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Automated Feature - Based Registration for Reverse Engineering of Human Models
Yongtae Jun,Kuiwon Choi 대한기계학회 2005 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.19 No.12
In order to reconstruct a full 3D human model in reverse engineering (RE), a 3D scanner needs to be placed arbitrarily around the target model to capture all part of the scanned surface. Then, acquired multiple scans must be registered and merged since each scanned data set taken from different position is just given in its own local co-ordinate system. The goal of the registration is to create a single model by aligning all individual scans. It usually consists of two sub-steps : rough and fine registration. The fine registration process can only be performed after an initial position is approximated through the rough registration. Hence an automated rough registration process is crucial to realize a completely automatic RE system. In this paper an automated rough registration method for aligning multiple scans of complex human face is presented. The proposed method automatically aligns the meshes of different scans with the information of features that are extracted from the estimated principal curvatures of triangular meshes of the human face. Then the roughly aligned scanned data sets are further precisely enhanced with a fine registration step with the recently popular Iterative Closest Point (ICP) algorithm. Some typical examples are presented and discussed to validate the proposed system.
Dynamic Mechanical Behavior of Ultra-High Molecular Weight Polyethylene Irradiated with Gamma Rays
Lee, Choon-Soo,Jho, Jae-Young,Park, Kuiwon,Hwang, Tae-Won The Polymer Society of Korea 2004 Macromolecular Research Vol.12 No.1
We have investigated the dynamic mechanical behavior of ultra-high molecular weight polyethylene (UHMWPE) irradiated with varying doses of gamma rays. A relaxation peak in the loss factor curve, which has not been reported previously in the literature, is observed at a temperature above the crystal melting temperature. The peak is unique to UHMWPE and appears to be related to the high degree of entanglement. Because the temperature and intensity of the peak are reduced by irradiation-induced chain scission and crosslinking, respectively, we believe that the peak is associated with disentanglement relaxation. The behavior of the storage modulus in the melt state agrees with the classical theory of rubber elasticity.
Osteogenic Potential of the Periosteum and Periosteal Augmentation for Bone-tunnel Healing
Youn Inchan,Suh J-K Francis,Choi Kuiwon The Korean Society of Medical and Biological Engin 2005 의공학회지 Vol.26 No.2
Periosteum and periosteum-derived progenitor cells have demonstrated the potential for stimulative applications in repairs of various musculoskeletal tissues. It has been found that the periosteum contains mesenchymal progenitor cells capable of differentiating into either osteoblasts or chondrocytes depending on the culture conditions. Anatomically, the periosteum is a heterogeneous multi-layered membrane, consisting of an inner cambium and an outer fibrous layer. The present study was designed to elucidate the cellular phenotypic characteristics of cambium and fibrous layer cells in vitro, and to assess whether structural integrity of the tendon in the bone tunnel can be improved by periosteal augmentation of the tendonbone interface. It was found the cells from each layer showed distinct phenotypic characteristics in a primary monolayer culture system. Specifically, the cambium cells demonstrated higher osteogenic characteristics (higher alkaline phosphatase and osteocalcin levels), as compared to the fibrous cells. Also in vivo animal model showed that a periosteal augmentation of a tendon graft could enhance the structural integrity of the tendon-bone interface, when the periosteum is placed between the tendon and bone interface with the cambium layer facing toward the bone. These findings suggest that extra care needs to be taken in order to identify and maintain the intrinsic phenotypes of the heterogeneous cell types within the periosteum. This will improve our understanding of periosteum in applications for musculoskeletal tissue repairs and tissue engineering.
Tumor-Targeting Multifunctional Nanoparticles for siRNA Delivery: Recent Advances in Cancer Therapy
Ku, Sook Hee,Kim, Kwangmeyung,Choi, Kuiwon,Kim, Sun Hwa,Kwon, Ick Chan Wiley (John WileySons) 2014 Advanced Healthcare Materials Vol.3 No.8
<P>RNA interference (RNAi) is a naturally occurring regulatory process that controls posttranscriptional gene expression. Small interfering RNA (siRNA), a common form of RNAi-based therapeutics, offers new opportunities for cancer therapy via silencing specific genes, which are associated to cancer progress. However, clinical applications of RNAi-based therapy are still limited due to the easy degradation of siRNA during body circulation and the difficulty in the delivery of siRNA to desired tissues and cells. Thus, there have been many efforts to develop efficient siRNA delivery systems, which protect siRNA from serum nucleases and deliver siRNA to the intracellular region of target cells. Here, the recent advances in siRNA nanocarriers, which possess tumor-targeting ability are reviewed; various nanoparticle systems and their antitumor effects are summarized. The development of multifunctional nanocarriers for theranostics or combinatorial therapy is also discussed.</P>
Activatable imaging probes with amplified fluorescent signals
Lee, Seulki,Park, Kyeongsoon,Kim, Kwangmeyung,Choi, Kuiwon,Kwon, Ick Chan Royal Society of Chemistry 2008 Chemical communications Vol.2008 No.36
<P>Current optical imaging probe applications are hampered by poor sensitivity and specificity to the target, but molecular-level fluorescent signal activation strategies can efficiently overcome these limitations. Recent interdisciplinary research that couples the imaging sciences to fluorophore, peptide, polymer, and inorganic-based chemistry has generated novel imaging probes that exhibit high sensitivity and low background noise in both <I>in vitro</I> and <I>in vivo</I> applications. This feature article introduces and discusses the various approaches described by the term “fluorescent signal activation methods” with respect to their unique imaging probe design strategies and applications.</P> <P>Graphic Abstract</P><P>This feature article introduces and discusses the various approaches described by the term “fluorescent signal activation methods” with respect to their unique imaging probe design strategies and applications. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b806854m'> </P>