겨울철 홍천강의 위생학적 수질조사연구

오덕철,김선균,주왕기,조동현,김우호,윤경민 江原大學校附設體力硏究所 1976 江原大學校附設體育科學硏究所論文集 Vol.- No.1

The water quality of the Hong-Cheon river was investigated during the winter season. The rate of contamination of the low tide was a little more than the high tide. But all values of the analyzed-items were similar to those in the clear water.

Specification and Simulation of a Macroeconometric Model for Measuring the Effects of Commercial Policies in a Developing Economy

Wang, Yen Kyun Institute of Economic Research, Seoul National Uni 1978 The Seoul National University economic review Vol.12 No.1

Target-oriented photofunctional nanoparticles (TOPFNs) for selective photodynamic inactivation of <i>Methicillin-resistant Staphylococcus aureus</i> (MRSA)

Wang, Kang-Kyun,Shin, Eon Pil,Lee, Hye-Jin,Jung, Seung-Jin,Hwang, Jeong-Wook,Heo, Il,Kim, Jong-Ho,Oh, Min-Kyu,Kim, Yong-Rok Elsevier 2018 Journal of photochemistry and photobiology Biology Vol.183 No.-

<P><B>Abstract</B></P> <P>To inactivate methicillin-resistant <I>Staphylococcus aureus</I> (MRSA) with minimum damage to host cells and tissue, target-oriented photofunctional nanoparticles (TOPFNs) were fabricated and characterized. MRSA is a predominant infective pathogen even in hospital and non-hospital environments due to its ability to develop high levels of resistance to several classes of antibiotics through various pathways. To solve this major problem, photodynamic inactivation (PDI) method applies to treat antibiotic-resistant bacteria. PDI involves the photosensitizer (PS) and light with a specific wavelength to be able to apply for a non-invasive therapeutic procedure to treat pathogenic bacteria by inducing apoptosis or necrosis of microorganisms. However, most current PDI researches have suffered from the instability of PDI agents in the biological environment due to the lack of selectivity and low solubility of PDI agents, which leads to the low PDI efficiency. In this study, the TOPFNs were fabricated by an esterification reaction to introduce hematoporphyrin (HP) and MRSA antibody to the surface of Fe<SUB>3</SUB>O<SUB>4</SUB> nanoparticles. The TOPFNs were designed as dispersible PDI agent in biological condition, which was effectively used for selectively capturing and killing of MRSA. The capture efficiency TOPFNs was compared with PFNs as a negative control. The results showed that the capture efficiency of TOPFNs and PFNs was 95.55% and 6.43% in MRSA and L-929 cell mixed condition, respectively. And TOPFNs have a selective killing ability for MRSA with minimum damage to L-929 cells. Furthermore, PDI effect of TOPFNs was evaluated on the mice <I>in vivo</I> condition in order to check the possibility of practical medical application.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Target-oriented photofunctional nanoparticles (TOPFNs) were successfully fabricated and characterized. </LI> <LI> Methicillin-resistant <I>Staphylococcus aureus</I> was completely photodynamic inactivated by TOPFNs. </LI> <LI> Also, photodynamic inactivation effect of MRSA by TOPFN was confirmed <I>in-vivo</I>. </LI> </UL> </P>

Free radical production in CA1 neurons induces MIP-1alpha expression, microglia recruitment, and delayed neuronal death after transient forebrain ischemia.

Wang, Hyo Kyun,Park, Ui Jin,Kim, Soo Yoon,Lee, Jin Hwan,Kim, Seung U,Gwag, Byoung Joo,Lee, Yong Beom The Society 2008 The Journal of neuroscience Vol.28 No.7

<P>Several studies report microglial accumulation and activation in the CA1 area in response to transient forebrain ischemia (TFI). Here we examine the possibility that free radicals and chemokines mediate the transient activation of microglia. Free radicals are produced primarily in CA1 pyramidal neurons within 2 h of TFI. Administration of trolox, a vitamin E analog, led to the inhibition of free radical production and recruitment of microglia in the CA1 area. In addition, intrahippocampal injection of Fe2+ triggered free radical production in CA1 neurons, followed by the recruitment and activation of microglial cells into this area. TFI-induced expression of macrophage inflammatory protein-1alpha (MIP-1alpha) was increased in CA1 neurons before microglial recruitment, and blocked by trolox. Moreover, the MIP-1alpha level was upregulated in cultured hippocampal neurons exposed to Fe2+, suggesting an essential role of free radicals in TFI-induced expression of MIP-1alpha. Intracerebroventricular injection of vMIP-2 (viral macrophage inflammatory protein-2), a broad-spectrum peptide antagonist of chemokine receptors, attenuated microglial recruitment and delayed CA1 neuronal degeneration after TFI. Our data suggest that free radicals produced in CA1 neurons contribute to the recruitment and activation of microglia and neurodegeneration through MIP-1alpha expression.</P>

A Reform on the Forward Foreign Exchange Market and Foreign Exchange Rate Determination in Korea with Foreign Exchange Policy Experiences of Taiwan

Wang, Yen Kyun the Center for International Studies, Inha Univers 1990 Pacific Focus Vol.5 No.1

Industrial and Financial Restructuring and Prevention of Recurrence of Another Economic Crisis in Korea

Wang, Yen Kyun 중앙대학교 경제연구소 2002 經濟論文集 Vol.- No.17

Specification and Simulation of Macroecometric Model for Measuring the Effects of Commercial Policies in a Developing Economy - The Case of Korea

Wang,Yen-Kyun 연세대학교 동서문제연구소 1978 東西硏究 JOURNAL OF EAST AND WEST STUDIES Vol.7 No.2

International trade and economic development theorists have insisted that policies which result in interest rates and exchange rates(in terms of domestic currency) below the market clearing level have debilitating effects on economic development. It has also been argued that high tariffs associated with overvaluation of domestic currency are inflationary. Empirical support for this position is provided by the model specified above and simulations thereof. Specifically, the results show that first, in an economy with capital shortage, a low real interest rate policy designed to protect industry has the effect of limiting the availability of fund for fixed investment, and involves a substantial loss of output and employment. The present low but structurally diverse interest rate policy in Korea should be abandoned in favor of a higher level closer to the equilibrium rate. Second, the general tariff level should be lowered and the exchange rate(in terms of foreign currency) should be also lowered so as to be close to the equibrium rate, thus curbing inflation and improving the trade balance. A tariff is inflationary, and reduces real final demand and output while a devaluation causes smaller price increases than tariffs, and increases output. In terms of an improvement in the trade balance a devaluation or a subsidy shows stronger effects than a tariff. A production subsidy or an export subsidy is superior to a tariff in terms of the allocative efficiency. Tariff rates on most commodities, especially on necessities, raw materials and semi-processed goods, either for export or domestic use, should be lowered to the minimum level. More important than a tariff is the abolition of import licensing, export-import link and quota system. It should be also noted that the maintenance of stable prices and the equilibrium exchange rate is very helpful for the abolition of the direct regulation of imports and the substantial reduction of tariffs. There is evidence that one unit of exports had a greater impact on GDP, industrial production and employment than one unit of fixed investment during the period, 1963 to 1972. In particular, one unit of exports was more stimulatory to agriculture, the light industry and service sectors, while one unit of fixed investment provided more stimulus to the heavy, chemical, and construction industries. The light industry has a larger production-induced effect and a smaller imports-induced effect that the heavy and chemical industries. The proposed model seems to be fruitful despite the limited availability of data. However, further research is needed on developing the monetary sector and the interactions between the monetary sector and the rest of the model.

Fabrication and characterization of antimicrobial surface-modified stainless steel for bio-application

Wang, Kang-Kyun,Kim, Bong-Jin,Il-Heo, Bong-Jin,Jung, Seong-Jin,Hwang, Jeong-Wook,Kim, Yong-Rok Elsevier 2017 Surface & Coatings Technology Vol.310 No.-

<P><B>Abstract</B></P> <P>We report a photofunctional stainless steel (PSS) that has antimicrobial property which is provided by reactive oxygen species (ROS) generated from the photosensitizer (PS). For the fabrication of the photofunctional stainless steel, the photosensitizer of hematoporphyrin (HP) was covalently bonded to the surface of 316L stainless steel (316LSS) through an esterification reaction. The PSS plate was investigated by x-ray photoelectron spectroscopy (XPS), reflectance UV–Vis absorption, and fluorescence spectroscopy. ROS generation from the PSS plate was studied by using the decomposition reaction of 1,3-diphenyl-isobenzofuran (DPBF). The results suggest that the immobilized photosensitizer molecules on the surface of the PSS plate still possess their intrinsic optical and functional properties including the ROS generation. The antimicrobial property of the PSS plate was successfully demonstrated with the decomposition of biofilm and the suppression of the biofilm formation on the surface of the PSS plate.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Photofunctional stainless steel (PSS) was fabricated and characterized. </LI> <LI> Biofilm was decomposed by the reactive oxygen species generated from PSS. </LI> <LI> The biofilm formation on the surface of PSS was inhibited with light irradiation. </LI> </UL> </P>

Eradication of <i>Plasmodium falciparum</i> from Erythrocytes by Controlled Reactive Oxygen Species via Photodynamic Inactivation Coupled with Photofunctional Nanoparticles

Wang, Kang-Kyun,Jang, Jin Woo,Shin, Eon Pil,Song, Hyung Wan,Hwang, Jeong Wook,Kim, Young Keun,Lim, Chae Seung,Kim, Yong-Rok American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.15

<P>We investigated the antimalarial effect of photodynamic inactivation (PDI) coupled with magnetic nanoparticles (MNPs) as a potential strategy to combat the emergence of drug-resistant malaria and resurgence of malaria after treatment. Because the malarial parasite proliferates within erythrocytes, PDI agents need to be taken up by erythrocytes to eradicate the parasite. We used photofunctional MNPs as the PDI agent because nanosized particles were selectively taken up by Plasmodium-infected erythrocytes and remained within the intracellular space due to the enhanced permeability and retention effect. Also, the magnetism of Fe3O4 nanoparticles can easily be utilized for the collection of photofunctional nanoparticles (PFNs), and the uptaken PFNs infected the erythrocytes after photodynamic treatment with external magnetics. Photofunctionality was provided by a photosensitizer, namely, pheophorbide A, which generates reactive oxygen species (ROS) under irradiation. PAs were covalently bonded to the surface of the MNPs. The morphology and structural characteristics of the MNPs were investigated by scanning electron microscopy and X-ray diffraction (XRD), whereas the photophysical properties of the PFNs were studied with Fourier transform infrared, absorption, and emission spectroscopies. Generation of singlet oxygen, a major ROS, was directly confirmed with time -resolved phosphorescence spectroscopy. To evaluate the ability of PFNs to kill malarial parasites, the PDI effect of PFNs was evaluated within the infected erythrocytes. Furthermore, malarial parasites were completely eradicated from the erythrocytes after PDI treatment using PFNs on the basis of an 8 day erythrocyte culture test.</P>

Fabrication of Photofunctional Nanoporous Membrane and Its Photoinactivation Effect of Vesicular Stomatitis Virus

Wang, Kang-Kyun,Kim, Bong-Jin,Ko, Si-Hwan,Choi, Dong Hoon,Kim, Yong-Rok Hindawi Limited 2012 Journal of nanomaterials Vol.2012 No.-

<P>Fabrication and photophysical study of photofunctional nanoporous alumina membrane (PNAM) were performed, and its application of photodynamic antimicrobial chemotherapy (PACT) was investigated. Nanoporous alumina membrane (NAM) was fabricated by two-step aluminium anodic oxidation process. Surface of the fabricated NAM was modified with organo-silane agent to induce covalent bonding between NAM and a photosensitizer (PtCP: [5,10,15-triphenyl-20-(4-methoxycarbonylphenyl)-porphyrin] platinum). PtCP was covalently bonded to the surface of the modified NAM by nucleophilic acyl substitution reaction process. The morphology and the photophysical properties of the fabricated PNAM were confirmed with field emission scanning electron microscope (FE-SEM), steady-state spectroscopies, and nanosecond laser-induced time-resolved spectroscopy. For the efficacy study of PNAM in PACT, an enveloped animal virus, vesicular stomatitis virus (VSV), was utilized as a target organism. Antiviral effect of the PNAM-PACT was measured by the extent of suppression of plaque-forming units (PFU) after the light irradiation. In the cultures inoculated with PACT-treated VSV, the suppression of PFU was prominent, which demonstrates that PNAM is a potential bio clean-up tool.</P>