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Protective Effects of a Lycium chinense Ethanol Extract through Anti-oxidative Stress on Acute gastric lesion mice (급성 위염 유발 마우스 동물 모델에서 구기자(枸杞子) 에탄올 추출물의 위점막 손상 보호 효과)

  • Lee, AhReum;Lee, JooYoung;Kim, MinYeong;Shin, Mi-Rae;Shin, SungHo;Seo, BuIl;Kwon, OJun;Roh, Seong-Soo
    • The Korea Journal of Herbology
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    • v.30 no.6
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    • pp.63-68
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    • 2015
  • Objectives : Gastric lesions affect many people around the world and their development are results of the imbalance between destructive and protective factors in the gastric mucosa. Lycium chinense has been widely used as a traditional Korean medicine, it was recently reported that they have potent anti-inflammatory effects in chronic hepatitis models. Therefore, this study aimed to investigate the anti-inflammatory activity of Lycium chinense extract (LCE) on HCl-Ethanol induced gastric lesion mice.Methods : The ICR mice were divided randomly into five groups of six animals each. Group A was normal mice, and group B was treated orally with 0.5 ml 150 mM HCl-60% Ethanol. Mice in group C and D were pre-treatment of LCE (100 mg/kg and 200 mg/kg bodyweight, p.o before HCl/ethanol treatment) and group E was orally administered sucralfate (10 mg/kg).Results : 150mM HCl/60% ethanol-induced gastric mucosal injury mice were ameliorated mucosal damage upon histological evaluation by treatment of LCE. Pre-treatment of LCE attenuated reactive oxidative species (ROS) and produces peroxynitrite (ONOO-) in stomach tissues. As results of stomach protein analyses, LCE effectively reduce inflammatory-related factors such as cyclooxygenase-2 (COX-2), tumor necrosis factor alpha (TNF-α), inducible nitric oxide synthase (iNOS) and interleukin-6 (IL-6) in gastric lesion mice. In addition, nuclear factor kappa B (NF-κB) and inhibitor of phosphorylation of nuclear factor kappa B (p-IκB) were down-regulated in LCE-administrated gastric lesion mice.Conclusions : Our discovery supports that the therapeutic activity of LCE ameliorate the development of gastric lesion via suppressing the oxidative stress and gastric partial inflammation induced by 150 mM HCl/60% ethanol.

Development of Chimeric Embryos Aggregated with Blastomeres from Parthenogenetic and in vitro Fertilized Bovine Embryos (소의 단위 발생란과 체외수정란 유래의 할구 응집에 의한 키메라 수정란(Chimeric Embryo)의 발달)

  • E. H. Yeao;Kim, Y. S.;Lee, S. L.;T. Y. Kang;D. O. Kwack;Lee, H. J.;S. Y. Choe
    • Journal of Embryo Transfer
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    • v.18 no.1
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    • pp.15-25
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    • 2003
  • 발생학에서 키메라(chimera)는 2개 이상의 다른 유전자형의 세포, 또는 다른 종의 세포로부터 만들어진 1개의 생물개체를 뜻하는 말로, 이는 초기 수정란의 발달과 포유류의 분화를 연구하는데 이용되고 있다. 키메라를 만드는 방법에는 할구와 내세포괴를 응집시키는 방법과 배반포 내에 여러 종류의 세포를 주입하는 방법이 있다 본 실험에서는 서로 다른 두 가지 방법의 활성화 처리법, 즉, ionomycin 처리 후 Cycloheximide (CHX) 또는 6-Dimetylaminopurine (6-DMAP)에 따른 단위 발생란의 분할과 단계적인 발달율을 살펴 보고자 하였으며, 서로 다른 방법에 의해 생산된 단위발생란 유래의 할구와 체외수정란 유래 할구를 응집하여 키메라 수정란(chimeric embryo)를 만든 후 체외수정란과 발달율을 비교해 보았다. 도축장 유래의 난소에서 난자를 채취하여 체외에서 22~24시간 성숙시킨 후 난구세포를 제거하고 metaphase II 단계의 난자를 5 $\mu$M ionomycin에 4분간 처리한 후, 10 $\mu$g/ml CHX/5 $\mu$g/ml cytochalasin B (CCB)에 5시간 또는 1.9 mM 6-DMAP에 4시간 처리하여 분할율과 배반포기 발달율을 비교 조사하였다. 난자 분할율에서는 체외수정란과 6-DMAP처리 단위 발생란에서 각각가 83.7 와 85.5%로 CHX/CCB 처리 단위발생란의 57.9%보다 유의적으로 높게(P<0.05) 나타났으며, 배반포기 발달율에 있어서는 체외수정란의 발달율이 27.8%로 6-DMAP처리 활성란 12.3%와 CHX/CCB 처리 활성란 5.3%보다 유의적으로 높게 (P<0.05) 나타났다. 키메라 수정란(chimeric embryo)은 서로 다른 두 가지 처리에 의해 생산된 단위발생란의 할구 2개와 체외수정란 유래의 할구 2개를 빈 투명대 내에서 응집시켜 제조하였다 빈 투명대 내에 키메라 수정란(chimeric embryos)의 8 세포기까지의 발달율은, 체외 수정란 할구 2개와 CHX/CCB 처리에 의한 할구 2개를 응집한 그룹은 46.1%, 체외 수정란 할구와 6-DMAP 유래 할구 2개를 응집한 그룹은 52.8% 였으며, handled control은 54.7%로 체외 수정란 77.7%에 비해 유의적으로 낮게(P<0.05) 나타났다. 배반포기까지의 발달율은 체외 수정란과 CHX/CCB에 의해 생산된 키메라 수정란(chimeric embryo)은 12.8%, 체외 수정란과 6-DMAP에 의한 키메라 수정란(chimeric embryo)은 18.8%로 handled control의 21.4%에 비해 유의적으로 낮았으며(P<0.05), 이들 키메라 수정란(chimeric embryos)은 체외 수정란의 34.9%에 비해 유의적으로 낮게(P<0.05)나타났다. 6-DMAP 처리 단위발생이 유기된 수정란 할구 2개와 체외수정란의 할구 2개의 응집에 의한 키메라 수정란(chimeric embryos)의 발달율이 CHX/CCB와 체외수정란의 응집에 의한 키메라 수정란(chimeric embryos)에 비해 다소 높게 나타났으나, 유의적인 차이는 없었다. 본 실험의 결과 서로 다른 방법에 의한 단위 발생란 유래의 할구와 체외 수정란 유래의 할구가 응집에 의한 재조합이 가능하였고 이들을 체외에서 배양하여 배반포기의 수정란까지 발달시켰다.

Assesment of Load and Resistance Factored Design Value for PHC Driven Pile (PHC 항타말뚝의 하중저항계수 산정)

  • Park, Jong-Bae;Park, Yong-Boo;Lee, Bum-Sik;Kim, Sang-Yeon
    • Land and Housing Review
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    • v.4 no.3
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    • pp.279-286
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    • 2013
  • Driving a prefabricated pile is the efficient construction method with low cost and excellent bearing capacity charateristics. But pile drinving method has often been changed to bored pile method with mechanical boring due to the unexpected problems occurred in the various domestic ground condition with landfill. So, pile driving method has more uncertainty than the Bored Pile method. This paper proposed LRFD design value which is one of limit states design method for the PHC driven pile used as building foundation to guarantee the reliable design with reduced uncertainty. This paper analysed 221 dynamic load test results(E.O.I.D : 93, Resrike : 128) and the different methods of estimating bearing design(Meyerhof method & SPT-CPT conversion method), and proposed LRFD value for each design reliability Index 2.33 and 3.0 for PHC driven pile. LRFD value of PHC driven pile represents 0.43~0.55 for Meyerhof method and 0.40~0.49 for SPT-CPT conversion method according to the deign reliability index.

Case Study on Design Efficiency and Bearing Capacity Characteristics of Bored PHC Piles (PHC 매입말뚝의 설계효율과 지지력 특성 사례분석)

  • Yun, Jung-Mann;Yea, Geu-Guwen;Kim, Hong-Yeon;Choi, Yong-Kyu
    • Journal of the Korean Geosynthetics Society
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    • v.18 no.3
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    • pp.45-53
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    • 2019
  • In this study, it was analyzed the cases of bored PHC piles designed for the building foundations. The overall length of the piles varies within a maximum of 35 m. However, the average length was 17.0 to 18.9 m depending on the kind of the bedrock, with no significant difference. The socket length entered into the bedrock was designed with approximately 58% of the whole piles being 1m, the minimum length of the specification, and up to 5m. Although the range in design efficiency was very large, on average it was about 70%, consistent with the usual known extent. Applications with low design efficiency were mainly shown on the foundation of low-rise buildings or rides with low design load. On the weathered rock, the design load, which governs the design result was widely distributed at 65 to 97% of allowable bearing capacity of ground. The ratio of allowable axial load of piles to allowable bearing capacity of ground is also widely distributed between 36 and 115%, so optimization efforts are required along with design efficiency. On the other hand, the allowable bearing capacity on the soft or hard rock was highly equal, mostly within 90% of the allowable axial load of piles. In the design, the end bearing resistance averaged over 75% of the allowable bearing capacity. However, the results of the dynamic pile load test show that the end bearing resistance was predominant under the E.O.I.D conditions, and in some cases, the end bearing resistance was at least 25% under the restrike conditions.

Prospect of Sustainable Organic Tea Farming in Lwang, Kaski, Nepa (네팔 르왕지역의 지속적 유기농차 재배 방향)

  • Chang, K.J.;Huang, D.S.;Park, C.H.;Jeon, U.S.;Jeon, S.H.;Binod, Basnet.
    • Journal of Practical Agriculture & Fisheries Research
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    • v.12 no.1
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    • pp.137-150
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    • 2010
  • Traditionally, like many people in mountain region of the Himalaya, the Lwang communities depend on mix of subsistence agriculture, animal husbandry, and seasonal migrant labor for their livelihoods. These traditional systems are characterized by low productivity, diverse use of available natural resources (largely for home consumption), limited markets, and some aversion for innovation. The potential to generate wealth through commerce has largely been untapped by these mountain residents and thus is undervalued in local and national economies. Introduction of organic tea farming is a part of Lwang community's several initiatives to break the vicious poverty cycle Annapurna Conservation Area Project (ACAP) played facilitating roles in all their efforts since beginning. In five years, the tea plantation emerged as a new means for secured a livelihood. This study aims to analyze the current practices in tea farming both in terms of farm management and soil nutrient status(technical) and the prosperity of the tea farmers (social). The technical aspect covers the soil and tea leaf analysis of various nutrients contents in the soil and tea leaf. Originally, the technical aspect of the study was not planned but later during the consultation with the advisor it was taken into consideration which added value to the research study. The sample were collected from different locations and analyzed on the field itself. The other part of the study i.e. the social aspect was done through questionnaire survey and focus group discussion. the tea farming provided them not only a new opportunity but also earned an identity in the region. This initiative was undertaken as a piloting measure. Now that the tea is in production with processing unit established locally, more serious consideration has to be given for better yield and economic prosperity. This research finding will help the community to analyze their efforts and make correction measures in tea garden management and application of fertilizer. It is also expected to fill up the gaps of knowledge and information required to reduce economic stresses and enhance capacity of farmers to make the tea farming a sustainable and beneficial business. The findings are expected to Sustainability of organic tea farming has direct impacts on biodiversity conservation compared to the other traditional farming practices that are more resource intensive. The study will also contribute to identify key action points required for reducing poverty while conserving environment and enhancing livelihoods

Anti-osteoarthritis effect of Boswellia serrata gum resin extract in monosodium iodoacetate-induced osteoarthritic Sprague-Dawley rats (Monosodium iodoacetate 유도 골관절염 동물모델에서 보스웰리아 검레진 추출물의 항골관절염 효과 연구)

  • Jae In Jung;Ryong Kim;Eun Ji Kim
    • Journal of Nutrition and Health
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    • v.56 no.3
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    • pp.231-246
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    • 2023
  • Purpose: The aim of this study was to investigate the anti-osteoarthritic effect of the ethanol extract of Boswellia serrata gum resin (FJH-UBS) enriched with keto-β-boswellic acid and 3-O-acetyl-11-keto-β-boswellic acid compared to the conventional Boswellia serrata extract by adding the process of removing oil with hexane, in the monosodium iodoacetate (MIA)-induced osteoarthritis rat model. Methods: Sprague-Dawley (SD) rats were orally administered 0, 40, or 80 mg of FJH-UBS/kg body weight (BW)/day for 5 weeks and injected with MIA intra-articularly into right knee joints on day 15 to induce osteoarthritis. Changes in the knee joint microarchitecture, cartilage degradation, the expression of inflammatory mediators, cytokines, and matrix metalloproteinases (MMPs) in serum and synovia were observed. Results: Oral administration of FJH-UBS (80 mg/kg BW/day) reduced MIA-induced knee swelling and cartilage degradation and increased the expression of type II collagen and aggrecan in articular cartilage. Furthermore, FJH-UBS administration reduced MIA-induced increases in the serum levels of prostaglandin E2, leukotriene B4, interleukin (IL)-1β, IL-6, and MMP-13, and MIA-induced increases in the mRNA expressions of inducible nitric oxide synthase, cyclooxygenase-2, 5-lipoxygenase, IL-1β, IL-6, TNF-α, MMP-2, MMP-9, and MMP-13 in the synovia of knee joints. Conclusion: These results indicate that FJH-UBS exerts its anti-osteoarthritic effects by suppressing the expressions of inflammatory cytokines and MMPs and, thus, cartilage degradation. Furthermore, they suggest that FJH-UBS has potential use as a functional food that improves joint and cartilage health.

Brief Introduction of Research Progresses in Control and Biocontrol of Clubroot Disease in China

  • He, Yueqiu;Wu, Yixin;He, Pengfei;Li, Xinyu
    • 한국균학회소식:학술대회논문집
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    • 2015.05a
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    • pp.45-46
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    • 2015
  • Clubroot disease of crucifers has occurred since 1957. It has spread to the whole China, especially in the southwest and nourtheast where it causes 30-80% loss in some fields. The disease has being expanded in the recent years as seeds are imported and the floating seedling system practices. For its effective control, the Ministry of Agriculture of China set up a program in 2010 and a research team led by Dr. Yueqiu HE, Yunnan Agricultural University. The team includes 20 main reseachers of 11 universities and 5 institutions. After 5 years, the team has made a lot of progresses in disease occurrence regulation, resources collection, resistance identification and breeding, biological agent exploration, formulation, chemicals evaluation, and control strategy. About 1200 collections of local and commercial crucifers were identified in the field and by artificiall inoculation in the laboratories, 10 resistant cultivars were breeded including 7 Chinese cabbages and 3 cabbages. More than 800 antagostic strains were isolated including bacteria, stretomyces and fungi. Around 100 chemicals were evaluated in the field and greenhouse based on its control effect, among them, 6 showed high control effect, especially fluazinam and cyazofamid could control about 80% the disease. However, fluzinam has negative effect on soil microbes. Clubroot disease could not be controlled by bioagents and chemicals once when the pathogen Plasmodiophora brassicae infected its hosts and set up the parasitic relationship. We found the earlier the pathogent infected its host, the severer the disease was. Therefore, early control was the most effective. For Chinese cabbage, all controlling measures should be taken in the early 30 days because the new infection could not cause severe symptom after 30 days of seeding. For example, a biocontrol agent, Bacillus subtilis Strain XF-1 could control the disease 70%-85% averagely when it mixed with seedling substrate and was drenching 3 times after transplanting, i.e. immediately, 7 days, 14 days. XF-1 has been deeply researched in control mechanisms, its genome, and development and application of biocontrol formulate. It could produce antagonistic protein, enzyme, antibiotics and IAA, which promoted rhizogenesis and growth. Its The genome was sequenced by Illumina/Solexa Genome Analyzer to assembled into 20 scaffolds then the gaps between scaffolds were filled by long fragment PCR amplification to obtain complet genmone with 4,061,186 bp in size. The whole genome was found to have 43.8% GC, 108 tandem repeats with an average of 2.65 copies and 84 transposons. The CDSs were predicted as 3,853 in which 112 CDSs were predicted to secondary metabolite biosynthesis, transport and catabolism. Among those, five NRPS/PKS giant gene clusters being responsible for the biosynthesis of polyketide (pksABCDEFHJLMNRS in size 72.9 kb), surfactin(srfABCD, 26.148 kb, bacilysin(bacABCDE 5.903 kb), bacillibactin(dhbABCEF, 11.774 kb) and fengycin(ppsABCDE, 37.799 kb) have high homolgous to fuction confirmed biosynthesis gene in other strain. Moreover, there are many of key regulatory genes for secondary metabolites from XF-1, such as comABPQKX Z, degQ, sfp, yczE, degU, ycxABCD and ywfG. were also predicted. Therefore, XF-1 has potential of biosynthesis for secondary metabolites surfactin, fengycin, bacillibactin, bacilysin and Bacillaene. Thirty two compounds were detected from cell extracts of XF-1 by MALDI-TOF-MS, including one Macrolactin (m/z 441.06), two fusaricidin (m/z 850.493 and 968.515), one circulocin (m/z 852.509), nine surfactin (m/z 1044.656~1102.652), five iturin (m/z 1096.631~1150.57) and forty fengycin (m/z 1449.79~1543.805). The top three compositions types (contening 56.67% of total extract) are surfactin, iturin and fengycin, in which the most abundant is the surfactin type composition 30.37% of total extract and in second place is the fengycin with 23.28% content with rich diversity of chemical structure, and the smallest one is the iturin with 3.02% content. Moreover, the same main compositions were detected in Bacillus sp.355 which is also a good effects biocontol bacterial for controlling the clubroot of crucifer. Wherefore those compounds surfactin, iturin and fengycin maybe the main active compositions of XF-1 against P. brassicae. Twenty one fengycin type compounds were evaluate by LC-ESI-MS/MS with antifungal activities, including fengycin A $C_{16{\sim}C19}$, fengycin B $C_{14{\sim}C17}$, fengycin C $C_{15{\sim}C18}$, fengycin D $C_{15{\sim}C18}$ and fengycin S $C_{15{\sim}C18}$. Furthermore, one novel compound was identified as Dehydroxyfengycin $C_{17}$ according its MS, 1D and 2D NMR spectral data, which molecular weight is 1488.8480 Da and formula $C_{75}H_{116}N_{12}O_{19}$. The fengycin type compounds (FTCPs $250{\mu}g/mL$) were used to treat the resting spores of P. brassicae ($10^7/mL$) by detecting leakage of the cytoplasm components and cell destruction. After 12 h treatment, the absorbencies at 260 nm (A260) and at 280 nm (A280) increased gradually to approaching the maximum of absorbance, accompanying the collapse of P. brassicae resting spores, and nearly no complete cells were observed at 24 h treatment. The results suggested that the cells could be lyzed by the FTCPs of XF-1, and the diversity of FTCPs was mainly attributed to a mechanism of clubroot disease biocontrol. In the five selected medium MOLP, PSA, LB, Landy and LD, the most suitable for growth of strain medium is MOLP, and the least for strains longevity is the Landy sucrose medium. However, the lipopeptide highest yield is in Landy sucrose medium. The lipopeptides in five medium were analyzed with HPLC, and the results showed that lipopeptides component were same, while their contents from B. subtilis XF-1 fermented in five medium were different. We found that it is the lipopeptides content but ingredients of XF-1 could be impacted by medium and lacking of nutrition seems promoting lipopeptides secretion from XF-1. The volatile components with inhibition fungal Cylindrocarpon spp. activity which were collect in sealed vesel were detected with metheds of HS-SPME-GC-MS in eight biocontrol Bacillus species and four positive mutant strains of XF-1 mutagenized with chemical mutagens, respectively. They have same main volatile components including pyrazine, aldehydes, oxazolidinone and sulfide which are composed of 91.62% in XF-1, in which, the most abundant is the pyrazine type composition with 47.03%, and in second place is the aldehydes with 23.84%, and the third place is oxazolidinone with 15.68%, and the smallest ones is the sulfide with 5.07%.

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Studies on a Plan for Afforestation at Tong-ri Beach Resort(II) -Analyses of Crown Amounts and Soil Properties in the Disaster-damage Prevention Forests of Pinus thunbergii PARL., the Valuation on Soil Properties for Planting and Planning for Afforestation- (통리(桶里) 해수욕장(海水浴場) 녹지대(綠地帶) 조성(造成)에 관(關)한 연구(硏究)(II) -곰솔 해안방재림(海岸防災林)의 수관량(樹冠量) 및 토양분석(土壤分析), 식재기반평가(植栽基盤評價) 및 녹지대계획(綠地帶計劃)-)

  • Cho, Hi Doo
    • Journal of Korean Society of Forest Science
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    • v.77 no.3
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    • pp.303-314
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    • 1988
  • Tong-ri beach has not enough vegetation to be enjoyed by the sea bathers and to be satisfied with preventing the disaster-damages, but mixed forest near the beach can work its funtions and the old forest of Pirus thunbergii $P_{ARL}$. near the beach do a Little. Therefore it is very urgent to plant more trees near the beach for bathers and disaster-damage prevention. This study was carried out for planning an afforestation, with reporting upon the crown amounts and soil properties of disaster-damage prevention forests of P. thunbergii $P_{ARL}$. planted on the coast sand dunes in 1970 and 1976, and with reporting upon the valuation on soil properties of the lands near the beach in order to set the afforestation site. The results are as follows : 1. In disaster-damage prevention forests, crown surface area and crown volume became increasingly greater in proportion to the height. To D.B.H., crown volume also became increasingly greater in proportion, but crown surface area was directly proportional. 2. In comparison to sail characteristics of sand dune, those of the forests were in large quantity in OM, T-N and avail. $SiO_2$, and almost in the same in avail. $P_2O_5$, but in small quantity in exchangeable canons : K, Ca, Mg and Na. 3. EC, Cl and pH were in small value in the forest soils, but CEC was in large value in those soils. 4. Above facts showed that the forests fulfill their functions for preventing disaster-damages and improve their soil properties. 5. The forests have naturally been thinned up to 34% in 17 years and 39% in 11 years, and one can easily pass through the forest(planted in 1970), because of its sufficient clear-length(2.71m) and its space to pass. 6. A plan for afforestation was oracle nut after judging several sites by the evaluation on the soil properties and considering the best relaxation and the prevention of the various disaster-damages upon which were reported in the last issue. 7. Afforestation should be kept for maintaining its appropriate density for best relaxation and disaster-damage prevention.

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Analysis of the Component and Immunological Efficacy of Chamaecyparis obtusa Leaf Extract (편백나무 잎 추출물의 성분분석과 면역효능에 관한 연구)

  • Kim, Joung Hee;Lee, Syng-Ook;Do, Kook Bae;Ji, Won Dae;Kim, Sun Gun;Back, Young Doo;Kim, Keuk-Jun
    • Korean Journal of Clinical Laboratory Science
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    • v.50 no.1
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    • pp.37-43
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    • 2018
  • Chamaecyparis obtusa (CO) has recently been attracting attention because of its beneficial effects on skin allergies, atopic dermatitis, and skin diseases, such as acne and eczema. In the present study, the extract from CO leaf grown in Jangseong gun, Jeollanam-do, Korea was evaluated for its anti-oxidant, anti-inflammatory, and anti-allergic effects in vitro. The total polyphenol content of the CO leaf extract was $25.89{\pm}0.31mg$ gallic acid equivalents (GAE)/g. Gas-chromatography mass-spectrometry (GC-MS) analysis revealed the presence of six compounds in the CO leaf extract: ${\alpha}-terpinene$ (3.03 mg/g), ${\alpha}-terpineol$ (9.48 mg/g), limonene (5.96 mg/g), borneol (59.78 mg/g), myrcene (4.85 mg/g), and sabinene (11.31 mg/g). The $RC_{50}$ values of the CO leaf extract for $H_2O_2$ and ABTS radical were $5.47{\pm}0.13mg/mL$ and $4.00{\pm}0.01mg/mL$, respectively. In addition, the CO leaf extract showed significant inhibitory effects on lipopolysaccharide-induced nitric oxide production in RAW 264.7 cells and IgE-induced release of ${\beta}-hexosaminidase$ (degranulation) in mast-cell like RBL-2H3 cells. The cell viability assay showed that the CO leaf extract ($100{\sim}800{\mu}g/mL$) did not affect the viability of human normal skin fibroblast CCD-986sk cells significantly. Overall, these results suggest that the CO leaf extract is a potential functional cosmetic ingredient that can exert anti-oxidant, anti-inflammatory, and anti-allergic effects.

Properties of Indium Tin Oxide Thin Films According to Oxygen Flow Rates by γ-FIB System (γ-FIB 시스템을 이용한 산소 유량 변화에 따른 산화인듐주석 박막의 특성 연구)

  • Kim, D.H.;Son, C.H.;Yun, M.S.;Lee, K.A.;Jo, T.H.;Seo, I.W.;Uhm, H.S.;Kim, I.T.;Choi, E.H.;Cho, G.S.;Kwon, G.C.
    • Journal of the Korean Vacuum Society
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    • v.21 no.6
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    • pp.333-341
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    • 2012
  • Indium Tin Oxide (ITO) thin films were prepared by RF magnetron sputtering with different flow rates of $O_2$ gas from 0 to 12 sccm. Electrical and optical properties of these films were characterized and analyzed. ITO deposited on soda lime glass and RF power was 2 kW, frequency was 13.56 MHz, and working pressure was $1.0{\times}10^{-3}$ Torr, Ar gas was fixed at 1,000 sccm. The transmittance was measured at 300~1,100 nm ranges by using Photovoltaic analysis system. Electrical properties were measured by Hall measurement system. ITO thin films surface were measured by Scanning electron microscope. Atomic force microscope surface roughness scan for ITO thin films. ITO thin films secondary electron emission coefficient(${\gamma}$) was measured by ${\gamma}$-Focused ion beam. The resistivity is about $2.4{\times}10^{-4}{\Omega}{\cdot}cm$ and the weighted average transmittance is about 84.93% at 3 sccm oxygen flow rate. Also, we investigated Work-function of ITO thin films by using Auger neutralization mechanism according to secondary electron emission coefficient(${\gamma}$) values. We confirmed secondary electron emission peak at 3 sccm oxygen flow rate.