• Journal of Environmental Policy
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• v.8 no.1
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• pp.49-72
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• 2009

To analyze the direct and indirect $CO_2$ emission structure according to industries in Korea, a hybrid IO table quantifying the section of energy in the IO table is needed. However, the results of the recent researches revealed differences in the total amount of $CO_2$ emission by researchers in addition to significant standard deviation in industrial distribution. This study intends to make comparative analysis of the existing method of making an IO table for energy and environment and presents an improvement scheme to contribute to an improvement in calculation of the total amount of $CO_2$ emission and estimation of the emission by industries in Korea. For this purpose, division was made into use as raw materials of energy and that as fuel and a new hybrid IO table was made by removing confounding factors caused by the product tax and subsidies. As a result, the oil and coal industry emitted 5.2 times less $CO_2$ after removing energy inputted as raw materials from the transaction table than before. The amount of $CO_2$ emission estimated by using the IO table based on basic price was found to be 2.7% less than by using the IO table based on the producer price.

• Journal of Environmental Policy
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• v.7 no.1
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• pp.1-29
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• 2008

The Ministry of Environment(MoE) of Korea has recently established the Environmental Health Act. This Act contains a clause related to implementation of Health Impact Assessment(HIA). So, selecting a landfill which was expected to have an influence on human health among major development projects, this study carried out the human risk assessment due to inhalation exposure to landfill gas emission and attempted to measure the possibility of domestic application of HIA in the future. The process for HIA on landfill site extension focusing on human risk assessment is as follows: The first step is to presume and calculate the amount of landfill gas emissions using LandGEM, The second step is to carry out exposure assessment using K-SCREEN Model which is used for predicting the concentration in a conservative method. The last step is to carry out human risk assessment of carcinogenic and non-carcinogenic substances. It is considered that it is likely to apply a technique for human risk assessment due to inhalation exposure to landfill gas emission performed here more specifically in the case of implementing HIA. In addition, it is also believed that more systematic studies are needed to overcome some weak points and limits found in this study and if these weak points and limits are improved more reliable outcomes will be produced.

• Journal of Periodontal and Implant Science
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• v.33 no.1
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• pp.13-26
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• 2003

Periodontal regeneration therapy with bone-substituting materials has gained favorable clinical efficacy by enhancing osseous regeneration in periodontal bony defect. As bone-substituting materials, bone powder, calcium phosphate ceramic, modified forms of hydroxyapatite, and hard tissue replacement polymer have demonstrated their periodontal bony regenerative potency. Bone-substituting materials should fulfill several requirements such as biocompatibility, osteogenecity, malleability, biodegradability. The purpose of this study was to investigate biocompatibility, osteo-conduction capacity and biodegradability of $Na_2O$, $K_2O$ added calcium metaphosphate(CMP). Beta CMP was obtained by thermal treatment of anhydrous $Ca_2(H_2PO_4)_2$. $Na_2O$ and $K_2O$ were added to CMP. The change of weight of pure CMP, $Na_2O$-CMP, and $K_2O$-CMP in Tris-buffer solution and simulated body fluid for 30 days was measured. Twenty four Newzealand white rabbits were used in negative control, positive control(Bio-Oss), pure CMP group, 5% $Na_2$-CMP group, 10% $Na_2O$-CMP goup, and 5% $K_2O$-CMP group. In each group, graft materials were placed in right and left parietal bone defects(diameter 10mm) of rabbit. The animals were sacrificed at 3 months and 6 months after implantation of the graft materials. Degree of biodegradability of $K_2O$ or $Na_2O$ added CMP was greater than that of pure CMP in experimental condition. All experimental sites were healed with no clinical evidence of inflammatory response to all CMP implants. Histologic observations revealed that all CMP grafts were very biocompatible and osseous conductive, and that in $K_2O$-CMP or $Na_2O$-CMP implanted sites, there was biodegradable pattern, and that in site of new bone formation, there was no significant difference between all CMP group and DPBB(Bio-Oss) group. From this result, it was suggested that all experimental CMP group graft materials were able to use as an available bone substitution.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.4
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• pp.677-683
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• 2008

The purpose of study was to compare the prevalences of severe early childhood caries(S-ECC) using two different diagnostic criteria. The subjects of this study included 401 preschool children from 36 to 71 months of the randomly selected seven nurseries in Iksan city. Severe early childhood caries was defined as (1) 1 or more cavitated, missing (due to caries), or filled smooth surfaces in primary maxillary anterior teeth or (2) a decayed, missing, or filled score of ${\geq}$4 (age 3), ${\geq}$5 (age 4), or ${\geq}$6 (age 5) surfaces. The prevalence determined by maxillary anterior caries and the prevalence determined by dmfs were 26.7%, 28.9% in 3 years, 32.4%, 30.4% in 4 years, 39.4%, 41.3% in 5 years, and 35.4%, 35.9% in all, respectively. The results suggest that the two diagnostic criteria of the severe early childhood caries yield almost the same results.

• Korean Journal of Construction Engineering and Management
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• v.12 no.1
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• pp.3-12
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• 2011

Technology based civilization has made a sustained advancement, resulting in economic growth and material prosperity. The outcome was the beginning of environmental destruction. Especially, in regard to construction, it has been recognized as a key culprit for pollution. As such, the construction industry has recently shown interest in the environment, as it has been applying environment friendly method of construction and reducing wastes. As the number of old common housing increases in our country, reconstruction and remodeling are implemented as a means of improvement. However, it can be said that remodeling is the inevitable option because of cost and environmental problems associated with reconstruction. As part of its feature, remodeling work is preceded by removal work. And, removal work inevitably creates construction wastes. Treatment of wastes that takes into consideration environmental aspects is important and for this, removal work that is based on environment friendly remodeling to ensure selective separation must be implemented. Yet, a removal work based on environment friendly remodeling has a lower level of output compared to existing methods. Because remodeling work by its nature has a post construction work which proceeds after it, securing work efficiency is important as the removal work is a critical path activity. Thus, the present study improves the work process of a removal work that is based on environment friendly remodeling so that it becomes a work process that includes work efficiency. For this, as a case study, old common housing has been selected, and a TACT process has been developed which is based on data acquired from environment friendly removal work. And, this study develops an optimal TACT process which is based on environment friendly remodeling by conducting a simulation for a 15 floor apartment.

• Korean Journal of Construction Engineering and Management
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• v.14 no.1
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• pp.124-132
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• 2013

An influx of the population to the city has soared due to industrialization. As times go by, cities become densely populated so Korean government started to construct a number of buildings including apartment housings. Because they have become functionally, structurally, esthetically deteriorated over the past two decades. some improvements are needed. There are mainly two ways to improve old buildings: remodeling and reconstruction. Between the two, the first one is more popular as it is less time-consuming and more eco-friendly. Demolition work comes first for both of them and it should not give negative effects since it is regarded as a CP(Critical path) in the overall process. For this reason, a thorough construction management must be done. The reality, however, demolition is managed by the construction manager's experiences and decisions. If the key factor of demolition which is the planning of manpower and machine equipment, is determined by unscientific and subjective judgments, its period and risk also will increase. In particular, eco-friendly demolition can be more risky because it's been rarely conducted. Therefore, scientific and objective ways of demolition management are needed. In this context, this paper aims at analyzing productivity in each process of demolition focusing on manpower and machinery equipment which are the main parts of demolition assuming that the demands of eco-friendly remodeling demolition projects will be increasing. At the same time, by estimating working period through the output, this paper would be helpful to set up the plans for overall project in earlier stage.

• Journal of Periodontal and Implant Science
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• v.34 no.2
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• pp.269-279
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• 2004

백악질 세포의 분리 및 배양방법을 확립하고, 이를 이용하여 백악질 세포의 형질특성을 알아보고자 하였다. 교정목적으로 발거된 소구치를 이용하여, 치은섬유아세포, 치주인대 세포 및 백악질 유래세포를 분리, 배양하였다. 백악질 유래 세포 배양시에는 백악질을 절제한 후 Collagenase P를 이용하여 백악질 유래 세포 외의 다른 세포의 개제를 배제하였고, 기질을 분해하여 세포의 분리 및 배양이 용이하도록 하였다. 분리 및 배양시기의 세포의 형태를 광화현미정을 이용하여 관찰하였다. 조골세포의 특성을 가지는 SaOs-2 세포를 대조군으로 이용하여 분리 및 배양된 세포군들을 동일한 조건으로 배양하였다. 3일 및 7일째에 세포증식도를 측정하였고 7일째에 ALPase 효소 활성도를 측정하였다. 각 세포의 형질 특성을 알아보기 위해 RT-PCR을 실시하여 조골세포 분화 표식자와 연관된 osteopontin(OPN), Alkaline phosphatase(ALP), type I collagen(COL-I), Bone sialoprotein(BSP), BMP-2 및 osteocalcin(OC)의 발현을 비교 관찰하였다. 백악질 유래 세포의 분리 및 배양을 시도한 5명의 치아 중에서 3명의 치아에서 세포군을 배양해 낼 수 있었다. 배양한 백악질 유래 세포는 섬유아세포와 유사한 형태와 증식을 보였다. ALPase 효소 활성도 검사 결과 백악질 유래 세포는 SaOs-2 세포보다 낮은 활성도를 나타내었으며, 배양된 세포의 RT-PCR 결과 백악질 유래 세포군에서는 ALPase의 발현이 나타나지 않았고, 다른 조골세포 표식자의 발현도 낮게 나타났다. 이는 백악질 유래 세포가 조골세포 및 다른 대조군의 세포와는 다른 형질 특성을 가지고 있다는 것을 시사한다. 이상의 관찰결과로 사람의 백악질 유래 세포롤 백악질의 절제 및 효소처리 방법으로 효과적인 분리 및 배양이 가능하며, 이는 향후 백악질 세포의 형질 특성 및 백악질 형성의 분자적 기전을 파악하는 중요한 연구자료로 활용 될 수 있을 것으로 사료된다.

• Journal of Periodontal and Implant Science
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• v.33 no.1
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• pp.1-11
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• 2003

Hydroxyapatite(HA) has been extensively used as bone graft materials and tooth implant surface coating materials because of its biocompatibility and osteoconductive properties. However, as HA is intrinsically poor in mechanical properties, zirconia($ZrO_2$) was incorporated with HA as reinforcing phases for improvement of mechanical properties. The purpose of this study was to investigate the biological activities of HA-coated zirconia through the cell proliferation test, measurements of alkaline phosphatase activity, and histologic examination. Four kinds of tested blocks were prepared according to the pore size (300-500${\mu}m$/500-700${\mu}m$) and the porosity (70%/90%). Cell proliferation and alkaline phosphatase activity was measured at 1, 7, 14 days. The number of cells proliferate after 7, 14 days were significantly increased in all groups when compared with that of the first day, but there was no significant difference between the 4 groups at each time period. At the 7 day, alkaline phosphatase activities of cells cultured in 4 groups were higher than that of the first day, but there was no significant difference between the 4 groups at each time period. The human gingival fibroblast and MG 63 cell was used to evaluate the cell cytotoxicity using MTT test. The materials tested in the current study turned out to be non-cytotoxic. In histologic examination(SEM), at 1 day there were many cells attached on the surfaces of all kinds of tested blocks. The number of cells were increased over time. At the 14 day, there were more cells proliferated than 1 day and some of the pores of blocks were partially filled with the proliferated cells. The in vitro response of osteoblast-like cells to the HA-coated zirconia showed comparable effect on transformation comparable to hydroxyapatite.

• Journal of Periodontal and Implant Science
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• v.34 no.2
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• pp.293-301
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• 2004

1. 연구 목적 Fibronectin은 세포외기질의 주요성분인 거대 당단백질로서, 조골세포의 부착과 증식 및 이동능에 중요한 역할을 담당한다고 알려져 있다. 이러한 fibronectin의 조골세포에 대한 영향을 실제 임상에 적용하기 위해서, 전체 fibronectin 단백질을 사용하는 것은 면역학적으로나 경제적으로 많은 단점을 안고 있어서, 유효한 반응단위만을 추출하여 활용하는 것이 바람직한 방법으로 알려져 있다. 이 연구의 목적은 세포부착에 주로 관여하는 fibronectin type III분절 중 10번 도메인이 조골양 세포에 미치는 영향을 전체 fibronectin단백질과 fibronectin type III 7-10 도메인 분절과 비교, 관찰하는 것이다. 2. 연구 방법 사람의 fibronectin을 기초로 한 적절한 primer로서, 유전자 재조합법을 이용하여 fibronectin type III 10 도메인과 fibronectin type III 7-10 도메인 분절을 얻었으며, 전체 fibronectin분자는 상용으로 준비하여 24-well 세포배양 용기에 도포하였다. 배양된 조골양세포(HOS cell)를 $1x10^5$ cells/well의 농도로 각 well에 분주하여 $37^{\circ}C$에서 1시간 배양을 하였다. Cell adhesion assay를 실시하기 위해 10% formaldehyde로 고정시키고 1% Crystal Violet으로 염색하여 광학현미경을 관찰 후 2% SDS를 처리하여 microplate reader기를 이용하여 570nm에서 혼탁정도를 측정하였다. 음성대조군으로는 RPMI 용액을 사용하였다. 동일한 방법을 이용하여 준비된 $35mm^2배양접시에 HOS cell을 $37^{\circ}C$에서 4일간 배양 후, MTS assay를 이용하여 세포 증식도에 미치는 영향을 관찰하였다. 6일째 405nm에서 활성화된 세포에서 분비된 p-nitrophenol을 이용한 alkaline phosphatase activity를 측정하였다. 3. 결과 및 고찰 Fibronectin type III 10 도메인은 HOS cell에 대한 생물학적인 효과면에서, 전체 fibronectin 분자 및 fibronectin type III 7-10 분절과 통계적으로 유사한 세포부착도를 보여주었으며, 세포증식도와 alkaline phosphatse 활성도면에서도 큰 차이가 나타나지 않았다. 이상의 연구결과로 볼 때, fibronectin type III 10 도메인이 조골세포의 증식을 목적으로 사용하는 생체재료의 표면개질 부착물질로 응용할 수 있는 가능성이 있다고 하겠다.

• Journal of the Korean Geosynthetics Society
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• v.15 no.1
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• pp.59-70
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• 2016

The purpose of this study is to review that the VE techniques can be used as a selection tool of borrow pit locations. The analysis of the soil investigation report is performed for the selection of proposed borrow pit site on a large-scale residential development area. Possible earthwork volume of mining is estimated and the weighting matrix evaluation is applied to the VE techniques. After determining the evaluation items for VE assessment, important degree was calculated. The Rating and evaluation of performance is carried out on a proposed borrow pit site. And, development priority has to be decided for a proposed borrow pit sites. As a result, the relative construction cost is closely related to the haulage distance. As the haulage distance increases, the relative construction cost will be increased. Therefore, it was confirmed quantitatively that haulage distance has a significant impact on the select of borrow pits. Also, it was found that the condition of borrow pits itself is important, but it cannot be ignored the impact of the life cycle cost for the selection of optimal borrow pit sites.