• 한국세라믹학회지
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• 제52권4호
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• pp.229-233
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• 2015

Currently, the majority of commercial white LEDs are phosphor converted LEDs made of a blue-emitting chip and YAG yellow phosphor dispersed in organic silicone. However, silicone in high-power devices results in long-term performance problems such as reacting with water, color transition, and shrinkage by heat. Additionally, yellow phosphor is not applicable to warm white LEDs that require a low CCT and high CRI. To solve these problems, mixing of green phosphor, red phosphor and glass, which are stable in high temperatures, is common a production method for high-power warm white LEDs. In this study, we fabricated conversion lenses with LUAG green phosphor, SCASN red phosphor and low-softening point glass for high-power warm white LEDs. Conversion lenses can be well controlled through the phosphor content and heat treatment temperature. Therefore, when the green phosphor content was increased, the CRI and luminance efficiency gradually intensified. Moreover, using high heat treatment temperatures, the fabricated conversion lenses had a high CRI and low luminance efficiency. Thus, the fabricated conversion lenses with green and red phosphor below 90 wt% and 10 wt% with a sintering temperature of $500^{\circ}C$ had the best optical properties. The measured values for the CCT, CRI and luminance efficiency were 3200 K, 80, and 85 lm/w.

• 대한화학회지
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• 제46권1호
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• pp.76-82
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• 2002

본 연구에서는 과학 개념 학습을 위한 소집단 토론에서 지식구성 과정에서의 언어적 상호작용을 촉진하기 위한 방안으로 인지적 역할 부여의 효과를 조사하였다. 중학교 1학년 학생 62명을 대상으로 설명, 반박, 정리, 조정 활동을 촉진하는 인지적 역할을 부여한 소집단 토론 수업(CR)과 특정한 역할을 부여하지 않은 소집단 토론 수업(NSR)을 9차시 동안 실시하였다. 수업 처치 후, 학업 성취도, 개념 이해도, 과학 학습 환경에 대한 인식, 토론에 대한 인식 검사를 실시하였다. 이원 공변량 분석 결과, 학업 성취도 점수에서 사전 성취 수준 하위 학생들의 경우 NSR 집단이 CR 집단보다 점수가 유의미하게 높았다. 개념 검사에서도 유사한 경향성이 나타났다. 과학 학습 환경 인식과 토론에 대한 인식 검사 점수에서는 집단 간에 유의미한 차이가 없었다.

• 대한치과보철학회지
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• 제39권2호
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• pp.184-196
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• 2001

The objective of this study was to investigate the influence of resin cements and ceramic etching on shear bond strength of Empress 2 ceramic and observe the change of microstructure of ceramic according to etching time. Sixty-six square ceramic specimens($6{\times}6{\times}1.5mm$) were prepared. 6 specimens were etched with different etching times(0, 10, 20, 30, 40 and 60 seconds) and observed by means of a scanning electron microscope(SEM). Other sixty specimens were divided into 6 groups with 10 specimens in each group. 3 groups were etched with 4% hydrofluoric acid and each groups was bonded with 3 resin cements(Variolink II, Super-Bond C&B, Panavia F). Each specimen was subjected to a shear load in an Instron at a cross-head speed of 0.5mm/min and was observed with SEM after mechanical testing to establish modes of failure. The results were as follows : 1. Within etched groups, Variolink II and Super-Bond C&B exhibited significantly greater bonding strengths than Panavia F(p<0.05) 2. Bond strength of etching groups had three to five times greater than that of no-etching groups. 3. All of no-etching groups showed adhesive failure and etching groups mostly showed mixed failure. And, 20-second etching specimen showed the most distinct lithium disilicate crystal. so it is considered that 20-second etching is optimal time for bonding.

• 대한수의학회지
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• 제53권4호
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• pp.217-224
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• 2013

Transgenic plants have been tested as an alternative host for the production and delivery of experimental oral vaccines. Here, we developed transgenic potatoes that express the major antigenic sites A and D of the glycoprotein S from transmissible gastroenteritis coronavirus (TGEV-$S_{0.7}$) under three expression vector systems. The DNA integration and mRNA expression level of the TGEV-$S_{0.7}$ gene were confirmed in transgenic plants by PCR and northern blot analysis. Antigen protein expression in transgenic potato was determined by western blot analysis. Enzyme-linked immunosorbent assay results revealed that based on a dilution series of Escherichia coli-derived antigen, the transgenic line P-2 had TGEV-$S_{0.7}$ protein at levels that were 0.015% of total soluble proteins. We then examined the immunogenicity of potato-derived TGEV-$S_{0.7}$ antigen in mice. Compared with the wild-type potato treated group and synthetic antigen treated group, mice treated with the potato-derived antigen showed significantly higher levels of immunoglobulin (Ig) G and IgA responses.

• Journal of Korean Neurosurgical Society
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• 제40권6호
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• pp.428-433
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• 2006

Objective : We investigated the pattern of glucose uptake in meningiomas using $^{18}F$-fluoro-2-deoxy-D-glucose[FDG] PET/CT. It was hypothesized that the degree of glucose uptake in each tumor could predict the histologic grade. Methods : In 19 patients with meningiomas, the Ki-67 proliferative index, standardized uptake values[SUV] of FDG uptake, tumor to contralateral gray matter ratio[TGR] of SUV, tumor size, edema grade, vascular endothelial growth factor[VEGF] expression, histopathologic grade and the blood supply pattern were assessed. Results : Of the 19 meningiomas, 8 were meningothelial, 1 fibrous, 2 transitional, 1 psammomatous, 2 angiomatous, and 5 atypical. The tumor proliferative index of Ki-67, tumor size, and peritumoral edema were larger in the histopathologic grade-2 meninigiomas than in the grade-1 meningioma group. There were no significant differences in SUV and TGR between two groups. Tumor size and peritumoral edema were significantly larger in VEGF-positive tumors than in negative tumors. Conventional angiography was performed in 12 patients. Dural supply was noted predominantly in 2 patients. Four patients had mainly pial cortical supply patterns. In tumors with more pial supply, VEGF was more frequently positive. There was a significant relation between SUV and Ki-67 and between SUV and peritumoral edema. Conclusion : We found FOG uptake in meningiomas is associated with proliferative potential, however, no clear limits of SUV and TGR can be set to distinguish between grade-1 and grade-2 meningiomas, which makes the assessment of malignancy grade using PET scan metabolic imaging difficult in individual cases.

• 대한핵의학회지
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• 제27권2호
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• pp.165-169
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• 1993

Functional cerebral impairments have been verified objectively by brain SPECT and q-EEG (quantitative electroencephalography). Microcerebral circulatory defects without anatomical changes can-not be detected by the brain CT or MRI. Brain SPECT using $^{99m}Tc$-HMPAO (Hexamethyl propyleneamine oxime) as a key radioisotope may be accepted as the useful method for identifying functional cerebral impairments. We studied 25 patients with mild head trauma to define whether the SPECT was helpful in detecting cerebral impairment. Results were as follows: The SPECT was positive in 23 patients out of 25, q-EEG positive in 16 patients and brain CT was positive in 3 cases. SPECT and q-EEG were more sensitive than CT, SPECT would be more useful method than brain CT to investigate cerebral function after head injury.

• 한국수정란이식학회지
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• 제28권2호
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• pp.79-85
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• 2013

The recent development in genetic assisted selection (combining traditional- and genome assisted selection method) and reproduction technologies will allow multiplying elite cow in Hanwoo small farm. This review describes the new context and corresponding needs for genome assisted selection schemes and how reproductive technologies can be incorporated to get more genetic gain for cow genetic improvement in Hanwoo. New improved massive phenotypes and pedigree information are being generated from commercial farm sector and these are allowing to do genetic evaluation using BLUP to get elite cows in Korea. Moreover cattle genome information can now be incorporated into breeding program. In this context, this review will discuss about combining the reproductive techniques (Multiple Ovulation Embryo Transfer; MOET) and genome assisted selection method to get more genetic gain in Hanwoo breeding program. Finally, how these technologies can be used for multiplication of elite cow in small farm was discussed.

• 한국수산과학회지
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• 제42권6호
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• pp.545-554
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• 2009

This study was conducted to develop and characterize of a high quality salted mackerel using enzymatic extracts of Ecklonia cava (EEC). In this study, potential antioxidative properties of EEC were evaluated by DPPH free radical scavenging activity, hydrogen peroxide scavenging activity, peroxide value, and fatty acid composition, and the antimicrobial properties were also measured by analysis for volatile basic nitrogen, pH, viable cells, Eschericia coli and biogenic amine. Compared to EEC-untreated salted mackerel, the salted mackerel with EEC was superior in antioxidative properties, while was negligible in the difference of antimicrobial properties. These results suggested that the high quality salted mackerel with antioxidative activity could be developed by treatment of EEC.

• 대한영양사협회학술지
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• 제21권2호
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• pp.154-172
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• 2015

The prevalence of obesity is continuing to increase. Self-perceived body image among women has drawn a lot of attention in Korea due to unhealthy weight control trials. This study was conducted to determine the relationship between self-perceived body image and dietary intakes among Korean women. For the analysis, 1,747 subjects were selected after eliminating those who were likely to have recently altered their diet based on the 2010 Korea National Health and Nutrition Examination Survey (KNHANES) data. The subjects were divided into three groups: underweight, normal, and obese groups according to their perception of body image. Daily nutrient intakes, NAR (Nutrient Adequacy Ratio), and food intake frequency were assessed according to age group and body image perception. Only energy intake showed differences among the three body image perception groups across all age groups, but not statistical differences. Analysis of NAR and the order of most frequently consumed food items confirmed these findings. The ratio of underweight women that perceived their body size as normal or overweight was higher with younger age. Incorrect body image perception and unhealthy weight control behaviors can cause nutritional problems. This study confirmed that nutritional knowledge is important for healthy weight control trials. Nutritional education for healthy dieting should be emphasized among Korean women.

• Tuberculosis and Respiratory Diseases
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• 제47권2호
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• pp.259-264
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• 1999

저자들은 흉부 불쾌감 및 호흡곤란을 주소로 내원한 19세 여자환자에서 우연히 흉부사진상 반월도(scimitar) 모양의 음영 및 우측 폐 형성부전이 발견되어 심초음파, 전산화 단층촬영 혈관조영술, 심도자 및 심혈관 조영술 등으로 확진하여 보존적 치료를 시행한 성인형 Scimitar 증후군을 경험하였기에 문헌고찰과 함께 보고하는 바이다.