• Journal of Korean Ophthalmic Optics Society
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• v.13 no.2
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• pp.51-57
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• 2008

Purpose: This study has been conducted to know how the size and position of the circle of least confusion has an influence on the vision for minimization of asthenopia when astigmatism is corrected and appropriated prescription to provided clear vision life. Methods: The method of the study has been worked on 68 students (136 eyes) of man and woman enrolled in university of Gyeong-gi-do aged 20 to 40, who have myopic astigmatism in order to know how the corrected vision changes according to the size and position of the circle of least confusion of astigmatism, the vision has been tested by giving the vision whose astigmatic power of 0.25D and 0.50D was just reduced, low correcting the astigmatic power into 0.50D, and at the same time inserting additionally spherical power -0.25D, all under a condition that the corrected vision after completely corrected astigmatism, and the axis of astigmatism was not changed. Results: The average vision was 1.047 when the astigmatic power was fully corrected, and in low correction of 0.25D, it was 0.914, and in low correction of 0.50, it was 0.772. It has been learned that the bigger the circle of least confusion was the bigger the range of vision reduction and the corrected vision in astigmatism has correlation with the size of the circle of least confusion. It has been examined that the average vision according to position of the circle of least confusion in astigmatism was 1.047 when the astigmatic power was completely corrected and focused on the retina with state of point, and in case that the astigmatic power was 0.50D of state of low correction, that is, the circle of least confusion was focused before retina, it was 0.828, and it was also 0.826 when the astigmatic power is low corrected with 0.50D and the circle of least confusion was focused on the retina. Explained briefly, It has been examined that in case that the state of low correction of the astigmatic power was same, the vision reduction was less in the image of the circle of least confusion focused upon the retina than in the image of its being focused before the retina. Conclusions: In case that the refractive power of cylindrical lens is reduced in test of wearability in astigmatism, there needs surely an adjustment of spherical lens that can place the circle of least confusion on the retina.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.191-198
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• 2009

Statement of problem: Ceramics have been important materials for the restoration of teeth. The demands of patients for tooth-colored restorations and the availability of various dental ceramics has driven the increased use of new types of dental ceramic materials. Improved physical properties of theses materials have expanded its use even in posterior crowns and fixed partial dentures. However, ceramic still has limitation such as low loading capability. This is critical for long-span bridge, because bridge is more subject to tensile force. Purpose: The wire reinforced ceramic was designed to increase the fracture resistance of ceramic restoration. The purpose of this study was to evaluate the fracture resistance of wire reinforced ceramic. Material and methods: Heat pressed ceramic(ingot No.200 : IPS Empress 2, Ivoclar Vivadent, Liechtenstein) and Ni-Cr wire(Alfa Aesar, Johnson Matthey Company, USA) of 0.41 mm diameter were used in this study. Five groups of twelve uniform sized ceramic specimens(width 4 mm, thickness 2 mm, length 15 mm) were fabricated. Each group had different wire arrangement. Wireless ceramic was used as control group. The experimental groups were divided according to wire number and position. One, two and three strands of wires were positioned on the longitudinal axis of specimen. In another experimental group, three strands of wires positioned on the longitudinal axis and five strands of wires positioned on the transverse axis. Three-point bending test was done with universal testing machine(Z020, Zwick, Germany) to compare the flexural modulus, flexural strength, strain at fracture and fracture toughness of each group. Fractured ceramic specimens were cross-sectioned with caborundum disc and grinded with sandpaper to observe interface between ceramic and Ni-Cr wire. The interface between ceramic and Ni-Cr wire was analyzed with scanning electron microscope(JSM-6360, JEOL, Japan) under platinum coating. Results: The results obtained were as follows: 1. The average and standard deviation in flexural modulus, flexural strength and fracture toughness showed no statistical differences between control and experimental groups. However, strain was significantly increased in wire inserted ceramics(P<.001). 2. Control group showed wedge fracture aspects across specimen, while experimental groups showed cracks across specimen. 3. Scanning electron microscopic image of cross-sectioned and longitudinally-sectioned specimens showed no gap at the interface between ceramic and Ni-Cr wire. Conclusion: The results of this study showed that wire inserted ceramics have a high strain characteristic. However, wire inserted ceramics was not enough to use at posterior area of mouth in relation to flexural modulus and flexural strength. Therefore, we need further studies.

• Journal of the Korean Society of Food Culture
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• v.21 no.2
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• pp.225-231
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• 2006

대황(Rhubarb)은 중국과 일본에서 혈액 순환제, 진통제, 신장치료제 등으로 전통적으로 사용되고 있는 약용식물이다. 이 연구에서는 한국산 R. undulatum L.의 뿌리 추출물, 미국산 R. rhabarbarum L.과 중국산 R. palmatum L.의 줄기 추출물의 두부 부패에 관여하는 미생물에 대한 항균 활성을 평가하였다. Rhubarb의 최적 추출을 위해서 각각 50%, 70%, 80% 에탄올을 용매로 사용하였으며, 항균 활성은 Kirby-Bauert test, minimum inhibitory concentration (MIC)과 minimum bactericide concentration (MBC)에 의해서 평가되었다. Kirby-Bauert test 결과, R. undulatum L.의 뿌리 추출물은 대부분 두부 부패균에 대해서 항균 활성을 가지는 것으로 나타났으며, R. rhabarbarum L.의 줄기 추출물의 경우는 $20{\mu}g/disc$의 농도에서는 항균 활성이 거의 나타나질 않았으나, 고농도로 갈수록 높은 항균 활성을 나타내었다. 또한 R. palmatum L.의 줄기 추출물은 고농도로 갈수록 항균 활성이 높아졌으나, Pseudomonas aeruginosa에 관해서는 항균 활성이 나타나지 않았다. MIC와 MBC에 의한 항균 활성 평가실험에서는, 세 종류의 rhubarb 추출물 중에서 phenolic 화합물이 가장 많이 함유되어 있는 R. undulatum L.의 뿌리 추출물보다 R. rhabarbarum L.의 줄기 추출물이 MIC와 MBC 값이 낮았다. 이는 phenolic 화합물의 양 이외에 낮은 pH가 항균 활성에 영향을 준 것으로 판단된다. 본 연구를 통해서 rhubarb 추출물은 두부 부패에 관여하는 미생물에 대해서 항균 활성을 가지는 것으로 나타났으며, 천연 항균제로써 식품에 적용 가능성이 있는 것으로 평가되었다. 87.1%이었으며, 아침을 매일 먹는 채식남학생은 78.8%, 비채식남학생은 33.3%, 채식여학생 47.1%, 비채식여학생 39.6%이었다. 또한 식사의 양은 과식한다는 응답이 채식남학생 24.2%, 비채식남학생 38.1%, 채식여학생은 29.4%, 비채식여학생 40.6%으로 비책식군의 과식율이 높았다. 5. 식품 섭취빈도는 두부 및 콩제품을 매일 섭취하는 경우는 채식남학생 54.6%, 비채식남학생 16.7%, 채식여학생은 38.2%, 비채식여학생이 16.8%이었다. 우유 및 유제품을 매일 섭취하는 경우는 채식남학생 6.1%, 비채식남학생 33.3%, 채식여학생 14.7%, 비채식여학생은 21.8%이었으며, 녹차, 커피 등 차를 마시지 않는다는 비율은 채식남학생 69.7%, 비채식남학생 28.6%, 채식여학생 29.4%, 비채식여학생 25.7%이었다. 인스턴트 식품을 매일 섭취한다는 응답율이 채식남학생 9.1%, 비채식남학생 21.4%, 채식여학생은 17.7%, 비채식여학생은 14.9%이었다. 6. 운동, 체중 조절 등에 대한 조사 결과 항상 운동을 하는 경우는 채식남학생 30.3%, 비채식남학생 28.6%, 채식여학생 14.7%, 비채식여학생 18.8%이었으며 운동시간은 $1{\sim}2$시간 하는 경우는 채식남학생 30.3%, 비채식남학생 38.1%, 채식여학생은 8.8%, 비채식여학생은 17.8%이었다. 체중에 만족하는 정도를 보면 채식남학생 57.6%, 비채식남학생 23.8%, 채식여학생은 23.5%, 비채식여학생은 15.8%가 만족한다고 하였다. 체중 조절 경험에서 경험이 있는 경우가 채식남학생 3.0%, 비채식남학생 31.0%, 채식여학생은 23.5%, 비채식여학생 31.7%이었다. 7. 골밀도 BQI값과와 몇가지 요인의 상관관계를 살펴보았을때, 채식남학생은 영양보충제의 섭취와 유의적인 양의 상관관계를, 해조류의 섭취정도와 유의적인 음의 상관관계를 나타내었다.

• Clinical and Experimental Pediatrics
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• v.46 no.9
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• pp.846-853
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• 2003

Purpose : Pneumoccocus is one of the most important causes of invasive infection through the childhood period and the prevelance of antibiotics resistance of pneumococcus is increasing worldwide. A 7-valent conjugate vaccine has been developed. It is important to know the prevalence of each serotype of pneumococci in the countries where the vaccine is used to estimate the coverage rate by the vaccine. Methods : One hundred and twenty seven strains of clinical isolates and 72 strains from healthy carriers recovered from Korean children during the period from 1997 to 2002 were subjected to determination of serotype by Quellung reaction and penicillin susceptibility with oxacillin disc diffusion test. Results : Forty-three per cent of clinical isolates were obtained from children under two years of age. Thirty strains(24%) were isolated from normally sterile body fluids. The frequent serotypes were 19F, 19A, 23F, 6A, 6B and 9V. Fifty-six per cent of the clinical isolates were represented in the current 7-valent protein conjugate pneumococccal vaccine, and 84% when the cross-reactive serotypes were included. Frequent serotypes of strains isolated from one to five year-old healthy children were 19F, 14, 11A, 23F, 18C, and 19A. Seventy-one per cent of the carrier strains were included in the 7-valent vaccine. Ninety-three per cent of the clinical isolates and 86% of carrier strains were not susceptible to penicilline. Conclusion : Fifty-six to 84% of pneumococci recovered from Korean children are covered by the current 7-valent protein conjugate pneumococcal vaccine and the prevalence of penicillin resistance was very high.

• Restorative Dentistry and Endodontics
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• v.33 no.6
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• pp.526-536
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• 2008

The purpose of this study was to compare the effect of various dentin bonding systems on microtensile bond strength of immediate dentin sealing (IDS) and delayed dentin sealing (DDS). Eighteen extracted permanent molars were used in this study. The teeth for DDS group were restored with a provisional restorations, and immersed in saline solution for 1 week, and divided into 3 subgroups according to various dentin bonding adhesives; SB subgroup (3 step total-etch adhesive), SE subgroup (2 step self-etch adhesive), XE subgroup (1 step self-etch adhesive). In IDS group, the teeth were divided into 3 subgroups, and applied with bonding adhesives as in DDS group. The teeth were restored with provisional restorations, and immersed in saline solution for 1 week. Indirect composite disc was cemented with resin cement, and all specimens were subjected to microtensile bond strength. The data were statistically analyzed with oneway ANOVA and Student t-test. The results were as follows: 1. The IDS group showed significantly higher ${\mu}TBS$ than DDS group in 3 step total-etch and 2 step selfetch adhesive (p < 0.05). 2. In IDS and DDS group, 3 step total-etch adhesive showed the highest ${\mu}TBS$ value, followed by 2 step self-etch, and 1 step self-etch adhesive. In IDS group, the ${\mu}TBS$ value for 1 step self-etch adhesive was significantly different from those of the other subgroups (p < 0.05), and in DDS group, there were statistical differences in all subgroup (p < 0.05). 3. Failure modes of tested dentin bonding adhesives were mostly mixed failure and only 1 step self-etch adhesive showed adhesive failure.

• Microbiology and Biotechnology Letters
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• v.45 no.3
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• pp.250-256
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• 2017

The prevalence of infections due to pathogenic bacteria such as Edwardsiella tarda, Streptococcus parauberis, and Photobacterium phosphoreum in fish farms in Jeju Island and their management by marine-derived biomaterials was studied. In this study, we isolated eight spices type of marine-derived biomaterials from four sea areas of Jeju Island. An antibiotic disc susceptibility test confirmed that the isolated marine-derived biomaterials showed weak resistance only to oxytetracycline and penicillin and sensitivity to the other antibiotics tested, and antimicrobial activity against fish pathogens with the inhibitory zone of 22 mm, 18 mm, and 19 mm for MD-02, MD-04, and MD-06 against E. tarda strains, respectively, and 19 mm, 22 mm, 30 mm, and 29 mm for MD-01, MD-02, MD-04, and MD-06 against S. parauberis strains, respectively, while all the marine-derived biomaterials showed antibacterial activity against P. phosphoreum. Among the eight biomaterials selected, Bacillus subtilis MD-02 displayed the greatest antibacterial activity against the three tested fish pathogens and also displayed susceptibility to antibiotics. The growth of Bacillus subtilis MD-02 was greatest with the carbon source, dextrine; nitrogen source, peptone; and mineral source, $MgSO_4{\cdot}7H_2O$. Hence, the present study confirmed that the isolate B. subtilis MD-02 from Jeju Island could be a potential antimicrobial agent against fish pathogens and a potential pharmacotherapeutic agent.

• Journal of the Korean Society of Radiology
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• v.9 no.2
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• pp.101-107
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• 2015

In anteroposterior radiation test for cervical vertebra, it is general that the incidence angle of X-ray is $15^{\circ}$ to $20^{\circ}$ degrees to head regardless of position. So this study suggests appropriate incidence angle of cervical vertebra depended on the position. From 1 January 2013 to 31 December 2013, cervical spine radiographys and magnetic resonance imaging was performed in 107 people who visited P Hospital located in Pusan. Among them, 39 people(men 24, women 15) were below 80 above 20 years old(average age 54 years) with normal cervical lordosis(normal $40^{\circ}{\pm}5^{\circ}$). In erect position, the incidence angle of cervical vertebra is measured from lateral radiographic images. And in supine position, it measured from MRI sagittal images. Results based on gender, the incidence angle of cervical vertebra in erect position was $25.9^{\circ}$ for men, women was $23.1^{\circ}$, showed statistically significant (p<0.05). And the angle in supine was $11.6^{\circ}$ for men, women was $12.6^{\circ}$, showed not statistically significant (p>0.05) An analysis of age group shows, the incidence angle of cervical vertebra in erect position was $24.6^{\circ}$ under 50, and $25.0^{\circ}$ over 50. The angle in supine was $12.0^{\circ}$ under 50, and $11.9^{\circ}$ over 50. And all of them showed not statistically significant (p>0.05). At all ages, the average of incidence angles in erect position were $24.8^{\circ}$, and the angle in supine was $12.0^{\circ}$, showed statistically significant (p<0.05). The cervical vertebra incidence angle for X-ray was $15^{\circ}$ to $20^{\circ}$ degrees to head in general. But, through the results, it is recommended that the angle is $24.8^{\circ}$ in erect and $12.0^{\circ}$ in supine position. It could be shown true anteroposterior(AP) view of cervical vertebra and accurate intervertebral fusion fixing devices.

• Food Science and Preservation
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• v.19 no.2
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• pp.167-172
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• 2012

The antimicrobial activities of $Smilax$ $china$ L. against spoilage bacteria isolated from $Mang-gae$ rice cake were investigated and the storage stability of the $Mang-gae$ rice cake was enhanced. Spoilage bacteria, which cause $Mang-gae$ rice cake to rot, were isolated from commercial $Mang-gae$ rice cake, and most of the isolated strains were identified as $Bacillus$ sp. After the leaves, roots, shoots, and stalks of the $Smilax$ $china$ L. were extracted using 50% ethanol as the solvent, their antimicrobial activities were investigated using the paper disc method by treating them with 50 ${\mu}L$ of $Bacillus$ $cereus$, which is known as a major pathogenic micro-organism in foods that contain starch, as the test organism. The antimicrobial activities of the extracts were compared according to the size of the clear zones around the paper discs. The root extract showed significant antimicrobial activities. When red beans, which are used as stuffing for $Mang-gae$ rice cake, were treated with the root extract of the $Smilax$ $china$ L., the viable cell count of the $Mang-gae$ rice cake was 5.04 Log CFU/g after 48-hr storage, and the cake showed significantly slower growth of bacteria than with commercial products. These results show that treatment of red beans with $Smilax$ $china$ root extract could improve the storage stability of $Mang-gae$ rice cake.

• Journal of Sericultural and Entomological Science
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• v.53 no.2
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• pp.135-142
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• 2015

The American cockroaches, Periplaneta americana L. was the most important worldwide pest species. It has been an public health problems. We were determinated life cycle and extraction of crude extracts by chemical reagents from cockraches (P. americana L.). The extracted crude solution has been antibacterial activity to gram negative bacteria (Pseudomonas aeruginosa, $6.44{\pm}1.03mm$), gram positive bacteria (Bacillus subtilis, $1.88{\pm}0.40mm$), and fungus (Candida albicans, $5.61{\pm}0.57mm$) using radial diffusion assay. We were analysed of up-regulation of Glutathione-S-transferases (GSTs) stimulation, indicating that antioxidantial protein from various classes are simultaneously expressed in a single insect upon infection or injury. The gene from Periplaneta americana L. were cloned, analysed sequence, and measured protein expression by Real Time PCR (Polymerase Chain Reaction).

• Journal of the Korean Wood Science and Technology
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• v.32 no.4
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• pp.8-17
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• 2004

Antifungal, antibacterial, and antioxidative activities of ethanol extracts from 65 families 263 species were investigated to select tree species for the utilization of natural fungicide or preservative resources. The antifungal activities of extracts from wood, leaf and bark were measured as hyphal growth inhibition rate using four plant pathogenic and five wood rotting fungi. High inhibitory effect on the fungi growth was found in five species of Pinaceae (Pinus koraiensis, P. rigida, P. densiflora, P. banksiana. Cedrus deodara), three species of Cupressaceae (Juniperus rigida, J. chinensis, Chamaecyparis obtusa) and three species of Leguminosae (Albizzia julibrisssin, Sophora japonica, Maackia amurensis), respectively. Antibacterial activities of ethanol extracts were determined by means of disc-agar plate diffusion method using three gram-positive and five gram-negative bacteria. The ethanol extracts, which showed prominent effect on the suppression of bacteria growth, were six species of Betulaceae (Carpinus tschonoskii, C. coreana, C. laxiflora, Alnus hirsuta, A. firma, Betula schmidtii), five species of Fagaceae (Castanopsis cuspidata var. sieboldii, Quercus serrata, Q. mongolica, Q aliena, C crenata), four species of Euphorbiaceae (Aleurites fordii, Sapium sebiferum, S japonicum Mallotus japonicus) and three species of Elaeagnaceae (Elaeagnus umbellata, Elaeagnus glanbra, Elaeagnus macrophylla). According to these results, the extracts from Zelkova serrata, Pinus densiflora, Maackia amurensis, Chamaecyparis obtusa and Juniperus chinensis could be available for natural fungicide or food preservatives, because ethanol extracts from these species indicated excellent antifungal and antibacterial activities. In order to test antioxidative activities of ethanol extracts, free radical scavenging method was adopted with 1,1-diphenyl-2-picrylhydrohydrazyl (DPPH). Free radical scavenging activity was proved very high in the extracts of eight species of Rosaceae (Eriobotrya japonica, Prunus takesimensis, P yedoensis, P padus, P armeniaca var. ansu, Chaenomeles sinensis, Stephanandra incisa, Rosa multiflora) and five species of Ericaceae (Rhododenron mucronulatum, R. scblippenbacbii, R. yedoense var. poukhanense, Vaccinium bracteatum, V oldbami), resvectively. It turned out from this study that only six species among 48 species of Rosaceae showed less than 80% free radical scavenging activity. As a consequences, it could be deduced that the components effective on antioxidative activity commonly exist in Rosaceae plant family.