Browsing by Author "Chen, KT"

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An aberrant autocrine activation of the platelet-derived growth factor alpha-receptor in follicular and papillary thyroid carcinoma cell lines
(2006-01-18)
Chen, KT
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Lin, JD
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Liou, MJ
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Weng, HF
;
Chang, CA
Platelet-derived growth factor receptor (PDGFR) can bind to its ligand and consequently possess a kinase activity, and which is associated with the carcinogenesis of different cell types, including astrocytomas, oligodendrogliomas. and glioblastoma. In a cDNA microarray analysis, we observe the over-expressed mRNA of both PDGF-A and PDGF-alpha receptor in thyroid carcinoma cells. And the elevated protein expressions of PDGF-A and PDGF-alpha receptor in thyroid carcinoma cells were also confirmed by a Western blot analysis. The phosphorylation of PDGF-alpha receptor evaluated by an antibody against Tyr 720-phosphate was found in thyroid carcinoma cells. The tyrosine kinase activity of PDGF-alpha receptor was inhibited by tyrphostin AG1295 and showed a dose-dependent inhibition for the proliferation of thyroid carcinoma cells. These findings imply that autocrine activation of PDGF-alpha receptor plays a crucial role in the carcinogenesis of thyroid cells. (c) 2005 Elsevier Ireland Ltd. All rights reserved.
An object based authoring tool for creating SCORM compliant course
(2005)
Su, JM
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Tseng, SS
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Weng, JF
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Chen, KT
;
Liu, YL
In recent years, how to reuse and share the teaching materials and instructional experiences among e-learning systems become more and more important. Sharable Content Object Reference Model (SCORM), the most popular international teaching materials standard, uses the metadata to specify the structure of every teaming object and proposes the content aggregation scheme to package these objects with XML language format. In 2004, the Sequencing and Navigation (SN) in SCORM 2004 also define the sequencing rules which can be used to control the sequencing, selecting and delivering of teaming activity for the desired, sequencing behavior. Learning contents in SN is organized into a hierarchical structure, namely Activity Tree (AT). However, for teachers/instructional designers, it is hard to understand the complicated sequencing rules in SN much less using it to construct a SCORM course with desired teaming guidance. Therefore, how to provide a user-friendly authoring tool to efficiently construct SCORM compliant course becomes an important issue. Therefore, in this paper, based upon the concept of Object Oriented Methodology (OOM), the complicated sequencing rules can be modularized into several basic components with corresponding sequencing rules in SN, called Sequencing Object (SO). Each SO is like a middleware, which represents a basic sequencing building block as a cluster in activity tree (AT) with some corresponding sequencing rules on the SCORM view and represents a basic sequencing graph on the users' view. By appropriately combining these SOs, users can easily construct a complex structure of course with desired teaming guidance. Then, a transformation algorithm is also proposed to firstly transform the created graph based course structure into Activity Tree (AT) with related sequencing rules, and then package the transformed activity tree and related physical teaming resources into a SCORM compliant course file. Moreover, the authoring tool can be easily upgraded by importing a new SO instead of redesigning the tool only for new SCORM version. Finally, a SCORM compliant course built by the object based authoring tool is executed on the SCORM RTE system. The results show that our approach is workable and efficient.
Identification of Atractylodes plants in Chinese herbs and formulations by random amplified polymorphic DNA
(2001-06-01)
Chen, KT
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Su, YC
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Lin, JG
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Hsin, LH
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Su, YP
AIM: An efficient, precise, and sensitive method for identifying Atractylodes plants has been established and will contribute significantly to quality control and scientific analysis in Chinese traditional medicine. METHODS: Twenty primers were applied for setting up the RAPD (randomly amplified polymorphic DNA) markers of Atractylodes plants, Atractylodes lancea DC (A lancea MG:), Atractylodes japonica Koidz (A japonica K), and Atractylodes ovata DC (A ovata DC). The primer OPF03, OPF05, and OPF14 could discriminate them successfully. The results were also able to apply on the Chinese formulations with Atractylodes purchased from local markets. RESULTS: RAPD was used to investigate phylogenetic relationships among and within closely related species. RAPD analysis reflects heritable changes in the nucleotides sequence in both the coding and noncoding regions, because it is conducted directly from the DNA level. This work first conducted RAPD analysis of Atractylodes plants to establish their RAPD makers. CONCLUSION: The RAPD markers could be applied extensively in the Chinese herbal formulations.
Identifying differentially expressed genes associated with metastasis of follicular thyroid cancer by cDNA expression array
(2001-01-01)
Chen, KT
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Lin, JD
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Chao, TC
;
Hsueh, C
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Chang, CA
Patients with follicular thyroid carcinoma have a higher incidence of metastasis than papillary thyroid carcinoma when thyroid cancer is diagnosed. The cDNA expression array technology is utilized herein to profile differentially expressed genes from metastatic human follicular thyroid carcinoma and reveal new tumor markers as well as target genes for therapeutic intervention. Tissue samples were obtained during surgical resection of the thyroid follicular carcinoma and metastatic tissue in the brain of the same patient. Two identical Atlas human cDNA expression arrays were hybridized with P-32-labeled cDNA probes derived from RNA of either primary thyroid cancer or metastatic tissue. Parallel analysis of the hybridized signals allowed us to identify the alteration of gene expression in the metastasis process. Eighteen genes significantly overexpressed and 40 genes significantly underexpressed were identified in the metastatic thyroid cancer. Genes that displayed an altered expression were associated with the processes of cell cycle regulation, apoptosis, DNA damage response, angiogenesis, cell adhesion and mobility, invasion, and immune response. An expression profile of genes that are associated with metastasis process of follicular thyroid cancer was also discussed. Further investigation is required to understand the precise relationship between the altered expression of these genes and the metastasis process of follicular thyroid cancer.
Nitrogen implantation and in situ HF vapor clean for deep submicrometer n-MOSFETs
(2002-01-01)
Chen, JH
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Lei, TF
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Chen, CL
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Chao, TS
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Wen, WY
This work describes a high performance and reliable deep submicrometer n-channel metal oxide semiconductor field effect transistor (n-MOSFET) with ultrathin gate oxide prepared by combining nitrogen gate electrode implantation and native-oxide-free in situ HF vapor preoxidation cleaning. The results herein reveal that the performance and reliability, including the leakage current of the ultrathin gate oxide, charge-to-breakdown, drain current, transconductance, charge pumping current, stress induced leakage current, and hot carrier reliability of n-MOSFETs are all significantly improved. The enhanced reliability and performance are attributed to the native-oxide-free process, smooth interface, and reduced incorporation of As in the gate oxide which results from HF vapor cleaning and nitrogen implantation. (C) 2001 The Electrochemical Society.