• 한국안전학회지
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• 제26권3호
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• pp.29-33
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• 2011

Experimental studies were performed to investigate the injury potential of BB pellets through gelatine based simulants. In order to record BB pellet movements penetrating into the target simulant, a high-speed video camera was used. In this study the first investigation involved the effects on concentrations, homogeneity and gelation times of the gelatine simulant. The second investigation involved the penetration depth of the pellets to the simulant by different distances between the BB gun and the simulant. The final one is associated with impact velocity, threshold velocity and penetration depth of the pellets by different kinetic energies of the BB gun. Results provided the basis in assessing the injury potential of BB pellets.

• International Journal of Computer Science & Network Security
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• 제22권3호
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• pp.319-325
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• 2022

By using the Blackboard (BB) system in the education sector, the educational process for both academics and students is facilitated. Two data resources were used to evaluate the use of the BB system by students of Umm Al-Qura University: statistical reports issued by the university and an online questionnaire. A total of 989 students from all colleges and different programmes provided by the university responded to the questionnaire survey. According to our findings, most students did not use the BB before the pandemic. Therefore, the sudden conversion to the BB system required intensive training courses. After the data analysis, the relationship between the use of the BB system before the pandemic and the problems students faced during the lockdown was revealed. The most critical issues raised by the respondents were: (1) "The voice of the lecturer went on and off during BB collaborate class", (2) "internet connection of the lecturer went on and off during BB collaborate class" and (3) "High possibility of IT problems during exams".

• Journal of Periodontal and Implant Science
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• 제24권2호
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• pp.303-320
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• 1994

치주조직의 재생을 위하여 다양한 방법이 제시되어 왔으나 최근에는 치주인대세포를 선택적으로 유도하여 증식시키는 방법으로 성장인자에 대한 연구가 진행되고 있다. 중배엽세포를 조절하는 인자 중의 하나인 혈소판유래성장인자(Platelet-Derived Growth Factor, 이하 PDGF-AA, BB로 표기)는 폴리펩타이드계 성장인자로써 다양한 세포들에 대해 증식, 이주 및 기질합성에 촉진효과가 있다고 보고된 바 있다. 본 연구는 배양된 치주인대세포에 혈소판유 래성장인자를 농도별로 주입해서 세포의 증식능, 단백질 및 교원질 합성능을 측정해 보고, 골형성세포로의 분화에 대한 표식인자로 알칼린인산효소활성도를 알아보므로서 혈소판유래성장인자가 치주인대세포에 미치는 영향을 규명하고자 하였다. 교정치료를 위해 내원한 환자로 부터 건강한 제일소구치를 발거하여 치주인대세포를 분리, 배양하여 PDGF-AA, BB를 주입시키지 않은 군을 대조군으로 하고, PDGF -AA, BB를 각각 0.1, 1, 10, 100ng/ml로 주입시킨 군을 실험군으로하여 DNA 합성능, 총단백질과 교원질 합성능 및 알칼린인산효소활성도를 측정하여 다음과 같은 결과를 얻었다. DNA 합성능에 미치는 PDGF -AA, BB의 효과는 양군 공히 농도가 증가함에 따라 증가하는 경향을 보였으나 100ng/ml의 PDGF-BB를 투여한 군에서는 대조군과 유사한 정도를 나타내었다. 치주인대세포의 총단백질 합성양에 미치는 PDGF -AA, BB의 효과는 PDGF-AA, BB투여군 공히 농도가 증가함에 따라 총단백질 합성양이 증가하는 경향을 보였으며, 총단백질 합성양에 대한 PDGF-BB의 효과가 PDGF-AA보다 100ng/ml 투여군에서 현저히 높게 나타났다. 총단백질을 교원질(collagenase digestible protein : CDP)과 비교원성 단백질(noncollagenous protein : NCP)로 분류하여 비교하였을때 PDGF-AA, BB 투여군 공히 농도가 증가함에 따라 비교원성 단백질 합성양과 교원질 합성양이증가하는 경향을 보였으며, 양군 모두에서 비교원성 단백질 합성양이 교원질 합성양보다 높게 나타났다. 총단백질에 대한 교원질의 상대적 비율은 양군 공히 농도가 증가함에 따라 감소하는 경향을 나타내므로써 PDGF-AA, BB는 교원질에 특이하게 합성을 증가시키는 효과는 없음올 나타내었다. 알칼린인산효소활성도는 7, 14일째에서 PDGF-AA, BB 투여군 모두 대조군과 별 차이를 보이지 않았다.

• Journal of Periodontal and Implant Science
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• 제26권2호
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• pp.396-413
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• 1996

Current acceptable methods for promoting periodontal regeneration are based on removal of diseased soft tissue. root treatment, guided tissue regeneration, introduction of new graft materials and biological mediators. Insulin-like growth factor-I(IGF-I) and Platelet-derived growth factor-BB(PDGF-BB), the members of the polypeptuyde growth factor family have been reported as the biological mediators which regulate a variety cellular matrix biologic activities of wound healing process including the cell proliferation, migration and extracellular matrix synthesis.The purposes of this study is to evaluate the combination effects of IGF-I and PDGF-BB on the cellular activity of the periodontal ligament cells to act as a regeneration promoting agent of periodontal tissue. Human periodontal ligament cells were prepared from the first premolar tooth extracted for the orthodontic treatment and were cultured in DMEM containing 10% FBS at the $37^{\circ}C$, 5% CO2 incubator. Author measured the DNA synthetic activity, and total protein, collagen and noncollagenous protein synthetic activities according to the concentration of 10,100ng/ml IGF-I and1,10 ng/ml PDGF-BB in combination. The results were as follows: Significantly increased in the 1 ng/ml PDGF-BB alone compared to the 10 ng/ml PDGF-BB alone(P<0.01) and in the 1 ng/ml PDGF-BB and 10, 100ng/ml IGF-I in combination compared to the 1 ng/ml PDGF-BB alone(P<0.05, P<0.0l). The synthetic activity of the total protein and collagen is significantly increased like to the synthetic activity of the DNA(P<0.05). The synthetic activity of the noncollagenous protein is increased according to the concentration of IGF_I, but not statistically statistically significant(P>0.05). The percent of the collagen is significantly in the 1ng/ml PDGF-BB and 10ng/ml IGF-I in combination compared to the 1ng/ml PDGF-BB alone(P<0.05) and in the 10ng/ml IGF-I in combination compared to the 10ng/ml PDGF-BB alone(P<0.05). The synthetic activity of the DNA is In conclusions, the percent study shows that PDGF-BB and IGF-I in combination have a potentiality to enhance the DNA synthesis and the total protein and collagen synthesis of The periodontal ligament cells, especially it is more significant in the low concentration of PDGF-BB compared to the high one. Thus, the PDGF-BB and IGF-I in combination may have important roles in promotion of periodontal litgment healing, and consequently, may useful for clinical application in periodontal regenerative procedures.

• Molecules and Cells
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• 제24권1호
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• pp.132-138
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• 2007

4-1BB (CD137), a member of the tumor necrosis factor receptor superfamily, is expressed on activated T-cells, and 4-1BB signaling due to interaction with 4-1BB ligand or ligation with anti-4-1BB monoclonal antibody (mAb) costimulates T cells. It has been shown that administration of anti-4-1BB mAb induces anti-tumor immunity in mice, but the nature of the cellular subsets responsible for this immunity is uncertain. In this study we found that anti-4-1BB mAb administration to B16F10 melanoma-bearing mice induced marked expansion of $CD11c^+CD8^+$ T-cells in parallel with suppression of pulmonary tumors. The mAb-treated mice produced higher levels of $IFN-{\gamma}$ in their tumor tissues, spleen and lymph nodes than mice exposed to control antibody. When the $CD11c^+CD8^+$ T-cells were purified and re-stimulated in vitro, they produced high levels of the Th1 cytokines, $IFN-{\gamma}$ and IL-2, but low levels of the Th2 cytokines, IL-4 and IL-10. Furthermore, they expressed high levels of 4-1BB and CD107a, a marker of activated cytotoxic T-lymphocytes. Our results suggest that $CD11c^+CD8^+$ T-cells play a role in the anti-tumor immunity induced by anti-4-1BB mAb.

• Journal of Periodontal and Implant Science
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• 제27권3호
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• pp.647-668
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• 1997

6 beagle dogs aged over one and half years and weighed 14 to 16 Kg were utilized in this study, Horizontal furcation defects were induced around 2nd, 3rd, and 4th premolars bilaterally, PDGF-BB in conjunction with EGF and PDGF-BB only were applied in the right and left premolars respectively. 2 animals were sacrificed at 4weeks, 8 weeks, and 12 weeks, after regenerative surgery respectively. Semi-thin sections using glass-knife were stained with toluidine blue for light microscopic study. The results were as follows: 1. At 4 weeks after regenerative surgery, bone formation in the PDGF-BB-applied site was thriving, but bone formation in the PDGF-BB-and-EGF-applied site was depressed. 2. Bony ankylosis was surely shown along the whole exposed root surface applied with PDGF-BB, but it was shown at the root surface near the base of the bone defect where was applied with PDGF-BB in conjunction with EGF. 3. Active bone formation was made from 8 weeks after regenerative surgery in the PDGF-BB- and-EGF-applied site. 4. Bone maturity as well as speed of bone formation in the PDGF-BB-applied site was superior to those in the PDGF-BB-and-EGF-applied site throughout the whole experimental period. Within the above results, PDGF-BB had the strong capability to form the new bone and EGF was not able to prevent the bony ankylosis thoroughly. However, EGF may have the possibility to prevent the bony ankylosis through the suppression of bone formation.

• Journal of Periodontal and Implant Science
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• 제27권1호
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• pp.129-150
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• 1997

The purpose of this study was to evaluate the effects of tetracycline(TC}, flurbiprofen, and PDGF-BB loaded biodegradable membranes on the cell-attachment, the activity of loaded PDGF-BB, in vivo release kinetics, and guided bone regenerative potentials. To evaluate the cell attachment to membranes, the number of gingival fibroblasts attached to each membrane(10% TC, 10% flurbiprofen, $200ng/cm^2$ PDGF-BB loaded membranes, drug-unloaded membrane) was counted by coulter counter and the morphologic pattern of attached cells was examined under SEM. To determine whether the activity of loaded PDGF-BB is sustained, the cellular growth and survival rate of gingival fibroblasts was used for both standard PDGF-BB and loaded PDGF-BB. For evaluation of in vivo release kinetics, drug-loaded membranes were implanted on the dorsal skin of the rats. On 1, 3, 7, 10, 14, 21, and 28 days after implantation, the amount of remaining drugs were measured by HPLC assay for TC and flurbiprofen, and by ${\gamma}-scintillation$ counter for $PDGF-BB^{1125}$. For evaluation of guided regenerative potential, the amount of new bone in the calvarial defect(5mm in diameter) of the rat was measured by histomorphometry 1 and 2 weeks after implantation of membranes. The number of cells attached to the PDGF-BB loaded membrane was largest as compared with the other mernbranes.(p< 0.05) The activity of loaded PDGF-BB was not significantly different from the activity of standard PDGF-BB.(p<0.05) After initial burst release of drug during the first 24 hours, drugs were gradually released for 4 weeks. Especially the release rate of PDGF-BB was nearly constant during 4 weeks. PDGF-BB loaded membranes(200, $400ng/cm^2$) were effective in guided bone regeneration as compared with drug-unloaded membrane. These results implicate that drug-loaded biodegradable membranes might be a useful for guided bone regeneration.

• 한국안전학회지
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• 제27권2호
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• pp.20-24
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• 2012

Experimental studies were performed to investigate the eye injury risks by different BB pellet materials. Four different BB pellet materials were used: plastic (P), silicon (S), rubber (R) and plastic covered with silicon (SR). The BB pellet images penetrating into the gelatine simulant were recorded by a high-speed video camera. The results obtained from the different pellet materials were discussed in terms of impact velocity and penetration depth; threshold velocity and projectile sectional density; eye injury risks by normalized energies. It was found that the P pellets caused higher impact velocity while the lower was SR pellets. The penetration depth and threshold velocity of the pellets were dependent on the impact velocity of the pellets, and the P pellets resulted in the higher eye injury risk while the lower was SP.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2005년도 하계학술대회
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• pp.210-216
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• 2005

BB-Manhole (통신장치 지하 수용구조물)은 초고속 서비스 제공에 필요한 각종 통신장비를 지하에 수용하기 위하여 내부 환경조절 기능을 갖춘 구조물로서 현재 옥외형 함체를 제한하고 있는 수도권 지역에 주로 설치하여 KT의 초고속 서비스 품질 개선 및 신규 가입자 유치에 적극 활용하고 있다. 최근 초고속 인터넷 사업의 경쟁이 심화되면서 가입자들은 보다 빠른 속도의 안정적인 서비스를 요구함에 따라 KT는 BB-x Series 를 이용하여 가입자 최전방에 광전송장비를 설치하고 있으나 집선 용량이 큰 현재의 BB-Manhole로는 경제성 부족으로 인하여 음성 2,400p 이하의 작은 셀 구축에 적용되지 못하는 단점이 있었다. 따라서 지하에 수용되어 있는 통신함체를 작업 시에만 부상시키는 방식을 적용하여 크기를 대폭 축소시킴으로써 회선당 단가를 낮춘 중형 BB-Manhole을 개발하게 되었는데, 본 논문에서는 이러한 중형 BB-Manhole의 특징과 개발과정에 대하여 소개하고자 한다.

• 한국식품영양학회지
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• 제21권4호
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• pp.416-424
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• 2008

In an effort to elucidate the differential actions of blueberry(BB) in both normal and cancer cells, we utilized human breast cell lines to assess the accumulation of radical oxygen species(ROS) and ROS-associated apoptosis in both human normal breast epithelial(MCF10A) and breast cancer(MCF7) cells. BB extract was added to the cultures at a final concentration of $20{\mu}g/m{\ell}$ for 0(control), 6, 12, and 24 hr intervals. The MCF10A cells evidenced no marked ROS accumulation in the presence of BB, whereas the MCF7 cells evidenced clear ROS accumulation upon BB treatment from 12 hours forward. The number of dying or dead cells did not increase in the BB-treated MCF10A cell groups, whereas that number increased profoundly from 12 hr forward. Furthermore, the expression levels of certain stress-related, and pro- and antiapoptotic gene products evidenced differential responses to BB treatment between the MCF10A and MCF7 cell groups. These results indicate that the components of BB extract differentiate cancer cells by not preventing ROS accumulation within cells and by inducing ROS-associated cell death in cancer cells. However, no marked ROS accumulation or induction of cell death was noted in the normal breast epithelial cells. The fact that BB extract exerted a differential effect on cancer cells opens further directions of research regarding the specific components that exert the differential BB-mediated effects in the selective prevention of normal cells and therapy for cancer tissues in the physiological body.