• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.617-623
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• 2004

Acidic drink has been known as a cause of tooth erosion. The purpose of this study is to verify the acid levels of orange juices in market and evaluate the erosion effects on the enamel of deciduous teeth by orange juices in relatively short period of time. With four kinds of orange juice selected from market, pH, buffering capacity and concentration of Ca and P ion were measured. And forty segments of normal enamel of deciduous incisors were divided into four groups and level of erosion was measured by surface hardness test before and after soaking at 50ml of orange juice for 10 minutes. The results of this study showed that the average pH of orange juices was 4.0 and this pH value was so acidic as to cause the tooth erosion. There were differences in small quantity for each group of teeth, however, the result was statistically so significant that orange juices can cause enamel erosion in relatively short period of time.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.3
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• pp.395-402
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• 2005

In considering the healing process of injured periodontal tissue, healing rate would be influenced by the cellular activity of periodontal fibroblasts(PDLFs). In addition, the reattachment among PDLFs should be induced for healing process. The purpose of this study was to evaluate the effects of epidermal growth factor(EGF) on the proliferation and attachment of PDLFs and to verify the efficacy of EGF as a storage media or a pre-replantation conditioner of traumatically avulsed tooth. Human recombinant epidermal growth factor(hrEGF) and human periodontal fibroblasts from first premolar were prepared. At first, MTT assay was done to evaluate the toxic effect on human periodontal fibroblast and the maximum cellular growth of EGF. Cellular proliferation rate was then compared between control group and 10ng/ml EGF added group. Also, western blot was done to evaluate the expression of fibronectin in both groups. The results were as follows: 1. From MTT assay, EGF showed no toxic effect on PDL fibroblasts. The highest proliferation was shown at 10ng/ml EGF. 2. In 10ng/ml EGF added group, the degree of proliferation of PDLFs was significantly higher than that in control group. 3. Fibronectin expression of EGF added group was also significantly higher than that of control group. From this study we could conclude that EGF enhanced the regeneration rate of periodontal fibroblast, which could be used as a pretreatment agent or a storage media for traumatically avulsed teeth.

• Proceedings of the Korean Reliability Society Conference
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• 2006.05a
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• pp.239-246
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• 2006

프레스다이용 코일스프링은 자동차 및 전자제품의 외형생산에 필요한 금형 내에 장착되는 금형용 스프링으로서 녹아웃 및 스트리퍼 등에 사용되고 있다. 프레스다이용 코일스프링이 사용 중 파손 시에는 고가인 금형의 손상 및 생산성에 영향을 미칠 수도 있기 때문에 사용 환경에서의 신뢰성확보가 요구되어지고 있다. 특히 중(重)하중 및 극중(極重)하중용 스프링은 과거 현장에서 파손사례가 자주 발생함으로 인해 외산을 선호하는 경향이 있는 형편이다. 이에 국산 스프링의 신뢰성검증 및 확보를 위해 신뢰성기반구축사업을 통해 신뢰성평가기준(RS D 0014)가 제정되었으며, 이 평가기준에 의거하여 국내 업체의 제품에 대해 신뢰성평가를 실시하였다. 프레스다이용 코일스프링의 파손원인은 주로 반복하중에 의한 피로파손과 일정한 변위의 변형으로 발생하는 코일스프링 자유높이의 축소로 크게 구분되어질 수 있다. 시험결과 주 파손양상은 피로에 의한 균열발생이었으며, 코일 끝단부와 끝단부 직하부의 코일과의 마찰에 의한 균열발생이 주원인이었다. 즉, 코일의 끝단면과 직하면 코일이 연속적으로 부딪침으로써 발생한 변형 및 마모에 의해 표면균열이 발생하고, 표면균열에서 반복적인 부하하중이 가해짐으로써 피로균열 진전을 통해 점차적으로 파손이 진행되어졌음을 알 수 있었다. 본 발표에서는 기준에 의거하여 로하중용 프레스 다이용 코일스프링을 평가한 신뢰성평가시험 결과에 대해 보고하고, 파단면 관찰과 외산제품과의 미세조직 및 조성 등의 비교분석결과 등을 기초로 파손원인을 분석한 결과에 대해 보고하고자 한다.제고할 수 있을 것으로 기대한다.X>$CdCl^+,\;CdSO_4$ 등이 형성되었다. 수은의 경우는 해수 및 증류수를 용출용매로 이용한 모든 경우에서 납, 구리, 카드뮴과는 달리 대부분 침전하였다. 더욱이 해수에 존재하는 고농도 염소($Cl^-$)와의 수착으로 인해 finite solid인 calomel($Hg_2Cl_2$)이 형성되어 대부분 침전(SI=0)되기 때문에 납, 구리, 카드뮴 보다 더 낮은 환경이동성을 갖을 것으로 사료된다. 상기 실험결과 용출용매로 증류수와 해수를 이용했을 때, 제강 슬래그에서 용출되는 납, 구리, 카드뮴, 수은의 용출 경향의 차이를 확인할 수 있었고 이에 따라서, 납, 구리, 카드뮴의 용출 유해성은 낮기 때문에 해양구조물로의 제강슬래그 유효이용은 적합할 것으로 판단되었다.im80%$로 계산되었다. 열형광선량계로 측정된 방사선량은 각각 1.8, 1.2, 0.8, 1.2, 0.8 (70 cm 거리) cGy로 측정되었으며, 환자의 복부 표면에서의 서베이메터를 이용한 측정량은 10.9 mR/h였다. 차폐구조물의 사용 시 전체 치료 동안에 태아선량은 약 1 cGy 정도로 평가되었다. 결론 : AAPM Report No.50의 자료에 따르면, 임산부의 방사선 치료 시 태아의 방사선 피폭선량은 5 cGy 이하일 경우에 방사선 피폭에 따른 태아의 위험이 거의 없는 것으로 제시되고 있다. 본원에서 차폐 구조물을 설치하였을 경우에 측정된 태아선량은 약 1 cGy로 측정되었고, 고안된 차폐구조물

• Journal of the Society of Cosmetic Scientists of Korea
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• v.39 no.1
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• pp.31-38
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• 2013

To substitute animal test, skin equivalents (SEs) have been developed for skin irritation and corrosion test. Recently, we have developed new SEs containing Cervi cornus Colla (CCC). In the present study, we used the SEs for cutaneous cytotoxicity test. Sodium dodecylsulfate (SDS) or sodium carbonate was applied to the SEs-, and the epidermal damage by H&E and immunohistochemical stains was evaluated. Our results showed that SDS or sodium carbonate affected the epidermal part of SEs containing CCC in a dose-dependent manner and decreased the expression of p63. It is concluded that SEs containing CCC could be used for an alternative model of animal test and would be greatly helpful in the development of in vitro irritation and corrosion test.

• Korean Journal of Food Science and Technology
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• v.19 no.1
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• pp.61-65
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• 1987

The milk protein portion contains sialic acid which may be used as an index for k-casein. In comparison with non fat dry milk (NFDM) and calcium caseinate, the solubility of NFDM protein isolates at the various pH was inferior. Another consideration for the low solubility relates to the possibility that k-casein may have been extracted or possibly modified by the action of alcohol. The k-casein is the principal stabilizing fraction for casein micelle and any changes which result in its destruction or removal would be expected to have potent results. During solvent treatment, 16.5% of sialic acid was extracted in the first extraction solvent, whereas the second treatment caused only a 4.0% loss, based on sialic acid analysis. A study was conducted on the effect of concentration of methanol on loss of sialic acid. The loss of sialic acid decreased as the concentration of methanol increased to above 62% in both the first and second extracted solvent. It appears that loss of sialic acid is attributed to the water fraction rather than the methanol fraction. The effect of addition of the dried extracted solids on solubility was investigated. Protein solubility of NFDM protein isolates was sharply increased by 10% addition of the extracted solids and, thereafter, decreased. Efforts to restore solubility by feeding-back the extracted material supported the concept that removal of surface k-casein may have been a possible factor.

• Journal of Life Science
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• v.13 no.3
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• pp.241-247
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• 2003

While the DNA-protein kinase (DNA-PK) complex, comprised of DNA-PKcs and Ku80, is primary involved in the repair of DNA double-strand breaks, it is also believed to participate in additional cellular processes. Here, treatment of embryo fibroblasts (MEFs) derived from either wild-type (Wt) or DNA-PKcs-null (DNA-$PKcs^{-/-}$) mice with various stress inducing agents revealed that adriamycin was markedly more cytotoxic for $Ku80^{-/-}MEFs$ and led to their long-term accumulation in the $G_2$/M phase. This differential response was not due to differences in DNA repair, since adrimycin-triggered DNA damage was repaired with comparable efficiency in both Wt and $Ku80^{-/-}MEFs$, but was associated with differences in the expression of important cell cycle regulatory genes. Our results support the notion that Ku80-mediated cytoprotection and $G_2$/M-progression are not only dependent on the cell's DNA repair but also may reflect Ku80's influence on additional cellular processes such as gene expression.

• Korean Journal of Food Science and Technology
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• v.46 no.4
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• pp.483-488
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• 2014

To examine the physiological effects of broccoli (Brassica oleracea var. italica) leaf, the bioavailable compounds in broccoli leaf extract, and its in vitro neuroprotective effects against $H_2O_2$-induced oxidative stress were examined in this study. The chloroform fraction of broccoli leaf extract had the highest total phenolic content of all the fraction than others, and the highest 2,2"-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical-scavenging activity and malondialdehyde (MDA) inhibitory effect. Intracellular reactive oxygen species (ROS) accumulation resulting in $H_2O_2$-treated in PC12 cells was significantly lower when the chloroform fraction was present in the medium compared to that in PC12 cells treated with $H_2O_2$ alone. In a cell viability assay performed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), the chloroform fraction showed protective effects against $H_2O_2$-induced neurotoxicity and inhibited lactate dehydrogenase (LDH) release into the medium. High-performance liquid chromatography (HPLC) analysis showed that ferulic acid was the predominant phenolic compound in chloroform fraction of broccoli leaf.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.11
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• pp.1540-1545
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• 2012

To investigate the inhibitory effects of Lespedeza cuneataextract (LC) on photo aging, skin aging was induced by UVB irradiation of hairless mice for 5 weeks. The skin erythema indices for the positive control (PC) and Lespedeza cuneata extract (LC-1%, 3%, and 5%) groups were lower than that of the control group. However, both lipid and water capacities of the PC and LC-3% groups were significantly higher than those of the control group. Skin wrinkles in the PC and LC-3% groups formed in a pattern of shallow furrows and thin crests. Skin TBARS contents and XO activity in the LC group were lower than those of the control group. The activities of GSH, SOD, and CAT in the LC-3% group were significant higher than those of the control group. Therefore, Lespedeza cuneata extract could be an effective natural herbal material for the inhibition of skin aging in hairless mice skin.

• Journal of Conservation Science
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• v.31 no.1
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• pp.1-11
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• 2015

Seated Amitabha Triad at Muwisa Temple (Treasure No. 1312) had been known as wooden Buddha statue, but a precise safety inspection revealed that the statue is terracotta Buddha statue made with clay. The clay layer of Amitabha Triad was conserved due to its severe damage. In this study, experiments were conducted to produce the most appropriate filler for the conservation treatment of the seated Amitabha Triad. Mixed clay samples with various ratios were produced and surface hardening state, crack, color change, and shrinkage of the samples during dry process were measured. Loess, fine sand powder, and cotton were used to produce the mixed clay for the filler with six different ratios and then 12 different concentration glues made with glutinous rice glue, Pachymeniopsis Elliptica glue, and animal glue were added as adhesives. Total 72 types of samples were prepared and comparative study was conducted. As a result, when the mixed clay contains 2.5% cotton compared to the weight per cent of loess and fine sand powder and also loess and fine sand in the mixed clay have a 15:1 ratio, the mixed clay had the lowest shrinkage. Animal glue is considered as an appropriate glue since it had small color change, low physical property change and shringkage. Therefore, mixed clay (loess:fine sand=15:1) mixed with 15ml animal glue is likely to be a suitable filler for conservation treatment of the seated amitabha triad at the Muwisa Temple.

• Microbiology and Biotechnology Letters
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• v.40 no.3
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• pp.274-277
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• 2012

Cytokinesis is the final stage of cell division, dividing one mother cell into two daughter cells. For the cutting of a plasma membrane during bacterial cytokinesis, a tubulin homolog FtsZ protein is recruited from the cytoplasm to the division site. FtsZ protein polymerizes in a GTP-dependent manner and its N-terminal domain has a GTPase activity. In this study, we have begun to characterize FtsZ from Staphylococcus aureus (SA). Full-length SA FtsZ was cloned into pRSFDuet-1 vector and the clone was transformed into a BL21 (DE3) star cell. The recombinant SA FtsZ protein was purified using Ni-NTA affinity chromatography and dialysis. Using a spectrofluorometer, we showed that SA FtsZ undergoes a GTP-dependant polymerization in vitro. The polymer of the SA FtsZ protein disappeared after a few minutes, suggesting that the polymer is degraded as the GTP is consumed. This assay system may well be applied for inhibitor screening targeting S. aureus FtsZ.