Unique structural topology and reactivities of the ABD tricycle in phomactin A

2005 ◽  
pp. 5784 ◽  
Author(s):  
Kevin P. Cole ◽  
Richard P. Hsung
Keyword(s):  
Structural Topology ◽  
Phomactin A

scholarly journals Total Synthesis of (±)-Phomactin A. Lessons Learned from Respecting a Challenging Structural Topology

2011 ◽  
Vol 76 (17) ◽  
pp. 7027-7039 ◽  
Author(s):  
Grant S. Buchanan ◽  
Kevin P. Cole ◽  
Yu Tang ◽  
Richard P. Hsung
Keyword(s):  
Total Synthesis ◽  
Lessons Learned ◽  
Structural Topology ◽  
Phomactin A

Unique Structural Topology and Reactivities of the ABD Tricycle in Phomactin A.

ChemInform ◽  
2006 ◽  
Vol 37 (16) ◽  
Author(s):  
Kevin P. Cole ◽  
Richard P. Hsung
Keyword(s):  
Structural Topology ◽  
Phomactin A

scholarly journals The Effect of Void Arrangement on the Pattern Transformation of Porous Soft Solids under Biaxial Loading

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1205
Author(s):  
Hai Qiu ◽  
Ying Li ◽  
Tianfu Guo ◽  
Shan Tang ◽  
Zhaoqian Xie ◽  
...  
Keyword(s):  
Biaxial Loading ◽  
Tensile Deformation ◽  
Biaxial Stress ◽  
Porous Solids ◽  
Biaxial Compression ◽  
Structural Topology ◽  
Soft Solids ◽  
Tension And Compression ◽  
Inclined Angle ◽  
Pattern Transformation

Structural topology and loading condition have important influences on the mechanical behaviors of porous soft solids. The porous solids are usually set to be under uniaxial tension or compression. Only a few studies have considered the biaxial loads, especially the combined loads of tension and compression. In this study, porous soft solids with oblique and square lattices of circular voids under biaxial loadings were studied through integrated experiments and numerical simulations. For the soft solids with oblique lattices of circular voids, we found a new pattern transformation under biaxial compression, which has alternating elliptic voids with an inclined angle. This kind of pattern transformation is rarely reported under uniaxial compression. Introducing tensile deformation in one direction can hamper this kind of pattern transformation under biaxial loading. For the soft solids with square lattices of voids, the number of voids cannot change their deformation behaviors qualitatively, but quantitatively. In general, our present results demonstrate that void morphology and biaxial loading can be harnessed to tune the pattern transformations of porous soft solids under large deformation. This discovery offers a new avenue for designing the void morphology of soft solids for controlling their deformation patterns under a specific biaxial stress-state.

scholarly journals Cryo-EM structure of mycobacterial cytochrome bd reveals two oxygen access channels

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Weiwei Wang ◽  
Yan Gao ◽  
Yanting Tang ◽  
Xiaoting Zhou ◽  
Yuezheng Lai ◽  
...  
Keyword(s):  
Rational Design ◽  
Pathogenic Bacteria ◽  
Structural Topology ◽  
Antimicrobial Drugs ◽  
E Coli ◽  
Cytochrome Bd ◽  
Cryo Electron Microscopy ◽  
Functional Mechanisms ◽  
The Relationship ◽  
Potential Oxygen

AbstractCytochromes bd are ubiquitous amongst prokaryotes including many human-pathogenic bacteria. Such complexes are targets for the development of antimicrobial drugs. However, an understanding of the relationship between the structure and functional mechanisms of these oxidases is incomplete. Here, we have determined the 2.8 Å structure of Mycobacterium smegmatis cytochrome bd by single-particle cryo-electron microscopy. This bd oxidase consists of two subunits CydA and CydB, that adopt a pseudo two-fold symmetrical arrangement. The structural topology of its Q-loop domain, whose function is to bind the substrate, quinol, is significantly different compared to the C-terminal region reported for cytochromes bd from Geobacillus thermodenitrificans (G. th) and Escherichia coli (E. coli). In addition, we have identified two potential oxygen access channels in the structure and shown that similar tunnels also exist in G. th and E. coli cytochromes bd. This study provides insights to develop a framework for the rational design of antituberculosis compounds that block the oxygen access channels of this oxidase.

Structural Topology Optimization Using Frame Elements Based on the Complementary Strain Energy Concept for Eigen-Frequency Maximization

2005 ◽  
Author(s):  
Akihiro Takezawa ◽  
Shinji Nishiwaki ◽  
Kazuhiro Izui ◽  
Masataka Yoshimura
Keyword(s):  
Topology Optimization ◽  
Cross Sections ◽  
Strain Energy ◽  
Optimization Procedure ◽  
Optimization Method ◽  
Structural Topology ◽  
Energy Concept ◽  
Conceptual Design Phase ◽  
Complementary Strain ◽  
Topology Optimization Method

This paper discuses a new topology optimization method using frame elements for the design of mechanical structures at the conceptual design phase. The optimal configurations are determined by maximizing multiple eigen-frequencies in order to obtain the most stable structures for dynamic problems. The optimization problem is formulated using frame elements having ellipsoidal cross-sections, as the simplest case. Construction of the optimization procedure is based on CONLIN and the complementary strain energy concept. Finally, several examples are presented to confirm that the proposed method is useful for the topology optimization method discussed here.

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