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A Study on the etching mechanism of $CeO_2$ thin film by high density plasma (고밀도 플라즈마에 의한 $CeO_2$ 박막의 식각 메커니즘 연구)

  • Oh, Chang-Seok;Kim, Chang-Il
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.38 no.12
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    • pp.8-13
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    • 2001
  • Cerium oxide ($CeO_2$) thin film has been proposed as a buffer layer between the ferroelectric thin film and the Si substrate in Metal-Ferroelectric-Insulator-Silicon (MFIS) structures for ferroelectric random access memory (FRAM) applications. In this study, $CeO_2$ thin films were etched with $Cl_2$/Ar gas mixture in an inductively coupled plasma (ICP). Etch properties were measured for different gas mixing ratio of $Cl_2$($Cl_2$+Ar) while the other process conditions were fixed at RF power (600 W), dc bias voltage (-200 V), and chamber pressure (15 mTorr). The highest etch rate of $CeO_2$ thin film was 230 ${\AA}$/min and the selectivity of $CeO_2$ to $YMnO_3$ was 1.83 at $Cl_2$($Cl_2$+Ar gas mixing ratio of 0.2. The surface reaction of the etched $CeO_2$ thin films was investigated using x-ray photoelectron spectroscopy (XPS) analysis. There is a Ce-Cl bonding by chemical reaction between Ce and Cl. The results of secondary ion mass spectrometer (SIMS) analysis were compared with the results of XPS analysis and the Ce-Cl bonding was monitored at 176.15 (a.m.u). These results confirm that Ce atoms of $CeO_2$ thin films react with chlorine and a compound such as CeCl remains on the surface of etched $CeO_2$ thin films. These products can be removed by Ar ion bombardment.

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Garlic powder intake and cardiovascular risk factors: a meta-analysis of randomized controlled clinical trials

  • Kwak, Jin Sook;Kim, Ji Yeon;Paek, Ju Eun;Lee, You Jin;Kim, Haeng-Ran;Park, Dong-Sik;Kwon, Oran
    • Nutrition Research and Practice
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    • v.8 no.6
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    • pp.644-654
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    • 2014
  • BACKGROUND/OBJECTIVES: Although preclinical studies suggest that garlic has potential preventive effects on cardiovascular disease (CVD) risk factors, clinical trials and reports from systematic reviews or meta-analyses present inconsistent results. The contradiction might be attributed to variations in the manufacturing process that can markedly influence the composition of garlic products. To investigate this issue further, we performed a meta-analysis of the effects of garlic powder on CVD risk factors. MATERIALS/METHODS: We searched PubMed, Cochrane, Science Direct and EMBASE through May 2014. A random-effects meta-analysis was performed on 22 trials reporting total cholesterol (TC), 17 trials reporting LDL cholesterol (LDL-C), 18 trials reporting HDL cholesterol (HDL-C), 4 trials reporting fasting blood glucose (FBG), 9 trials reporting systolic blood pressure (SBP) and 10 trials reporting diastolic blood pressure (DBP). RESULTS: The overall garlic powder intake significantly reduced blood TC and LDL-C by -0.41 mmol/L (95% confidence interval [CI], -0.69, -0.12) (-15.83 mg/dL [95% CI, -26.64, -4.63]) and -0.21 mmol/L (95% CI, -0.40, -0.03) (-8.11 mg/dL [95% CI, -15.44, -1.16]), respectively. The mean difference in the reduction of FBG levels was -0.96 mmol/L (95% CI, -1.91, -0.01) (-17.30 mg/dL [95% CI, -34.41, -0.18]). Evidence for SBP and DBP reduction in the garlic supplementation group was also demonstrated by decreases of -4.34 mmHg (95% CI, -8.38, -0.29) and -2.36 mmHg (95% CI, -4.56, -0.15), respectively. CONCLUSIONS: This meta-analysis provides consistent evidence that garlic powder intake reduces the CVD risk factors of TC, LDL-C, FBG and BP.

Fungal Occurrence in Fresh and Dried Red Pepper (건고추 생산단계 중 고추의 곰팡이 발생)

  • Kim, Sosoo;Baek, Seul Gi;Hwang, Injun;Kim, Se-Ri;Jung, Gyusuck;Roh, Eunjung;Jang, Ja Yeong;Kim, Jeomsoon;Lee, Theresa
    • Journal of Food Hygiene and Safety
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    • v.34 no.6
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    • pp.571-575
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    • 2019
  • Fungal occurrence during production of dried red pepper was investigated using red pepper samples collected at harvest, before and after washing, and before, during or after drying. Fungal incidence was evaluated by counting the number of fungal colonies grown after incubating random pepper cuts on potato dextrose agar plates. Washing with ground water had no significant effect on reduction of fungal contamination. Fungal increase was observed in some samples, and the insides of washer and containers were contaminated with fungi. Drying caused significant fungal increase regardless of drying method although the fungal incidence after machine drying was lower than that after greenhouse drying. Fungal increase was observed in the samples being dried in a greenhouse and some mycotoxigenic species were also detected. Therefore, the most important control point for fungal contamination during dried pepper production appears to be the drying process, especially in a greenhouse.

Construction of hsf1 Knockout-mutant of a Thermotolerant Yeast Strain Saccharomyces cerevisiae KNU5377 (고온내성 연료용 알코올 효모균주 Saccharomyces cerevisiae KNU5377에서 HSF1 유전자의 변이주 구축)

  • Kim Il-Sup;Yun Hae-Sun;Choi Hye-Jin;Sohn Ho-Yong;Yu Choon-Bal;Kim Jong-Guk;Jin Ing-Nyol
    • Journal of Life Science
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    • v.16 no.3 s.76
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    • pp.454-458
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    • 2006
  • HSF1 is the heat shock transcription factor in Saccharomyces cerevisiae. S. cerevisiae KNU5377 can ferment at high temperature such as $40^{\b{o}}C$. We have been the subjects of intense study because Hsf1p mediates gene expression not only to heat shock, but to a variety of cellular and environmental stress challenges. Basing these facts, we firstly tried to construct the hsf1 gene-deleted mutant. PCR-method for fast production of gene disruption cassette was introduced in a thermotolerant yeast S. cerevisiae KNU5377, which allowed the addition of short flanking homology region as short as 45 bp suffice to mediate homologous recombination to kanMX module. Such a cassette is composed of linking genomic DNA of target gene to the selectable marker kanMX4 that confers geneticin (G418) resistance in yeast. That module is extensively used for PCR-based gene replacement of target gene in the laboratory strains. We describe here the generation of hsf1 gene disruption construction using PCR product of selectable marker with primers that provide homology to the hsf1 gene following separation of haploid strain in wild type yeast S. cerevisiae KNU5377. Yeast deletion overview containing replace cassette module, deletion mutant construction and strain confirmation in this study used Saccharomyces Genome Deletion Project (http:://www-sequence.standard.edu/group/yeast_deletion_project). This mutant by genetic manipulation of wild type yeast KNU5377 strain will provide a good system for analyzing the research of the molecular biology underlying their physiology and metabolic process under fermentation and improvement of their fermentative properties.

Effect of extraction socket granulation tissue graft on the regeneration of horizontal furcation defect (발치와의 육아조직 이식이 치근이개 결손부의 재생에 미치는 영향)

  • Oh, Mok-Hoon;Han, Soo-Boo;Son, Sung-Heui;Yang, Seung-Min;Ko, Jae-Seung
    • Journal of Periodontal and Implant Science
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    • v.26 no.3
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    • pp.735-751
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    • 1996
  • An ultimate goal of periodontal therapy is to stop the disease process and to regenerate a functionally-oriented periodontium destroyed as a result of periodontal disease. The purpose of this study was to observe the effect of grafting granulation tissue obtained from extraction socket on the regeneration of horizontal furcation defect. Six dogs were used in this study. All mandibular first and third premolars were extracted. At 2, 3, and 5 days after extraction, tissues were obtained from extraction socket of 1 mongrel dog and examined by light microscope. Granulation tissue obtained at 5 days after extraction was chosen as the graft material. Five days later, horizontal furcation defects were created surgically at mandibular second and fourth premolars in the right and left side of the 5 beagle dogs. The entrance area of the artificially prepared "key hole" defects were about $3\;4mm^2$. By random selections, 2 exposed furcation defects were grafted with granulation tissue obtained from extraction socket as experimental group and 1 furcation defect was as control. The flaps were replaced to their original position and sutured with 4-0 chromic cat-gut. Three dogs were sacrificed 4 weeks and two dogs 8 weeks after surgery, and the prepared specimens were examined by light microscope. At 4 weeks, furcations were filled with epithelial lining and fibrous connective tissue infiltrated with chronic inflammatory cells. New bone formation was observed in all groups. Only experimental group showed new cementum formation. At 8 weeks, new cementum, functional arrangement of new PDL fiber, root resorption, and some ankylotic union of newly formed alveolar bone and root surface were observed in all groups. Experimental group showed that epithelial downgrowth was inhibited and new bone formation was more active compared to control. The success rate of the furcation defect healing was higher in experimental group than control. These results suggested that grafting of granulation tissue obtained from extraction socket which combined with reconstructive periodontal flap surgery may promote periodontal regeneration of horizontal furcation defect.

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A Study on the Self-care of the Menopausal Symptoms of Middle-Aged Women (중년 여성의 갱년기 증상과 자기건강관리 (Self-Care)와의 관련성 조사연구)

  • 김희은;김초강
    • Korean Journal of Health Education and Promotion
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    • v.10 no.1
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    • pp.72-86
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    • 1993
  • The purpose of this study is to find out the menopausal symptom of middle-aged women and their self-care on it. This study also intended to awaken the relationship of the menopausal symptom and self-care and to provide basic data on the health education of middle-aged women. For this purpose, the study (1) identified respondents background variables, (2) found menopausal symptom and the state of self-care, (3) analyzed relationship between general character, menopausal symptom, and self-care, (4) analyzed the relationship of menopausal symptom and self-care for 543 random sampled women in City of Incheon. The questionnaire consisted of 25 questions on the menopausal symptom interview by Neugarton translated by Jung Hae Ran(1985) and questions of the self-care inventory by Orem reconstructed by Sung Moon Hee(1988). The data were analyzed by using frequency, percentage, t-test, X²-test, pearson's correlation coefficient with SPSS statistical package. The results of this study could be summed up as follows ; 1. The Degree of menopausal symptom were graded from 25 to 75. (x 40.85, s. d. 8. 6.) 2. The test of relationship between the individual background and the menopausal symptom revealed that there seemed to be statistically significant correlation between the sexual life, life-content, the level of education, menstruation(p<0.000). 3. In the test of relationship between the individual background and the self-care process, (1) in case of insight of symptom, there seemed to be statistically significant correlation between the self-content(r=0.1463), sexual life(r= -0.1376), menstruation(r=0.1561), and artificial abortion(r=0.1577), (p<0.001), (2) In case of self-health control, there seemed to be statistical correlation between the states of menstruation and the number of induced abortion. (3) In case of self-health decision, there seemed to be statistically significant correlation between the number of visiting hospitals or clinics and the level of education(r=0.106), the self-content(r=0.1235), induced abortion(r=0.1343) (p<0.0000). And also individual background can show the 40.21 percent of self-health maintenance. 4. The relationship between menopausal symptom and self-care has a significant meaning to the insight of symptom, self-health decision according to the groups of menopausal symptom(p<0.000), but it doesn't have any meaning to self-health control. And self-health maintenance can manifest the 19.88 percent of menopausal symptom.

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Analysis of Coastal Area Utilization by Consultation of Marine Environmental Impact Assessment Related-Systems (해양환경영향평가 관련 협의에 의한 연안이용분석)

  • Lee, Dae-In;Eom, Ki-Hyuk;Kwon, Kee-Young;Kim, Gui-Young;Yoon, Sung-Soon;Jang, Ju-Hyoung
    • Journal of Environmental Impact Assessment
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    • v.17 no.2
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    • pp.97-103
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    • 2008
  • This study presented politic proposals and diverse utilization-type in coastal areas by analyzing results of reviewed related-statements of marine environment during the one year period of 2007 by Marine Environmental Impact Assessment Center. Total of 358 cases were reviewed, which was a significant increase from 270 in 2006. Consultation on the utilization of sea areas (CUSA) accounted for the largest number of 165 (46.1%) and it was followed by 104 cases of environmental impact assessment (EIA) (29.0%) and 89 cases of prior environmental review (PER) (24.9%). As such, evaluation statements (EIA+PER) related to consultations of the Ministry of Environment accounted for approximately 54% of the entire cases reviewed. To analyze the overall results of reviewing marine-related evaluation statements, utilization and planning were conducted by 47.9%, 38.4% and 13.7% in the South Sea, West Sea and East Sea of Korea, respectively. In evaluation statements (EIA+PER), port construction, industrial complex construction, urban management plan and road construction took up most of the part by 40.9%, 20.2%, 10.4% and 7.3%, respectively. In terms of CUSA-statement, it was evaluated that consultations were mostly carried out on use and reclamation of public water surface in coastal areas and on sea aggregate extraction process in EEZ. The largest number of plans for coastal use were established for Jeollanam-do, followed by Gyeongsangnam-do, Chungcheongnam-do, Gyeongsangbuk-do and Gyeonggi-do. In particular, development plans were concentrated on Jeollanam-do and Gyeongsangnam-do with stable marine environment and outstanding view of the nature. In most cases, these regions are adjacent to the areas designated as a sea area for environmental management and fisheries resources protection zone. Therefore, conflicts exist between development and preservation. Also, rather than random development, more detailed marine environmental impact assessment, gathering of public opinions and politic harmony are essentially required. For efficient coastal management and environmentally sound and sustainable development, fulfilling consistent and transparent coastal policies as well as active and reliable decision making to center on coastal environment by management bodies will be important.

A Study on Curriculum of Dental Hygienists (치과위생사 교육과정 연구)

  • Park, II-Soon
    • Journal of Korean society of Dental Hygiene
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    • v.4 no.2
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    • pp.193-207
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    • 2004
  • The aims of the study are as following : First, define and clarify the role and function of the dental hygienist. Second, based on thai definition, present an improved dental hygienist curriculum, improving their special competence. This study seeks to present a way for promoting role of dental hygienists as independent specialists, rather than as auxiliaries, contributing to better dental service in the process. The research was pursued by surveying by questionnaire those directly related to dental hygiene. They are 58 professors of dental hygiene, 164 dentists, 253 dental hygienists and 496 dental hygiene students, selected by the method of simple random sampling. Due to the small size of the sample, professors' group was analysed only through frequency and probabilities. For groups with larger samples(dentists, dental hygienists, dental hygiene students), methods of chi square(${\chi}^2$) tests, frequency analysis and one-way ANOVA were used in their analysis. Conclusions of the study are as following : First, role and function of the dental hygienist was defined and clarified. According to the analysis of the survey, main role of the dental hygienists as perceived by 62.9% of dentists was supporting treatments and managing patients and facility. This perception by dentists differs significantly to perception of other groups, which saw main role of dental hygienists as preventive dental treatment and dental hygiene education. Also, only 20.2% of dental hygienists perceived patients and facility management as their main role. This divergence of perception between groups weakens speciality competence of dental hygienists. To strengthen dental hygienists' speciality competence, preventive dental treatment and dental hygiene education must be defined as main role of dental hygienists. Furthermore, role of dental hygienists can be categorized into cooperative and auxiliary role. Second, in order to strengthen speciality competence of dental hygienists, their education must be augmented with curriculum emphasizing cooperative role. Specifically, courses on preventive dental treatment, dental hygiene education and dental X-ray photography must become compulsory, as well as becoming more comprehensive and organized. Also, training in schools and hospitals must be focused on those subjects. In addition, courses concerning auxiliary role must be incorporated into optional courses and more pedagogical courses are needed to widen students' career choices. Third, practical relevance of national dental hygienist certification examination must be heightened. In the survey, all groups gave negative response to questions concerning practical relevance of national dental hygienist certification test. Specifically, contents of the tests must be changed to test participants' competence in the cooperative area. Also, the test itself must be strengthened by adding practical examination to the certification scheme, as well as having more difficult examinations.

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Shared Tree-based Multicast RP Re-Selection Scheme in High-Speed Internet Wide Area Network (고속 인터넷 환경에서 공유 트리 기반 멀티캐스트 RP 재선정 기법)

  • 이동림;윤찬현
    • The KIPS Transactions:PartC
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    • v.8C no.1
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    • pp.60-67
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    • 2001
  • Multicast Protocol for multimedia service on the Internet can be classified into two types, e.g., source based tree and shared tree according to difference of tree construction method. Shared tree based multicast is known to show outstanding results in the aspect of scalability than source based tree. Generally, There have been lots of researches on the method to satisfy QoS constraints through proper Rendezvous Point (RP) in the shared tree. In addition, as the multicast group members join and leave dynamically in the service time, RP of the shared tree should b be reselected for guranteeing Qos to new member, But, RP reselection method has not been considered generally as the solution to satisfy QoS C constraints. In this paper, new initial RP selection and RP reselection method are proposed, which utilize RTCP (Real Time Control Protocol) report packet fields. Proposed initial RP selection and RP reselection method use RTCP protocol which underlying multimedia application service So, the proposed method does not need any special process for collecting network information to calculate RP. New initial RP selection method s shows better performance than random and topology based one by 40-50% in simulation. Also, RP reselection method improves delay p performance by 50% after initial RP selection according to the member’s dynamicity.

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Development of Improved Clustering Harmony Search and its Application to Various Optimization Problems (개선 클러스터링 화음탐색법 개발 및 다양한 최적화문제에 적용)

  • Choi, Jiho;Jung, Donghwi;Kim, Joong Hoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.3
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    • pp.630-637
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    • 2018
  • Harmony search (HS) is a recently developed metaheuristic optimization algorithm. HS is inspired by the process of musical improvisation and repeatedly searches for the optimal solution using three operations: random selection, memory recall (or harmony memory consideration), and pitch adjustment. HS has been applied by many researchers in various fields. The increasing complexity of real-world optimization problems has created enormous challenges for the current technique, and improved techniques of optimization algorithms and HS are required. We propose an improved clustering harmony search (ICHS) that uses a clustering technique to group solutions in harmony memory based on their objective function values. The proposed ICHS performs modified harmony memory consideration in which decision variables of solutions in a high-ranked cluster have higher probability of being selected than those in a low-ranked cluster. The ICHS is demonstrated in various optimization problems, including mathematical benchmark functions and water distribution system pipe design problems. The results show that the proposed ICHS outperforms other improved versions of HS.