Busan, South Korea
Busan, South Korea

Dongseo University is a major private university located in the port city of Busan, South Korea. It has approximately 12,000 undergraduate students and 500 graduate students, including 600 international students from 27 countries. It employs 350 full-time faculty members. The current president is Jekuk Chang . Wikipedia.

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Barrera F.N.,Yale University | Fendos J.,Yale University | Fendos J.,Dongseo University | Engelman D.M.,Yale University
Proceedings of the National Academy of Sciences of the United States of America | Year: 2012

The pHLIP peptide has three states: (I) soluble in aqueous buffer, (II) bound to the bilayer surface at neutral pH, and (III) inserted as a transmembrane (TM) helix at acidic pH. The membrane insertion of pHLIP at low pH can be used to target the acidic tissues characteristic of different diseases, such as cancer. We find that the α-helix content of state II depends on lipid acyl chain length but not cholesterol, suggesting the helicity of the bound state may be controlled by the bilayer elastic bending modulus. Experiments with the P20G variant show the proline residue in pHLIP reduces the α-helix content of both states II and III. We also observe that the membrane insertion pKa is influenced by membrane physical properties, following a biphasic pattern similar to the membrane thickness optima observed for the function of eukaryotic membrane proteins. Because tumor cells exhibit altered membrane fluidity, we suggest this might influence pHLIP tumor targeting. We used a cell insertion assay to determine the pKa in live cells, observing that the properties in liposomes held in the more complex plasma membrane. Our results show that the formation of a TM helix is modulated by both the conformational propensities of the peptide and the physical properties of the bilayer. These results suggest a physical role for helix-membrane interactions in optimizing the function of more complex TM proteins.

Lee J.,Dongseo University
Archives of Pharmacal Research | Year: 2010

Cyclophilins (Cyps) are ubiquitously expressed proteins that are evolutionarily conserved. CypA is the most abundant among the Cyps and is expressed in the cytosol. With its chaperone and PPIase activities, CypA contributes to the maintenance of correct conformation of nascent or denatured proteins and also provides protection against environmental insults. Also, its expression is induced in response to a wide variety of stressors including cancer. Upregulation of CypA in small cell lung cancer, pancreatic cancer, breast cancer, colorectal cancer, squamous cell carcinoma and melanoma has been reported. In some cancers a correlation between CypA overexpression and malignant transformation has been established. While molecular partners of CypA that promote cancer development are yet to be discovered, various mechanisms have been proposed to account for the cytoprotective functions of CypA during cancer development. CypA may promote the survival of cells under the stressful condition of cancer. CypA may well be essential for maintaining the conformation of oncogenic proteins, signalling proteins for cell proliferation, antiapoptotic components, transcription factors, or cell motility regulatory proteins. Antioxidant effects of CypA, which have been suggested by some researchers, may also become critical to reactive oxygen species (ROS) creating an oncogenetic environment. Developing new CypA inhibitors for therapeutics has been surmised from the cytoprotective functions of CypA and its overexpression in many cancer types. Therefore, CypA can be further investigated as a useful tool for early diagnosis, treatment and prevention of human cancers. © 2010 The Pharmaceutical Society of Korea and Springer Netherlands.

Shin H.J.,Dongseo University
Journal of Biotechnology | Year: 2010

NahR, a transcriptional regulator for naphthalene degradation in response to salicylate, is a central element in the microbial biosensor for detection of naphthalene and salicylate. To maximize the sensitivity of the biosensor, we have chosen a rational design of highly-sensitive microbial biosensors by introducing site directed mutagenesis to nahR gene. Eight single mutants (N169A, N169C, N169K, N169S, R248H, R248M, R248Q, and R248Y) were made at residues 169 and 248 known as the central inducer-recognition and the C-terminal multimerization domain. The effects of these mutations were examined by monitoring expression of a firefly luciferase (luc) reporter gene under the control of NahR. We found that all mutants at residues 248 and N169C show increased sensitivity (maximum ~50-fold) compared to wild type, respectively. R248M shows response even at toxic concentration, 5. mM. The results show the feasibility and potential versatility of mutational approach for the development of the highly-sensitive microbial biosensors. © 2010 Elsevier B.V.

Kumar P.,Dongseo University | Lee H.-J.,Dongseo University
Sensors | Year: 2012

Healthcare applications are considered as promising fields for wireless sensor networks, where patients can be monitored using wireless medical sensor networks (WMSNs). Current WMSN healthcare research trends focus on patient reliable communication, patient mobility, and energy-efficient routing, as a few examples. However, deploying new technologies in healthcare applications without considering security makes patient privacy vulnerable. Moreover, the physiological data of an individual are highly sensitive. Therefore, security is a paramount requirement of healthcare applications, especially in the case of patient privacy, if the patient has an embarrassing disease. This paper discusses the security and privacy issues in healthcare application using WMSNs. We highlight some popular healthcare projects using wireless medical sensor networks, and discuss their security. Our aim is to instigate discussion on these critical issues since the success of healthcare application depends directly on patient security and privacy, for ethic as well as legal reasons. In addition, we discuss the issues with existing security mechanisms, and sketch out the important security requirements for such applications. In addition, the paper reviews existing schemes that have been recently proposed to provide security solutions in wireless healthcare scenarios. Finally, the paper ends up with a summary of open security research issues that need to be explored for future healthcare applications using WMSNs. © 2012 by the authors.

Lee J.,Dongseo University
Korean Journal of Physiology and Pharmacology | Year: 2013

Hepatocellular carcinoma (HCC) related to hepatitis B virus (HBV) and hepatitis C virus (HCV) infections is thought to account for more than 80% of primary liver cancers. Both HBV and HCV can establish chronic liver inflammatory infections, altering hepatocyte and liver physiology with potential liver disease progression and HCC development. Cyclophilin A (CypA) has been identified as an essential host factor for the HCV replication by physically interacting with the HCV non structural protein NS5A that in turn interacts with RNA-dependent RNA polymerase NS5B. CypA, a cytosolic binding protein of the immunosuppressive drug cyclosporine A, is overexpressed in many cancer types and often associated with malignant transformation. Therefore, CypA can be a good target for molecular cancer therapy. Because of antiviral activity, the CypA inhibitors have been tested for the treatment of chronic hepatitis C. Nonimmunosuppressive Cyp inhibitors such as NIM811, SCY-635, and Alisporivir have attracted more interests for appropriating CypA for antiviral chemotherapeutic target on HCV infection. This review describes CypA inhibitors as a potential HCC treatment tool that is contrived by their obstructing chronic HCV infection and summarizes roles of CypA in cancer development.

Jang J.-Y.,Kwangwoon University | Shin D.,Dongseo University | Kim E.-S.,Kwangwoon University
Optics Express | Year: 2014

We propose a novel approach to optically refocus threedimensional (3-D) objects on their real depth from the captured elemental image array (EIA) by using a sifting property of the periodic d-function array (PDFA) in integral-imaging. By convolving the PDFAs whose spatial periods correspond to each object's depth with the sub-image array (SIA) transformed from the EIA, a set of spatially filtered-SIAs (SF-SIAs) for each object's depth can be extracted. These SF-SIAs are then inversetransformed into the corresponding versions of the EIAs, and from these, 3- D objects with their own perspectives can be reconstructed to be refocused on their depth in the space. The feasibility of the proposed method has been confirmed through optical experiments as well as ray-optical analysis. © 2014 Optical Society of America.

Hwang J.,Dongseo University | Han H.,Sejong University
Tourism Management | Year: 2014

The purpose of this research was to examine the antecedents and consequences of brand prestige in the luxury cruise industry in order to provide luxury cruise managers with practical strategies for maximizing and utilizing brand prestige. Based on the existing theoretical background, it was hypothesized that eight types of cruise experience factors influence the formation of brand prestige: food quality, service quality, staff/crew attractiveness, entertainment, ship facilities, ports of call, programs/places for children, and cabin quality. In addition, it was proposed that brand prestige can result in three managerial outcomes: well-being perception, customer brand identification, and brand loyalty. A conceptual model was developed and tested using the empirical data collected from 330 U.S. luxury cruise passengers. The results showed that all of the proposed hypotheses were statistically supported. The key theoretical/managerial implications that were derived from the analysis are presented and discussed in the last part of the article. © 2013 Elsevier Ltd.

Shin H.J.,Dongseo University
Applied Microbiology and Biotechnology | Year: 2012

In this study, recombinant bacterial biosensors were immobilized in an agarose matrix and used for the simple and disposable field monitoring of phenolic compounds. In brief, Escherichia coli cells harboring the pLZCapR plasmid, which was previously designed to express the β-galactosidase reporter gene in the presence of phenolic compounds, were immobilized in agarose gel with or without a substrate [chlorophenol red β-galactopyranoside (CPRG)] and dispensed to the wells of a 96-well plate. Analytes were added to the wells, and color development was monitored either directly from wells containing intact cells co-immobilized with CPRG (SYS I), or using cells that were lysed prior to the addition of CPRG (SYS L). SYS L showed relatively higher intensities and faster color development than SYS I. However, both systems developed a red color (representing hydrolysis of CPRG) in the presence of 10 μM to 10~100 mM phenol, with maximum responses seen at 1~5 and 50 mM phenol for SYS I and SYS L, respectively. Other phenolic compounds (2-chlorophenol, 2-methylphenol, 3-methylphenol, 4-chlorophenol, 2-nitrophenol, resorcinol, catechol, and 2,5-dimethylphenol) were also detected by the systems, with varied detection ranges and responses. The agarose-immobilized biosensors were stable for 28 days, retaining 39~69% of their activities when stored at 4°C without nutrients or additives. The immobilized biosensors described herein do not require the on-site addition of a substrate (in the case of SYS I), the pretreatment of samples, or the use of unwieldy instruments for the on-site monitoring of phenolic compounds from environmental samples. © 2011 Springer-Verlag.

A method for displaying three-dimensional integral images using a mask and a time division multiplexing which is configured in such a way that a three-dimensional image is displaced in a space as an element image obtained from a three-dimensional object is passed through a lenslet and a mask, the mask consisting of a blocking region through which an element image does not pass and a transmission region through which an element image passes, for thereby displaying three-dimensional images. The present invention is advantageous to play back a three-dimensional image the resolutions of which are enhanced in a depth-based integral imaging method using a time division display of an element image and a masked image.

Disclosed is a depth-priority integral imaging display method using a nonuniform dynamic mask array which makes it possible to enhance the resolutions in both horizontal and vertical directions in such a way to change a division boundary of a mask pattern and use a two-times time multiplexing. It is possible to enjoy the images of clear resolutions even in the product of 60 Hz, and the afterimages at the division boundary may be eliminated by changing the dividing direction of the mask, so the images with clearer resolutions can be displayed.

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