• Imaging Science in Dentistry
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• 제32권3호
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• pp.141-145
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• 2002

Purpose : The purpose of this study was to propose standard values for alveolar and basal bone in normal adult mandibles, and radiologically analyze the remodeling process of the edentulous mandible by examining molar areas and comparing them to the established normal values. Materials and Methods : Panoramic and CT scans of mandible were performed on 20 normal adults and 20 edentulous or partially edentulous adults. In both groups, arch half diameter and distance of alveolar bone were measured. Also the distance from the mandibular canal to the caudal edges, the buccal and lingual external borders of basal bone, were measured. A statistical comparison between the mean values of normal and edentulous mandibles was carried out in the selected areas. Results : There was evidence of decreasing arch half diameter and distance in the edentulous mandible, but statistically no significant change was seen between the normal and edentulous alveolar bone. There was evidence of decreasing buccal basal bone and increasing in the lingual basal bone in the edentulous mandible. A statistically significant difference between normal and edentulous mandibles was noted in the buccal basal bone. Conclusion: There was an inward and forward atrophic change of the edentulous mandibular molar area compared to the control. CT scanning required the use of sophisticated and expensive procedures to analyze the remodeling process of edentulous mandibles. Consequently, the development and application of a more simplified and objective radiographic procedure for broad and long-term study of remodeling procedures of edentulous mandible was recommended.

• 치과방사선
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• 제29권1호
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• pp.43-53
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• 1999

Purpose: The aim of this study was to analyze radiologically the location and course of the mandibular canal and to observe the alveolar and basal bone changes during the remodeling procedures of atrophic mandible. Materials and Methods: CT scanning was performed on dry 30 edentulous or partially dentulous mandibles. In 48 edentulous lower halves, measuring areas were determined by three points in the length of the mandibular canal. The distance from the mandibular canal towards cranial and caudal edges, buccal and lingual external borders of the body of the mandible were measured. A statistical comparison between the mean values of different classes of mandibular body was carried out in the selected areas. Results: The distance between the mandibular canal and caudal borders of the body of the mandible and lingual borders dose not change in the atrophic process of mandible. The mandibular canal within the mandible courses downwards from mandibular foramen towards mesial and subsequently it gets to the mental foramen. The distance between the mandibular canal and buccal external border of basal bone changes similar to the change of cranial borders of alveolar bone in the atrophic process of mandible. Conclusion: CT scanning was very effective and practicable to analyze the location and course of the mandibular canal and to observe the alveolar and basal bone changes of atrophic mandible. Also more detailed investigation of basal bone changes observed during the remodeling procedures of atrophic mandibles seems reasonable to rely on the massive anthropologic collections of atrophic mandibles combined with CT scanning.

• Journal of Nutrition and Health
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• 제33권4호
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• pp.386-394
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• 2000

This study was conducted to investigate the effects of shellfish hydrolysate on lipid metabolism in rats fed high fat diet. Male Sprague-Dawley rate weighting approximately 110g were fed basal control diet, high fat diet and high fat diet plus 4 different shellfish hydrolyates for 4 weeks. The shellfish hydrolysates from the different sources, were oyster, hard-shelled mussel, little neck clam and march clam. After 4 weeks, serum GOT, GPT, ${\gamma}$-GTP, triglyceride and total cholesterol was significantly decreased in shellfish hydrolysates supplementation with high fat diet compared to basal control and high-fat group(p<0.05). The total lipid and cholesterol content in liver showed significant decrease(p, 0.05). There were no different in serum GPT, HDL-cholesterol, liver total cholesterol and lipid of rats between basal control diet and high-fat diet. The unsaturated fatty acids, specific components of shellfishes were a little components in shellfish hydrolysate as they were a low and not different among the groups and were most well reflected in liver and plasma. Considering digestive and absorptive process of in human body, it was assumed that the hypolipidemic effect of shellfish was not under the influence of unsaturated fatty acids but the other components, peptides, taurine and betaine and so on was detected in the process of hyperlipidemia induced by high-fat diet.

• 한국터널지하공간학회 논문집
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• 제20권4호
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• pp.717-729
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• 2018

연약지반 수직구 굴착 중에는 주변 지반의 하중으로 인한 굴착면의 히빙이 발생할 위험이 있기 때문에 굴착 설계 시 지반 안정성에 대한 고려가 필수적이다. 그러나 연약지반 히빙 안전율 산정은 2차원 산정식으로 수행하여야 하므로 수직구의 3차원 형상을 고려하지 못하는 문제가 있다. 본 연구에서는 수직구 굴착 시 히빙 안전율에 대한 선행 연구를 보완하여 3차원 효과를 반영하는 히빙에 대한 안전율 식을 제안하였으며, 해당 식이 기존 식에 비해 3차원 원형 수직구 굴착에서의 히빙 안정성을 더 적절하게 반영할 수 있음을 확인하였다.

• Journal of Nutrition and Health
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• 제31권8호
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• pp.1217-1225
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• 1998

This study was conducted to investigate the effects of shellfish on lipid metabolism in rats fed high fat supplements. Male sprague-dawley rats weighting approximately 165g were fed a basal diet, a high fat diet, or a high fat diet plus shellfish for 4 weeks. The shellfishes on the were oyster, hard-shelled mussel, little neck clam, and march clam. Alfter 4 weeks high fat diet, supplementation of 20% lard significantly increased plasma. GOT, GPT, ${\gamma}$-GTP , and liver triglyceride (TG). Plasma GOT, GPT, ${\gamma}$-GTP , triglyceride, and total cholestrerol levels were significantly lower in shellfish groups than in basal and high-fat groups regardless of high-fat supplementation (p<0.05). The total lipid and cholesterol content in liver showed similar results(p<0.05). There were no differences in glucose, HDL-cholesterol in plasma and total cholesterol and total lipid in liver between basal and high-fat supplemented diets. Liong chain fatty acids, specific components of shellfishes group, were exclusively higher than in basal and high-fat diets, and were most well-reflected in liver and plasma. From the above results, the hypolipidemic effects of shellfish were detected in the process of inducing hyperlipidemia by high-fat supplement.

• Geomechanics and Engineering
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• 제8권6호
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• pp.811-828
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• 2015

Proper modelling of the basal resistance terms is key in simulating the motion of fluidized granular flow. In this paper, standard depth-averaged governing equations of granular flow are used together with the classical Coulomb, Voellmy, and velocity dependent friction models (VDFM). A high-resolution modified TVDLF method is implemented to solve the partial differential equations without numerical oscillations. The effects of basal resistance terms on the motion of granular flows such as geometric shape evolution, travel times and final deposits are analyzed. Based on the numerical results, the predictions of the front and rear end positions and developing length of granular flow with Coulomb friction model show excellent agreements with experiment results reported by Hutter et al. (1995), and illustrate the validity of the numerical approach. For the Voellmy model, the higher value of turbulent coefficient than reality may obtain more reasonable predicted runout for the small-scale avalanche or granular flow. The energy exchange laws indicate that VDFM is different from the Coulomb and Voellmy models, although the flow characteristics of both three models fit the measurements and observations very well.

• 한국주조공학회지
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• 제13권5호
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• pp.476-483
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• 1993

The influence of substrate materials on the degree of basal porosity during spray casting process has been investigated. Different conditions of droplet spreading on the substrate were induced by varying the substrate material. Flat sections of cast iron and aluminum have been spray deposited via spray casting process onto an aluminum substrate, a low carbon steel substrate, and an alumina based refractory substrate. Results for cast iron and aluminum sprayed onto the aluminum substrate showed significant improvements in the surface condition and degree of basal porosity with evidence of substrate deformation that round pits ranging from $5{\mu}m$ to $20{\mu}m$ in diameter are distributed on the surface of aluminum substrate. The lowest level of porosity was developed in alumina based refractory material. Several mechanisms for porosity formation were discussed with droplet impact pressure and droplet spreading. Adopting a spray cutting mechanism for removing the periphery of spray cone, porosity level was remarkably decreased.

• 한국재료학회지
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• 제31권7호
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• pp.397-402
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• 2021

In this study, binderless-WC, WC-6 wt%Co, WC-6wt% 1 and 2.5 B₄C materials are fabricated by spark plasma sintering process (SPS process). Each fabricated WC material is almost completely dense, with a relative density up to 99.5 % after the simultaneous application of pressure of 60 MPa. The WC added Co and Co-B₄C materials resulted in crystalline growth. The WC with HCP crystal structure has respective interfacial energy (basal facet direction: 1.07 ~ 1.34 J·m^-2, prismatic direction: 1.43 ~ 3.02 J·m^-2) that depends on the grain growth direction. It is confirmed that the continuous grain growth, biased by the basal facet, which has relatively low energy, is promoted at the WC/Co interface. As abnormal grain growth takes place, the grain size increases more than twice from 0.37 to 0.8 um. It is found through analysis that the hardness property also greatly decreases from about 2661.4 to 1721.4 kg/mm², along with the grain growth.

• Applied Microscopy
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• 제25권2호
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• pp.39-52
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• 1995

Pinealocytes in the lower vertebrate are known to have photoreceptive function. These photoreceptor cells have been characterized morphologically in various species of lower vertebrates. No such ultrastructural studies, however, were reported in fresh water turtle. The purpose of this study is to characterize the pinealocytes and the phylogenetic evoluton of these cells is discussed in terms of functional analogy. I. Light microscopy: The pineal body was divided into incomplete lobules by connective tissue septa containing blood vessels, and parenchymal cells were arranged as irregular cords or follicular pattern. In the lobules, glandular lumina were present and contained often densely stained materials. II. Electron microscopy: The pineal parenchyma had three categories of cells: photoreceptor cells, supportive cells and nerve cells. The photoreceptor cells had darker cytoplasm compared to the supportive cells, and the enlarged apical cytoplasm(inner segment) containing abundant mitochondria and dense cored vescles protruded into the glandular lumen in which lamellar membrane stacks(outer segment), dense membranous materials, and cilia were present. Some of these lamellated membrane stacks appeared to be dege-nerating while others were apparently newly formed. Constricted neck portion of the photoreceptor cells contained longitudinally arranged abundant microtubules. centrioles and cross-striated rootlets. Cell body had well developed Golgi apparatus, abundant mitochondria, dense granules($0.5{\sim}1{\mu}m$), dense cored vesicles($70{\sim}100nm$), and rough endoplasmic reticulum occasionally with dense material within its cisterna. Basal portion of the photoreceptor cells had basal processes often with synaptic ribbons, which terminate in the complicated zone of cellular and neuronal processes. Synatpic ribbons often made contact with the nerve processes and the cell processes of neighboring cells. In some instances, these ribbons were noted free within the basal process and were also present at the basal cell mem-brane facing the basal lamina. Obvious nerve endings with clear and dense cored vesicles were observed among the parenchymal cells. Photoreceptor cells of the snapping turtle pineal body were generally similar in fine structure to those of other lower verterbrates reported previously, and suggested to have both photoreceptive and secretory functions which were modulated by pinealofugal and pinealopedal nerves. The supportive cells were characterized by having large dense granules($0.3{\sim}1{\mu}m$), abundant ribosomes, well developed Golgi apparatus and rough endoplasmic reticulum. These cells were furnished with microvilli on the luminal cell surfaces, and often had centrioles, striated rootlets, abundant filaments especially around the nucleus, and scattered microtubules. Some supportive cells had cell body close to the lumen and extended a long process reaching to basal lamina, which appeared to be a glial cell. Nerve cells within the parenchyma were difficult to identify, but some large cells located basally were suspected to be nerve cells, since they had synaptic ribbon contact with photoreceptor cells.

• 한국지역지리학회지
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• 제18권2호
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• pp.129-140
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• 2012

제주도 폭포의 지형 특성을 파악하기 위하여 한라산 산록과 서귀포 해안지대에 소재하는 26개 폭포를 대상으로 용암류의 형태와 물리적 성질에 의해 폭포를 분류하고, 후퇴프로세스를 검토하였다. 폭포벽과 폭호를 구성하고 있는 용암류 유형과 매수에 근거하여 단일 용암류형, 복수 용암류형, 기저부 연암형 및 용암류 암괴형으로 유형화할 수 있다. 단일 용암류형 폭포는 조면암이나 조면안산암 분포지역에, 복수 용암류형 폭포와 기저부 연암형 폭포는 현무암이 나 조면현무암 분포지역에 잘 발달하여 폭포 유형에 용암류의 암질이 반영되고 있다. 폭포의 후퇴프로세스는 단일 용암류형 폭포에서는 감경사적 후퇴나 교체후퇴가 나타나는 반면 기저부 연암형 폭포는 전형적인 평행후퇴를 한다. 복수 용암류형 폭포는 용암류의 물리적 성질에 따라 세 후퇴 유형을 모두 보인다. 수직절리가 잘 발달한 용암류가 폭포벽을 만들고 있으므로 대부분의 폭포는 수직에 가까운 폭포벽을 지닌다.