• Restorative Dentistry and Endodontics
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• v.25 no.4
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• pp.575-586
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• 2000

In this study, adaptation of compomer to saliva contaminated dentin was evaluated with scanning electron microscope(SEM) and confocal laser scanning microscope(CLSM). For the SEM study, the occulusal surfaces of thirty two molar teeth were grounded to exposure dentin surfaces. The specimen were randomly assigned to control and three experimental groups with four samples in each group. In control group, Dyract and F-2000 compomer were bonded on the specimens according to the manufactures direction. Experimental groups were subdivided into three groups. They were contaminated with saliva on dentin surfaces ; Experimental group 1 : Saliva was dried with compressed air. Experimental group 2 : Saliva was rinsed with air-water spray and dried. Experimental group 3 : After polymerization of an adhesive, they were contaminated with saliva, and then saliva was rinsed with air-water spray and dried. Dyract and F-2000 compomer were bonded on saliva-treated dentin surfaces. The interfaces between dentin and compomer were observed with SEM. For the CLSM study, Class V cavities were prepared in buccal and ligual surfacess of thirty two molars. The specimens were divided into control and experimental groups. Class V cavities in experimental group were contaminated with saliva and those surfaces in each experimental groups received the same treatments as for the SEM study. Cavities were applied Prime & Bond 2.1 and F-2000 compomer primer/adhesive that were mixed with fluorescein, and then were filled with Dyract and F-2000 compomer. Specimens were embedded in transparent acrylic resin and sectioned buccolingual1y with diamond wheel saw, and then mounted on cover slide for CLSM study. The interface between cavity and compomer was observed by fluoresence imaging with a CLSM. The results were as follows : 1. In SEM exammination of Dyract group, control group, experimental group 2, 3 showed close adaptation to dentin and hybrid layer of $3{\sim}4{\mu}m$ diameter. Interfacial gap between compomer and dentin in experimental group 1 was wider than in control group. 2. In SEM examination of F-2000 group, adaptation to dentin of control group was closer than Dytact control group, but hybrid-like layer was not observed. Interfacial gap between compomer and dentin in experimental group 1 was wider than in Dyract experimental group 1. 3. In dissolution specimens of Dyract and F-2000 group, resin tags penetrated through dentinal tubules in control group and experimental group 1 and 3, but the penetration of resin tag was irregular and partial in experimental group 1. 4. In CLSM exammination of Dyract and F-2000 group, adhesive patterns of control and experimental groups showed same as in SEM. This result suggests the treatment methods, rinsing & drying, repeating all adhesive procedures, will produce good effect on adaptation of compomer to dentin if the dentin surface or polymerized adhesive is contaminated by saliva.

• Restorative Dentistry and Endodontics
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• v.27 no.1
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• pp.16-23
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• 2002

Physical properties of composite resins such as strength, resistance to wear, discoloration, etc depend on the degree of conversion of the resin components. The purpose of this study was to evaluate the degree of conversion of the composite resins according to the thickness of tooth structure penetrated by light and applied light curing time. The coronal portions of extracted human teeth (one anterior tooth, three posterior tooth) was embedded by pink denture material. the mounted teeth were cut into three illumination sections (1mm thickness enamel section, 1mm thickness dentin section, 2mm thicknes dentin section) and one backing section with cutting wheel. Thin resin films were made by using 6kg pressure between slide glass during 5 minutes Thin resin film was light cured on coupled illumination section during 40sec, 80sec and 120sec. each illumination section was coupled as follows; no tooth structure(X), ename section(E), enamel section + 1mm dentin section(ED1), enamel section + 2mm dentin section(ED2), enamel section + 1mm dentin section + 2mm dentin section(EDD). To simulate the clinical situation more closely, thin resin films was cured against a backing section of tooth structure. The degree of conversion of carbon double bonds to single bonds in the resin films were examined by means of Fourier Transform Infrared Spectrometer. The results were obtained as follows ; 1 As curing time was increased, conversion rate was increased and as tooth thickness which was penetrated by curing light was increased, conversion rate was decreased. 2. At all tooth thickness groups, conversion rate between 80sec and 120sec was not significantly increased(P＞0.05). 3. At 40sec group and 80sec, conversion rate between no tooth structure(X) group and 1mm enamel section(E) group was not significantly decreased(P＞0.05). 4. At 80sec group and 120sec, conversion rate between 1mm enamel section(E) group and 1mm enamel section + 1mm dentin section(ED1) group was not significantly decreased(P＞0.05).

• Journal of Biomedical Engineering Research
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• v.23 no.3
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• pp.235-241
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• 2002

The detection of tubercle bacilli (TB) from sputum smear is one of the fast and inexpensive methods for diagnosis of tuberculosis. For this method. sputum smears are usually flexed by heating and stained by acid-fast staining method, and then examined under an optical microscope. Two Procedures are commonly used fur TB staining. One is hot staining and the other is cold staining method. The Ziehl-Neelsen method which is a hot staining method is widely used in Korea because its stained color is more vivid However, the conventional automated stainer has to fix the sputum smear on a slide manually and the stain is not so vivid because it has not heating function. In an effort to save labor and minimize variations in manual staining Procedure. we developed an automated stainer with heating function. The entire staining process is fully automated. from fixation to final washing and drying. With the automated methods, five slides can be flexed and stained in 21 minutes at consistent high quality We compared the concordance rate between the two methods for 91 sputum samples to validate the stain quality of the developed automated stainer. As the results, the concordant rate between the two methods was 95% and there was no significant difference (p>0.05)

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.489-497
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• 2000

Since Chinese cabbages weigh 3 to 5kgf and are big in size at the time of harvest, handling operations such as harvesting, loading and unloading including transportation require the highest labor demand among all other cultivation processes. Recently, though several cabbage harvesters were developed in Japan and Europe, those harvesters were not suitable for Chinese cabbages cultivated in Korea because of the size and shape. The cabbage harvester is almost meaningless without any proper cabbage piling and pallet unloading mechanism. Most harvesters developed so far adopted a sort of slide and free falling way in collecting cabbages into the pallet. Three or four labors are usually required for cleaning incoming cabbages and loading those in the pallet. Because of the required time for piling cabbages without severe damage and the required space capacity to carry empty and loaded pallets, harvesting speed should be adjusted in accordance with time required for consecutive operations. Up to now, any automatic or semi-automatic collecting device has not been developed in the world to pile cabbages on the layer one by one into the pallet in the ordered way with little damage and to unload pallet from the harvester continuously during the harvest process. To compromise system expenses and function, Semi-automatic cabbage piling and pallet unloading mechanism was devised and it required one labor. The foldable mesh pallet with a size of 1050mm x 1050mm x 1000mm and holding capacity of around 70 cabbages was utilized. The prototype for piling and unloading mechanism was composed of three parts such as feeding device, automatic piling device with retractable bellows, and pallet unloading device. Prior to developing the prototype, the geometric properties and the amount of the damage of the cabbage caused during the piling operation were investigated. Considering the height of the pallet, a series of cabbage carrying plates were mounted to the bracket chain to lift and to carry cabbages to the loading device. Indoor laboratory experiments showed that the cabbage carrying chain conveyor worked successfully. Considering the conveying speed 0.46m/sec of the pull up belt from the cabbages on the ground, the speed of cabbage carrying chain conveyor worked property in the range of 0.26m/sec to 0.36m/sec. The system allowed the operator to modify the position of cabbage slightly. Overall system worked successfully resulting into almost same capacity without severe damage to the cabbage as human did.

• Research in Plant Disease
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• v.24 no.2
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• pp.132-137
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• 2018

Melanose caused by Diaporthe citri is a serious disease on yuzu fruits. Moisture is the most important to infect after the pycnidiospores are released. In order to understand how dryness and moisture interruption affect on germination, the conidial suspensions on slide glass were dried for 0-48 h. For the moisture interruption experiment, moisture was supplied for 10 h then interrupted for 0-6 h depending on the treatments. Germinations on the treatments with longer than 15 h of dryness were less than 10%. And those with longer than 3 h of moisture interruption were less than 30%. Compared with other fungal phytopathogens, D. citri was xero-sensitive. Germination on yuzu feel medium was measured under 15, 20, 25, 30, $35^{\circ}C$ with 3, 6, 9, 12, 15, 18, and 24 h of wetness. The minimum wetness periods achieving 10% and 50% germinations were 4.5 and 13 h, and the optimum temperatures were $29.1^{\circ}C$ and $29.2^{\circ}C$, respectively. From the yuzu medium study, the regression equations to be required wetness period achieving 10% and 50% germinations on various temperatures were $Wh_{50%}=0.1093{\times}T^2-6.3762{\times}+106.08$ and $Wh_{10%}=0.082{\times}T^2-4.8025{\times}T+74.861$.

• Parasites, Hosts and Diseases
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• v.48 no.3
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• pp.237-243
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• 2010

Comprehensive quarterly serosurveillance on scrub typhus in small mammals collected from military training sites located near the Demilitarized Zone (DMZ), northern Gyeonggi-do (Province), ROK was conducted to determine the potential rodent-borne and associated ectoparasite disease risks to military personnel. A total of 1,196 rodents and insectivores representing 8 species, Apodemus agrarius (87.3%, n = 1,044), Mus musculus (5.4%, n = 65), Crocidura lasiura (3.3%, n = 40), Microtus fortis (2.6%, n = 31), Micromys minutus (0.3%, n = 4), Tscherskia triton (0.3%, n = 4), Rattus norvegicus (0.3%, n = 4), and Myodes regulus (0.3%, n = 4) were assayed for the presence of antibodies to Orientia tsutsugamushi. O. tsutsugamushi antibodies were detected in 6 of 8 species and seroprevalence determined; A. agrarius (45.6%), M. musculus (23.1%), M. fortis (48.4%), M. minutus (50.0%), T. triton (50.0%), and R. norvegicus (25.0%). A total of 31,184 chigger mites collected from 508 rodents and insectivores were slide-mounted and 10 species belonging to 4 genera were identified. Leptotrombidium pallidum (53.4%) was the most frequently collected, followed by L. pal pale (15.7%), Neotrombicula tam/yai (14.3%), L. orientate (10.7%), L. zetum (3.1%), Walchia fragilis (2.1%), and L. gemiticutum (0.8%), while the remaining 3 species, L subintennedium, N. gardellai, and Euschoengastia koreaensis were rarely observed (prevalence < 10%). In contrast to previous surveys, higher chigger indices of the primary scrub typhus vectors, L. pallidum (165.4), L. orientale (45.0), and L. palpate (21.4), were observed during the spring season.

• Parasites, Hosts and Diseases
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• v.47 no.2
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• pp.185-187
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• 2009

The prevalence of Enterobius vermicularis infection among preschool children was reported to be low based on a 5-year screening program in Taipei City, Taiwan. The Taipei City government intended to terminate the E. vermicularis screening program among preschool children. Thus, we were entrusted with confirming whether pinworm infections among preschool children in Taipei City had truly declined. From each of 12 administrative districts 2-3 kindergartens were randomly selected for investigation. In total, 4,349 children were examined, of which 2,537 were boys and 1,812 were girls. The cellophane tape adhered to a glass slide was used, and all examinations were done by certified medical technologists. Results indicated that the overall prevalence rate of pinworm infections was 0.62% (27/4,349). Although the infection rate was higher among boys (0.67%, 17/2,537) than in girls (0.55%, 10/1,812), no significant difference was found ($X^2$=0.399, P=0.62). According to the administrative district, the infection rate ranged from no positive cases of E. vermicularis infection in the Xinyi, Zhongzhen, and Wanhua Districts (0%; 0/299, 0/165, and 0/358, respectively), to 0.26% (1/131) in Songshan District, with the highest rate of 1.88% (7/373) in Wenshan District. Because the overall infection rate (0.62%, 27/4,349) in the present study was unchanged compared to that (0.40%, 197/49,541) previously reported in 2005, we propose that regular pinworm screening and treatment programs should be continued in some parts of Taipei City.

• Journal of the Korean Society of School Health
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• v.6 no.1
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• pp.45-57
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• 1993

The purpose of this study was to survey the current status of informal health education which elementary school nurses have performed in these days. The questionaire survey in this study was obtained from 154 (74.0%) out of 208 elementary school nurses in Kyungbuk province. This study is about their health educational conditions, contents, attitudes. The results are summarized as follows. 1. General characteristics of respondents 1) As for age distribution, thirties with 56.5% is larger than any other group 2) As for school size, below 18 classes with 48.1% is the highest 3) As for the place in which the work, country side (below county) with 65.7% is the highest 4) 89.6% of total respondents have graduated from nurse college 5) Their total career below 10 years is 68.2% 6) Their clinical career below one year is 35.7% 2. Actual conditions of health education 1) The rate of respondents who execute health education is 75.3% out of 154 respondents 2) Health education does not execute because the task of school nurses is busy. This percentage is 55.3% 3) Respondents who draw up a yearly health education plan are 84.5% 4) Weekly health education classes with 1~2 times are 79.3% and teaching time with 89.7% is physical class. 5) 75.0% of total respondents don't use the textbook in health education and the reason is that the contents of nextbook are poor. 6) In health education, teaching aids with VTR, slide flims, charts etc. are 80.2% 7) 82.8% of total respondents don't evaluate the result of teaching 3. Analysis of contents of health education and attitudes of school nurses. 1) The rate of private sanitation for keeping health with 64.7% is high among the contents 2) 90.9% of total respondents demand health education and 92.9% of then demand its independence of a subject. 3) The degrees of school principals' help and understanding are 90.3%, and those of teachers are 89.6% 4) The degrees of school nurses' confidence are high at 35.1% 5) Regular health education classes a week of a school nurse with 3~4 times are 40.9% 6) The greatest difficulty in health education with 70.1% is lack of teaching aids.

• Korean Journal of Materials Research
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• v.4 no.3
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• pp.319-328
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• 1994

Aluminium and titanium precursors containing $\beta$-diketonate ligands were used for the synthesis of polymeric sols of alumina and titania by sol-gel methods. To prepare polymeric sols by solgel processing, we synthesized modified precursors having chelating organic ligands. With these precursors it was found to be possible to control both hydrolysis and polycondensation reaction rates which resulted in ultrafine particles few nms of average size. The optimum molar ratio of acid to alkoxide for alumina sol was 0.3-0.4 and that of water to alkoxide &as 1. On the other hand, the corresponding ratios for titania sol were found be 0.25-0.20 and 1 respectively. Dynamic light scattering measurements indicated that the average particle size in both sols was in the order of few nms. SEM photographs were taken to observe crack-free and smooth surfaces of coated membranes after sintering at $450^{\circ}C$. Alumina coated membrane on a slide glass had about 4-4.5$\mu \textrm{m}$, thickness and titania coated one had 2-2.5$\mu \textrm{m}$, thickness. And according to TEM photographs, the grain size of titania was smaller than 30nm and that of alumina was in the range of few $\AA$s to 2nms. An X-ray diffraction study revealed that alumina was $\gamma$ phase and titania was anatase crystal.

• Journal of Sensor Science and Technology
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• v.4 no.3
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• pp.60-70
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• 1995

Polycrystalline $Cd_{1-x}Zn_{x}S$ thin film were grown on slide glass(corning-2948) substrate using a chemical bath deposition (C.B.D) method. They were annealed at various temperature and X -ray diffraction patterns were measured by X-ray diffractometor in order to study $Cd_{1-x}Zn_{x}S$ polycrystal structure using extrapolation method of X-ray diffraction patterns for the CdS, ZnS sample annealed in $N_{2}$ gas at $550^{\circ}C$. It was found hexagonal structure which had the lattice constant $a_{0}\;=\;4.1364{\AA}$, $c_{0}\;=\;6.7129{\AA}$ in CdS and $a_{0}\;=\;3.8062{\AA}$, $c_{0}\;=\;6.2681{\AA}$ in ZnS, respectively. Hall effect on these sample was measured by Van der Pauw method and then studied on carrier density and mobility depending on temperature. We measured also spectral response, sensitivity maximum allowable power dissipation and response time on these sample.