Investigation of an NEA Diamond Vacuum Microtriode Array

Abstract

The properties and characteristics of vacuum microtriodes based on NEA diamond surfaces were modelled. Specifically, an NEA diamond vacuum microtriode array was investigated using electrical measurements, electron optics software, and microwave circuit simulation. Data for emission current versus applied voltage for various anode-to-cathode distances for diamond NEA surfaces was analyzed and various parameters were extracted. Electron optics software was used to determine Fowler-Nordheim and space-charge-limited DC I-V characteristics for each microtriode. Microwave circuit simulation was done to determine the behavior of arrays of these vacuum microtriodes in an RF amplifier circuit.

The length and the secondary structure of the D-stem of human selenocysteine tRNA are the major identity determinants for serine phosphorylation.

“…Using pure tRNA(ser)sec and tRNAser transcribed in vitro by T7 RNA polymerase, we first confirmed earlier reports that seryl-tRNA(ser)sec is phosphorylated, but seryl-tRNAser is not (Maenpaa and Bemfield, 1970;Sharp and Stewart, 1977;Hatfield et al, 1982;Lee et al, 1989b). This observation (Figure 2) clearly indicates that identity elements for the specific and exclusive phosphorylation of seryl-tRNA(ser)sec must be present in the tRNA(ser)sec domain.…”

“…Table II, row h). These results are consistent with earlier reports that only seryl-tRNA(ser)sec is phosphorylated and tRNAser is not (Maenpaa and Bernfield, 1970;Sharp and Stewart, 1977;Hatfield et al, 1982;Lee et al, 1989b). The fact that seryl-tRNA(Ser)sec is phosphorylated, but seryl-tRNAser is not, indicates that identity elements for phosphorylation must be located in regions specific for tRNA(Ser)sec.…”

“…This seryl-tRNA is further converted into selenocysteyl-tRNA(ser)sec in the presence of selenocysteine synthase and other proteins (Leinfelder et al, 1990;Forchhammer et al, 1991;Mizutani et al, 1991). In contrast to E. coli seryl-tRNA(ser)sec and all seryl-tRNAs r, the serine moiety of mammalian seryl-tRNA(ser)sec has been shown to be phosphorylated to form phosphoseryl-tRNA(ser)sec (Maenpaa and Bernfield, 1970;Sharp and Stewart, 1977;Hatfield et al, 1982;Lee et al, 1989b). The kinase has been purified from bovine liver .…”

“…Therefore, the function of phosphoseryl-tRNA(ser)sec remains unknown. tRNAs(ser)sec from E. coli (Schon et al, 1989), bovine liver (Diamond et al, 1981;Hatfield et al, 1982), HeLa and mouse cells (Kato et al, 1983) have been characterized. tRNA(ser)sec genes have also been isolated from E. coli (Leinfelder et al, 1988), Proteus vulgaris (Heider et al, 1989) and a number of animals (O'Neill et al, 1985;Lee et al, 1990).…”

“…tRNA(ser)sec genes have also been isolated from E. coli (Leinfelder et al, 1988), Proteus vulgaris (Heider et al, 1989) and a number of animals (O'Neill et al, 1985;Lee et al, 1990). Three models for the secondary structure of vertebrate tRNA(ser)sec have been suggested (Diamond et al, 1981;Hatfield et al, 1982;Bock et al, 1991). One is favoured by the data from structure probing and computer modelling (Sturchler et al, 1993).…”