• Journal of Korean Dental Science
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• 제2권1호
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• pp.42-47
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• 2009

Objective : The purpose of this study was to evaluate the effects of low level lasers on bone healing and new bone formation around titanium dental implants in canine models. 18 oxidized surface treated implants and a Dens-bio laser were used. Study design : Low level lasers were irradiated with a total of 8J for 4 minutes by pulse wave type and 1 minute by continuous type. For the experimental group, a low level laser was used to irradiate the first premolar implant's insertion area at the time of insertion, a low level laser was used to irradiate the second premolar implant's insertion area daily for one week after implant insertion, and a low level laser was used to irradiate the third molar implant's insertion area daily for 2 weeks postoperatively. At the conclusion of the study, sacrificed tissue sections were made from investing tissue and observed under an optical microscope. Results : The rate of new bone formation around the implant showed no significant difference between the control group and the experimental group. New bone formation rates of the control and experimental group 2 weeks following implant placement were higher than that of immediately after implant placement and 1 week after implant placement. Conclusions : Based on these results, a low-level laser showed no statistically significant increase in bone formation following implant placement.

• 한국균학회지
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• 제15권3호
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• pp.142-148
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• 1987

대두(大豆) 탄저병(炭疽病)(C. truncatum)을 공시(供試)하여 In vitro에서 광(光), pH 및 영양원(營養源)과 In vivo에서 시비수준(施肥水準)(P, K 및 Ca)이 부착기형성(附着器形成)에 미치는 영향(影響)을 조사(調査)한 바는 다음과 같다. 1. 3시간(時間) 및 6시간(時間)이 지난후의 조사(調査)에 따르면 광처리(光處理)를 한 것이 암처리(暗處理)를 한 것보다 부착기형성률(附着器形成率)이 양호(良好)하였다. 그러나 시간이 진행(進行)됨에 따라서는 각처리(各處理)에서 부착기형성률(附着器形成率)이 높아졌다. 2. 부착기형성(附着器形成)에 적정 pH는 $pH\;6{\sim}8$이었다. 3. 탄소원(炭素源) 및 질소원(窒素源) 공(供)히 무처리구(無處理區)에서 부착기형성률(附着器形成率)이 양호(良好)하였고 농도(濃度)가 높을수록 억제되는 경향이었으며 질소원(窒素源)에 비(比)하여 탄소원(炭素源)에서의 부착기형성률(附着器形成率)이 양호(良好)하였다. 그리고 시간(時間)이 경과함에 따라서 부착기형성률(附着器形成率)이 상승했다. 4. 3시간(時間) 경과후의 조사(調査)에서는 인산 및 칼륨처리(處理)는 증시(增施)했을 경우 다소 부착기형성(附着器形成)이 억제되었으나, 칼슘처리(處理)에 있어서는 무비구(無肥區)<표준비구(標準肥區)<2배비구(培肥區)의 순(順)으로 부착기형성(附着器形成)이 상당히 억제되는 경향이었다. 그러나 시간(時間)이 경과함에 따라서는 부착기형성률(附着器形成率)이 시비수준(施肥水準)과 관계없이 상당히 증가(增加)됨을 보였다.

• 한국환경농학회지
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• 제17권2호
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• pp.150-155
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• 1998

To investigate effects of organic matter application on heavy metal uptake of infant rice seeding, the various amount of organic matter(peat and $Bio-com^{(R)}$)was applied on Cd or Cu treated nursery bed soil. No growth difference was observed up to 20mg/kg of Cu treatment. Above 20mg/kg of Cu treatment, the seeding height and top dry weight were decreased but the Cu uptake by seeding was increased with increasing Cu treatment level. The mat formation was poor above 20mg/kg of Cu treatment, however, the seeding peat application level. All peat treatment resulted better mat formation than control. The seeding height and top dry increasing Cd treatment level. The mat formation was not effected by either Cd treatment level or organic matter sources. The effect of peat and $Bio-com{(R)}$ application on Cd uptake by infant rice seeding was not observed at all Cd treatments level.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.141-143
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• 2012

The present study is aiming at numerically analyze the soot formation processes coupled with gas reaction mechanism in turbulent non-premixed and partially premixed flames. In order to realistically represent turbulence-chemistry interactions with detailed chemical kinetics and soot formation behaviour related to the turbulent non-premixed and partially premixed flames, the transient flamelet[1] and flamelet based level-set approach[2] are coupled with soot formation based on the two equation model [3] and DQMOM (Direct Quadrature Method of Moment)[4].

• 상하수도학회지
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• 제19권2호
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• pp.181-192
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• 2005

This study evaluated the effect of factors influencing the initial biofilm formation in drinking water distribution pipe by running experiments using a $2^{4-1}$ fractional factorial experimental design with a replicate. Important variables used for assessing biofilm formation included BDOC(biodegradable dissolved organic carbon), viable heterotrophic bacteria present in drinking water, water temperature, and shear stress at two levels each. Based on the statistical analysis of biofilm levels measured as attached HPC(heterotrophic plate count) and community-level assay, the main factors that have significant effects on biofilm formation were found to be viable heterotrophic bacteria and BDOC. Water temperature only exhibited significant effect on the levels of attached HPC, while shear stress was not a significant factor under given conditions. Moreover, the statistical analysis revealed that interactions between the important variables were not statistically significant at a 0.05 significance level.

• Nutritional Sciences
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• 제8권4호
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• pp.242-249
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• 2005

It is well established that zinc plays an important role in bone metabolism and mineralization. The role of zinc in bone formation is well documented in animal models, but not much reported in cell models. In the present study, we evaluated zinc deficiency effects on osteoblastic cell proliferation, alkaline phosphatase activity and expression, and extracellular matrix bone nodule formation and bone-related gene expression in osteoblastic MC3T3-E1 cells. To deplete cellular zinc, chelexed-FBS and interpermeable zinc chelator TPEN were used. MC3T3-E1 cells were cultured in zinc concentration-dependent (0-15 ${\mu}M\;ZnCl_2$) and time-dependent (0-20 days) manners. MC3T3-E1 cell proliferation by MTT assay was increased as medium zinc level increased (p<0.05). Cellular Ca level and alkaline phosphatase activity were increased as medium zinc level increased (p<0.05). Alkaline phosphatase expression, a marker of commitment to the osteoblast lineage, measured by alkaline phosphatase staining was increased as medium zinc level increased. Extracellular calcium deposits measured by von Kossa staining for nodule formation also appeared higher in Zn+(15 ${\mu}M\;ZnCl_2$) than in Zn-(0 ${\mu}M\;ZnCl_2$). Bone formation marker genes, alkaline phosphatase and osteocalcin, were also expressed higher in Zn+ than in Zn-. The current work supports the beneficial effect of zinc on bone mineralization and bone-related gene expression. The results also promote further study as to the molecular mechanism of zinc deficiency for bone formation and thus facilitate to design preventive strategies for zinc-deficient bone diseases.

• The Journal of Advanced Prosthodontics
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• 제12권5호
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• pp.316-321
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• 2020

PURPOSE. The stress distribution and microgap formation on an implant abutment structure was evaluated to determine the relationship between the direction of the load and the stress value. MATERIALS AND METHODS. Two types of three-dimensional models for the mandibular first molar were designed: bone-level implant and tissue-level implant. Each group consisted of an implant, surrounding bone, abutment, screw, and crown. Static finite element analysis was simulated through 200 N of occlusal load and preload at five different load directions: 0, 15, 30, 45, and 60°. The von Mises stress of the abutment and implant was evaluated. Microgap formation on the implant-abutment interface was also analyzed. RESULTS. The stress values in the implant were as follows: 525, 322, 561, 778, and 1150 MPa in a bone level implant, and 254, 182, 259, 364, and 436 MPa in a tissue level implant at a load direction of 0, 15, 30, 45, and 60°, respectively. For microgap formation between the implant and abutment interface, three to seven-micron gaps were observed in the bone level implant under a load at 45 and 60°. In contrast, a three-micron gap was observed in the tissue level implant under a load at only 60°. CONCLUSION. The mean stress of bone-level implant showed 2.2 times higher than that of tissue-level implant. When considering the loading point of occlusal surface and the direction of load, higher stress was noted when the vector was from the center of rotation in the implant prostheses.

• 한국환경생태학회지
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• 제24권2호
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• pp.186-193
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• 2010

2006~2008년 동안 새만금 간척지에서 조성된 인공 염생식물 군락지와 새만금 방조제 배수갑문 수위 관리의 연관성을 밝히기 위해 배수갑문 수위특성 및 사유, 염생식물 군락지의 공간적인 분포와 형성 과정, 수위변화에 따른 염생식물 분포공간분석을 시도하였다. 배수갑문 수위조절의 특성을 분석한 결과, 파종 후 생장기의 평균수위와 연평균 수위와의 차이는 유사했으며, 연간 최저수위 및 최고수위가 파종 후 생장기에 나타났다. 3년동안 4,315만$m^2$에 염생식물 군락지가 형성되었으며 총 2,673만$m^2$에 대해 인공적인 염생식물 군락 조성이 시도되어 291만$m^2$을 제외한 표고 약 1m 이상의 2,382만$m^2$(89.1%)에 염생식물 군락지가 형성된 것으로 추정되었다. 파종지역 염생식물 군락지 형성에서 해수의 평균수위나 최저수위보다도 최고수위가 결정적인 요인으로 작용하였으며, 경운 및 토양 피막 여부가 군락지 형성의 2차적인 요인으로 작용한 것으로 보인다.

• Plant Biotechnology Reports
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• 제5권2호
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• pp.187-195
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• 2011

The gesneriaceous perennial plant Titanotrichum oldhamii has beautiful foliage and attractive bright yellow flowers. However, breeding of T. oldhamii by conventional sexual hybridization may be difficult because sexual reproduction of this species is very rare. In the present study, plant regeneration systems via both direct and indirect formation of adventitious shoots from leaf explants were established as the first step toward breeding T. oldhamii by using biotechnological techniques. Adventitious shoots were formed efficiently on medium containing $0.1mg\;l^{-1}$ benzyladenine. Histological observation showed that shoot formation on this medium occurred directly from leaf epidermal cells without callus formation. On the other hand, leaf explants formed calluses on medium containing $0.1mg\;l^{-1}$ 2,4-dichlorophenoxyacetic acid. The calluses could be maintained by monthly subculturing to fresh medium of the same composition. When the calluses were transferred to plant growth regulator-free medium, they formed adventitious shoots. Directly and indirectly formed shoots rooted well on medium containing $0.1mg\;l^{-1}$ indole-3-butyric acid. Plantlets thus obtained were successfully acclimatized and grew vigorously in the greenhouse. Flow cytometry analysis indicated that no variation in the ploidy level was observed in plants regenerated via direct shoot formation, whereas chromosome doubling occurred in several plants regenerated via indirect shoot formation. Regenerated plants with the same ploidy level as the mother plants showed almost the same phenotype as the mother plants, whereas chromosome-doubled plants showed apparent morphological alterations: they had small and crispate flowers, and round and deep green leaves.

• Applied Science and Convergence Technology
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• 제25권5호
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• pp.98-102
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• 2016

The level set method has recently become popular in the simulation of semiconductor processes such as etching, deposition and photolithography, as it is a highly robust and accurate computational technique for tracking moving interfaces. In this research, full three-dimensional level set simulation has been developed for the investigation of focused ion beam processing. Especially, focused ion beam induced nanodot formation was investigated with the consideration of three-dimensional distribution of redeposition particles which were obtained by Monte-Carlo simulation. Experimental validations were carried out with the nanodots that were fabricated using focused $Ga^+$ beams on Silicon substrate. Detailed description of level set simulation and characteristics of nanodot formation will be discussed in detail as well as surface propagation under focused ion beam bombardment.