GJ 367b: A dense, ultrashort-period sub-Earth planet transiting a nearby red dwarf star

[Figure: see text].

Hydride spectroscopy of the diffuse interstellar medium: new clues on the gas fraction in molecular form and cosmic ray ionization rate in relation to H3+

The Herschel-guaranteed time key programme PRobing InterStellar Molecules with Absorption line Studies (PRISMAS)(1) is providing a survey of the interstellar hydrides containing the elements C, O, N, F and Cl. As the building blocks of interstellar molecules, hydrides provide key information on their formation pathways. They can also be used as tracers of important physical and chemical properties of the interstellar gas that are difficult to measure otherwise. This paper presents an analysis of two sight-lines investigated by the PRISMAS project, towards the star-forming regions W49N and W51. By combining the information extracted from the detected spectral lines, we present an analysis of the physical properties of the diffuse interstellar gas, including the electron abundance, the fraction of gas in molecular form, and constraints on the cosmic ray ionization rate and the gas density.

Critical role of Qa1b in the protection of mature dendritic cells from NK cell-mediated killing

Molecular interactions in natural killer (NK) cell-mediated killing of dendritic cells (DC) have under recent years come under scrutiny. Upon stimulation with IFN-gamma or lipopolysaccharide, DC become relatively resistant to NK cell-mediated lysis. In the present study, we investigated the role of Qa1(b) on DC and its receptor NKG2A on NK cells in the protection of mature DC from NK cells. We demonstrate that while both NKG2A+ and NKG2A- NK cells can efficiently lyse unstimulated DC, NKG2A+ NK cells but not NKG2A- NK cells are largely impaired in their ability to lyse mature DC. Similarly, mature DC from mice expressing H-2D(b), whose leader peptide sequence binds and stabilizes Qa1(b), were resistant to NK cell-mediated killing, suggesting that stable Qa1(b) expression contributes to the protection of mature DC. This finding was further validated by the demonstration that addition of the Qdm leader peptide could protect TAP1-/- DC from NK cell-mediated lysis both in vitro and in vivo. The present data suggest that stable expression of Qa1 on the surface of mature DC contributes to the protection of DC from NK cell-mediated lysis.