• Proceedings of the PSK Conference
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• 2003.10b
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• pp.157.3-158
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• 2003

The antioxidant and anticancer properties of a medicinal plant, Betula platyphylla var. japonica were investigated. The total methanol extract of B. platyphylla var. japonica had protective effects against hydrogen peroxide ($H_2O_2$) in the Chinese hamster lung fibroblast (V79-4) cell line and induced apoptotic cell death in human promyelocytic leukemia (HL-60) cells, a cancer cell line. B. platyphylla var. japonica extract significantly increased cell viability against $H_2O_2$. The extract also showed high 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity ($IC_50$ 2.4 mg/ml) and lipid peroxidation inhibitory activity ($IC_50$ below 4.0 mg/ml). (omitted)

• Transactions on Electrical and Electronic Materials
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• v.16 no.6
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• pp.303-307
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• 2015

Multilayered films of ITO (In₂O₃:SnO₂ = 9:1)/SiO₂ were deposited on soda-lime glass by RF/DC magnetron sputtering at 500℃ to improve the energy conversion efficiency of dye-sensitized solar cells (DSSCs). The light absorption of the dye was improved by decrease in light reflectance from the surface of the DSSCs by using an ITO film. In order to estimate the optical characteristics and compare them with experimental results, a simulation program named EMP (essential macleod program) was used. EMP results revealed that the multilayered thin films showed high transmittance (approximate average transmittance of 79%) by adjusting the SiO₂ layer thickness. XRD results revealed that the ITO and TiO₂ films exhibited a crystalline phase with (400) and (101) preferred orientations at 2 θ = 26.24° and 35.18°, respectively. The photocurrent-voltage (I-V) characteristics of the DSSCs were measured under AM 1.5 and 100 mW/cm² (1 sun) by using a solar simulator. The DSSC fabricated on the ITO film with a 0.1-nm-thick SiO₂ film showed a Voc of 0.697 V, J_sc of 10.596 mA/cm² , FF of 66.423, and calculated power conversion efficiency (η_AM1.5) of 5.259%, which was the maximum value observed in this study.

• Journal of Electrochemical Science and Technology
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• v.9 no.3
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• pp.195-201
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• 2018

To enhance the performance of cathodes at low temperatures, a Cu-coated cathode is prepared, and its electrochemical performance is examined by testing its use in a single cell. At $620^{\circ}C$ and a current density of $150mAcm^{-2}$, a single cell containing the Cu-coated cathode has a significantly higher voltage (0.87 V) during the initial operation than does that with an uncoated cathode (0.79 V). According to EIS analysis, the high voltage of the cell with the Cu-coated cathode is due to the dramatic decrease in the high-frequency resistance related to electrochemical reactions. From XPS analysis, it is confirmed that the Cu is initially in the form of $Cu_2O$ and is converted into CuO after 150 h of operation, without any change in the state of the Ni or Li. Therefore, the high initial cell voltage is confirmed to be due to $Cu_2O$. Because $Cu_2O$ is catalytically active toward $O_2$ adsorption and dissociation, $Cu_2O$ on a NiO cathode enhances cell performance and reduces cathode polarization. However, the cell with the Cu-coated cathode does not maintain its high voltage because $Cu_2O$ is oxidized to CuO, which demonstrates similar catalytic activity toward $O_2$ as NiO.

• Journal of Korean Medicine for Obesity Research
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• v.21 no.2
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• pp.69-79
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• 2021

Objectives: This study aimed to compare the anti-obesity effects of raw and pickled garlic in vitro in 3T3-L1 preadipocytes. Methods: The pickled garlic samples comprised the following: garlic aged in vinegar (VG), garlic aged in soy sauce, and vinegar (1:1, v/v) (PG) and raw garlic (RG) as control. Hexane, butanol, and distilled water were used to prepare the fractions. The pancreatic lipase inhibitory activity was used as a measure of anti-obesity effects of the extracts. The lipid droplet accumulation and triglyceride content in the 3T3-L1 cells were measured using Oil red O staining and triglyceride assay kits, respectively. The adipogenesis related protein expression levels were analyzed using the kits and the western blot method. Results: The pancreatic lipase inhibitory activity of the garlic extracts (VG, PG, RG) was the highest in the butanol fraction, and the inhibitory effect was the highest in RG, followed by PG and VG. All garlic butanol extracts suppressed triglyceride accumulation in differentiated adipocytes (P<0.05) through the activation of cyclic adenosine monophosphate (AMP), AMP-activated protein kinase, carnitine palmitoyl transferase-1, and the inhibition of fatty acid synthase. Raw garlic extracts significantly inhibited the expression of proteins involved in adipogenesis as compared to pickled garlic. Conclusions: Raw garlic has the potential to be an effective natural material for reducing obesity compared to pickled garlic with vinegar or soy sauce.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3223-3228
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• 2016

Reports indicate that 15-deoxy-delta-12,14-prostaglandin-J2 (15d-PGJ2) has anticancer activities, but its mechanisms of action have yet to be fully elucidated. We therefore investigated the effects of 15d-PGJ2 on the human breast cancer cell lines, MCF-7 (estrogen receptor $ER{\alpha}+/ER{\beta}+$) and MDA-MB-231 ($ER{\alpha}-/ER{\beta}+$). Cellular proliferation and cytotoxicity were determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays while apoptosis was determined by fluorescence microscopy and flow cytometry using annexin V-propidium iodide (PI) staining. ER expression was determined by Western blotting. Intracellular calcium was stained with Fluo-4 AM while intracellular caspase activities were detected with Caspase-$FLICA(R)$ and measured by flow cytometry. We showed that 15d-PGJ2 caused a significant increase in apoptosis in MCF-7 and MDA-MB-231 cells. $ER{\alpha}$ protein expression was reduced in treated MCF-7 cells but pre-incubation with the $ER{\alpha}$ inhibitor' ICI 182 780' did not affect the percentage of apoptotic cells. The expression of $ER{\beta}$ was unchanged in both cell lines. In addition, 15d-PGJ2 increased intracellular calcium ($Ca^{2+}$) staining and caspase 8, 9 and 3/7 activities. We therefore conclude that 15d-PGJ2 induces caspase-dependent apoptosis that is associated with an influx of intracellular $Ca^{2+}$ with no involvement of ER signaling.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2000.10a
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• pp.64-65
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• 2000

Cancer is a general term subjected to a series of malignant tumor diseases which may affect many different parts of the human body. These cancer diseases are characterized by a rapid and uncontrolled formation of abnormal cells in the body. Cancer chemotherapeutic agents can often provide the prolongation of life and occasionally cures. To date many kinds of compounds have been obtained from plants kingdom as anti-neoplastic and anti-cancerous agents. However, there is no special type of compounds for cancer therapy. In our laboratory, anti-tumor and cytotoxic screenings on higher plants collected in Japan, China, Korea, Southeast Asia and South America have been done by using Sarcoma 180 ascites in mice, P388 lymphocytic leukemia in mice, Chinese hamster lung V-79 cells, P388 cells and nasopharynx carcinoma (KB) cells. The family, Simaroubaceae consists of about 20 genera and 120 species, mainly shrubs and trees, distributed in tropical and subtropical country. Simaroubaceae is classified as RUTALES, together with Rutaceae, Burseraceae, Meliaceae, Malpighiaceae and Polygalaceae. The members differ from the Rutaceae in not containing oil glands. Bitter principles are a characteristic of the family, Simaroubaceae. The genera include Quassia (Simarouba) (40 spp.), Picrasma (Aeschrion) (6 spp.), Brucea (10 spp.), Soulamea (10 spp.), Ailanthus (10 spp.) and Perriera (1 spp.) etc.. Surinam quassia derived from Quassia amara growing in Guianas, north Brazil and Venezuela is used in traditional medicines for stomachic, anti-amoebic, anti-malarial and anti-anaemic properties. Also, various parts of a number of plants of the family Simaroubaceae have been used in traditional medicine for the treatment of a variety oi diseases including cancer, amoebic, dysentery and malaria. Then, the research has established that it is the quassinoid content of these plants that is responsible for above activities. In this meeting, I will present on anti-tumor and anti-malarial activities and their active principles of Simaroubaceae plants, Eurycoma longifolia, Ailanthus vilmoriniana, Simaba cedron and Brucea mullis which have been studied in our laboratory.

• Bulletin of the Korean Chemical Society
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• v.31 no.10
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• pp.2923-2928
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• 2010

This study examined the synthesis of the crystal structure of bis(2,2'-bipyridine)nitrato zinc (II) nitrate, $[Zn(bipy)_2(NO_3)]^+NO_3^-$ using a microwave treatment at 300 W and 60 Hz for the application to dye-sensitized solar cells. The simulated complex structure of the complex was optimized with the density functional theory calculations for the UV-vis spectrum of the ground state using Gaussian 03 at the B3LYP/LANL2DZ level. The structure of the acquired complex was expected a penta-coordination with four nitrogen atoms of bipyridine and the oxygen bond of the $NO_3^-$ ion. The reflectance UV-vis absorption spectra exhibited two absorptions (L-L transfers) that were assigned to the transfers from the ligand ($\sigma$, $\pi$) of $NO_3$ to the ligand ($\sigma^*$, $\pi^*$) of pyridine at around 200 - 350 nm, and from the non-bonding orbital (n) of O in $NO_3$ to the p-orbital of pyridine at around 450 - 550 nm, respectively. The photoelectric efficiency was approximately 0.397% in the dye-sensitized solar cells with the nanometer-sized $TiO_2$ at an open-circuit voltage (Voc) of 0.39 V, a short-circuit current density (Jsc) of $1.79\;mA/cm^2$, and an incident light intensity of $100\;mW/cm^2$.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2000.10b
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• pp.11-13
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• 2000

Cancer is a general term subjected to a series of malignant tumor diseases which may affect many different parts of the human body. These cancer diseases are characterized by a rapid and uncontrolled formation of abnormal cells in the body. Cancer chemotherapeutic agents can often provide the prolongation of life and occasionally cures. To date many kinds of compounds have been obtained from plants kingdom as anti-neoplastic and anti-cancerous agents. However, there is no special type of compounds for cancer therapy. In our laboratory, anti-tumor and cytotoxic screenings on higher plants collected in Japan, China, Korea, Southeast Asia and South America have been done by using Sarcoma 180 ascites in mice, P388 lymphocytic leukemia in mice, Chinese hamster lung V-79 cells, P388 cells and nasopharynx carcinoma (KB) cells. The family, Simaroubaceae consists of about 20 genera and 120 species, mainly shrubs and trees, distributed in tropical and subtropical country. Simaroubaceae IS classified as RUTALES, together with Rutaceae, Burseraceae, Meliaceae, Malpighiaceae and Polygalaceae. The members differ from the Rutaceae in not containing oil glands. Bitter principles are a characteristic of the family, Simaroubaceae. The genera include Quassia (Simarouba) (40 spp.), Picrasma (Aeschrion) (6 spp.), Brucea (10 spp.), Soulamea (10 spp.), Ailanthus (10 spp.) and Perriera (1 spp.) etc.. Surinam quassia derived from Quassia amara growing in Guianas, north Brazil and Venezuela is used in traditional medicines for stomachic, anti-amoebic, anti-malarial and anti-anaemic properties. Also, various parts of a number of plants of the family Simaroubaceae have been used in traditional medicine for the treatment of a variety of diseases including cancer, amoebic, dysentery and malaria. Then, the research has established that it is the quassinoid content of these plants that is responsible for above activities. In this meeting, I will present on anti-tumor and anti-malarial activities and their active principles of Simaroubaceae plants, Eurycoma longifolia, Ailanthus vilmoriniana, Simaba cedron and Brucea mollis which have been studied in our laboratory.

• Microbiology and Biotechnology Letters
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• v.28 no.2
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• pp.97-104
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• 2000

Screening of Biologically Active Essential Oils from Ligusticum tenuissimum. Kim, Min-Hae, Young-Gil Kim, Jin-Ha Lee, Keo-Pyo Hong, Jung-Ki Hong, Young-Joon Kong, and Hyeon-Yong Lee*. Division of Food and Biotechnology, Kangwon National University, Chunchon 200-701, Korea, 1 Regional Crop Development Station, Kangwon Agricultural Research & Extension Services, Chunchon 200-150, Korea-The biological activities of the crude essential oils from Ligusticum tenuissimum and the control(phthalic anhydride) were compared. About 60% of the growth of MCF7, A549, and Rep3B cells were inhibited by adding 1.0 mg/ml of the crude essential oils and below 40% was observed by the control. Cytotoxicity on human normal lung cell(IMR90) was scored as 34.4% for the crude oil and 26.4% for control, respectively. It was found that the crude essential oils were more effective than the control in anti mutagenecity tested by both Rec-assay and CRG V79 cells. The growth of human T-cell(Jurkat) was enhanced up to 1.21 times by adding the crude essential oil compared with the control. 50% of a-glucosidase activity was inhibited by both the crude essential oil and the control. ACE activities were inhibited 80.1 % and 65.3% by adding 1.0 mg/ml of the crude oil and the control, respectively. The higher enhancement of glutathione-S-transferase activity was observed in the crude oil than those in the control: 301 % v.s 234% at 1.0 mg/ml of the treatment. Thrombolytic activity was measured as 42.9% and 28.6% for the crude oil and the standard, respectively. The effect of the oil on the nerve cells PCI2, was observed as follows: the neurite of PCl2 cells was lengthened up to 255 /-lm longer than 205 /-lm of control. The number of neurite-bearing cells were about two times higher than control. The survival ratio of the crude essential oil was also increased up to 56.4% which was about two fold higher than in control.

• Current Photovoltaic Research
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• v.4 no.3
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• pp.108-113
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• 2016

III-V compound semiconductor based thin film solar cells promise relatively higher power conversion efficiencies and better device reliability. In general, the thin film III-V solar cells are fabricated by an epitaxial lift-off process, which requires an $Al_xGa_{1-x}As$ ($x{\geq}0.8$) sacrificial layer and an inverted solar cell structure. However, the device performance of the inversely grown solar cell could be degraded due to the different internal diffusion conditions. In this study, InGaP/GaAs double-junction solar cells are inversely grown by MOCVD on GaAs (100) substrates. The thickness of the GaAs base layer is reduced to minimize the thermal budget during the growth. A wide band gap p-AlGaAs/n-InGaP tunnel junction structure is employed to connect the two subcells with minimal electrical loss. The solar cell structures are transferred on to thin metal films formed by Au electroplating. An AlAs layer with a thickness of 20 nm is used as a sacrificial layer, which is removed by a HF:Acetone (1:1) solution during the epitaxial lift-off process. As a result, the flexible InGaP/GaAs solar cell was fabricated successfully with an efficiency of 27.79% under AM1.5G illumination. The efficiency was kept at almost the same value after bending tests of 1,000 cycles with a radius of curvature of 10 mm.