Investigation of the Effects of Electron Translational Nonequilibrium on Numerical Predictions of Hypersonic Flow Fields

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90681/1/AIAA-2011-3136-683.pd

Meteorin regulates mesendoderm development by enhancing nodal expression

During gastrulation, distinct lineage specification into three germ layers, the mesoderm, endoderm and ectoderm, occurs through an elaborate harmony between signaling molecules along the embryonic proximo-distal and anterior-posterior axes, and Nodal signaling plays a key role in the early embryonic development governing embryonic axis formation, mesoderm and endoderm specification, and left-right asymmetry determination. However, the mechanism by which Nodal expression is regulated is largely unknown. Here, we show that Meteorin regulates Nodal expression and is required for mesendoderm development. It is highly expressed in the inner cell mass of blastocysts and further in the epiblast and extra-embryonic ectoderm during gastrulation. Genetic ablation of the Meteorin gene resulted in early embryonic lethality, presumably due to impaired lineage allocation and subsequent cell accumulation. Embryoid body culture using Meteorin-null embryonic stem (ES) cells showed reduced Nodal expression and concomitant impairment of mesendoderm specification. Meteorin-null embryos displayed reduced levels of Nodal transcripts before the gastrulation stage, and impaired expression of Goosecoid, a definitive endoderm marker, during gastrulation, while the proximo-distal and anterior-posterior axes and primitive streak formation were preserved. Our results show that Meteorin is a novel regulator of Nodal transcription and is required to maintain sufficient Nodal levels for endoderm formation, thereby providing new insights in the regulation of mesendoderm allocation.open1113sciescopu

Impact of dielectric separation on transition point and accessible flow enthalpy of inductive plasmas

In order to develop inductive electric propulsion systems towards flight-ready status, an investigation into the influence of the dielectric separation between plasma and inductive coil has been conducted. This was completed by varying the wall thickness of the thruster discharge tube. The investigation assessed discharges of argon and an argon-nitrogen mixture. Additionally, results of a similar investigation utilising air have been included for comparison. The sum of these investigations showed two contrasting trends. The argon condition exhibited a preference for thicker walls, with transitions to the higher inductive regime occurring at lower input powers with increasing wall thickness. Results for Ar:N2 and air showed the opposite, with system thermal power increasing with decreasing wall thicknesses. This behaviour has been proposed to include contributions of both the mechanical dielectric separation caused by the choice of chamber wall thickness, and the gasdynamic dielectric separation owing to the discharge thermal boundary laye