In our previous paper, we synthesized poly-3-hydroxybutyrate [P(3HB)] by using the waterorganic-solvent two-phase reaction system (TPRS), in which (R)-3-hydroxybutyrylCoA [(R)-3HBCoA] was continuously supplied to PHA synthase by the ester exchange reaction between CoA and thiophenol in thiophenyl (R)-3HB [(R)-3HBTP]. By applying TPRS to the screening, we found a lactate-(LA-) polymerizing enzyme from PHA synthases. The enzyme was an engineered PHA synthase, which stereoselectively copolymerized (R)-LA together with (R)-3HB. NMR and GPC revealed that the TPRS successfully synthesized poly(lactate-co-(3-hydroxybutyrate)) [P(LA-co-3HB)] using the LA-polymerizing enzyme as a catalyst. The molar ratios of LA in the copolymers were controllable in the range of 0 to 36 mol% by varying the ratio of (R)-LATP and (R)-3HBTP fed into the TPRS. The number-average molecular weight and the polydispersity of P(36 mol%-co-3HB) were 1.1 × 10 4 and 1.4, respectively. This is the first report on the chemo-enzymatic synthesis of P(LA-co-3HB) by a LA-polymerizing enzyme.

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Brasilicardins, bacterial diterpenoid natural products that display highly potent immunosuppressive activity, are promising immunosuppressant drug candidates. Structurally, they can be described as hybrids of terpenoids, amino acids, and saccharides, and share a characteristic highly strained anti‐syn‐anti‐fused perhydrophenanthrene terpenoid scaffold (ABC‐ring system) with two quaternary asymmetric carbon atoms. A unified and stereoselective total synthesis of all four brasilicardins has been designed based on the strategic use of an intramolecular conjugate addition. The ABC‐ring system was initially constructed with high stereocontrol by novel intramolecular conjugate additions of Weinreb amides and in situ generated (Z)‐vinyl copper species. The late‐stage common intermediate was subjected to stereoselective installation of the amino acid component, followed by introduction of the saccharide unit via glycosylation to accomplish the total synthesis of brasilicardins A–D. Our synthesis offers opportunities to synthesize various brasilicardin analogues for biological and pharmacological investigations.

In recent years, properties of high temperature superconducting (HTS) tapes, especially in-field performance and mechanical strength, have been continuously improved. The HTS tapes have been widely used for high field (>20 T) magnet researches and there are several technical challenges including field attenuation of an HTS magnet by screening currents induced within the HTS tapes. Several publications reported that the screening currents, induced by penetration of self magnetic fields into 2 HTS tapes within an HTS magnet, weakened a field constant of the HTS magnet. The result may demonstrate that the screening current changes an overall current density distribution in HTS tapes and, as a consequence, the generated magnetic field. Therefore, it is necessary to investigate the screening current distribution in an HTS tape. This paper reports numerical simulation of the screening current distribution in an HTS tape of high field magnets using 2D finite element method with the E-J characteristic of the HTS tape taken into account. Self magnetic field distribution and its orientation to the HTS tape are also considered to compute critical currents and locally generated electric fields, two key components to figure out the distribution of screening currents.

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