• Journal of Korean Society of Forest Science
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• v.100 no.4
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• pp.623-629
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• 2011

The detectable levels and population fluctuations of phytoplasmas infecting dwarf mulberry trees were investigated using nested-PCR and competitive-PCR methods. Samples of five different types were studied : A. petiole of a leaf that displays dwarf symptoms, B. petiole from apparently healthy leaf residing on a branch also supports a leaf with dwarf symptoms, C. the branch portion that supports a leaf with dwarf symptoms, D. the leaf petiole from healthy appearing leaves on branch with no dwarf symptoms, and branch portion of branch with no dwarf symptoms, E. the rootlets of trees with dwarf symptoms. These 5-parts were collected from each tree during June - April, once in every two months. The phytoplasma was detected from all parts of collected mulberry samples during all seasons using nested-PCR with AS-1/AS-2 primer pairs. The phytoplasma was detected until $10^4$ dilution using direct-PCR method, but it was detected until $10^{13}$ dilution by the nested-PCR method. The density of pytoplasma was found to be $7.94{\times}10^{18}-10^{12}copies/{\mu}L$ in mulberry trees. The density of phytoplasma was observed throughout the year in all samples of mulberry trees. The highest rates of phytoplasma was found in the samples B and C during the early growing season followed by the sample A and D during the dormant season. Samples C and E displayed the highest phytoplasma density followed sample D. The density of phytoplasma appeared stable during all the seasons for samples C and A. The result of the present study demonstrates the utility of nested-PCR and competitive-PCR for detection and determination of population fluctuations of phytoplasmas in plant tissues.

• Journal of the Korean Magnetics Society
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• v.14 no.1
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• pp.38-44
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• 2004

The iron doped colossal magnetoresistance materials with La-Ba-Mn-O perovskites structure have been synthesized by chemical reaction of sol-gel methods. Their crystallographic and magnetic properties have been studied with x-ray diffraction, VSM, RBS, Mossbauer spectroscopy, and magnetoresistance measurements. The crystal structure of the La$\_$0.67/Ba$\_$0.33/Mn$\_$0.99/Fe$\_$0.01/ $O_3$ at room temperature was determined to be orthorhombic of Pnma. The lattice parameters a$\_$0/ and c$\_$0/ increased gradually, but b$\_$0/ deceased with increase of iron substitution. The magnetization and coercivity deceased, also the Curie temperature decreased from 360 K as x increased from 0.00 to 0.05. Magnetoresistence measurements were carried out, and the maximum MR ($\Delta$$\rho$/$\rho$(0)) was observed at 281 K, about 9.5 % in 10 kOe. The temperature of maximum resistance (R$\_$MAX/) decreased with increasing substitution of Fe ions and a semiconductor-metal transition temperature (T$\_$SC-M/) decreased too. This phenomena show that ferromagnetic transition temperature decreased by substituting Fe for Mn ions, it decreases double exchange interaction. This result accords with magnetic structure of neutron diffraction. Mossbauer spectra of La$\_$0.67/Ba$\_$0.33/Mn$\_$0.99/Fe$\_$0.01/ $O_3$were taken at various temperatures ranging from 15 to 350 K. With lowering temperature of the sample, two magnetic phases were increased and finally it showed the two sharp sextets of spectra at 15 K. The isomer shift at all temperature range is about 0.3 mm/s relative to Fe metal, which means that both Fe ions are Fe$\^$3+/ states.Fe$\^$3+/ states.

• Journal of the Korean Ceramic Society
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• v.40 no.2
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• pp.206-211
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• 2003

Effects of substrates and buffer layer upon the formation of crystalline phases and ferroelectricity of $YMnO_3$ thin films were investigated. The hexagonal $YMnO_3$ was easily formed on Si(100) while the mixed phases, hexagonal and orthorhombic $YMnO_3$, on $Pt(111)/TiO_2/SiO_2/Si$ substrate. When the $Y_2O_3$ buffer layer of 70 nm thick was inserted between the substrates and the $YMnO_3,$ the c-axis oriented hexagonal single phase formed on both substrates, Si(100) and $Pt(111)/TiO_2/SiO_2/Si$. The leakage current density of the hexagonal $YMnO_3$ thin films was lower than that consisting of mixed phases, hexagonal and orthorhombic. Furthermore the hexagonal $YMnO_3$ with c-axis preferred orientation showed the lowest leakage current density. The remnant polarization from a P-E hysteresis curve for the $YMnO_3$ formed on Si(100) was 0.14 without buffer layer and $0.24_{mu}C/cm^2$ for that with buffer layer. For the $Pt(111)/TiO_3/SiO_3/Si$ substrates, the specimen without $Y_2O_3$buffer layer did not show the hysteresis curve, while the buffer-layered has the remnant polarization of $1.14_{mu}C/cm^2$. It was concluded that the leakage current density and the ferroelectricity for the $YMnO_3$ thin films could be controlled by varying crystalline phases and their preferred orientation which depend on the kind of substrates and whether the $Y_2O_3$buffer layer exist or not.

• Journal of Life Science
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• v.30 no.3
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• pp.304-312
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• 2020

Agarase can be used in the field of basic science, as well as for production of agar-derived high-functional oligosaccharides and bioenergy production using algae. In 2012, we summarized the classification, origin, production, and applications of agar. In this paper, we briefly review the literature on the recombinant expression of agarases from 2012 to the present. Agarase genes originated from 19 genera, including Agarivorans, Flammeovirga, Pseudoalteromonas, Gayadomonas, Catenovulum, Microbulbifer, Cellulophaga, Saccharophagus, Simiduia, and Vibrio. Of the 47 recombinant agarases, there were only two α-agarases, while the rest were β-agarases. All α-agarases produced agarotetraose, while β-agarases yielded many neoagarooligosaccharides ranging from neoagarobiose to neoagarododecaose. The optimum temperature ranged between 25 and 60℃, and the optimum pH ranged from 3.0 to 8.5. There were 14 agarases with an optimum temperature of 50℃ or higher, where agar is in sol state after melting. Artificial mutations, including manipulation of carbohydrate-binding modules (CBM), increased thermostability and simultaneously raised the optimum temperature and activity. Many hosts and secretion signals or riboswitches have been used for recombinant expression. In addition to gene recombination based on the amino acid sequence after agarase purification, recombinant expression of the putative agarase genes after genome sequencing and metagenome-derived agarases have been studied. This study is expected to be actively used in the application fields of agarase and agarase itself.

• Korean Journal of Environment and Ecology
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• v.30 no.6
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• pp.1057-1066
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• 2016

This study examined how 'forest name' or 'information of forest healing effectiveness' influence their perceived environmental restorativeness (PER) and perceived healing effectiveness (PHE). Study area was the 'Forest Healing Road (FHR)' in Mudeungsan National Park. Data were collected from 247 visitors selected by convenient sampling method using questionnaire survey during May-June, 2015. Respondents who read interpretive signs (forest name and information on forest healing effectiveness of FHR were written) installed along the FHR were regarded as placebo group and respondents who didn't read them as control group. The results showed that there were no overall differences on PER and PHE between control and placebo groups. Placebo group, however, rated more positive on 'being away' factor of PER than control group. All four factors (i.e., being away, coherence, fascination, comparability) of PER statistically influenced PHE (p<0.001), and these factors explained 51.1% of PHE. The 'coherence' was the most influential to PHE, followed by 'being away', 'comparability', and 'fascination' in order. Placebo effects on PER were shown in male, in lower age group(age${\leq}54$), or respondents with lower visiting experience to FHR(${\leq}20$ times/year). Placebo effects on PHE were found in male, in small group (${\leq}2$ persons), in respondents who visited 'alone' or 'with relatives/family', or in respondents with lower visiting experience to FHR(${\leq}20$ times/year). Some research and managerial implications were suggested.

• Korean Journal of Environment and Ecology
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• v.30 no.3
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• pp.423-433
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• 2016

This study compared the effect of different types of sounds(no sounds, sounds of nature, music, and sounds of children playing) on profile of mood states(POMS) in a healing forest. Data were collected from 231 respondents selected from among visitors to the 'Healing Field' in 'Jangseong Chukryongsan Pyeonbaek Healing Forest' in October, 2012. Each respondent was exposed to one type of sound. The results showed that there were differences in POMS among the different sound treatment groups. Sounds of children playing showed negative effects on POMS. Unexpectedly, however, sounds of nature and musical sounds had no effects on POMS. These tendencies were consistently found not only for total mood disturbance score (TMDS) but also for POMS by factors (i. e. tension, anger, vigor, fatigue, confusion, depression). Perceived crowding level was positively correlated with TMDS(r=0.568) and POMS by factors (range: r=0.331 - 0.571). This paper discusses the research results and suggests several managerial implications.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.198-198
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• 2015

전기변색재료는 전압을 인가하였을 때 전계방향에 따라 가역적으로 색이 변화하는 재료를 말한다. 스마트윈도우용 전기 변색재료는 지속적으로 전기를 가해줄 필요 없이 한번 변색되면 색이 지속되는 특징을 가지므로 에너지 효율적으로 우수하여 태양열 차단 창호나 디스플레이 분야에 응용될 것으로 기대된다. 이러한 전기 변색재료에는 산화형 전기 변색 재료, 환원형 전기 변색 재료가 있는데 이중 가장 널리 연구되고 있는 재료는 환원형 전기변색재료이다. 대표적인 재료로 $WO_3$가 쓰이는 데 이는 전기 변색적 특성이 우수하고 또한 내구성이 다른 재료에 비해 우수하다는 장점 때문이다. 그러나, 상용화를 위해서는 내구성의 개선이 요구되고 있다. 한편, $TiO_2$는 안정성이 매우 뛰어나지만 전기변색적 특성이 $WO_3$에 비해 낮은 점이 지적되고 있다. 이러한 $WO_3$ 및 $TiO_2$ 박막은 스퍼터링 또는 sol-gel법 등으로 제작되고 있는데, 일반적으로 스퍼터링의 경우 치밀한 박막이 형성되기 때문에 Porous 한 박막을 얻기 힘들다. 따라서 본 연구에서는 기판에 입사하는 스퍼터 입자들의 각도를 조절하여 shadowing 효과로 인해 박막의 구조가 porous해지는 Glancing angle deposition을 도입하였다. 이러한 증착법을 이용하여 $WO_3$와 $TiO_2$를 각도를 조절하여 증착하고 $TiO_2$와 $WO_3$ 박막의 특성을 비교하여 본다. 두께 300 nm를 가지는 $WO_3$ 및 $TiO_2$ 박막은 GLAD RF 마그네트론 스퍼터링법을 이용하여 Corning glass(corning E-2000)기판 위에 증착하였다. 기판 입사 각도는 $0^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$로 증착하였고 직경 3 in의 $TiO_2$, $WO_3$ 타겟을 사용하였다. 또한 스퍼터링 파워는 400 W, 작업압력 1.0 Pa, 그리고 스퍼터링 가스는 O2/Ar+O2 유량 10%에서 30%로 증착을 상온에서 진행하였다. 전기화학적 특성을 평가하기 위하여 $TiO_2$ 및 $WO_3$ 박막을 100 nm 두께의 ITO/glass 위에서 증착하였다. 박막의 미세구조는 XRD와 SEM을 통해 확인하였고, 전기화학적 특성은 Ar 분위기의 Glove box안에서 parstat 2273을 통해 측정하였다. 전해질은 1 M $LiPF_6/PC$로 진행하였고, 대향 전극는 Pt전극을, 참고 전극은 칼로멜 전극을 사용하였다. Potential 범위는 2 V에서 4 V로 진행하였고, scan rate는 50 mV/s로 측정하였다. 투과도는 UV/VIS spectrometer로 측정하였다. 전기변색 특성의 상관관계 및 에 대해서는 학회 당일 발표할 예정이다.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.2
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• pp.82-94
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• 2014

The purpose of this study is to investigate the cause of increasing dry zones through analyzing relationships between land cover and Vegetation Temperature Condition Index(VTCI) using Landsat 4-5 TM satellite images in Central Dry Zones of Myanmar. As a result of land cover classifications, while vegetation areas gradually decrease, residential area and cropland were increased. VTCI analysis shows that region (a) showed a gradual decrease in the area of severely arid, and increase in the area of moderate dry and wet, which sums up to a slight decrease in aridity. Region (b) also showed to increase in dry areas and severe aridity. The result of relational analysis between VTCI and land cover change showed high ratio of land cover change, from severe arid area to forest and residential farmland. The average VTCI decreased in the changed land covers, which indicates the relationship between aridity and land cover change and a gradual increase in the arid area was identified.

• Journal of Society of Preventive Korean Medicine
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• v.22 no.1
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• pp.107-127
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• 2018

Objectives : The present study investigated the anti-obese and blood flow improvement activities of aqueous extracts of ginseng berry (GBe) on the mild diabetic obese mice as compared with metformin. Methods : After end of 56 days of continuous oral administrations of GBe 150, 100 and 50 mg/kg, or metformin 250 mg/kg, anti-obese and blood flow improvement effects - the changes of body weights, body and abdominal fat density by in live dual-energy x-ray absorptionmetry (DEXA), tail bleeding time, prothrombin time (PT), activated partial thromboplastin time (aPTT), serum total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL) and high density lipoprotein (HDL) levels, aorta and serum cyclic guanosine monophosphate (cGMP), nitric oxide (NO) and endothelin (ET)-1 levels, aorta phosphorylated PI3K (pPI3K), phosphorylated Akt (pAkt) and phosphorylated p38 MAPK (pp38 MAPK) levels were systemically analyzed. In addition, aorta vascular dilation and constriction related gene mRNA expressions - PI3K, Akt, eNOS, p38 MAPK and ET-1 were also analyzed by realtime RT-PCR. Results : The obesity and related blood flow impairment, induced by 84 days of continuous HFD supply, were significantly inhibited by 56 days of continuous oral treatment of GBe 150, 100 and 50mg/kg, dose-dependently, and they also dramatically normalized the changes of the aorta vascular dilation and constriction related gene mRNA expressions, also dose-dependently. Especially, GBe 150 mg/kg constantly showed favorable inhibitory activities against type II diabetes related obesity and vascular disorders through PI3K/Akt pathway and p38 MAPK mediated cGMP, NO and ET-1 expression modulatory activities, as comparable to those of metformin 250 mg/kg in HFD mice. Conclusion : By assessing the key parameters for anti-obese and blood flow improvement activities on the HFD-induced mild diabetic obese mice, the present work demonstrated that GBe 150, 100 and 50 mg/kg showed favorable anti-obese and blood flow improvement effects in HFD-induced type II diabetic mice, through PI3K/Akt pathway and p38 MAPK mediated cGMP, NO and ET-1 expression modulatory activities.

• Journal of Chest Surgery
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• v.29 no.8
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• pp.807-815
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• 1996

The protective effect of'ischemic preconditioning'on ischemid-reperfusion injury of heart has been reported in various animal species. but without known mechAnism in detail, In An attempt to investigate the cardioprotective mechanism of ischemic preconditioning, we examined the effects of nitric oxide(UO) synthesis in preconditioned heart of rat The isolated hearts perfused by Langendorfr's method were ex- posed to 30min global ischemia followed by 30min reperfusion with oxygenated Krebs-Henseleit(K-H) sol- ution. Ischemic preconditioning was performed with three episodes of Sm n ischemia and Smin repeyfusion before the induction of prolong ischemia(30min)-reperfusion(30min). Ischemic preconditioning prevented the depression of cardiac function(left ventricular pressure .K heart rate) observed in the ischemia- reperfusion hearts and reduced the release of lactate dehydrogenase during the reperfusion period. On electromicroscopic pictures, myocardial ultrastructures wore relatively well preserved in isthemic preconditioned hearts. N6_nitro-L-arginine methyl ester(L-NAME) an inhibitor of L-arginine citric oxide pathway, was infused at a rate O.Smllmin In a dose of 10mg kg-1 before the initial ischemic preconditioning. neither the protection of cardiac function nor the reduction of LDH releAse in ischemic preconditioning hearts was altered in the presence of added L-NAME On ultrastructural finding, the preservation of morphology in ischemic preconditioning heart was not change by the pretreatment of L-UAME. The failure of the WO synthesis inhibitor to reduce t e effect of ischemic preconditioning may be related to be species specific in that NO may allot be the trigger for ischemic preconditioning in rats.