Design Synthesis of Adaptive Mesoscopic Cellular Structures with Unit Truss Approach and Particle Swarm Optimization Algorithm

Cellular material structures have been engineered at the mesoscopic scale for high performance and multifunctional capabilities. However, the design of adaptive cellular structures - structures with cellular configurations, sizes, and shapes designed for a specific geometric and loading context - has not been sufficiently investigated. In this paper, the authors present a design synthesis method with the use of unit truss approach and particle swarm optimization algorithm to design adaptive cellular structures. A critical review is presented to show the pros and cons of the new design synthesis method and an existing homogenization method. The research extends the application of additive manufacturing in the design of new materials for high performances and benefits its long-term growth.Mechanical Engineerin

Blastocyst quality and reproductive and perinatal outcomes : a multinational multicentre observational study

Funding H.Z. is supported by a Monash Research Scholarship. B.W.J.M. is supported by an NHMRC Investigator grant (GNT1176437). R.W. is supported by an NHMRC Emerging Leadership Investigator grant (2009767).Peer reviewedPublisher PD

A Unit Cell Approach for Lightweight Structure and Compliant Mechanism

Cellular structures are present from the atomic level all the way up to patterns found in human skeleton. They are prevailing structures in the nature and known for their excellent mechanical, thermal, and acoustic properties. Two typical types of cellular structures, lightweight structures and compliant mechanisms, are investigated. Lightweight structures are rigid and designed to reduce weight, while increasing strength and stiffness. Compliant mechanisms are designed to transform motions and forces. Most available artificial lightweight structures are patterns of primitives. However, the performance of lightweight structures can be enhanced by using adaptive cellular structures with conformal strut orientations and sizes, like the trabeculae in femoral bone. Bending, torsion, and nonlinear behaviors of compliant mechanisms have not been sufficiently studied. In order to design adaptive cellular structures, a new unit cell, the unit truss is proposed. The unit truss approach facilitates the design of adaptive cellular structures for enhanced mechanical properties via geometric modeling, finite element analysis, shape optimization, and additive fabrication. Four research questions, which address representation, structural analysis, design synthesis, and manufacturing respectively, are raised and answered. Unit truss enables representation and mechanics analysis for adaptive cellular structures. A synthesis method using engineering optimization algorithms is developed to systematically design adaptive cellular structure. Two examples, graded cellular structure for prosthesis and compliant mechanism for morphing wings, are studied to test the unit truss approach.Ph.D.Committee Chair: Rosen, David; Committee Member: Ebert-Uphoff, Imme; Committee Member: Garmestani, Hamid; Committee Member: McDowell, David; Committee Member: Mistree, Farrokh; Committee Member: Rossignac, Jare

Computer-aided design methods for the additive fabrication of truss structure

M.S.David W. Rose

Design Synthesis of Mesoscopic Cellular Structures With Unit Truss Approach and Particle Swarm Optimization Algorithm

This paper was presented at the Proceedings of the The Seventeenth Solid Freeform Fabrication Symposium, Austin, TX, August 14-16, 2006.Cellular material structures have been engineered at the mesoscopic scale for high performance and multifunctional capabilities. However, the design of adaptive cellular structures - structures with cellular configurations, sizes, and shapes designed for a specific geometric and loading context - has not been sufficiently investigated. In this paper, the authors present a design synthesis method with the use of unit truss approach and particle swarm optimization algorithm to design adaptive cellular structures. A critical review is presented to show the pros and cons of the new design synthesis method and an existing homogenization method. The research extends the application of additive manufacturing in the design of new materials for high performances and benefits its long-term growth

Design of a Graded Cellular Structure For an Acetabular Hip Replacement Component

This paper was presented at the Proceedings of the The Seventeenth Solid Freeform Fabrication Symposium Austin, TX, August 14-16, 2006.The state-of-the-art porous coatings become more and more popular in uncemented prostheses to make bone grow into implants for biological fixation. In this paper, graded cellular structures are proposed for uncemented prostheses to enhance stability on implant-bone interfaces. As an example study, the authors develop a new acetabular implant with gradient porosity for hip replacement. A gradient porous acetabular component with cellular structure could match the bone’s elasticity. Material is adaptively distributed from high porosity at the bone-implant interface to solid metal at the joint’s articulating surface. The new acetabular prosthesis would replace metal-on-polyethylene bearing with metal-on-metal bearing for less wear. The design problem of acetabular component is formulated and a requirement list is elaborated. A detailed design of the prosthesis with a graded cellular structure is presented. The design concept is validated with a comparison to the existing products according to the design requirements.National Science Foundation (Grants #DMI-0522382; DMI-0522382)

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field