The stellar populations in the low-luminosity, early-type galaxy NGC59

Low luminosity galaxies may be the building blocks of more luminous systems. Southern African Large Telescope (SALT) observations of the low luminosity, early-type galaxy NGC59 are obtained and analysed. These data are used to measure the stellar population parameters in the centre and off-centre regions of this galaxy, in order to uncover its likely star formation history. We find evidence of older stars, in addition to young stars in the emission line regions. The metallicity of the stellar population is constrained to be [Z/H] ~ -1.1 to -1.6, which is extremely low, even for this low luminosity galaxy, since it is not classed as a dwarf spheroidal galaxy. The measured [alpha/Fe] ratio is sub-solar, which indicates an extended star formation history in NGC59. If such objects formed the building blocks of more massive, early-type galaxies, then they must have been gaseous mergers, rather than dry mergers, in order to increase the metals to observed levels in luminous, early-type galaxies

Cell Free DNA of Tumor Origin Induces a 'Metastatic' Expression Profile in HT-29 Cancer Cell Line

BACKGROUND: Epithelial cells in malignant conditions release DNA into the extracellular compartment. Cell free DNA of tumor origin may act as a ligand of DNA sensing mechanisms and mediate changes in epithelial-stromal interactions. AIMS: To evaluate and compare the potential autocrine and paracrine regulatory effect of normal and malignant epithelial cell-related DNA on TLR9 and STING mediated pathways in HT-29 human colorectal adenocarcinoma cells and normal fibroblasts. MATERIALS AND METHODS: DNA isolated from normal and tumorous colonic epithelia of fresh frozen surgically removed tissue samples was used for 24 and 6 hour treatment of HT-29 colon carcinoma and HDF-alpha fibroblast cells. Whole genome mRNA expression analysis and qRT-PCR was performed for the elements/members of TLR9 signaling pathway. Immunocytochemistry was performed for epithelial markers (i.e. CK20 and E-cadherin), DNA methyltransferase 3a (DNMT3a) and NFkappaB (for treated HDFalpha cells). RESULTS: Administration of tumor derived DNA on HT29 cells resulted in significant (p/=1, p/=1, p</=0.05), including increased expression of key adaptor molecules of TLR9 pathway (e.g. MYD88, IRAK2, NFkappaB, IL8, IL-1beta), STING pathway (ADAR, IRF7, CXCL10, CASP1) and the FGF2 gene. CONCLUSIONS: DNA from tumorous colon epithelium, but not from the normal epithelial cells acts as a pro-metastatic factor to HT-29 cells through the overexpression of pro-metastatic genes through TLR9/MYD88 independent pathway. In contrast, DNA derived from healthy colonic epithelium induced TLR9 and STING signaling pathway in normal fibroblasts

Impaired leukocyte influx in cervix of postterm women not responding to prostaglandin priming

<p>Abstract</p> <p>Background</p> <p>Prolonged pregnancies are associated with increased rate of maternal and fetal complications. Post term women could be divided into at least two subgroups, one where parturition is possible to induce by prostaglandins and one where it is not. Our aim was to study parameters in cervical biopsies in women with spontaneous delivery at term (controls) and compare to those that are successfully induced post term (responders), and those that are not induced (non-responders), by local prostaglandin treatment.</p> <p>Methods</p> <p>Stromal parameters examined in this study were the accumulation of leukocytes (CD45, CD68), mRNAs and/or proteins for the extracellular matrix degrading enzymes (matrix metalloproteinase (MMP)-2, MMP-8 and MMP-9), their inhibitors (tissue inhibitor of MMP (TIMP)-1 and TIMP-2), interleukin-8 (IL-8), the platelet activating factor-receptor (PAF-R), syndecan-1 and estrogen binding receptors (estrogen receptor (ER)α, ERβ and G-coupled protein receptor (GPR) 30) as well as the proliferation marker Ki-67.</p> <p>Results</p> <p>The influx of leukocytes as assessed by CD45 was strongest in the responders, thereafter in the controls and significantly lower in the non-responders. IL-8, PAF-R and MMP-9, all predominantly expressed in leukocytes, showed significantly reduced immunostaining in the group of non-responders, while ERα and GPR30 were more abundant in the non-responders, as compared to the controls.</p> <p>Conclusion</p> <p>The impaired leukocyte influx, as reflected by the reduced number of CD45 positive cells as well as decreased immunostaining of IL-8, PAF-R and MMP-9 in the non-responders, could be one explanation of the failed ripening of the cervix in post term women. If the decreased leukocyte influx is a primary explanation to absent ripening or secondary, as a result of other factors, is yet to be established.</p

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Multi-messenger Observations of a Binary Neutron Star Merger

International audienceOn 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of $\sim 1.7\,{\rm{s}}$ with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg(2) at a luminosity distance of ${40}_{-8}^{+8}$ Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 $\,{M}_{\odot }$. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at $\sim 40\,{\rm{Mpc}}$) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position $\sim 9$ and $\sim 16$ days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta