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A Study on the Improvement of Employment Rate of Dental Technology School Graduates in Daegu and the Supply and Demand of Dental Technician Work Forces (대구지역 치기공과 학생의 취업률 향상과 치과기공사의 인력수급에 관한 연구)

  • Lee, Jong-Do;Jung, Young-Hae
    • Journal of Technologic Dentistry
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    • v.31 no.1
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    • pp.37-54
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    • 2009
  • The purpose of this thesis is to address the imbalance between supply and demand of dental lab technicians and to propose its solutions by analyzing the improvement of employment rate of graduates of dental technology schools in Daegu area and the supply and demand of the technician workforce. Preliminary and full-scale surveys were performed from Aug. 10 to Oct. 10 in 2008 on 150 junior students of dental technology schools who finished their on-the-job-training and 150 dental technicians who were working for dental laboratory in Daegu by self-assessment questionnaire. Followings are the findings of this study. First, regarding the gender of the dental technicians, 32.7% of respondents were female 67.3% were male. Concerning age, respondents younger than 29 years-old occupied the highest percentage(39.3%). With respect to the lab technology school they graduated, DaeguHealthCollege took the largest proportion of 87.3%. With regard to interpersonal relationship at the school, 58.0% of respondents felt their relationship 'smooth'. Second, about the motive of choosing to be a lab technician, the biggest proportion of the respondents(34.7%) replied that 'because it is professional'. Regarding the degree of satisfaction about the profession, 'so-so' was the answer with the biggest percentage(51.3%) followed by 'satisfied'(32.0%) and 'unsatisfied'(16.7%). It showed that respondents were generally satisfied with their major. Third, regarding relevance of on-the-job-training with 'preparation for the employment', highest percentage of both students and lab technicians(50.0%) replied 'so-so'. With respect to 'necessity of practical education', highest percentage of the students and lab technicians replied 'relating didactic education in college to the real world' with 52.7% and 40.7% respectively. With regard to 'the aim of on-the-sport-training', 'practical training of didactic education' was chosen by 54.0% and 47.3% respectively. Fourth, with regard to the 'types of college education advantageous for the employment', both students and lab technicians groups chose 'practical training' with the highest percentage. Concerning 'helpfulness of clinical training on employment', students answered 'so-so' and 'helpful' by 50.0% and 42.7% respectively and dental technicians replied similarly by 50.0% and 46.0% respectively. Fifth, with regard to the influence of financial factors on the supply and demand of dental technician(question #1), 68.0% of respondents agreed that 'salary plays key role in the supply and demand of the work force'. Concerning the question about working condition, respondents requested better working environment. With reference to interpersonal relationship at the laboratory, respondents replied that interpersonal relationship affects the duration of the employment it was found out that there were many conflicts with colleagues or dental office. Sixth, regarding the satisfaction about their profession according to the characteristics of the respondents more respondents were 'satisfied'(10.30 points) with their profession and 'unsatisfied' were 9.47 points and the difference was statistically significant(p<0.05). According to the findings of this study, practical education on campus and on-the-job-training are as important as didactic education at class due to the characteristics of dental technology major. It was found that more practical training is related to higher employment rate. Therefore, efficiency of on-the-job-training by college education should be increased raise employment rate of the graduates and reduce the unemployment. Up-to-date information needs to be promptly delivered and future vision should be presented to the students to raise their satisfaction about the profession. In addition, to reduce dental technician's frequent change of their workplace after facing with the reality of the profession after graduation, related organizations should make an effort to present better future than now.

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A comparative study on bond strength and adhesive failure pattern in bracket bonding with self-etching primer (Self-etching Primer를 이용한 교정용 브라켓 부착시 전단결합강도와 파절양상에 관한 비교연구)

  • Kim, You-Kyoung;Lee, Jin-Woo;Cha, Kyung-Suk
    • The korean journal of orthodontics
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    • v.34 no.4 s.105
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    • pp.325-332
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    • 2004
  • A self-etching primer that combines the etchant and primer in one chemical compound saves time and should be mote cost-effective to the clinician and patient. The purpose of this study was to evaluate the clinical effectiveness of a self-etching primer by measuring shear bond strengths according to various conditions and observing adhesive failure patterns. For this Investigation, 120 upper and lower premolars extracted for orthodontic purposes were used and randomly divided into six groups of twenty teeth each. Human premolars were embedded in a metal cylinder with orthodontic resin. Metal brackets and ceramic brackets were bonded with XT primer and self-etching primer by means of XT adhesive. Upon curing, plasma arc light and visible light were used. After bonding, the shear bond strength was tested by Instron universal testing machine, and the amount of residual adhesive that remained on the tooth after debonding was measured by stereoscope and assessed with an adhesive remnant index. The results were as fellows: 1. When brackets were bonded, if other conditions remained the same, there was no significant difference in shear bond strength due to the type of primer - either self-etching primer or XT primer. 2. When metal brackets were bonded, there was no significant difference in shear bond strength according to the source of light - plasma arc light or visible light - and type of primer. 3. There was a very significant difference in shear bond strength according to the type of brackets - metal or ceramic brackets. The shear bond strength of ceramic brackets was stronger than metal brackets. 4. When the adhesive failure patterns of metal brackets bonded with self-etching primer were observed by using the adhesive remnant index, the bond failure of the metal bracket occurred more frequently at the bracket-adhesive. The failure of the ceramic bracket, however, occurred more frequently at the enamel-adhesive interface. The adhesive failure patterns of metal brackets bonded with XT primer observed the same patterns. The above results suggest that self-etching primer can be clinically useful for bonding the brackets without fear of a decrease in shear bond strength.

A comparative study of electroplating and electroless plating for diameter increase of orthodontic wire (교정용 선재의 직경 증가를 위한 전기도금법과 무전해도금법의 비교연구)

  • Kim, Jae-Nam;Cho, Jin-Hyoung;Sung, Young-Eun;Lee, Ki-Heon;Hwang, Hyeon-Shik
    • The korean journal of orthodontics
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    • v.36 no.2 s.115
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    • pp.145-152
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    • 2006
  • The purpose of this study was to evaluate electroless plating as a method of increasing the diameter of an orthodontic wire in comparison with eletroplating. After pretreatment plating of the 0.016 inch stainless steel orthodontic wire, electroless plating was performed at $90^{\circ}C$ until the diameter of the wire was increased to 0.018 inch. During the process of electroless plating, the diameter of the wire was measured every 5 minutes to examine the increasing ratio of the wire's diameter per time unit. And to examine the uniformity, the diameter at 3 points on the electroless-plated orthodontic wire was measured. An X-ray diffraction test for analyzing the nature of the plated metal and a 3-point bending test for analyzing the physical property were performed. The electroless-plated wire group showed a increased tendency for stiffness, yield strength, and ultimate strength than the electroplated wire group. And there was a statistically significant difference between the two groups for stiffness and ultimate strength. In the electroless-plated wire group, the increasing ratio of the diameter was $0.00461{\pm}0.00003mm/5min$ (0.00092 mm/min). In the electroplated wire group, it was $0.00821{\pm}0.00015mm/min$. The results of the uniformity test showed a tendency for uniformity in both the plating methods. The results of this study suggest that electroless plating of the wire is closer to the ready-made wire than electroplating wire in terms of the physical property. However, the length of plating time needs further consideration for the clinical application of electroless plating.

Antigenotoxic and Anticarcinogenic Effects of Styela plicata (오만둥이(Styela plicata)의 항유전독성 및 대장암 억제효과에 관한 연구)

  • Seo, Bo-Young;Kim, Jung-Mi;Lee, Seung-Cheol;Park, Eun-Ju
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.38 no.7
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    • pp.839-845
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    • 2009
  • Colorectal cancer is the third most common malignant neoplasm in the world. Much attention has been focused on reducing colon cancer risk through medical properties of natural compound that could act as anticarcinogens. In this study, we evaluated the antioxidant and antigenotoxic effects of Styela plicata (S. plicata) from in vitro experiments. S. plicata extracts showed antioxidant activity measured by TRAP assay and antigenotoxic effect in $200{\mu}M$ $H_2O_2$ induced DNA damage in human leukocytes. Especially, freeze-dried S. plicata extracted with methanol showed the highest level of TRAP (0.225 mM) and inhibition of DNA damage (66.8%). Additionally we observed the effect of S. plicata on the formation of aberrant crypt foci (ACF) induced by dimethylhydrazine (DMH) and DMH induced DNA damage (by comet assay) in male SD rats. The animals were divided into three groups and fed high-fat and low fiber diet (100 g lard+20 g cellulose/kg diet) without (normal control and DMH control) or with a 3% (w/w) of lyophilized S. plicata powder (DMH+S. plicata). One week after beginning the diets, rats were treated with DMH (30 mg/kg, s.c.) for 6 weeks except for normal control group, which was treated saline instead; dietary treatments were continued for the entire experiment. Nine weeks after DMH injection, administration of S. plicata resulted in reduction of ACF numbers, to 82.7% of the carcinogen control value ($7.67{\pm}2.04$ vs. $1.33{\pm}0.53$: p<0.01). S. plicata supplementation induced antigenotoxic effect on DMH-induced DNA damage in the blood cell (% tail intensity: $6.79{\pm}0.26$ vs. $6.13{\pm}0.22$). These data indicate that S. plicata extract has antigenotoxic and anticarcinogenic effects from in vitro experiments and S. plicata exerts a protective effect on the process of colon carcinogenesis, possibly by suppressing the DMH-induced DNA damage in blood cell and the development of preneoplastic lesions in colon.

Effect of Waxy Barley Bread with Trans Fat on the Lipid Profile and Fatty Acid Composition in Healthy Korean Adults (Trans 지방을 첨가한 찹쌀보리빵의 섭취가 건강한 성인의 혈장 지질수준과 지방산 조성에 미치는 영향)

  • Noh, Kyung-Hee;Huh, Young;Jang, Ji-Hyun;Shin, Jin-Hyuk;Lee, Mi-Ock;Lee, Kyung-Sik;Lee, Seong-Hwan;Kim, Do-Hoon;Park, Yong-Kyu;Cho, Kyung-Hwan;Song, Young-Sun
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.38 no.10
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    • pp.1353-1361
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    • 2009
  • This study investigated the effect of waxy barley on the incorporation trans fat (tFA) into plasma lipid and lipid profile through 6 weeks trial. 39 healthy volunteers were divided into 2 groups and fed waxy barley bread (WBG) or wheat bread (WG) containing equivalent amounts of tFA (elaidic acid rich, 3.75 g/day), respectively. Plasma lipid profiles and fatty acid composition at 0, 2, 4, 6 weeks after a respective bread were studied. Plasma lipid was extracted by the method of Folch, esterified by acid transmethylation and analyzed by gas chromatography. The fatty acid composition reflected the fatty acid proportion of the test fat. However, consumption of waxy barley bread with tFA for 6 weeks affected plasma fatty acid composition including tFA. Incorporation of tFA into plasma lipid was significantly lowered compared to WBG than in WG after 6 weeks of consumption. Furthermore, saturated fatty acids such as C16:0 and C18:0 levels were also significantly lowered in WBG than in WG. Furthermore, plasma total cholesterol level and TG/HDL-cholesterol ratio were also significantly lowered in WBG compared to WG at 2, 4 and 6 weeks. These results suggest that waxy barley bread with high $\beta$-glucan lowered plasma trans, saturated fatty acid and total cholesterol levels though the inhibition of lipid absorption.

Community Structure of Macrobenthic Assemblages around the Wolseong Nuclear Power Plant, East Sea of Korea (월성 원자력발전소 주변해역에 서식하는 대형저서동물의 군집구조)

  • Seo, In-Soo;Moon, Hyung-Tae;Choi, Byoung-Mi;Kim, Mi-Hyang;Kim, Dae-Ik;Yun, Jae-Seong;Byun, Ju-Young;Choi, Hue-Chang;Son, Min-Ho
    • Korean Journal of Environmental Biology
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    • v.27 no.4
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    • pp.341-352
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    • 2009
  • This study was carried out to investigated community structure of macrobenthic assemblages around the Wolseong Nuclear Power Plant, East Sea of Korea and seasonal sampling was performed from October 2007 to July 2008. A total of 163 macrobenthic fauna were collected. The overall average macrobenthos density and biomass were 1,005 individuals $m^{-2}$ and $21.81\;gWWt\;m^{-2}$, respectively. Based on the LeBris (1988) index, there were 10 dominant species accounting for approximately 69.00% of total individuals. The major dominant species were the polychaetes Spiophanes bombyx (349 inds. $m^{-2}$), Mediomastus californiensis (82 inds. $m^{-2}$), Sigambra tentaculata (55 inds. $m^{-2}$), Magelona japonica (50 inds. $m^{-2}$), Scoletoma longifolia (33 inds. $m^{-2}$) and the Unidentified amphipod (Amphipoda spp., 72 inds. $m^{-2}$). The conventional multi-variate statistics (cluster analysis and non-metric multi-dimensional scaling) applied to assess spatial variation in macrobenthic assemblages. Cluster analysis and nMDS ordination analysis based on the Bray-Curtis similarity identified 2 major station groups. The major group 1 was associated with sand dominated stations and was characterized by high abundance of the bivalves Mactra chinensis, Siliqua pulchella and the polychaete Protodorvillea egena. On the other hand, major group 2 was connected with mud dominated stations and was numerically dominated by the polychaetes M. californiensis, M. japonica, Sternaspis scutata, S. longifolia and the bivalves Thyasira tokunagai and Theora fragilis. However, macrobenthic community structure were no significant differences between the environmental variables (sediment type and depth) and heated discharge.

An Investigation of Microbial Contamination of Ready-to-Eat Products in Seoul, Korea (서울지역 유통판매 중인 즉석섭취.편의식품의 위해 미생물 오염도 조사)

  • Kim, Hee-Yun;Oh, Seon-Woo;Chung, So-Young;Choi, Seon-Hee;Lee, Ji-Won;Yang, Ji-Yeon;Seo, Eun-Chae;Kim, Yong-Hoon;Park, Hee-Ok;Yang, Cheul-Young;Ha, Sang-Chul;Shin, Il-Shik
    • Korean Journal of Food Science and Technology
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    • v.43 no.1
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    • pp.39-44
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    • 2011
  • This study was carried out to examine microbiological contamination of ready-to-eat products and to propose a draft-standard and specifications according to food types. RTE foods were classified into 6 groups including fish products, meat products, breads, rices, salads, and fresh cut foods. The prevalence rates of pathogens detected from all samples were compared among food categories. The pH ranges for all RTE samples were between 3.8 and 7.3. Total aerobic cell counts ranged from 2 to 6 log CFU/g. Bread, rice and fresh-cut foods showed significantly higher counts, which ranged above 4.0 log CFU/g among the samples. Two kinds of rice were above the level of the KFDA Food Code standard for Eschrichia coli. The prevalence rate of E. coli in the rice was 6.7%. For Staphylococcus aureus, one fish product and one bread-product had levels above 2 log CFU/g. Bacillus cereus counts for all samples were below the level of 3 log CFU/g. Listeria monocytogenes was not detected in the samples. Therefore, these data suggest that the primary microbial hazard factors for ready-to-eat foods and risk assessments should focus on E. coli, S. aureus, and B. cereus.

Using the METHONTOLOGY Approach to a Graduation Screen Ontology Development: An Experiential Investigation of the METHONTOLOGY Framework

  • Park, Jin-Soo;Sung, Ki-Moon;Moon, Se-Won
    • Asia pacific journal of information systems
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    • v.20 no.2
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    • pp.125-155
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    • 2010
  • Ontologies have been adopted in various business and scientific communities as a key component of the Semantic Web. Despite the increasing importance of ontologies, ontology developers still perceive construction tasks as a challenge. A clearly defined and well-structured methodology can reduce the time required to develop an ontology and increase the probability of success of a project. However, no reliable knowledge-engineering methodology for ontology development currently exists; every methodology has been tailored toward the development of a particular ontology. In this study, we developed a Graduation Screen Ontology (GSO). The graduation screen domain was chosen for the several reasons. First, the graduation screen process is a complicated task requiring a complex reasoning process. Second, GSO may be reused for other universities because the graduation screen process is similar for most universities. Finally, GSO can be built within a given period because the size of the selected domain is reasonable. No standard ontology development methodology exists; thus, one of the existing ontology development methodologies had to be chosen. The most important considerations for selecting the ontology development methodology of GSO included whether it can be applied to a new domain; whether it covers a broader set of development tasks; and whether it gives sufficient explanation of each development task. We evaluated various ontology development methodologies based on the evaluation framework proposed by G$\acute{o}$mez-P$\acute{e}$rez et al. We concluded that METHONTOLOGY was the most applicable to the building of GSO for this study. METHONTOLOGY was derived from the experience of developing Chemical Ontology at the Polytechnic University of Madrid by Fern$\acute{a}$ndez-L$\acute{o}$pez et al. and is regarded as the most mature ontology development methodology. METHONTOLOGY describes a very detailed approach for building an ontology under a centralized development environment at the conceptual level. This methodology consists of three broad processes, with each process containing specific sub-processes: management (scheduling, control, and quality assurance); development (specification, conceptualization, formalization, implementation, and maintenance); and support process (knowledge acquisition, evaluation, documentation, configuration management, and integration). An ontology development language and ontology development tool for GSO construction also had to be selected. We adopted OWL-DL as the ontology development language. OWL was selected because of its computational quality of consistency in checking and classification, which is crucial in developing coherent and useful ontological models for very complex domains. In addition, Protege-OWL was chosen for an ontology development tool because it is supported by METHONTOLOGY and is widely used because of its platform-independent characteristics. Based on the GSO development experience of the researchers, some issues relating to the METHONTOLOGY, OWL-DL, and Prot$\acute{e}$g$\acute{e}$-OWL were identified. We focused on presenting drawbacks of METHONTOLOGY and discussing how each weakness could be addressed. First, METHONTOLOGY insists that domain experts who do not have ontology construction experience can easily build ontologies. However, it is still difficult for these domain experts to develop a sophisticated ontology, especially if they have insufficient background knowledge related to the ontology. Second, METHONTOLOGY does not include a development stage called the "feasibility study." This pre-development stage helps developers ensure not only that a planned ontology is necessary and sufficiently valuable to begin an ontology building project, but also to determine whether the project will be successful. Third, METHONTOLOGY excludes an explanation on the use and integration of existing ontologies. If an additional stage for considering reuse is introduced, developers might share benefits of reuse. Fourth, METHONTOLOGY fails to address the importance of collaboration. This methodology needs to explain the allocation of specific tasks to different developer groups, and how to combine these tasks once specific given jobs are completed. Fifth, METHONTOLOGY fails to suggest the methods and techniques applied in the conceptualization stage sufficiently. Introducing methods of concept extraction from multiple informal sources or methods of identifying relations may enhance the quality of ontologies. Sixth, METHONTOLOGY does not provide an evaluation process to confirm whether WebODE perfectly transforms a conceptual ontology into a formal ontology. It also does not guarantee whether the outcomes of the conceptualization stage are completely reflected in the implementation stage. Seventh, METHONTOLOGY needs to add criteria for user evaluation of the actual use of the constructed ontology under user environments. Eighth, although METHONTOLOGY allows continual knowledge acquisition while working on the ontology development process, consistent updates can be difficult for developers. Ninth, METHONTOLOGY demands that developers complete various documents during the conceptualization stage; thus, it can be considered a heavy methodology. Adopting an agile methodology will result in reinforcing active communication among developers and reducing the burden of documentation completion. Finally, this study concludes with contributions and practical implications. No previous research has addressed issues related to METHONTOLOGY from empirical experiences; this study is an initial attempt. In addition, several lessons learned from the development experience are discussed. This study also affords some insights for ontology methodology researchers who want to design a more advanced ontology development methodology.

Fertility status of Jeju volcanic ash soil and its improvement (제주도전토양(濟州道田土壤)의 비옥도현황(肥沃度現況)과 개량(改良))

  • Ryu, In Soo;Yoo, Sun-Ho;Yoon, Jung Hai
    • Korean Journal of Soil Science and Fertilizer
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    • v.8 no.3
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    • pp.121-133
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    • 1975
  • Soils of the agricultural land derived mostly from volcanic ash in Jeju island may be characterized by relatively high PH, high contents of organic matter and exchangeable bases, and significantly low content of available phosphorus. The PH, organic matter, and available phosphorus of the soils in northern Jeju are 6.1, 12.6%, and 23 ppm, while those of the soils in the southern Jeju are 6.4, 3.7 %, and 76 ppm respectively. Upland soils in Jeju may be classified into 4 groups on the basis of soil fertility: black soil, very dark brown soil, dark brown, and red yellow soil. The organic matter content of black soil, very dark soil and dark brown soil is 15%, 7%, and 3% respectively. The soils of high organic matter content show the high phosphorus absorption coefficient, low content of available phosphorus, and low degree of the base saturation. The soil productivity for barley in the northern Jeju is higher than that in the southern Jeju and the productivity in the western Jeju is higher than that in the eastern part. The productivity for barley is in decreasing order of dark brown soil, very dark brown soil and black soil. Yields of potato and sweet potato in Jeju are higher than in the mainland. Those crops are considered to be tolerant to aluminumtoxicity. The response of sweet potato to nitrogen, phosphorus, and potassium in Jeju soils is lower than that in the mainland, while the response of barley and rape to nitrogen and phosphorus is higher than that in the mainland. The response to fertilizer applied is greater in the northern Jeju than in the southern Jeju. Lime requirement for the Jeju soils calculated on the basis of laboratory tests is so tremendous that single application of lime required might induce adverse effect. Most of the phosphorus applied to the Jeju soils is readily fixed as unavailable form and application of phosphorus in the level of 30 to 40 kg/10a is thought to give little effect.

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Clinical Observations in Vancomycin-Resistant Enterococci Isolated from Pediatric Patients (소아 환아에서 분리된 Vancomycin 내성 장구균에 대한 임상적 고찰)

  • Lee, Dong Woo;Lee, Kyung Jae;Jang, Gwang Choen;Kim, Dong Soo;Lee, Kyung Won;Park, Eun Suk
    • Pediatric Infection and Vaccine
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    • v.8 no.2
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    • pp.199-205
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    • 2001
  • Purpose : Since the first report of vancomycin-resistant enterococci(VRE) in 1986, the resistance to vancomycin in enterococci has been increasingly rapidly. In this study, we investigated the clinical manifestations of pediatric patients with VRE and the pattern of the antibiotic use with increasing the rate of VRE in pediatrics Methods : We studied retrospectively 36 pediatric patients who were isolated VRE from January 1998 to December 2000. We classified patients into ICU and non ICU groups and reviewed species of VRE, specimens in which VRE were first detected and procedures performed before VRE detected. Results : We have found that the number of pediatric patients isolated VRE is increasingly annually in this study. In addition, the number of VRE-isolation in the ICU group and in patients who were operated or who underwent active procedures is much higher than that of in the non ICU group and in patients who were taken medication only. Enterococcus faecium is the main species of VRE. VRE showed high resistance to almost all antibiotics except tetracycline, and resistance was closely related to the duration of hospitalization and history of the antibiotic use. The proportion of the cephalosporin use was higher than any other antibiotic before VRE detection. In contrast, that of teicoplanin was higher than any other antibiotic after VRE detection(P<0.05). The cases of superinfection is higher in the ICU group than in non ICU group. Conclusion : In the hospital level, prevention of nosocomial infection through proper administrative policies, through surveillance of high risk VRE regions and prudent antibiotic use can prevent VRE outbreaks and corresponding side effects.

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