The conversion of ornithine to citrulline requires ornithine carbamoyl transferase (OCT; EC 2.1.3.3), but apart from normal hepatocytes and a few minimal deviation hepatomas, most cultured cells cannot perform this transfer (Sugimura et al, 1992), and therefore ornithine rarely substitutes for arginine in culture (Eagle, 1955).
One critical piece of advice is rarely mentioned: substituting one hormone product for another is not the answer, since there is now no way to know whether any hormone product is safer than Prempro.
Under crowded conditions, changes between noise targets and Gabors (target change; blue points in Figure 2A) were rarely detected when the substituted Gabor matched the flanker orientation (with performance approaching the false alarm rate).
However, these techniques are now rarely used and have been substituted by medical hormonal treatment.
In Part I, the panel felt that bowling, golf and racket sports are done rarely in the DR and substituted instead fishing (for bowling), baseball or swimming (for golf), and basketball (for racket sports).
While the entire practice relies on fantasy and semiotics, it is rarely a substitute for real-life interpersonal relationships....virtual environments are perfect for a person who is experimenting with sexual experiences and identity.
Like Actual Sunlight, where despite his frustration, his determination, and his introspection Evan never accomplishes much, in Little Red Lie, characters' thoughts and feelings are rarely a substitute for power, money, or employability.
Generic substitution was rarely done; in South Africa for instance, only 14% of pharmacists substituted branded drugs, despite the fact that nearly half of prescribed medicines had generic equivalents [ 41].
If they were authentic, they would represent heteroplasmic mixtures of deleted and substituted variants that have so far only rarely been observed in non-human mtDNA outside homopolymeric C tracts [28].
