Olivomycin and related antibiotics XXVIII. Monomeric composition of aureolic acid and proof that the antibiotics LA-7017 and mithramycin are identical to it
Summary1. It has been shown that aureolic acid, antibiotic LA-7017, and mithramycin are identical.2. It has been established that aureolic acid is a glycoside of chromomycinone (I) and contains the monosaccharides D-olivose (II), D-oliose (III), and D-mycarose (IV) in a ratio of 3 : 1 : 1.
Aureolic Acid Group of Anti-tumour Antibiotics
SINCE 1953 several antibiotics of similar biological and physico-chemical properties have been described. These are aureolic acid1, aburamycin2, LA-7017 (ref. 3), M5-18903 (ref. 4), chromomycin5, antibiotic 2410 (ref. 6), NSC A-649 (ref. 7), olivomycin8, mithramycin9 and antibiotics 232, 3014, 7193, 11296 (ref. 10) and SK-229 (ref. 11). Two members of this group, olivomycin and chromomycin, were subjected to extensive chemical research which resulted in the isolation and structural elucidation of their components, olivomycins A, B, C, D (ref. 12) and chromomycins A2, A3, A4 (ref. 13). The other members of the group, however, have been only scantily investigated.
Techno-economic analysis of solar thermal power plants using liquid sodium as heat transfer fluid
Abstract Solar thermal power plants with central receiver and thermal storage are expected to be one key technology in future electricity generation, because they are renewable and due to the thermal storage independent of the current solar radiation. State-of-the-art solar power plants often use molten nitrate salts as heat transfer fluid. The use of liquid sodium instead leads to lower electricity generation costs. Sodium has a high thermal conductivity and thus large heat transfer rates are possible. Hence, a smaller absorber surface is sufficient for the same thermal power. As a result, the sodium receiver achieves a higher efficiency at lower investment cost. Additionally, the aiming strategy, which reduces the peak heat flux on molten salt receivers isn’t necessary for sodium. Even at high heat flux densities, the absorber tubes will be cooled sufficiently due to the high heat transfer coefficients. Therefore, the sodium receiver in this analysis is designed for one single aim point, resulting in a heat flux density of q mean = 1.06 MW / m 2 and q peak = 2.99 MW / m 2 . The state-of-the-art system with molten salt considers q mean = 0.51 MW / m 2 and q peak = 1.0 MW / m 2 . The presented techno-economic analysis of two sodium based concepts compared to a reference system with molten salt results in up to 16% lower electricity generation costs.