One of the isoamylase isoforms, CMI294C, is required for semi-amylopectin synthesis in the rhodophyte Cyanidioschyzon merolae.

Most rhodophytes synthesize semi-amylopectin as a storage polysaccharide, whereas some species in the most primitive class (Cyanidiophyceae) make glycogen. To know the roles of isoamylases in semi-amylopectin synthesis, we investigated the effects of isoamylase gene (CMI294C and CMS197C)-deficiencies on semi-amylopectin molecular structure and starch granule morphology in Cyanidioschyzon merolae (Cyanidiophyceae). Semi-amylopectin content in a CMS197C-disruption mutant (ΔCMS197C) was not significantly different from that in the control strain, while that in a CMI294C-disruption mutant (ΔCMI294C) was much lower than those in the control strain, suggesting that CMI294C is essential for semi-amylopectin synthesis. Scanning electron microscopy showed that the ΔCMI294C strain contained smaller starch granules, while the ΔCMS197C strain had normal size, but donut-shaped granules, unlike those of the control strain. Although the chain length distribution of starch from the control strain displayed a semi-amylopectin pattern with a peak around degree of polymerization (DP) 11-13, differences in chain length profiles revealed that the ΔCMS197C strain has more short chains (DP of 3 and 4) than the control strain, while the ΔCMI294C strain has more long chains (DP ≥12). These findings suggest that CMI294C-type isoamylase, which can debranch a wide range of chains, probably plays an important role in semi-amylopectin synthesis unique in the Rhodophyta.

Iridium(III)-Catalyzed Asymmetric Site-Selective Carbene C-H Insertion during Late-Stage Transformation.

C-H functionalization has recently received considerable attention because C-H functionalization during the late-stage transformation is a strong and useful tool for the modification of the bioactive compounds and the creation of new active molecules. Although a carbene transfer reaction can directly convert a C-H bond to the desired C-C bond in a stereoselective manner, its application in late-stage material transformation is limited. Here, we observed that the iridium-salen complex 6 exhibited efficient catalysis in asymmetric carbene C-H insertion reactions. Under optimized conditions, benzylic, allylic, and propargylic C-H bonds were converted to desired C-C bonds in an excellent stereoselective manner. Excellent regioselectivity was demonstrated in the reaction using not only simple substrate but also natural products, bearing multiple reaction sites. Moreover, based on the mechanistic studies, the iridium-catalyzed unique C-H insertion reaction involved rate-determining asynchronous concerted processes.

Biological-data-based finite-element stress analysis of mandibular bone with implant-supported overdenture.

BACKGROUND: This study aimed to evaluate the stress distribution in a mandibular bone with an implant-supported overdenture by a biological-data-based finite element analysis (FEA) utilizing personal CT images and in vivo loading data, and to evaluate the influence of the number and alignment of implants and bone conditions on the stress in peri-implant bone. METHODS: FEA models of a mandible were constructed for two types of overdentures: 4 implants supported overdenture (4-OD) and 2 implants supported overdenture (2-OD). The geometry of these models was constructed from CT images of a subject, who wore an implant-supported overdenture. The magnitude and direction of the loads on the implants for two types of overdentures during the maximal voluntary clenching were measured with 3D force transducers. FEA using these loads was carried out to observe stress distributions in peri-implant bone. RESULTS: Higher stress was observed in cortical bone around the implant neck. Stress in peri-implant bone for 4-OD was reduced in comparison with those for the 2-OD. For the 4-OD, notwithstanding such reduction of the stress, the stress concentrated at the cortical bone around the implant aligned with large deviation from load direction. CONCLUSIONS: In this study, biological data from a certain subject was successfully duplicated to the FEA models. The results demonstrate the mechanical prominence of using more implants. Even in 4 implants model, high stress was found around an implant with a large inclination and with thin cortical bone. This suffices to demonstrate the capability and usefulness of the biological-data-based FEA.

Stress distribution in the peri-implant bone with splinted and non-splinted implants by in vivo loading data-based finite element analysis.

The aim of this study was to evaluate stress distribution in peri-implant bone and to investigate the influence of splinting implants by finite element analysis (FEA) with in vivo loading data. The magnitude and direction of the force exerted on implants during maximal voluntary clenching of a subject were recorded with 3-D piezoelectric force transducers. FEA using in vivo loading data was conducted on splinted and non-splinted models with two implants. Overall, the splinted model reduced stress in peri-implant bone in comparison with the non-splinted model.

Bifurcations to diversify geometrical patterns of shear bands on granular material.

The mechanism to diversify geometrical patterns on granular material was elucidated using a group-theoretic image analysis of patterned shear bands, with associated numerical bifurcation analysis. Pattern formation of granular materials took the course of the evolution of a diamondlike diffuse bifurcation breaking uniformity, followed by further bifurcation, mode jumping, and the formation and disappearance of shear bands through localization. A chaotic explosive increase of possible postbifurcation states was emphasized as a mechanism to diversify geometrical patterns.