The stellar metallicity distribution in intermediate latitude fields with BATC and SDSS data

Based on the Beijing-Arizona-Taiwan-Connecticut (BATC) and Sloan Digital Sky Survey (SDSS) photometric data, we adopt SEDs fitting Method to evaluate the metallicity distribution for \sim40,000 main-sequence stars in the Galaxy. According to the derived photometric metallicities of these sample stars, we find that the metallicity distribution shift from metal-rich to metal-poor with the increase of distance from the Galactic center. The mean metallicity is about of 1.5 \pm 0.2dex in the outer halo and 1.3 \pm 0.1 dex in the inner halo. The mean metallicity smoothly decreases from -0.4 to -0.8 in interval 0 < r \leq 5 kpc. The fluctuation in the mean metallicity with Galactic longitude can be found in interval 4 < r \leq 8 kpc. There is a vertical abundance gradients d[Fe/H]/dz\sim -0.21 \pm 0.05 dex kpc-1 for the thin disk (z \leq 2 kpc). At distance 2 < z \leq 5 kpc, where the thick disk stars are dominated, the gradients are about of -0.16 \pm0.06 dex kpc-1, it can be interpreted as a mixture of stellar population with different mean metallicities at all z levels. The vertical metallicity gradient is - 0.05 \pm0.04 dex kpc-1 for the halo (z > 5 kpc). So there is little or no metallicity gradient in the halo

The stellar halo of the Galaxy

Stellar halos may hold some of the best preserved fossils of the formation history of galaxies. They are a natural product of the merging processes that probably take place during the assembly of a galaxy, and hence may well be the most ubiquitous component of galaxies, independently of their Hubble type. This review focuses on our current understanding of the spatial structure, the kinematics and chemistry of halo stars in the Milky Way. In recent years, we have experienced a change in paradigm thanks to the discovery of large amounts of substructure, especially in the outer halo. I discuss the implications of the currently available observational constraints and fold them into several possible formation scenarios. Unraveling the formation of the Galactic halo will be possible in the near future through a combination of large wide field photometric and spectroscopic surveys, and especially in the era of Gaia.Comment: 46 pages, 16 figures. References updated and some minor changes. Full-resolution version available at http://www.astro.rug.nl/~ahelmi/stellar-halo-review.pd

Uncovering the multifaceted roles played by neutrophils in allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a life-saving procedure used for the treatment of selected hematological malignancies, inborn errors of metabolism, and bone marrow failures. The role of neutrophils in alloHSCT has been traditionally evaluated only in the context of their ability to act as a first line of defense against infection. However, recent evidence has highlighted neutrophils as key effectors of innate and adaptive immune responses through a wide array of newly discovered functions. Accordingly, neutrophils are emerging as highly versatile cells that are able to acquire different, often opposite, functional capacities depending on the microenvironment and their differentiation status. Herein, we review the current knowledge on the multiple functions that neutrophils exhibit through the different stages of alloHSCT, from the hematopoietic stem cell (HSC) mobilization in the donor to the immunological reconstitution that occurs in the recipient following HSC infusion. We also discuss the influence exerted on neutrophils by the immunosuppressive drugs delivered in the course of alloHSCT as part of graft-versus-host disease (GVHD) prophylaxis. Finally, the potential involvement of neutrophils in alloHSCT-related complications, such as transplant-associated thrombotic microangiopathy (TA-TMA), acute and chronic GVHD, and cytomegalovirus (CMV) reactivation, is also discussed. Based on the data reviewed herein, the role played by neutrophils in alloHSCT is far greater than a simple antimicrobial role. However, much remains to be investigated in terms of the potential functions that neutrophils might exert during a highly complex procedure such as alloHSCT

CDK12 Inhibition Reverses De Novo and Acquired PARP Inhibitor Resistance in BRCA Wild-Type and Mutated Models of Triple-Negative Breast Cancer

© 2016 The Author(s) Although poly(ADP-ribose) polymerase (PARP) inhibitors are active in homologous recombination (HR)-deficient cancers, their utility is limited by acquired resistance after restoration of HR. Here, we report that dinaciclib, an inhibitor of cyclin-dependent kinases (CDKs) 1, 2, 5, and 9, additionally has potent activity against CDK12, a transcriptional regulator of HR. In BRCA-mutated triple-negative breast cancer (TNBC) cells and patient-derived xenografts (PDXs), dinaciclib ablates restored HR and reverses PARP inhibitor resistance. Additionally, we show that de novo resistance to PARP inhibition in BRCA1-mutated cell lines and a PDX derived from a PARP-inhibitor-naive BRCA1 carrier is mediated by residual HR and is reversed by CDK12 inhibition. Finally, dinaciclib augments the degree of response in a PARP-inhibitor-sensitive model, converting tumor growth inhibition to durable regression. These results highlight the significance of HR disruption as a therapeutic strategy and support the broad use of combined CDK12 and PARP inhibition in TNBC