• 대한치과교정학회지
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• 제44권5호
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• pp.263-267
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• 2014

Objective: To three-dimensionally elucidate the effects of occlusal hypofunction on the periodontal ligament and alveolar bone proper of rat molars by micro-computed tomography (micro-CT). Methods: Occlusal function in the molar area was restricted by attaching an anterior bite plate on the maxillary incisors and a metal cap on the mandibular incisors of 5-week-old male Wistar rats for 1 week. The periodontal ligament space and alveolar bone proper around roots of the mandibular first molar were assessed by histology and micro-CT. Results: The periodontal ligament space was narrower and the alveolar bone proper was sparser and less continuous in the hypofunction group than in the control group. Further, both the volume of the periodontal ligament and the volumetric ratio of the alveolar bone proper to the total tissue in the region of interest were significantly lower in the hypofunction group (p < 0.05). Conclusions: Occlusal hypofunction induces atrophic changes in the periodontal ligament and alveolar bone proper of rat molars.

• Applied Biological Chemistry
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• 제46권4호
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• pp.280-284
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• 2003

농업용 살균제와 살충제로서의 활용성 진단과 예측평가 자료로 사용하기 위하여 상용화 된 살균제 133품목과 살충제 152품목의 활성 성분들에 대하여 소수성(LogP), 쌍극자능율(DM), HOMO 및 LUMO 에너지, molar refractivity(MR), polarizability(Pol), van der Waals 분자 표면적 및 부피(Vol), 분자량 및 수화 에너지(hydralion energy) 등, 10 가지의 다양한 물리-화학 파라미터들을 계산하였다. 그리고 살균제와 sterol 생합성 저해제 (DMI: demethylation inhibitor) 및 살충제와 acetylcholine esterase 저해제(AChE)이 가지는 특정한 물리-화학 파라미터들의 범위 값을 설정하였다. 그 결과에 기초하여 다양한 화합물들이 작물 보호제로서 살균제와 살충제로의 활용 가능성이 예측될 것으로 판단되었다.

• 멤브레인
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• 제13권4호
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• pp.268-282
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• 2003

불완전 분리의 실질적인 분리투과 특성을 근거로 하는 모사모델을 이용하여 투과증발 막촉진 에스터화 반응의 실질적인 거동을 연구하였다. 막의 분리효율, 막의 물제거 능력을 모델에 포함시킴으로써 반응모사를 통하여 이들이 막촉진반응에 어떻게 영향을 끼치는지를 체계적으로 관찰할 수 있었다. 막을 통한 비완전분리가 일어날 경우에 초기 반응물 몰비율이 1이 아닐 때 반응 혼합물중 소량으로 존재하는 반응성분이 투과되거나, 혹은 초기 반응물 몰비율이 1인 반응 혼합물중 어느 반응성분이 투과되든지 반응이 완결될 수 없었다. 생성물인 에스터가 물과 함께 일부 투과될 경우 정방향 반응속도를 증가시켜 시간에 따른 반응 전환률을 증가시킨다. 막을 통한 불완전 분리시 막을 통한 투과로 인하여 발생하는 반응혼합물의 부피감소로 인하여 반응성분 뿐 아니라 생성성분의 농도가 증가되는데 이들 농도증가가 반응속도에 상반된 영향을 끼친다; 반응물 농축은 반응속도를 증가시키나 생성물 농축은 역방향의 반응을 촉진시킴으로서 반응속도를 감소시킨다. 반응초기에는 반응물 농축효과가 우세하나 반응이 진행됨에 따라 생성물 농축효과가 우세하여 반응속도를 저하시킴이 모사결과 관찰되었다.

• Journal of the Korean Wood Science and Technology
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• 제20권4호
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• pp.73-84
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• 1992

It was observed that the hot-water extract of the bark of Kalopanax pictus N. had the highest anti-complementary activity among the 11 kinds of forest materials. Methanol-and ethanol-soluble portions had low anti-complementary activities, but crude polysaccharide. HKP-0 had a high activity of 80%. HKP-0 contained 54.8% of total sugar and 27.9% of protein. The neutral sugars of HKP-0 consisted of mainly arabinose, galactose and glucose. HKP-4 fraction obtained by cetavlon treatment of HKP-0 showed the highest anti-complementary activity of 90%. The activity was not changed by pronase digestion bu decreased greatly by periodate oxidation. HKP-4 consisted of mainly arabinose and glucose with molar ratio of 1.0 : 22.4, HKP-4-I, an unabsorbed fraction from HKP-4 on DEAE Sepharose CL-6B column showed higher yield and activity than those of absorbed fractions. HKP-4-I was homogeneous, and its molecular weight was about 25,000. HKP-4-I contained 84.0% of neutral sugar and consisted of arabinose and glucose with molar ratio of 1.0 : 11.2. The anti-complementary activity of HKP-4-I was not decreased by the treatment of polymyxin B, and the polysaccharide activated both classical and alternative pathway in complement system. Void volume fraction obtained from HKP-4-I hydrolyzed with ${\alpha}$-amylase on Sephadex G-25 column only had a high anti-complementary activity.

• 한국결정성장학회지
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• 제11권6호
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• pp.290-296
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• 2001

균질한 형상, 좁은 입도분포 그리고 순도가 높은 미립 금속분말은 첨단산업분야에서 응용분야가 점차 확대되고 있다. 본 연구에서는 Polyol법을 이용한 마이크론 크기의 단분산 코발트 분말을 합성하였다 Polyol이 환원제 역할을 하였다. 반응온도, 반응시간, 분산제첨가 및 전구체의 농도 등을 변화시켜 코발트의 입자 크기, 형상 그리고 응집현상을 제어하고자 하였다. 최적의 합성조건은 E.G/DiE/G 부피비 1:4,$Co(OH)<_{2}$polyol 몰비 0.08~0.32 반응온도 $210^{\circ}C$, PVP/Co$(OH)_2$ 몰비 0.4이었다.

• 치과방사선
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• 제9권1호
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• pp.25-31
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• 1979

The utilization of x-ray for diagnosis and examination is increasing by about 5-15% every year, therefore, it would be mandatory to protect the patients from exposures and so, studies in this field are performed even now. In dental field, the area of irradiation is limited any to the head and neck area, but the irradiated angle is varied following the objected tooth, so the adjacent structures lens and thyroid gland would be fragile to radiation. And the scattered radiation is one of the complicated problems in the protection because of specificity of dental x-ray and its object structures. The author, by using TLD (Thermo luminescent Dosimeter; Teledyne Isotopes-Model 7300, Element; TLD 200(CaF₂:Dy) and Capintec(Capintec Model 192, PM-30 Diagnostic chamber 28㎖ active volume), tried a measurement of air dose distribution of the scattered radiation and the irradiated dose of lens and thyroid gland under the condition of taking the film on the left maxillary molar. The results were as follows: 1. The half value layer of adapted dental x-ray machine was measured, and is 1.44㎜ Al. 2. The time of irradiation on the left maxillary molar in the Alderson Rando Phantom, the measured doses of left and right lens, and thyroid gland were 8,9mR, 1,2mR and 2,8mR. Under the same conditions, the scattered radiation at the distance of 1 meter from the phantom were 84 μR at the front side, 11μR at the back side, 18μR at the right side and 72μR at the left side. 3. Under the same conditions, the dose showed higher value by about 5% in the presence of object(phantom) than in the case of absence.

• 한국물환경학회지
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• 제35권3호
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• pp.201-208
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• 2019

In this study, we analyzed composition of the bioflocculant, which strain YG-02 produces. First, supernatant and suspension from centrifugation of culture fluid of the strain, were used in the flocculation experiment. As a result, the SVI(sludge volume index) added with the suspension, was 182 mL/g, same as the control group with no additive, and the SVI added with supernatant, was 164 mL/g. So, the result above showed that flocculation capacity of the bioflocculant, was dependent on the substance which strain YG-02 produces, not on factors such as the body of germs. As a result of the thermostability test on substances that cause flocculation, the flocculation effect was significantly reduced, compared to the result of the flocculation test, before applying heat to the culture fluid, and it was able to assume that the substance that causes flocculation, was damaged by heat. Additionally, to understand the component of the bioflocculant, analyzation of sugar composition and fatty acid, was conducted. As a result, sugar composition was the polysaccharide consisting of glucose: lactose with molar ratio of 90.75:9.25. Fatty acid content was detected, as 0.0012 g/100g, showing that it contained glycolipid in the bioflocculant. Such results show that the bioflocculant which strain YG-02 produces, is the new bioflocculant, different from bioflocculantstudiedto date.

• The Journal of Advanced Prosthodontics
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• 제13권1호
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• pp.12-23
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• 2021

Purpose. The aim of the study was to compare the lingualized implant placement creating a buccal cantilever with prosthetic-driven implant placement exhibiting excessive crown-to-implant ratio. Materials and Methods. Based on patient's CT scan data, two finite element models were created. Both models were composed of the severely resorbed posterior mandible with first premolar and second molar and missing second premolar and first molar, a two-unit prosthesis supported by two implants. The differences were in implants position and crown-to-implant ratio; lingualized implants creating lingually overcontoured prosthesis (Model CP2) and prosthetic-driven implants creating an excessive crown-to-implant ratio (Model PD2). A screw preload of 466.4 N and a buccal occlusal load of 262 N were applied. The contacts between the implant components were set to a frictional contact with a friction coefficient of 0.3. The maximum von Mises stress and strain and maximum equivalent plastic strain were analyzed and compared, as well as volumes of the materials under specified stress and strain ranges. Results. The results revealed that the highest maximum von Mises stress in each model was 1091 MPa for CP2 and 1085 MPa for PD2. In the cortical bone, CP2 showed a lower peak stress and a similar peak strain. Besides, volume calculation confirmed that CP2 presented lower volumes undergoing stress and strain. The stresses in implant components were slightly lower in value in PD2. However, CP2 exhibited a noticeably higher plastic strain. CONCLUSION. Prosthetic-driven implant placement might biomechanically be more advantageous than bone quantity-based implant placement that creates a buccal cantilever.

• 폴리머
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• 제30권1호
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• pp.56-63
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• 2006

층상구조의 폴리이미드 제조를 위해 다양한 곁가지 길이를 가지고 있는 두 종류의 디아민 단량체를 합성하였으며, 이를 이용하여 친수성 유연 곁가지와 친유성 유연 곁가지를 가지는 단일 중합 및 공중합 폴리이미드를 합성하였다. 강직한 주사슬의 충간은 유연한 곁가지로 인해 공간이 채워지게 되므로 곁가지의 길이가 특정 길이에 이르게 되면 주사슬과의 반발력으로 인하여 층상구조를 갖는 폴리이미드를 형성하게 된다. 친유성기를 도입한 단일중합체 폴리이미드의 경우 알킬곁가지의 길이가 증가함에 따라 층간거리가 $32.7\~48{\AA}$으로 증가하였고, 친수성기를 곁가지의 길이에 따라 도입한 경우에는 $7\~10.5{\AA}$으로 증가함을 X선 회절을 통해 확인하였다. 친유, 친수성기가 동시에 도입된 공중합체 폴리이미드의 경우에도 서로 다른 성질을 갖는 곁가지의 반발력에 의해 층상구조의 형성이 가능함을 알 수 있었다. 이를 분자모델링을 통한 이론적 구조계산과 비교해 본 결과, 유연한 곁가지의 길이에 따라 층간간격과 몰부피가 증가하는 층상구조의 폴리이미드 형성을 확인하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제8권1호
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• pp.43-50
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• 1995

This study was carried out to investigate the effects of activated carbon (AC) on growth, ruminal charateristics, blood profiles and feed digestibility in sheep, using roughage-based or concentrate-based diets. Twelve Suffolk breed of sheep of similar age and weight were distributed into 4 groups in a $2{\times}2$ factorial design. Two groups were fed a roughage-based diet with (R + AC) and without AC (R - AC), while the other two were fed a concentrate-based diet with (C + AC) and without AC (C - AC), respectively. The addition of 0.3% AC was based on dry matter of feed offered to animals. The incorporation of AC in roughage and concentrate based diets had no marked effects on feed intake, daily gain and feed conversion of the animals within experimental diets. The results obtained might be due to the low level of AC added in the diet. The animal on both concentrate-based diets were higher than the roughage-based diets in terms of daily gain and feed conversion ratio. However, it was observed that the animals provided with AC in the concentrate-based diet did not suffer from diarrhea and easily adjusted to high concentrate feeding. Further, the pH value for all diets before feeding was noted to be similar. After feeding, however, pH was shown to be higher in R + AC (p < 0.05) than in C + AC diet. Rumen protozoa number was decreased after feeding for both + AC diets, but in C - AC diet it was higher than in the roughage-based diets. For ammonia-nitrogen, C - AC was found to be higher than C + AC diet and the roughage-based diets before feeding. Total volatile fatty acid concentration, propionate and valerate molar ratios for both diets and time of collection were not affected. However, acetate, butyrate and valerate molar ratios were observed to be affected by diets and time of collections. The diets with AC increased (p < 0.05) before feeding for acetate molar ratio, but not different within diet, however, the roughage diets were found to be higher (p < 0.05) in acetate than the concentrate diet. In the blood parameters, the glutamic pyruvic transaminase (GPT), red and white blood cell (RBC, WBC) counts and packed cell volume (PCV) did not differ within and among the diets. Likewise, the WBC differential count in both diets with either - AC or + AC were similar in trend. However, lymphocyte count was noted to be increased in R + AC than the R - AC diet. The addition of AC in both diets did not affect nutrient digestibilities within diets.