• Korean Journal of Optics and Photonics
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• v.17 no.5
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• pp.469-474
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• 2006

A $1{\times}16$ thermo-optic switch with small excess loss using multimode interference(MMI) couplers is designed, fabricated, and measured. This paper introduces the proposed $1{\times}16$ thermo-optic switch, and discusses the measurement results. The $1{\times}16$ thermo-optic switch is farmed as 4-stage which consists of 15 unit devices. The unit devices are the $2{\times}2$ thermo-optic switches with Mach-Zehnder interferometer(MZI) structure. The characteristics of the $1{\times}16$ thermo-optic switch depends strongly on each unit device. The unit deviceconsists of two 3-dB general interference MMI couplers and two single mode waveguide arms as a phase shifter. First of all, the 3-dB optical splitter and $2{\times}2$ MZI thermo-optic switch have been tested to confirm the characteristics of the unit devices of the $1{\times}16$ MZI thermo-optic switch. Using the measurement results of the unit devices, the $1{\times}16$ MZI thermo-optic switch can be produced with better characteristics. The resultant structure of the MMI coupler with the optical light source of wavelength of 1550nm for the $1{\times}16$ thermo-optic switch is that the width and the optimized length are $25{\mu}m\;and\;1580{\mu}m$, respectively. The smallest excess loss fur the unit device is -0.5dB and the average excess loss is -0.7dB.

• Journal of Microbiology and Biotechnology
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• v.31 no.9
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• pp.1231-1240
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• 2021

Members of the genus Bacillus are known to play an important role in promoting plant growth and protecting plants against phytopathogenic microorganisms. In this study, 21 isolates of Bacillus spp. were obtained from the root micro-ecosystem of Suaeda glauca. Analysis of the 16S rRNA genes indicated that the isolates belong to the species Bacillus amyloliquefaciens, Bacillus velezensis, Bacillus subtilis, Bacillus pumilus, Bacillus aryabhattai and Brevibacterium frigoritolerans. One of the interesting findings of this study is that the four strains B1, B5, B16 and B21 are dominant in rhizosphere soil. Based on gyrA, gyrB, and rpoB gene analyses, B1, B5, and B21 were identified as B. amyloliquefaciens and B16 was identified as B. velezensis. Estimation of antifungal activity showed that the isolate B1 had a significant inhibitory effect on Fusarium verticillioides, B5 and B16 on Colletotrichum capsici (syd.) Butl, and B21 on Rhizoctonia cerealis van der Hoeven. The four strains grew well in medium with 1-10% NaCl, a pH value of 5-8, and promoted the growth of Arabidopsis thaliana. Our results indicate that these strains may be promising agents for the biocontrol and promotion of plant growth and further study of the relevant bacteria will provide a useful reference for the development of microbial resources.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.16
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• pp.6947-6951
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• 2015

Background: Oral carcinoma (OC) remains one of the most difficult malignancies to cure. Hesa-A is an Iranian herbal-marine compound that has shown promising anti-tumor properties against various human tumors. However, its mechanism of action remains to be addressed. The present study was conducted to evaluate the effect of two doses of Hesa-A on mRNA expression of erb$\backslash$b2 as a main prognosticator tumor marker for OC in an animal model. Materials and Methods: A total of 60 rats were randomly divided into 5 groups of 12 animals each. Rats in carcinoma groups received 0, 250 and 500mg/kg body weight doses of Hesa-A 3 times a day. The other two groups were considered as treated and untreated control groups. At the end of the experiment, animals were sacrificed and tongue tissues subjected to H and E staining and real time PCR. Results: Our results showed that compared to the control group, erb$\backslash$b2 was over-expressed ~ 30% in the carcinoma group. After treatment with 250mg/kg and 500mg/kg body weight of Hesa-A, erb$\backslash$b2 levels dropped by 24.1% and 3.4 % respectively compared to the control carcinoma group (p<0.01, p<0.0001). Moreover, there was a significant relation between erb$\backslash$b2 mRNA content and observed pathological changes in studied groups (p<0.05). Conclusions: These data provide insight into mechanism(s) by which Hesa-A may improve clinical outcome of oral carcinoma by affecting oncogene erb$\backslash$b2 expression and suggest Hesa-A as an effective chemotherapeutic agent in treatment of HER+tumors.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.11
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• pp.1019-1022
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• 2016

In this paper, a 2~16 GHz GaN wideband power amplifier MMIC s designed and fabricated using the nonuniform power amplifier design technique that utilizes drain shunt capacitors to simultaneously provide each transistor with the optimum load impedance and phase balance between input and output transmission lines. The power amplifier MMIC chip that is fabricated using the $0.25{\mu}m$ GaN HEMT foundry process of Win Semiconductors occupies an area of $3.9mm{\times}3.1mm$ and shows a linear gain of larger than 12 dB and an input return loss of greater than 10 dB. Under a continuous-wave mode, it has a saturated output power of 36.2~38.5 dBm and a power-added efficiency of about 8~16 % in 2 to 16 GHz.

• Korean Journal of Materials Research
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• v.5 no.7
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• pp.880-887
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• 1995

Melt spun YB $a_2$C $u_3$A $g_{15}$ and YbB $a_2$C $u_3$A $g_{x}$(x=5, 16 and 53) precursor alloy ribbons were oxidized at 263~322$^{\circ}C$, and heat-treated at 872~89$0^{\circ}C$ under 1.0atm oxygen pressure. In addition, about ten ribbons were stacked and coupled by pressing, and then followed the same heat treatment. YB $a_2$C $u_3$ $O_{7-{\delta}}$(1-2-3) or YbB $a_2$C $u_3$ $O_{7-{\delta}}$(1-2-3) phase was formed in both the ribbons and the multilayered specimens. The formed 1-2-3 phases were not texturized in all the ribbons, but slightly texturized in the multilayered specimens. $J_{c}$ was not achieved in all the ribbons at 77K and zero magnetic field. Among the multilayered specimens, YB $a_2$C $u_3$A $g_{15}$ and YbB $a_2$C $u_3$A $g_{16}$ showed $J_{c}$ of 260 and 180A/$\textrm{cm}^2$, respectively. YB $a_2$C $u_3$A $g_{15}$ and YbB $a_2$C $u_3$A $g_{16}$ are considered to be the appropriate compositions in producing textured superconducting oxides with improved $J_{c}$ by pressing. Onset critical temperature ( $T_{on}$ ) of the multilayered YB $a_2$C $u_3$A $g_{15}$ was 92K while those of YbB $a_2$C $u_3$A $g_{x}$(x=5 , 16 and 53) were 88~90K. , 16 and 53) were 88~90K.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.13
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• pp.5585-5585
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• 2015

• Korean Journal of Plant Resources
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• v.22 no.4
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• pp.317-322
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• 2009

In the present study, the effect of ethanol extracts of leaf and root of Rosa multiflora on the proliferation of B16 cells, tyrosinase activity and melanin synthesis were investigated. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide(MTT) assay demonstrated that the cell viability upon treatment with Rosa multiflora extract(0-200 ${\mu}g$/ml) was similar to that of untreated control. Treatment with leaf or root extracts(200 ${\mu}g$/ml) decreased the in vitro tyrosinase activity to about 65% of that in untreated control. Similarly, the intracellular tyrosinase activity of B16 cells decreased in a concentration-dependent manner. Furthermore, the melanin synthesis of B16 cells decreased by the two extracts in a concentration dependent manner. However, the extracts did not change the level of tyrosinase mRNA, as determined by RT-PCR. These results demonstrated that the Rosa multiflora extracts inhibit the tyrosinase dependent melanin biosynthesis, and therefore, are candidates for skin-whitening agents.

• Journal of Acupuncture Research
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• v.18 no.1
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• pp.186-201
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• 2001

Purpose ; In order to study the effect of Houttuyniae herbal acupuncture on growth of melanoma B 16 and immunity in mice, the Control group with normal saline acupunchure after subcutaneous inoculation of B16BL6 cells, the Sample I with Houttuyniae herbal acupuncture manufactured by distilled water extraction method after subcutaneous inoculation of B16BL6 cells and the Sample II with Houttuyniae herbal acupuncture manufactured by alcohol extraction method after subcutaneous inoculation of B16BL6 cells were divided. Methods ; To evauluate the effect of Houttuynias herbal acupuncture on growth of melanoma B16 in mice, the weight of mouse melanoma, body weight, spleen index( $\sqrt(Weight of spleen/Body weight){\times}100$), lymphocytes numbers in mouse peripheral blood and spleen tissue, the percentage of CD4+ T cells, CD8+ and the ratio of CD4+/CD8+ in mouse peripheral blood and spleen tissue are measured. Results ; In study of the weight of mouse melanoma, Houttuyniae herbal acupuncture groups(Sample I, Sample II) showed statistically significant inhibitory effect. And in study of effect of reduction of change in body weight of mouse, Sample I showed statistically significant inhibitory effect, too. In study of reduction of spleen index, lymphocytes numbers in mouse spleen tissue, and the percentage of CD4+ and the ratio of CD4+/CD8+ T cells in mouse peripheral blood, Houttuyniae herbal acupuncture groups(Sample I, Sample II ) showed with statistically significant inhibitory effect. Also, Sample I showed inhibitory effect of reduction of the percentage of CD8+ T cells in mouse peripheral blood and spleen tissue and Sample II showed inhibitory effect of reduction of the percentage of CD4+ and the ratio of CD4+/CD8+ T cells in mouse spleen tissue with statistical significance. Conclusions ; The inhibitory effect of reduction of lymphocytes numbers in mouse peripheral blood and IL-2 productivity, Houttuyniae herbal acupuncture groups(Sample I, Sample II) didn't show significant effect.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.1
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• pp.33-38
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• 2004

Melanin pigmentation in human skin is a major defense mechanism against ultraviolet light of the sun, but abnormal pigmentation such as freckles, liver spot could be a serious aesthetic problem. Nearly all studies are mainly concentrated on searching for the materials that have inhibitory activities on tyrosinase. In this work, to isolate phenolic compounds from Gastrodia elata, we purified the extract through solvent fractionation, column chromatography, and recrystallization. They were identified as 4-hydroxybenzyl alcohol 1, bis(4-hydroxyphenyl)methane 2, gastrodin (4-${\beta}$-D-glucopyranosyloxybenzyl alcohol) 3 on the base of spectroscopic evidences. In order to investigate their depigmentation effect, inhibitory activity against mushroom tyrosinase and inhibitory activity of melanin synthesis in B16 melanoma cells were evaluated in vitro. We have found that 4-hydroxybenzyl alcohol 1 and gastrodin (4- ${\beta}$-D-glucopyranosyloxybenzyl alcohol) 3 have no tyrosinase inhibitory activity, but inhibit the melanin synthesis in B16 melanoma cells. Tyrosinase inhibitory activities of bis(4-hydroxyphenyl)methane 2 (IC$\_$50/ = 400 $\mu\textrm{g}$/mL) and butanol fraction (IC$\_$50/ = 46 $\mu\textrm{g}$/mL) were lower/higher than that of arbutin (IC$\_$50/ = 114 $\mu\textrm{g}$/mL), but inhibitory activities of melanin synthesis in B16 melanoma cells were much higher than that of arbutin. Especially, tyrosinase inhibitory activities of isolated phenolic fraction (IC$\_$50/ = 2.37 $\mu\textrm{g}$/mL) from butanol fraction was very higher than that of arbutin (IC$\_$50/ = 114 $\mu\textrm{g}$/mL). Therefore, these results suggest that isolated phenolic compounds from Gastrodia elata have inhibitory activity against mushroom tyrosinase and inhibitory activity of melanin synthesis in 816 melanoma cells in vitro.

• Journal of Life Science
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• v.20 no.11
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• pp.1617-1624
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• 2010

Recently, it has been found that Asiasari radix showed a hypopigmenting effect on melanogenesis through activation of mitogen-activated protein kinase (MEK)/extracellular signal-activated kinase (ERK) in B16F10 melanoma cells. However, the hypopigmenting effect of A. radix on the $\alpha$-melanocyte stimulating hormone ($\alpha$-MSH)-stimulated melanogenesis has remained unknown. The purpose of this study was to investigate the inhibitory mechanism of the partially purified A. radix (PPAR)-induced hypopigmentating effects on $\alpha$-MSH-stimulated melanogenesis in B16F10 mouse melanoma cells. PPAR strongly inhibited tyrosinase activity and leads to decreased melanin synthesis in $\alpha$-MSH-stimulated B16F10 melanoma cells. PPAR also decreased the $\alpha$-MSH-induced over-expression of the melanogenic enzymes, tyrosinase, tyrosinase-related protein (TRP)-1, dopachrome tautomerase (Dct) and microphthalmia-associated transcription factor (MITF). We further showed that PPAR inhibits $\alpha$-MSH-induced melanogenesis via phosphorylation of MEK/ERK and PI3K/Akt, and that their activation was blocked by MEK inhibitors, PD98059 and PI3K inhibitors, LY294002 in $\alpha$-MSH-stimulated B16F10 melanoma cells. These results suggest that PPAR inhibits $\alpha$-MSH-induced melanogenesis by activation of MEK/ERK and PI3K/Akt through MITF degradation, which may lead to down-regulation of tyrosinase.