Growth and characterization of Si-based light-emitting diode with beta-FeSi2-particles/Si multilayered active region by molecular beam epitaxy

We fabricated single-, double- and triple-layered beta-FeSi2-particles structure on Si(001) substrates by reactive deposition epitaxy (RDE) for beta-FeSi2 and by molecular beam epitaxy (MBE) for Si, and realized electroluminescerice (EL) at 310K. Photoluminescence (PL) measurements revealed that the 77K PL intensity of beta-FeSi2 increased almost proportionally with the number of beta-FeSi2-particles/Si layers. It was also found that the multilayered structure enhanced the EL intensity of beta-FeSi2 particularly at low temperatures

The N-Terminus of GalE Induces tmRNA Activity in Escherichia coli

BACKGROUND: The tmRNA quality control system recognizes stalled translation complexes and facilitates ribosome recycling in a process termed 'ribosome rescue'. During ribosome rescue, nascent chains are tagged with the tmRNA-encoded SsrA peptide, which targets tagged proteins for degradation. In Escherichia coli, tmRNA rescues ribosomes arrested on truncated messages, as well as ribosomes that are paused during elongation and termination. METHODOLOGY/PRINCIPAL FINDINGS: Here, we describe a new translational pausing determinant that leads to SsrA peptide tagging of the E. coli GalE protein (UDP-galactose 4-epimerase). GalE chains are tagged at more than 150 sites, primarily within distinct clusters throughout the C-terminal domain. These tagging sites do not correspond to rare codon clusters and synonymous recoding of the galE gene had little effect on tagging. Moreover, tagging was largely unaffected by perturbations that either stabilize or destabilize the galE transcript. Examination of GalE-thioredoxin (TrxA) fusion proteins showed that the GalE C-terminal domain is no longer tagged when fused to an N-terminal TrxA domain. Conversely, the N-terminus of GalE induced tagging within the fused C-terminal TrxA domain. CONCLUSIONS/SIGNIFICANCE: These findings suggest that translation of the GalE N-terminus induces subsequent tagging of the C-terminal domain. We propose that co-translational maturation of the GalE N-terminal domain influences ribosome pausing and subsequent tmRNA activity