with the only exception of Si) is nearly solar, at odds with typical halo stars and globular clusters of similar metallicity; (c) Y, Ba, La and Eu abundances are also significantly lower than in Galactic field stars and star clusters of similar metallicity. Hence we confirm the Lee et al. classification of NGC 5694 as a cluster of extra-galactic origin. We provide the first insight on the Na-O and Mg-Al anti-correlations in this cluster: all the considered stars have very similar abundance ratios for these elements, except one that has significantly lower [Na/Fe] and [Al/Fe] ratios, suggesting that some degree of early self-enrichment has occurred also in this cluster.Comment: Accepted for publication by MNRAS. 15 pages, 8 figures, 4 table

Kinematics of a globular cluster with an extended profile: NGC5694

We present a study of the kinematics of the remote globular cluster NGC5694 based on GIRAFFE@VLT medium resolution spectra. A sample of 165 individual stars selected to lie on the Red Giant Branch in the cluster Color Magnitude Diagram was considered. Using radial velocity and metallicity from Calcium triplet, we were able to select 83 bona-fide cluster members. The addition of six previously known members leads to a total sample of 89 cluster giants with typical uncertainties <1.0 km/s in their radial velocity estimates. The sample covers a wide range of projected distances from the cluster center, from ~0.2 arcmin to 6.5 arcmin = 23 half-light radii (r_h). We find only very weak rotation, as typical of metal-poor globular clusters. The velocity dispersion gently declines from a central value of sigma=6.1 km/s to sigma = 2.5 km/s at ~2 arcmin = 7.1= r_h, then it remainins flat out to the next (and last) measured point of the dispersion profile, at ~4 arcmin = 14.0 r_h, at odds with the predictions of isotropic King models. We show that both isotropic single-mass non-collisional models and multi-mass anisotropic models can reproduce the observed surface brightness and velocity dispersion profiles.Comment: Accepted for publication by MNRAS. Pdflatex, 10 pages, 10 figure

Stem-like plasticity and heterogeneity of circulating tumor cells : current status and prospect challenges in liver cancer

Poor prognosis and high recurrence remain leading causes of primary liver cancer-associated mortality. The spread of circulating tumor cells (CTCs) in the blood plays a major role in the initiation of metastasis and tumor recurrence after surgery. Nevertheless, only a subset of CTCs can survive, migrate to distant sites and establish secondary tumors. Consistent with cancer stem cell (CSC) hypothesis, stem-like CTCs might represent a potential source for cancer relapse and distant metastasis. Thus, identification of stem-like metastasis-initiating CTC-subset may provide useful clinically prognostic information. This review will emphasize the most relevant findings of CTCs in the context of stem-like biology associated to liver carcinogenesis. In this view, the emerging field of stem-like CTCs may deliver substantial contribution in liver cancer field in order to move to personalized approaches for diagnosis, prognosis and therapy

Stemness Features in Liver Cancer

Heterogeneity is a cardinal hallmark of cancer, including primary liver cancer (PLC), and occurs at different layers including putative cell-of-origin. Current evidence suggests that within cellular subpopulations in PLC there are stem-like cells, the cancer stem cells (CSCs). The CSC concept has been recently proposed as an explanation of such intra-tumor heterogeneity. According to this model, CSCs are responsible for tumor initiation, recurrence, metastasis as well as drug-resistance. However, although the CSC hypothesis is intriguing and supported by a large number of experimental studies, there are still open questions regarding the origin of putative CSCs. Since chemo-resistance and recurrence represent major issues in PLC treatment, the development of new therapeutic strategies is needed, for which a good understanding of tumor behavior and in particular of CSCs biology is an imperative prerequisite. In this review we summarize the regulatory pathways that support CSC features in PLC. Moreover, we highlight the key features of hepatic CSC, in terms of enhanced drug-resistance, increased metastatic potential and metabolic rearrangement. Knowledge of the molecular mechanisms underlying CSC biology may provide novel options for PLC combination therapies

HST resolves stars in a tiny body falling on the dwarf galaxy DDO 68

We present new Hubble Space Telescope (HST) imaging of a stream-like system associated with the dwarf galaxy DDO 68, located in the Lynx-Cancer Void at a distance of D$\sim$12.65 Mpc from us. The stream, previously identified in deep Large Binocular Telescope images as a diffuse low surface brightness structure, is resolved into individual stars in the F606W (broad V) and F814W ($\sim$I) images acquired with the Wide Field Camera 3. The resulting V, I color-magnitude diagram (CMD) of the resolved stars is dominated by old (age$\gtrsim$1-2 Gyr) red giant branch (RGB) stars. From the observed RGB tip, we conclude that the stream is at the same distance as DDO 68, confirming the physical association with it. A synthetic CMD analysis indicates that the large majority of the star formation activity in the stream occurred at epochs earlier than $\sim$1 Gyr ago, and that the star formation at epochs more recent than $\sim$500 Myr ago is compatible with zero. The total stellar mass of the stream is $\sim10^{6} M_{\odot}$, about 1/100 of that of DDO~68. This is a striking example of hierarchical merging in action at the dwarf galaxy scales.Comment: ApJ in pres

A high fraction of Be stars in young massive clusters: evidence for a large population of near-critically rotating stars

Recent photometric analysis of the colour-magnitude diagrams (CMDs) of young massive clusters (YMCs) have found evidence for splitting in the main sequence and extended main sequence turn-offs, both of which have been suggested to be caused by stellar rotation. Comparison of the observed main sequence splitting with models has led various authors to suggest a rather extreme stellar rotation distribution, with a minority (10−30\%) of stars with low rotational velocities and the remainder (70−90\%) of stars rotating near the critical rotation (i.e., near break-up). We test this hypothesis by searching for Be stars within two YMCs in the LMC (NGC 1850 and NGC 1856), which are thought to be critically rotating stars with decretion disks that are (partially) ionised by their host stars. In both clusters we detect large populations of Be stars at the main sequence turn-off (∼30−60\% of stars), which supports previous suggestions of large populations of rapidly rotating stars within massive clusters

Racial disparities in fifth-grade sun protection: Evidence from the Healthy Passages study

Background/Objectives: Despite rising skin cancer rates in children, multiple studies reveal inadequate youth sun-protective behavior (eg, sunscreen use). Using Healthy Passages data for fifth-graders, we set out to determine sunscreen adherence in these children and investigated factors related to sunscreen performance. Methods: Survey data were collected from 5119 fifth-graders and their primary caregivers. Logistic regression was used to assess associations between sunscreen adherence and performance of other preventive health behaviors (eg, flossing, helmet use) and examine predictors of sunscreen adherence. Analyses were repeated in non-Hispanic black, Hispanic, and non-Hispanic white subgroups. Results: Five thousand one hundred nineteen (23.4%) children almost always used sunscreen, 5.9% of non-Hispanic blacks (n = 1748), 23.7% of Hispanics (n = 1802), and 44.8% of non-Hispanic whites (n = 1249). Performing other preventive health behaviors was associated with higher odds of sunscreen adherence (all P \u3c.001), with the greatest association with flossing teeth (odds ratio = 2.41, 95% confidence interval = 1.86-3.13, P \u3c.001). Factors for lower odds of sunscreen adherence included being male and non-Hispanic black or Hispanic and having lower socioeconomic status. School-based sun-safety education and involvement in team sports were not significant factors. Conclusion: Our data confirm low use of sun protection among fifth-graders. Future research should explore how public health success in increasing prevalence of other preventive health behaviors may be applied to enhance sun protection messages. Identifying risk factors for poor adherence enables providers to target patients who need more education. Improving educational policies and content in schools may be an effective way to address sun safety