• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제35권5호
• /
• pp.294-298
• /
• 2009

Purpose: The development of a microvascularization is important for the homeostasis of normal bone. Vascular endothelial growth factor (VEGF) is one of the most important factors in vessel formation. The purpose of this study was to examine VEGF-related autocrine growth in periosteal-derived cells. Materials and methods: Periosteal-derived cells were obtained from mandibular periosteums and introduced into the cell culture. After passage 3, the periosteal-derived cells were further cultured for 21 days in an osteogenic inductive culture medium containing dexamethasone, ascorbic acid, and $\beta$-glycerophosphate. Results: The expression of four VEGF isoforms and VEGFRs was observed in periosteal-derived cells. Treatment with cultures with VEGFR-1 and VEGFR-2 Kinase Inhibitor inhibited osteoblastic differentiation and alkaline phosphatase (ALP) activity of periosteal-derived cells. In addition, exogenous VEGF treatment increased calcium content in the periosteal-derived cells. Conclusion: These results suggest that VEGF might act as an autocrine growth molecule during osteoblastic differentiation of cultured human periosteal-derived cells.

• 한국환경보건학회지
• /
• 제46권2호
• /
• pp.136-149
• /
• 2020

Objectives: The purpose of this study was to perform an aggregate human risk assessment for benzene in an industrial complex using the CalTOX model and to improve the reliability and predictability of the model by analyzing the uncertainty and sensitivity of the predicted assessment results. Methods: The CalTOX^TM 4.0 beta model was used to evaluate a selected region, and @Risk 7.6 software was used to analyze uncertainty and sensitivity. Results: As a result of performing the aggregate risk assessment on the assumption that 6.45E+04 g/d of benzene would be emitted into the atmosphere over two decades, 3% of the daily source term to air remained in the selected region, and 97% (6.26E+04 g/d) moved out of the region. As for exposure by breathing, the predicted LADD_inhalation was 2.14E-04 mg/kg-d, and that was assessed as making a 99.99% contribution to the LADD_total. Regarding human Risk_cancer assessment, the predicted human cancer risk was 5.19E-06 (95% CI; 4.07E-06-6.81E-06) (in the 95th percentile corresponding to the highest exposure level, a confidence interval of 90%). As a result of analyzing sensitivity, 'source term to air' was identified as the most influential variable, followed by 'exposure time, active indoors (h/day)', and 'exposure duration (years)'. Conclusions: As for the results of the human cancer risk assessment for the selected region, the predicted human cancer risk was 5.19E-06 (95% CI; 4.07E-06-6.81E-06) (in the 95th percentile, corresponding to the highest exposure level, a confidence interval of 90%). As a result of analyzing sensitivity, 'source term to air' was found to be most influential.

• 한국환경과학회지
• /
• 제10권1호
• /
• pp.21-25
• /
• 2001

The Keum river has been utilized for drinking water supply of several city including Kunsan city and is deepening pollution state due to numerous municipal and industrial discharges. The concentration BOD in river is affected by the organic loading from a tributary and the algae biomass that largely happen to under eutrophication state. In the eutrophic water mass such as the Keum river, the autochthonous BOD was very important part for making a decision of water quality management, because it was accounted for majority of the total BOD. The predict of water quality has important meaning for management of water quality pollution of the Keum river. The purpose of this study will manage and predict water quality of the Keum river using QUAL-2E model considering the autochthonous BOD. The estimation of autochthonous BOD represented that the relationship between BOD and chlorophyll a. The regression equation was shown to be autochthonous BOD=$\beta$(sub)5$\times$chlorophyll a. The results of this study may be summarized as followed; The QUAL-2E model was calibrated with the data surveyed in the field of the study area in June, 1998. The calculated value by QUAL-2E model are in good agree to measured value within relative error of 7.80~20.33%. Especially, in the case of the considering autochthonous BOD, the calculated value of BOD were fairly good coincided with the observed values within relative error of 15%. But the case of not considering autochthonous BOD, relative error of BOD was shown to be 43.2%. In order to attain II grade of water quality standard in Puyo station which has a intake facility of water supply, we reduced to the pollutants loading of tributaries. In the case of removed 100% BOD of tributaries, the BOD of Puyo station was 4.07mg/$\ell$, belong to III grade of water quality standard. But in the case of removed 88% nutrient of tributaries, it was satisfied to II grade of water quality standard as below 3mg/$\ell$ of BOD. For estimation of autochthonous BOD in Keum river, we are performed simulating in accordance with reduction of nutrient load(50~100%) under conditions removal 90% organic load. Occupancy of autochthonous BOD according to nutrient loading reductions were varied from 25.97~79.51%. Occupancy of autochthonous BOD was shown to be a tendency to increasing in accordance with reduction of nutrient loading. Showing the above results, the nutrient that one of the growing factor of algae was important role in decision of BOD in the Keum river. For the water quality management of the Keum river, therefore, it is necessary to considering autochthonous BOD and to construction of advanced sewage treatment plant for nutrient removal.

• Journal of Periodontal and Implant Science
• /
• 제33권1호
• /
• pp.13-26
• /
• 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.

• 대한치과기공학회지
• /
• 제30권1호
• /
• pp.25-31
• /
• 2008

Cp-Ti and Ti-6Al-4V alloys commonly used dental implant materials, particularly for orthopaedic and osteosynthesis because of its suitable mechanical properties and excellent biocompatibility. This alloys have excellent corrosion behavior in the clinical environment. The first factor to decide the success of dental implantation is sufficient osseointegration and high corrosion resistance between on implant fixture and its surrounding bone tissue. In this study, in order to increase corrosion resistance and biocompatibility of Cp-Ti and Ti-6Al-4V alloy that surface of manufactured alloy was coated with TiN by RF-magnetron sputtering method. The electrochemical behavior of TiN coated Cp-Ti and Ti-6Al-4V alloy were investigated using potentiodynamic (EG&G Co, PARSTAT 2273. USA) and potentiostatic test (250mV) in 0.9% NaCl solution at 36.5 $\pm$ 1$^{\circ}C$. These results are as follows : 1. From the microstructure analysis, Cp-Ti showed the acicular structure of $\alpha$-phase and Ti-6Al-4V showed the micro-acicular structure of ${\alpha}+{\beta}$ phase. 2. From the potentiodynamic test, Ecorr value of Cp-Ti and Ti-6Al-4V alloys showed -702.48mV and -319.87mV, respectively. Ti-6Al-4V alloy value was higher than Cp-Ti alloy. 3. From the analysis of TiN and coated layer, TIN coated surface showed columnar structure with 800 nm thickness. 4. The corrosion resistance of TiN coated Cp-Ti and Ti-6Al-4V alloys were higher than those of the non-coated Ti alloys in 0.9% NaCl solution from potentiodynamic test, indicating better protective effect. 5. The passivation current density of TiN coated Cp-Ti and Ti-6Al-4V alloys were smaller than that of the noncoated implant fixture in 0.9% NaCl solution, indicating the good protective effect resulting from more compact and homogeneous layer formation.

• Journal of Periodontal and Implant Science
• /
• 제25권3호
• /
• pp.478-486
• /
• 1995

Periodontal therapy for treatment of periodontitis involves the elimination of bacterial plaque and elimination of the anatomic defects by regenerative procedure. The purpose of this study was to evaluate on the biological effect of magnolia and Ginkgo biloba extract to the antimicrobial, antiinflammatory and cellular activity. Antimicrobial assay was performed with the diffusion method of the extract by measuring of growth inhibitory zone of B. cereus from blood agar plate. Effect of the extract to cellular activity of gingival fibroblast were examined using MTT method and measured the result with optical density on 570nm by ELISA reader. Inhibitory effects of $PGE_2$ production from gingival fibroblast was performed with the addition of $IL-l{\beta}$ and the extract to the well and examined to the product of $PGE_2$ from cell by ELISA reader. In vivo anti-inflammatory effect was performed with injection examined with clinically and histologically for their extent of mecrosis and inflammation. Antimicrobial activity of Magnolia extract showed significantly higher activity than that of control. However, GBE did not showed significant activity to compare with control, and mixture of Magnolia and GBE extract showed significantly higher activity than that of control. The effect of cellular activity to gingival fibroblast showed no significant differences of between control and Magnolia extract. However, GBE showed significantly higher rate of cellular activity to compare with control and even to PDGF-BB, and also showed same degree of cellular activity even though mixed with Magnolia extract. The inhibitory effect of $PGE_2$ production showed significantly reduction of $PGE_2$ production to compare with control, but its inhibitory effect was not much strong to compare with Indomethacin. In vivo, antiinflammatory effect of Magnolia extract to P. gingivalis injection of Hamster buccal check showed significantly reduction of inflammatory cell infiltration and tissue necrosis, but GBE showed no effect on the inhibition of inflammatory process. These results suggested that Magnolia and GBE extract possessed different kind of biological activity and also can be compensated on their activity with each other for elimination of bacterial plaque and anatonical defect.

• Journal of Radiation Protection and Research
• /
• 제24권3호
• /
• pp.155-160
• /
• 1999

환경 중에는 핵실험 및 원자력 발전소에서 방출되는 여러 가지 방사성 핵종들과 천연방사성 핵종들이 존재한다. 이 중에서 원자력발전소 운영과 관련하여, 환경 중의 인공방사성 핵종에 대한 관심이 높아지고 있다. 핵실험이나 원자력발전소와 관련된 인공방사선 핵종들은 주로 핵분열 생성물들로서, 그 수가 200여종에 이른다. 이 중에서도 $^{90}Sr$과 $^{137}Cs$은 선량특성상 특히 주목되어 왔다. 본 논문에서는 환경준위의 $^{90}Sr$ 정량 분석 방법에 대한 연구를 수행하였다. 환경 중의 $^{90}Sr$은 저준위이며, 특성 감마선과는 달리 연속 스팩트럼의 베타선원으로, $^{89}Sr$, $^{90}Y$ 및 다른 방사성 핵종들과 혼합되어 있기 때문에 정량적인 분석이 매우 어렵다. 저준위 방사성 스트론튬 분석을 위해서는 농축 과정 및 분석에 영향을 주는 타 방사성 핵종과의 화학적 분리과정이 필요하다. 그 동안 국내 여러 기관에서 공통적으로 스트론튬 회수율 산정을 위해 중량법을 사용하였고, 화학분리절차도 중량법을 사용하기에 적합하도록 개발하여 사용하였다. 최근 분석기기의 발달로 인해서, ppm 이나 ppb 단위의 안정원소 분석을 쉽게 할 수 있다는 점에 근거하여, 원자분광분석기기(ICP : Inductively Coupled atomic Plasma emission spectrophotometer)를 사용한 회수율 산정 및 그에 적합한 절차를 개발하였다. 개발된 절차는 기존의 중량법에 비해서 화학적 처리절차가 훨씬 간편하면서도 정확도가 높아서, 환경방사성 스트론튬의 정량분석에 적절히 사용될 수 있다.

• Journal of Korean Biological Nursing Science
• /
• 제5권1호
• /
• pp.23-33
• /
• 2003

본 연구는 체중 3.0kg의 가토 수컷 10마리를 이용하여 피부의 외상을 입힌 후 개방드레싱과 밀봉드레싱이 상처의 치유과정에서의 효과와 형태학적 차이를 비교하기 위해 1cm의 절개창과 $1.0{\times}0.2cm$의 피부절제창을 만든 후 개방드레싱군은 1일 2회 betadine으로 소독한 후 상처부위를 노출시켜 5, 10 및 15일째에 관찰하였으며, 밀봉드레싱군은 매일 betadine으로 소독하고 1% silver sulfadiazine 크림을 도포한 후 거즈를 덮어 5, 10 및 15일째에 광학현미경으로 관찰하여 다음과 같은 결론을 얻었다. 피부를 절개한 군과 절제한 군을 개방드레싱 및 밀봉드레싱을 각각 시행한 5일 후에는 딱지가 형성되었고 표피의 재생은 상처의 가장자리에서부터 시작하였다. 진피의 표층에는 호중구, 단구 및 림프구의 침윤이 일어났고 부종과 섬유아세포의 증식이 경하게 일어났다. 수상 후 개방드레싱 및 밀봉드레싱을 시행한 10일 후에는 딱지는 탈락되었고 표피는 재생되어 연속적이었다. 모세혈관의 수와 염증세포의 침윤은 감소하였다. 부종과 섬유아세포의 증식은 더욱 증가하였다. 수상 후 개방 및 밀봉드레싱을 시행한 후 15일에는 표피의 재생은 완성되어 각질이 형성되었다. 진피에는 염증세포의 침윤, 부종 및 혈관의 증식은 소실되었고 섬유아세포 및 교원섬유의 양은 증가하였다. 피부를 절개한 군은 절제 군에 비해 반흔의 양은 적었고 드레싱방법에따른 치유과정의 차이는 없었다. 이상의 성적으로 보아 상처의 치료는 드레싱의 방법보다 상처의 소독이 중요한 역할을 하는 것으로 사료된다.

• 대한한의학회지
• /
• 제27권3호
• /
• pp.51-62
• /
• 2006

Objective: Although chronic non-bacterial prostatitis is a common disease, it is very difficult to treat effectively. Lygodium japonicum has traditionally been used in treatment of urinary tract inflammation and voiding disturbance. In this study, we investigated the therapeutic effects and action mechanism of Lygodium japonicum in the rat model of non-bacterial prostatitis induced by castration and testosterone treatment. Methods: Five-month-old rats were treated with $17\beta-estradiol$ after castration for induction of experimental non-bacterial prostatitis, which is similar to human chronic prostatitis in histopathological profiles. Lygodium japonicum and testosterone were administered as an experimental specimen and a positive control, respectively. The prostates were evaluated by histopathological parameters including the epithelial score and epithelio-stromal ratio for glandular damage, proliferating cell nuclear antigen (PCNA) labeling index for cyto-proliferation and a TUNEL (deoxyuridine triphosphate biotin nick end-labeling) assay for cell apoptosis. Results: While prostates of control rats revealed severe acinar gland atrophy and stromal proliferation, the rats treated with Lygodium japonicum showed a lesser range of tissue damage. Epithelial score was improved in Lygodium japonicum than that of the control (P<0.05). The epithelio-stromal ratio was lower in Lygodium japonicum when compared to that of the control (P<0.05). Although there was no difference in PCNA and TUNEL positive cells of the glandular epithelia, we found an decreased number of PCNA positive cell and concurrent increase of TUNEL positive cells in the stroma of Lygodium japonicum treated rats (P<0.01). Conclusions: These findings suggest that Lygodium japonicum may protect the glandular epithelial cells and also inhibit stromal proliferation in association with suppression of cyto-proliferation and stimulation of apoptosis. We concluded that Lygodium japonicum may be a useful remedy agent for treating the chronic non-bacterial prostatitis.

• 대한토목학회논문집
• /
• 제14권6호
• /
• pp.1299-1308
• /
• 1994

본 연구는 사장교의 차량하중에 의한 동적거동을 파악하고자 수치해석상 비교적 간단한 일본의 풍리(豊里)(Toyosato)대교(大橋)의 자료를 근거로하여 수치해석 대상모델을 구조형식별로, 여러가지 설계변수-즉, (1) 경간비, (2) 중앙경간장과 주탑높이와의 비, (3) 거어더의 강성, (4) 주탑의 강성, (5) 케이블의 강성-을 변화시켜 수치해석을 수행하여 동적거동을 파악하고, 그 결과를 가지고 설계변수의 영향 및 충격계수의 변화에 대하여 비교 분석하였다. 이때 변위 및 단면력의 영향선을 구하기 위한 해석은 전달행렬법을 이용하였으며, 동적해석에 있어서는 평면구조계의 집중질량계로 모델을 가정하여 차량과 교량의 운동방정식을 유도한 후 모드중첩법을 사용하여 각 질점에 대한 변위 및 단면력의 동적시간이력을 구하였다.