• Journal of The Korean Association For Science Education
• /
• v.31 no.4
• /
• pp.513-527
• /
• 2011

There have been studies about conceptual ecology making a profound study of conceptual changes in learners' cognitive structure. Because learners' cognitive structure have been compared to ecology, it is natural to think that conception in learner's cognitive structure have a niche as species in ecology have niches. Therefore, it is necessary to study niche approach about conception that learners recognize in their cognitive structure. The purposes of this study were to identify relationships among conceptions that 5th grade elementary school students recognize about photosynthesis and to identify how these relationships among conceptions about photosynthesis change before and after a class of photosynthesis in curriculum in terms of an approach of ecological niche which are composed of 3 domains - diversity of conceptions, relevance and frequency rate of conceptions, and competition among conceptions. Open ended questionnaire was developed by 4 fields: photosynthetic place, photosynthetic products, photosynthetic materials needed and environment factors of photosynthesis. The subjects sampled in this study were 310 5th grade elementary students in 5 cites. Before and after classes in photosynthesis in science curriculum, students were asked to write down conceptions that they knew about the 4 fields of photosynthesis of questionnaire and to write down scales of relevance from 1 to 30 about how they think the conceptions are related to the field of photosynthesis. The results of this study showed the following: First, most students have had a variety of conceptions and commonly recognized 'light' and 'water' as concepts in photosynthesis. Second, students still recognized their preconceptions like 'soil' and 'root,' etc. that were far from scientific conceptions of photosynthesis although they took classes in photosynthesis. Third, students needed to take the various strategies of teachers because they did not recognized scientific conceptions appropriately about photosynthetic fields. Fourth, it appeared that photosynthetic conceptions recognized by students had status in terms of relevance and frequency rate of conceptions, and competition among conceptions, and that they looked like the niche of conceptions in their conceptual ecologies.

• Journal of dental hygiene science
• /
• v.12 no.4
• /
• pp.404-412
• /
• 2012

The main object of this study is to render a better dental education to mental disabilities, teachers, and their parents. By providing a better dental education to them, mental disabilities would understand the importance of their oral hygiene. The study was held in Seoul at two different locations, named H and E mental welfare facilities. Ninety Three mental disabilities were studied by observing their oral behavior, simple oral hygiene index and plaque index prior and post to dental education. At the end of education, following result were gathered from two mental facilities. First, the level of oral behavior in Class 1,2, and 3 mental disabilities were observed prior and post to the dental education. Overall, there was no significant difference among Class 1 mental disabilities with the dental education. Second, in simple oral hygiene index, the severity of mental illness has affected on their oral behavior (F=6.322, p<.001). Third, in simple oral hygiene index, the frequency of dental education, regardless of severity of mental illness has affected on their oral hygiene (F=5.961, p<.01). Fourth, the plaque index also illustrated that the frequency of dental education, regardless of severity of dental illness has affected on their oral hygiene (F=5.126, p<.05). Finally, the general characteristics of mental disabilities according to changes in oral health awareness to gender, age, disability type, educational level do not statistically significant in all variables. Their simple oral hygiene index and plaque index advanced, although after a while they started to lose focus, which brought back their old habits. Nevertheless, in conclusion I believe that helping mental disabilities more frequently to constant reminder, will not only keep them entertained, but help them realize how important oral hygiene practice is, hopefully increasing and benefiting those with mental disabilities for future reference.

• Journal of the Korean Society of Floral Art and Design
• /
• no.44
• /
• pp.33-51
• /
• 2021

This thesis analyzes the formal characteristics of Dutch flower still life from the 17th century to the early 18th century and looks into the relevance with the Dutch art market from a macro perspective. The 17th Flower Still Life is to represent social hierarchy in that as the imported exotic, recherch items, the flowers were classified in the terms of their rarity and expensiveness. For this intriguing research, the subject is circumscribed to a vase of flowers, which is the quintessence of In the form of various Dutch Flower Still Life. Dutch society in the early 17th century was centered on the civilian class engaged in trade and commerce, which allowed them to purchase art works to show off their wealth, economic benefits and satisfaction of aesthetic tastes. Among them, the popularity of flower still life was related to the concentrated demand for rare flowers from the new continent. Accordingly, exact depiction and sense of the three dimensional manner were highly regarded in the early flower still life. For the tastes of the wealthy citizens who succeeded in business, the identity of flowers and the actual screen were considered as important. However, after the mid 17th century, economic growth in the Netherlands put an end, and the art market was also on a downward path. The demand class of flower still life has gotten farther away from the spirit of businessmen and has changed into city aristocrats who were stable rentiers. Their tastes laid emphasis on subjective sensibility, which meant that aristocratic, asymmetric, and dramatic chiaroscuro were preferred rather than being realistic. Furthermore, in the 18th century illusionistic realism was abandoned as an expression method of the planar characteristics and a new era in the floral still life was ushered with the reinforcement of decorative effect. From this perspective, it is not an exaggeration to say that romanticism, which is thought of as the beginning of Contemporary Art, originated from the aesthetic taste of Dutch civic culture.

• Korean Journal of Environmental Biology
• /
• v.26 no.3
• /
• pp.159-169
• /
• 2008

This study was aimed to classify the intertidal macrozoobenthic community status after 2 years of Sea Prince oil spill, and oil spill effects along oil spreading track from heavily impacted to unaffected reference site. Field sampling was initiated in late February and continued through November 1998 seasonally, after 2.5 years of oil spill. 7 rocky sampling sites were selected among coastal regions coated and/or affected by the Sea Prince spilled oil. Identified species was 158 species, 65 family, 24 order, 9 class, 5 phylum. Mollusca was the dominant faunal group comprising 100 species (63.3%), and followed by 38 species of Crustacea (24.1%), 12 species of Echinodermata (7.6%), 5 species of Porifera (3.2%), and 3 species of Cnidaria (1.9%). On Dugpo of Sori Island, the fewest species was collected from 28 species to 35 species seasonally among sampling stations. But far away Dugpo toward Gamak Bay, the number of species increased, collecting the maximum on Sohwoenggan Island. At the wreck site of Sori Island, especially the species number of attached animals such as poriferans and anthozoans was very low compared to another site. The density and biomass on the higher tidal zone increased toward the low affected sites, but biomass on middle tidal zone decreased. The invertebrate biomass of study area was dependent on the sessile animals. The major dominant species were small-sized barnacles, Chthmallus challengeri, periwinkles, Littorina brevicula, mussels, Septifer virgatus, and so on. The biomass of C. challengeri and L. brevicula on the higher tidal zone was highest in the wreck site of Sori Island and decreased further and further. However, mussels on the middle tidal zone showed the inverse trends because of the larger individual size of mussel inhabited in Sori Island than those of another sites. As a result of community analysis, the effect of oil spill was not found distinctly. Several ecological indices and cluster analysis did not show the meaningful variation with oil track despite of the conspicuous differences among tidal heights. These indicate that the macrozoobenthic community level of oil spreaded zone recovered in some degree after the Sea Prince oil spill accident, but population or individual levels of dominant sessile animals took more recovery times.

• The korean journal of orthodontics
• /
• v.30 no.1 s.78
• /
• pp.33-41
• /
• 2000

Although it is well known that the chincup, used to correct a skeletal class III malocclusion in growing children, reduce the mandibular prognathism by arresting the growth of the mandibular length and rotating the mandible posteroinferiorly, the majority of the studies about chincup is focused on condylar head that plays an Important role in mandibular growth. The aim of this study was to evaluate the morphologic change of the mandibular symphysis where extraoral force is applied directly during chincup treatment. The data lot this study were obtained from lateral cephalometric radiographs of 62 growing children(chincup group:32, control group:30) with mixed dentition who had been accepted lot the orthodontic treatment at Chonbuk National University Dental Hospital. The results were as follows : 1. Symphysis height was increased both in chincup therapy group and control group during treatment. Symphysis depth was decreased or maintained the initial values in chin cup therapy group, whereas increased in control group. Posterior symphysis depth was decreased both in chin cup therapy group and control group, but anterior svmphysis detph was increased in control group, whereas decreased in chincup therapy group. 2. Chin depth and chin curvature were increased in control group, whereas maintained or decreased in chincup therapy group during treatment. Chin angle, menton ang1e and symphysis angle were decreased in control group, whereas increased in chincup therapy group. It suggested that bone deposition in pogonion area that occur normally with mandibular growth was supressed by direct contact of chincup. 3. When growing children wear chincup, symphysis morphology was maintained due to inhibition of forward growth at mandibular symphysis. It may be due to the suppression of bone deposition in anterior part of symphysis.

• Journal of Preventive Medicine and Public Health
• /
• v.27 no.4 s.48
• /
• pp.711-734
• /
• 1994

Among chemical agents in herbicides, dioxin (2, 3, 7, 8-tetrachloro dibenzo-$\rho$-dioxin : TCDD), a chemical contaminant in herbicides sprayed during the Vietnam War has been known to be the major agent causing toxic effects. Approximately 320,000 korean soldiers participated the Vietnam War from 1964 to 1974. Although the potential hazards of the herbicides among Korean veterans exposed were implicated, the problem had not been a public issue until 1991 when Korean veterans were informed U.S. companies, the herbicides manufacturer payed fund, from which a trust fund for New Zealand and Australian Class members were established in 1985. After a series of appeals and demonstration by the Korean Veterans demanding medical care and compensation for their serious health damages, a bill of medical care and compensation for herbicides victims was promulgated in March 1993 and become effective from May 1993, This study was carried out with two major objectives : the first to understand the health problems caused from the herbicides by reviewing literatures published, and the second to examine the nature and extent of health impacts among Korean veterans exposed and to develop valid study methods for the major study by interviewing and reviewing records on a part of veterans (638 persons) registered and completed medical examination in Seoul Veterans Administration Hospital from June to October 1993. The results obtained are as followings: 1. The literature review of 107 papers revealed that 1) Dioxin is teratogenic, carcinogenic and affects almost all organs including nervous, endocrine, and reproductive systems in animal experiments. 2) The diseases showing evidence of causal association were Hodgkin's disease, non-Hodgkin's disease, lung cancer, lymphoma, soft tissue sarcoma, chloroacne and polyneuropathy when judged on the basis of consistency in study results and biological plausibility. 2. Interview and medical record review study on 638 veterans, though limited validity owing to lack of control group, crude estimates of dioxin exposure levels (no biomarkers measurable), and uncertainty of diagnosis, showed that: 1) Most of the study subject's were in their 40's of age and had been dispatched to Vietnam during the period from $1965{\sim}1970$ around one year. 2) Most frequently complained symptoms in medical examination were motor weakness (32%), sensory abnormalities in extremities (23%), skin diseases (22%), and pain in extremities (20%) whereas in Interview they were more frequent in order of skin problem (44%), motor weakness (38%), sensory abnormalities and pain in extremities(17% and 19% each). Kappa indices on the same category of complaints between two sources of information were variable and relatively low. 3) On medical examination, only a part of the 638 subjects had initial impression (442 pts) and final diagnosis (218 pts) suggesting decision making on diagnosis appeared to be difficult even with all available modern medical technologies: in initial impression disorders from peripheral and central neuropathy were predominant whereas in final diagnosis various types of skin disorder were most frequent 4) When dose-response relationship between several conditions (from questionnaire) and arbitrary exposure scores were examined by CMH linear trend test, spontaneous abortion, sexual problems and health problem of offsprings showed statistically significant linear trends. However, pregnancy, accident and suicidal attempts did not show any relationship in this study capacity. 5) Among complaints, psychosis and neurosis (anxiety, phobia) in interview study, and memory disorder and psychosis in medical record study revealed linear trend. 6) Skin disorder was the only condition showing linear trend in initial impression and none in final diagnosis on medical examination. Even though objective to select out dioxin-related disease or group of diseases from this study was not achieved the research experiences provided firm basis for developing various methodological approaches. 3. From this preliminary study we concluded that a larger scale major epidemiologic study on health impacts of herbicides among Korean veterans exposed is not only Indispensible but also well designed study with more valid exposure information and diagnosis may be able to establish causal relationship between certain groups of diseases and exposure to the herbicides among Korean veterans.

• The Journal of Korean Academy of Prosthodontics
• /
• v.53 no.3
• /
• pp.207-214
• /
• 2015

Due to the limitations of conventional removable partial denture prostheses to treat a cleft lip & palate patient who shows scar tissue on upper lip, excessive absorption of the maxillary residual alveolar ridge, and class III malocclusion with narrow palate and undergrowth of the maxilla, 4 implants were placed on the maxillary edentulous region and a maxillary removable implant-supported partial denture was planned using a CAD/CAM milled titanium bar. Unlike metal or gold casting technique which has shrinkage after the molding, CAD/CAM milled titanium bar is highly-precise, economical and lightweight. In practice, however, it is very hard to obtain accurate friction-fit from the milled bar and reduction in retention can occur due to repetitive insertion and removal of the denture. Various auxiliary retention systems (e.g. $ERA^{(R)}$, $CEKA^{(R)}$, magnetics, $Locator^{(R)}$ attachment), in order to deal with these problems, can be used to obtain additional retention, cost-effectiveness and ease of replacement. Out of diverse auxiliary attachments, $Locator^{(R)}$ has characteristics that are dual retentive, minimal in vertical height and convenient of attachment replacement. Drill and tapping method is simple and the replacement of the metal female part of $Locator^{(R)}$ attachment is convenient. In this case, the $Locator^{(R)}$ attachment is connected to the milled titanium bar fabricated by CAD/CAM, using the drill and tapping technique. Afterward, screw holes were formed and 3 $Locator^{(R)}$ attachments were secured with 20 Ncm holding force for additional retention. Following this procedure, satisfactory results were obtained in terms of aesthetic facial form, masticatory function and denture retention, and I hereby report this case.

• Journal of Korean society of Dental Hygiene
• /
• v.7 no.1
• /
• pp.91-103
• /
• 2007

The purpose of this study was to pave the way for the development of oral health promotion programs for children from the low-income class. The subjects in this study were 322 children from the city of Incheon. Some of them visited local childcare centers, and the others attended six different adjacent elementary schools. Their awareness of oral health, oral health behavior and preventive-treatment experience were investigated in May 2005, and whether there were any characteristics in their visit of dental institutions was checked. Besides, whether their parents advised them to brush their teeth before turning in was examined. The findings of the study were as follows: 1. 22.0 percent of the children investigated were visiting local childcare centers, and 78.0 percent weren't. The guardians of the former group largely received high-school(50.7%) and middle-school or lower education(22.5%), and those of the latter group mostly received high-school(41.0%) and college- or higher education(35.5%)(pE0.001). The common monthly mean house-hold income of the former was one million won or less(54.9%) or ranged from 1.01 to 2.00 million won(19.7%), and the most prevalent monthly mean household income of the latter was between 2.01 and 3.50 million won(28.7%). The second most dominant monthly mean household income of the latter ranged from 1.01 to 2.00 million won(28.3%), and the third most common one was 3.50 million won or more(12.0%)(pE0.001). 2. The most prevalent daily toothbrushing frequency among the local childcare center visitors was twice(39.4%), followed by three times(19.7%). The third largest group of the visitors brushed their teeth after each meal(19.7%). The most dominant daily toothbrushing frequency among the non-users of local child care centers was twice(54.2%), followed by three times(29.1%)(pE0.01). As to the way of toothbrushing, 58.2 percent of the visitors and 74.9 percent of the non-visitors brushed their teeth by turning their toothbrush or up and down(pF0.05). 62.0 percent of the former and 74.9 percent of the latter always brushed their teeth before turning in, and whether they visited local childcare centers made a significant difference to that(pE0.05). 3. 69.7 percent of the non-visitors were always advised by their parents to do toothbrushing before turning in, and the visitors who were given the same advice all the time numbered 29.6 percent(pE0.001). 4. 56.4 percent of the visitors and 72.1 percent of the non-visitors had ever visited dental institutions over the past year. Dental hospitals and clinics were identified as the dental institutions that they visited the most, and they mostly received dental-caries treatment or had a tooth out there. 49.3 percent of the visitors and 35.1 percent of the non-visitors had ever had a toothache. 5. Sealant was experienced by 42.3 percent of the visitors and 46.2 percent of the non-visitors to prevent dental caries(pF0.05). 33.8 percent of the visitors underwent fluoride application, and that rate was higher than that of the non-visitors with the same experience that stood at 22.7 percent(pE0.05). The visitors mainly acquired knowledge on oral health through other channels that weren't specified in the questionnaire(28.2%), and the non-visitors did it mostly at dental clinics(39.0%)(pE0.001).

• Journal of Korean Home Economics Education Association
• /
• v.22 no.1
• /
• pp.51-65
• /
• 2010

The purpose of this study was to raise the awareness of LOHAS(Lifestyle of Health and Sustainability) in the secondary school students. We extracted the related contents to LOHAS from the unit of 'The choice and maintenance of clothing' in the second-year's textbook of Technology-Home Economics, and selected the learning subjects. We also developed the new teaching-learning process plan on practical problem focused lesson, and applied them to the eight classes located in Siheung, Gyeonggi-do, for 5 hours per each class. The learning subjects of the teaching-learning process plan included five items as followings; general awareness, organic fashion, natural fabric, recycled material fashion, and natural dyeing, which were related to LOHAS consumption. The overall topic of the teaching-learning process plan was 'What should do to raise the awareness of LOHAS in order to practice LOHAS consumption in the choice of clothing'. Consequently, the results were abtained as follow; The general awareness of LOHAS as well as the awareness of LOHAS consumption in the choice of clothing increased after classes significantly, compared to those before. Thirty-four materials including worksheets, reading materials and teacher's guide could help to raise the awareness of LOHAS. Also these classes enabled the students to raise their awareness of LOHAS, to improve their opinions and attitudes on LOHAS consumption in the choice of clothing, and to take an interest in the lesson of Home-Economics. This study might have the educational significance in that it made the students directly participate in the national and social trend of the awareness of LOHAS, and upgrade their quality as good LOHAS consumers. Also further teaching-learning process plan in Home-Economics are necessary to promote the awareness of LOHAS for better health, environment, and society.

• Restorative Dentistry and Endodontics
• /
• v.24 no.1
• /
• pp.166-179
• /
• 1999

Apical sealing is essential for the success of surgical endodontic treatment. Root-end cavity is apt to be contaminated with moisture or blood, and is not always easy to be dried completely. The purpose of this study was to evaluate the influence of dry methods of retrocavity on the apical seal in endodontic surgery. Apical seal was investigated through the evaluation of apical leakage and adaptation of filling material over the cavity wall. To investigate the influence of various dry methods on the apical leakage, 125 palatal roots of extracted human maxillary molar teeth were used. The clinical crown of each tooth was removed at 10 mm from the root apex using a slow-speed diamond saw and water spray. Root canals of the all the specimens were prepared with step-back technique and filled with gutta-percha by lateral condensation method. After removing of the coronal 2 mm of filling material, the access cavities were closed with Cavit$^{(R)}$. Two coats of nail polish were applied to the external surface of each root. Apical three millimeters of each root was resected perpendicular to the long axis of the root with a diamond saw. Class I retrograde cavities were prepared with ultrasonic instruments. Retrocavities were washed with physiologic saline solution and dried with various methods or contaminated with human blood. Retrocavities were filled either with IRM, Super EBA or composite resin. All the specimens were immersed in 2% methylene blue solution for 7 days in an incubator at $37^{\circ}C$. The teeth were dissolved in 14 ml of 35% nitric acid solution and the dye present within the root canal system was returned to solution. The leakage of dye was quantitatively measured via spectrophotometric method. The obtained data were analysed statistically using one-way ANOVA and Duncan's Multiple Range Test. To evaluate the influence of various dry methods on the adaptation of filling material over the cavity wall, 12 palatal roots of extracted human maxillary molar teeth were used. After all the roots were prepared and filled, and retrograde cavities were made and filled as above, roots were sectioned longitudinally. Filling-dentin interface of cut surfaces were examined by scanning electron microscope. The results were as follows: 1. Cavities dried with paper point or compressed air showed less leakage than those dried with cotton pellet in Super EBA filled cavity (p<0.05). However, there was no difference between paper point- and compressed air-dried cavities. 2. When cavities were dried with compressed air, dentin-bonded composite resin-filled cavities showed less apical leakage than IRM- or Super EBA-filled ones (p<0.05). 3. Regardless of the filling material, cavities contaminated with human blood showed significantly more apical leakage than those dried with compressed air after saline irrigation (p<0.05). 4. Outer half of the cavity showed larger dentin-filling interface gap than inner half did when cavities were filled with IRM or Super EBA. 5. In all the filling material groups, cavities contaminated with blood or dried with cotton pellets only showed larger defects at the base of the cavity than ones dried with paper points or compressed air.