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Search Results: 1 - 10 of 56366 matches for " Chi-Shiang Wei "
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Suppression of Heregulin-β1/HER2-Modulated Invasive and Aggressive Phenotype of Breast Carcinoma by Pterostilbene via Inhibition of Matrix Metalloproteinase-9, p38 Kinase Cascade and Akt Activation
Min-Hsiung Pan,Ying-Ting Lin,Chih-Li Lin,Chi-Shiang Wei,Chi-Tang Ho,Wei-Jen Chen
Evidence-Based Complementary and Alternative Medicine , 2011, DOI: 10.1093/ecam/nep093
Abstract: Invasive breast cancer is the major cause of death among females and its incidence is closely linked to HER2 (human epidermal growth factor receptor 2) overexpression. Pterostilbene, a natural analog of resveratrol, exerts its cancer chemopreventive activity similar to resveratrol by inhibiting cancer cell proliferation and inducing apoptosis. However, the anti-invasive effect of pterostilbene on HER2-bearing breast cancer has not been evaluated. Here, we used heregulin-β1 (HRG-β1), a ligand for HER3, to transactivate HER2 signaling. We found that pterostilbene was able to suppress HRG-β1-mediated cell invasion, motility and cell transformation of MCF-7 human breast carcinoma through down-regulation of matrix metalloproteinase-9 (MMP-9) activity and growth inhibition. In parallel, pterostilbene also inhibited protein and mRNA expression of MMP-9 driven by HRG-β1, suggesting that pterostilbene decreased HRG-β1-mediated MMP-9 induction via transcriptional regulation. Examining the signaling pathways responsible for HRG-β1-associated MMP-9 induction and growth inhibition, we observed that pterostilbene, as well as SB203580 (p38 kinase inhibitor), can abolish the phosphorylation of p38 mitogen-activated protein kinase (p38 kinase), a downstream HRG-β1-responsive kinase responsible for MMP-9 induction. In addition, HRG-β1-driven Akt phosphorylation required for cell proliferation was also suppressed by pterostilbene. Taken together, our present results suggest that pterostilbene may serve as a chemopreventive agent to inhibit HRG-β1/HER2-mediated aggressive and invasive phenotype of breast carcinoma through down-regulation of MMP-9, p38 kinase and Akt activation.
An Efficient Probability-based t out of n Secret Image Sharing Scheme
Chi-Chen Chang,Yu-Zheng Wang,Chi-Shiang Chan
International Journal of Signal Processing, Image Processing and Pattern Recognition , 2009,
Abstract: Noar and Shamir presented the concept of visual cryptography. Many researches following it go down the same track: to expand the secret pixels to blocks. As a result, the size of the secret image becomes larger, and the quality of the expanded secret image becomes worse. In order to prevent the pixels from expanding, Yang has proposed hisprobability-based visual secret sharing scheme, where the concept of probability is employed to pick out pixels from the black or white sets. In this paper, we shall propose a new scheme that is a modified version of Yang’s scheme. Our experimental results show that we can obtain better recovered image quality with high contrast.
Fly-DPI: database of protein interactomes for D. melanogaster in the approach of systems biology
Lin Chung-Yen,Chen Shu-Hwa,Cho Chi-Shiang,Chen Chia-Ling
BMC Bioinformatics , 2006, DOI: 10.1186/1471-2105-7-s5-s18
Abstract: Background Proteins control and mediate many biological activities of cells by interacting with other protein partners. This work presents a statistical model to predict protein interaction networks of Drosophila melanogaster based on insight into domain interactions. Results Three high-throughput yeast two-hybrid experiments and the collection in FlyBase were used as our starting datasets. The co-occurrences of domains in these interactive events are converted into a probability score of domain-domain interaction. These scores are used to infer putative interaction among all available open reading frames (ORFs) of fruit fly. Additionally, the likelihood function is used to estimate all potential protein-protein interactions. All parameters are successfully iterated and MLE is obtained for each pair of domains. Additionally, the maximized likelihood reaches its converged criteria and maintains the probability stable. The hybrid model achieves a high specificity with a loss of sensitivity, suggesting that the model may possess major features of protein-protein interactions. Several putative interactions predicted by the proposed hybrid model are supported by literatures, while experimental data with a low probability score indicate an uncertain reliability and require further proof of interaction. Fly-DPI is the online database used to present this work. It is an integrated proteomics tool with comprehensive protein annotation information from major databases as well as an effective means of predicting protein-protein interactions. As a novel search strategy, the ping-pong search is a na ve path map between two chosen proteins based on pre-computed shortest paths. Adopting effective filtering strategies will facilitate researchers in depicting the bird's eye view of the network of interest. Fly-DPI can be accessed at http://flydpi.nhri.org.tw. Conclusion This work provides two reference systems, statistical and biological, to evaluate the reliability of protein interaction. First, the hybrid model statistically estimates both experimental and predicted protein interaction relationships. Second, the biological information for filtering and annotation itself is a strong indicator for the reliability of protein-protein interaction. The space-temporal or stage-specific expression patterns of genes are also critical for identifying proteins involved in a particular situation.
Reducing the Foreign Body Reaction by Surface Modification with Collagen/Hyaluronic Acid Multilayered Films
Cindy Yi Chi Hsieh,Fang-Wei Hu,Wen-Shiang Chen,Wei-Bor Tsai
ISRN Biomaterials , 2014, DOI: 10.1155/2014/718432
Abstract: Biological response against foreign implants often leads to encapsulation, possibly resulting in malfunction of implants devices. The aim of this study was to reduce the foreign body reaction by surface modification of biomaterials through layer-by-layer deposition of type I collagen (COL)/hyaluronic acid (HA) multilayer films. Polydimethylsiloxane (PDMS) samples were coated with alternative COL and HA layers with different layers. We found that the in vitro adhesion, proliferation, and activation of macrophage-like cells were greatly decreased by COL/HA multilayered deposition. The PDMS samples modified with 20 bilayers of COL/HA were implanted in rats for 3 weeks, and the thickness of encapsulation surrounding the samples was decreased by 29–57% compared to the control unmodified PDMS. This study demonstrates the potential of COL/HA multilayer films to reduce foreign body reaction. 1. Introduction Biological response against artificial implants leads to encapsulation of implants, which often causes malfunction of implants or patients’ agonies due to capsular contracture [1–3]. For example, capsule contracture of fibrous tissues overlying silicone breast implants may cause the implant rupture and become painful [3]. When a foreign material is implanted into a host, the interaction between the material and the surrounding injured tissues causes acute inflammation, similar to the natural healing process that usually lasts for a week [1, 2]. Chronic inflammation with the participation of monocytes, macrophages, and foreign body giant cells (FBGCs) may occur with a duration of less than 3 weeks if the wound is not healed [1]. Macrophages try to eliminate the foreign object from the host. However, the implant is too large to be phagocytosized, so activated macrophages fuse together to form multinucleated FBGCs [1]. The inability of FGBCs in eliminating the foreign object will lead to a route to encapsulation of the implant with dense collagen matrix that is secreted by fibroblasts in order to wall the foreign object off the host [1, 2]. Macrophages can be considered as a hallmark due to their critical roles in guiding through the entire wound healing process [2, 4]. Activated macrophages release biosignals such as interleukins to induce the formation of FBGCs as well as collagen synthesis from fibroblasts. To prevent these undesirable events from occurring, scientists have sought suitable surface modifications on biomaterials to prevent capsule formation by altering the hydrophilicity, topology, roughness, and surface chemistry of surfaces [5, 6].
Characteristics of pncA mutations in multidrug-resistant tuberculosis in Taiwan
Yu-Chi Chiu, Shiang-Fen Huang, Kwok-Woon Yu, Yu-Chin Lee, Jia-Yih Feng, Wei-Juin Su
BMC Infectious Diseases , 2011, DOI: 10.1186/1471-2334-11-240
Abstract: MDRTB isolates were collected from six hospitals in Taiwan from January 2007 to December 2009. pncA gene sequencing, pyrazinamidase activity testing, and spoligotyping were performed on all of the isolates. PZA susceptibility was determined by the BACTEC MGIT 960 PZA method. The sensitivity and specificity of pncA gene analysis were estimated based on the results of PZA susceptibility testing.A total of 66 MDRTB isolates, including 37 Beijing and 29 non-Beijing strains, were included for analysis. Among these isolates, 36 (54.5%) were PZA-resistant and 30 (45.5%) were PZA-susceptible. The PZA-resistant isolates were more likely to have concomitant resistance to ethambutol and streptomycin. Thirty-seven mutation types out of 30 isolates were identified in the pncA gene, and most of them were point mutations. The sensitivities of pncA gene sequencing for PZA susceptibility in overall isolates, Beijing and non-Beijing strains were 80.6%, 76.2%, and 86.7% respectively, and the specificities were 96.7%, 93.8%, and 100% respectively.More than half of the MDRTB isolates in this study are PZA-resistant. Analysis of pncA gene mutations helped to identify PZA-susceptible MDRTB isolates, especially in non-Beijing strains.Despite the recent advances in management, tuberculosis (TB) remains a leading cause of mortality and morbidity worldwide. The emergence of multidrug-resistant tuberculosis (MDRTB) further constitutes a serious threat to the control of TB. In Taiwan, the incidence of TB was 63.2/100,000 population in 2007 and 62.0/100,000 population in 2008 (1). The Taiwan drug resistance surveillance program revealed that the combined drug resistance rates in 2005 were 10.1% for isoniazid (INH), 6.2% for rifampicin (RIF), and 4.0% for MDRTB (2). Among the various genotypes of Mycobacterium tuberculosis (MTB), the Beijing genotype is the dominant strain in Taiwan (3, 4).Pyrazinamide (PZA) is an important first-line anti-tuberculosis (anti-TB) drug that is used in short-course
Optimization of Bearing Locations for Maximizing First Mode Natural Frequency of Motorized Spindle-Bearing Systems Using a Genetic Algorithm  [PDF]
Chi-Wei Lin
Applied Mathematics (AM) , 2014, DOI: 10.4236/am.2014.514208

This paper has developed a genetic algorithm (GA) optimization approach to search for the optimal locations to install bearings on the motorized spindle shaft to maximize its first-mode natural frequency (FMNF). First, a finite element method (FEM) dynamic model of the spindle-bearing system is formulated, and by solving the eigenvalue problem derived from the equations of motion, the natural frequencies of the spindle system can be acquired. Next, the mathematical model is built, which includes the objective function to maximize FMNF and the constraints to limit the locations of the bearings with respect to the geometrical boundaries of the segments they located and the spacings between adjacent bearings. Then, the Sequential Decoding Process (SDP) GA is designed to accommodate the dependent characteristics of the constraints in the mathematical model. To verify the proposed SDP-GA optimization approach, a four-bearing installation optimazation problem of an illustrative spindle system is investigated. The results show that the SDP-GA provides well convergence for the optimization searching process. By applying design of experiments and analysis of variance, the optimal values of GA parameters are determined under a certain number restriction in executing the eigenvalue calculation subroutine. A linear regression equation is derived also to estimate necessary calculation efforts with respect to the specific quality of the optimization solution. From the results of this illustrative example, we can conclude that the proposed SDP-GA optimization approach is effective and efficient.

Research Issues and Challenges for Multiple Digital Signatures
Min-Shiang Hwang,Cheng-Chi Lee
International Journal of Network Security , 2005,
Abstract: In this paper, we surveyed several well-known batch verification multiple digital signatures. These schemes can batch verify multiple digital signatures which need only one verification instead of $t$ verifications. However, a number of weaknesses of these schemes are pointed out. According to our proposed issues and challenges, we compared and analyzed them. To sum up these schemes, a secure and efficient multiple digital signatures scheme which needs only one verification remains an open problem.
Authenticated Encryption Schemes: Current Status and Key Issues
Min-Shiang Hwang,Chi-Yu Liu
International Journal of Network Security , 2005,
Abstract: Nyberg and Ruppel first proposed a signature scheme with message recovery based on DSA in 1993, and the authenticated encryption scheme is a special application of their scheme. Afterward, there are many papers proposed about the authenticated encryption schemes. The signature scheme can reduce the transmitted cost, because the message has been contained in the signature of the message and the signer does not necessary to send the receiver the message and the signature. The scheme is very suitable for the key agreement application, because a key is a small amount of a message. In order to comprehend and interpret the authenticated encryption schemes overall, we discuss the evolution and the existed problems of authenticated encryption schemes.
Dynamical Responses of a Valveless Fluid Loop Excited by the Impact of a Compression Actuator
Chi-Chung Wang,Tian-Shiang Yang
Physics , 2011,
Abstract: Valveless pumping assists in fluid transport in various organisms and engineering systems. In a previous work, to study the actuator impact effects on valveless pumping, we constructed a piecewise-linear lumped-parameter model for a closed-loop system, which consists of two distensible fluid reservoirs connected by two rigid tubes. The preliminary asymptotic and numerical results of that work indicated that the system dynamics is rather rich and complex, and strongly depends upon the driving frequency of the actuator (which periodically compresses one of the distensible reservoirs) and other system parameters. Here, a more comprehensive numerical study on the aforementioned model is carried out, so as to clarify how many different types of system responses can be excited, and to locate the parameter boundaries within which each type exists. Moreover, by examining the driving-frequency dependences of a number of characteristic phases (such as the phase of the compression cycle at which the actuator collides with or separates from the distensible reservoir it acts upon), the interrelations between different types of system responses are identified.
China’s Energy Diplomacy: SOE Relations in the Context of Global Distribution and Investment Pattern  [PDF]
Hui-Chi Yeh, Chi-Wei Yu
Advances in Applied Sociology (AASoci) , 2012, DOI: 10.4236/aasoci.2012.24043
Abstract: This article addresses the mercantilist connotations of China’s energy diplomacy through empirical and quantitative approaches by arguing that: firstly, the economic logic motivating Chinese enterprises is not the key variable in the formulation of foreign investment decisions; secondly, the energy security policies of the Chinese government are key variables which decide the distribution of SOEs’ foreign investment; thirdly, China’s energy diplomacy is mercantilist in nature due to the weakness of its SOEs in the structure of the international market; finally, under the premise of satisfying its government’s energy security policy, SOEs have autonomy in their approaches to investment. Therefore, it may be reasoned that under specific conditions, mercantilism and liberalism can both explain China’s energy diplomacy. This article provides compelling evidence supporting this reasoning, through analyzing cases studies in the Middle East, Central Asia and Africa.
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