• 대한견주관절학회:학술대회논문집
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• 대한견주관절학회 2009년도 제17차 학술대회
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• pp.128-129
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• 2009

This study suggests isolated Type IV-MO or Type IV-LO fractures could be treated with nonsurgical treatment because they do not interfere with normal elbow kinematics. Valgus and external rotation instability were influenced by total articular surface, however, posterior and proximal translation were influenced by isolated articular surface involvement of coronoid. Further clinical studies are warranted to validate these in vitro findings.

• Animal cells and systems
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• 제3권4호
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• pp.407-412
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• 1999

The influence of eating habits and food type on the ultrastructural characteristics of the digestive tracts was studied under the scanning and transmission electron microscopes in two crustacean decapods (Hemigrapsus penicillatus De Haan; mud crab, Pinnotheres cyclinus Shen; symbiotic crab). The relative ratio of the length of midgut versus hindgut was 1:1 in the mud crab, but 4:1 in the symbiotic crab. Observation through the scanning electron microscope revealed that the midguts of both species have densely-arranged longitudinal mucosal folds with a smooth surface. In the hindgut of the mud crab, mucosal folds were longitudinally oriented, clusters of two to five spines were observed on the cuticular surface, and the length of the spine in the distal hindgut was longer than that in the proximal portion. In the symbiotic crab, the mucosal folds were irregulary arranged, and numerous rudimentary spinal structures were noted on the cuticular surface. Through observation of a transmission electron microscope, the epithelial cells of the midgut in both species had numerous microvilli, but the length of the microvilli was slightly longer in the mud crab than in the symbiotic crab. The central layer of the basement membrane and the muscular layer of the midgut were more developed in the mud crab than in the symbiotic crab. The thickness of the cuticular layer over the hindgut surface in the mud crab was about 4 times than that of the symbiotic crab.

• 대한소아치과학회지
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• 제36권3호
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• pp.387-393
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• 2009

본 연구는 상악 유전치부의 치간공간과 인접면 우식의 상관관계를 평가해보고자 하였다. 익산에 거주하는 만3-7세의 어린이 555명을 대상으로 하였으며 탐침이 통과하는지 여부로 치간공간이 있음과 없음으로 분류하였고 와동이 형성되었거나 법랑질 표면이 연화되었을 경우 인접면 우식이 존재하는 것으로 판단하였다. 연구 결과 다음과 같은 결론을 얻었다. 1. 상악 유전치부의 치간공간은 영장류 공간이 77.4%, 발육공간이 유측절치와 유중절치 사이에서 54.4%, 양유중절치 사이에서 39.0%로 나타났다. 2. 인접면 우식발생율은 우측유견치가 6.3%, 우측유측절치가 14.7%, 우측유중절치가 33.5%, 좌측유중절치가 33.7%, 좌측유측절치가 16.0%, 좌측유견치가 4.7%로 나타났다. 3. 치간공간의 수가 많을수록 상악 유전치의 우식발생율은 낮아졌으나 그 상관관계(r=-0.024)는 미약하였다. 4. 상악 유전치부에 공간이 존재하지 않을 경우 존재할 때 보다 평균 우식발생율이 높았으며, 치간공간이 전혀 존재하지 않는 경우 한 곳이라도 치간공간이 존재하는 경우보다 평균 우식발생율이 2배 이상 높은 것으로 나타났다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.345-346
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• 2008

Most pedestrian-vehicle crashes involve frontal impacts, and the vehicle front structures are responsible for most pedestrian injuries. The vehicle bumper contacts the lower legs at first. The leading edge of the hood (bonnet) strikes the proximal upper leg and finally, the head and upper torso hit the top surface of the hood or windscreen. In essence, the pedestrian wraps around the front of the vehicle until pedestrian and vehicle are traveling at the same speed. Since the hood surface is made from sheet metal, it is a relatively compliant structure and does not pose a major risk for severe head trauma. However, serious head injury can occur when the head hits a region of the hood with stiff underlying structures such as engine components. The solution is to provide sufficient clearance between the hood and underlying structures for controlled deceleration of a pedestrian's head. However, considerations of aerodynamic design and styling can make it extremely difficult to alter a vehicle's front end geometry to provide more under-hood space. In this study, the safe hood will be developed by designing new conceptual inner panel in order to decrease the pedestrian's head injuries without changing hood outer geometry.

• 농업생명과학연구
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• 제43권6호
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• pp.59-65
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• 2009

Combinations of plant growth regulators, darkness treatments, and the order of expanding leaves for explants were evaluated for optimizing in vitro shoot regeneration rate of 'Whangkeumbae' pear. In a MS medium, supplemented with $8.88{\mu}M$ 6-benzylaminopurine (BA) and $0.49{\mu}M$ indole-3-butyric acid (IBA), green foci were observed on the surface of the callus 8 days after culture initiation. Some adventitious buds were later induced from those green foci, resulting in the appearance of normal shoots. In a medium containing $22.20{\mu}M\;BA$, the surface of the callus became compact and greenish, and many adventitious buds were formed over the entire area of the callus surface. When comparing BA concentration via histological observation, the section which had been treated with $22.20{\mu}M\;BA$ exhibited closer cell aggregation than those with $8.88{\mu}M\;BA$. The darkness treatment enhanced the formation of adventitious shoots for up to 3 weeks. The youngest two expanding leaves, proximal to the shoot apex, were proved to be the most regenerative, and yielded the highest shoot number per regenerating leaf. A fourth strength MS medium, which was supplemented with $0.54{\mu}M\;NAA$, yielded good quality plantlets, with regard to root number and root length.

• The Korean Journal of Physiology and Pharmacology
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• 제23권1호
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• pp.71-79
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• 2019

Body surface potential map, an electric potential distribution on the body torso surface, enables us to infer the electrical activities of the heart. Therefore, observing electric potential projected to the torso surface can be highly useful for diagnosing heart diseases such as coronary occlusion. The BSPM for the heart of a patient show a higher level of sensitivity than 12-lead ECG. Relevant research has been mostly based on clinical statistics obtained from patients, and, therefore, a simulation for a variety of pathological phenomena of the heart is required. In this study, by using computer simulation, a body surface potential map was implemented according to various occlusion locations (distal, mid, proximal occlusion) in the left anterior descending coronary artery. Electrophysiological characteristics of the body surface during the ST segment period were observed and analyzed based on an ST isointegral map. We developed an integrated system that takes into account the cellular to organ levels, and performed simulation regarding the electrophysiological phenomena of the heart that occur during the first 5 minutes (stage 1) and 10 minutes (stage 2) after commencement of coronary occlusion. Subsequently, we calculated the bipolar angle and amplitude of the ST isointegral map, and observed the correlation between the relevant characteristics and the location of coronary occlusion. In the result, in the ventricle model during the stage 1, a wider area of ischemia led to counterclockwise rotation of the bipolar angle; and, during the stage 2, the amplitude increased when the ischemia area exceeded a certain size.

• Journal of Plant Biology
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• 제37권2호
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• pp.203-221
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• 1994

한국산 나자식물 5과 12속 19분류군을 대상으로 광학현미경, 주사전자현미경 및 투과전자현미경을 이용하여 화분의 형태를 비교 관찰하고 기재하였으며, 각 과별 검색표를 작성하였다. 분류학적으로 볼 때 취급된 나자식물의 화분립은 모양, 크기, 표면상태, 표면무늬, 기낭의 유무 및 돌기의 유무에 의해 뚜렷이 구분되어 속간 및 속 이하의 분류군에는 유용하였으나, Pinus속내의 종들은 본 연구에서 관찰된 화분립의 크기나 표면무늬에 의해서는 화분형질의 중복으로 인해 종분류는 유용하지 않은 것으로 밝혀졌다. 소나무과내의 Picea속에 속하는 P. koraiensis의 화분립은 기낭의 형태가 불규칙하고, 몸체에 비해 기낭의 크기가 크며, 표벽이 얇기 때문에 기낭을 갖는 Pinus속과 Abies속의 분류군과는 차이점이 뚜렷하다. 또한 Abies속의 특징으로 기재된 모부의 중앙부위에서 기낭쪽으로 갈수록 표벽이 얇아진다는 점, 화분림 몸체의 표면이 비교적 굴곡이 심하지 않다는 점과 화분립의 크기가 크다는 점으로 볼 때 P. koraiensis는 기낭을 갖는 Pinus속과 Abies속 중 Abies속과 화분학적으로 유연관계가 가까운 것으로 추정된다. 투과전자현미경관찰을 통해 기낭을 갖는 화분립을 조사한 결과 근극에는 내표벽과 외표벽이 모두 존재하나, 서로 분리되어 외표벽은 기낭과 연결되고 내표벽은 원극을 이룬다. 또한 구과목의 분류군들에 있어 소나무과를 제외한 주목과, 난우송과 및 측백나무와 일부 분류군의 내표벽이 여러 층으로 구성된 관상구조로 나타났다. 주사전자현미경으로 기낭을 관찰한 결과 표면무늬는 유공상이고 미세한 pit가 존재하는 것으로 관찰되었다. 기낭의 표면무늬는 광학현미경상에서 망상으로 보이나 투과전자현미경으로 관찰해 본 결과 이는 기낭내부의 망상구조가 광학현미경하에서 투시된 것으로 밝혀졌다.

• Applied Microscopy
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• 제30권1호
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• pp.61-72
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• 2000

U. unicinctus 난자를 대상으로 인공수정 후 수정막 형성에 따른 물질적 기원과 첨체반응 등에 관련된 구조변화에 대하여 광학현미경과 전자현미경을 이용하여 관찰하였다. 관찰결과에 의하면 1차 수정막의 물질은 과잉의 정자에 대한 효과적 방어 기능을 보유한 난외막 표층 기원의 물질이었으며, 2차 수정막은 피질과립의 분비에 의하여 형성되었다. 3차 수정막은 광학현미경하에서 특이한 구조의 관찰은 없었으나 전자현미경에 의한 관찰시 많은 입자상 물질들로 구성되었으며, 수정 후 60분에는 이들 입자물질의 응집에 의해서 수정막은 경과되는 것으로 관찰되었다. 1차 수정막과 난외막 표층의 유사성 그리고 1차 수정막의 형성과 미세융모의 퇴화가 동시적인 사건이라는 것은 미세융모가 U. unicinctus에서 정자의 수용체로 작용할 수 있는 것으로 추정할 수 있었다. 첨체소관에 의한 난세포막 침투시 침체 단부에서 과립상의 물질이 표층(surface coat)에 확산되었다. 첨체소관은 첨체의 기부에서 시작되고, 첨체간격을 통하여 신장되었다.

• Journal of Periodontal and Implant Science
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• 제30권2호
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• pp.443-455
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• 2000

The aim of periodontal therapy is a removal of a bacterial plaque butthe instrumentation for plaque control has two nature : removal of a bacterial plaque and increase of surface roughness. Complication of instrumentation is enable to damage to the root surface and artificial crown. Therefore this study was conducted to evaluate the effects of repeated instrumentation on the marginal portion of artificial crown. Fifteen proximal surfaces of ten extracted periodontally diseased maxillary first molars were used. The finish line was placed on the root surface, and then the crown was casted and cemented in usual manner. Three kinds of instruments: hand curet, ultrasonic scaler, and ultrasonic curet were used. After instrumentation, final polishing was done with rubber cup and pumice. And surface changes were evaluated by stereomicroscope and scannig probe microscope. Roughness was increased after instrumentation in all groups, and was decreased after polishing except ultrasonic scaler group. Roughness in the ultrasonic scaler group was lower than others, and roughness after polishing in the hand curet group was lower than others. These results indicate that polishing procedure is recommended, because periodontalinstruments increase the surface roughness and induce the irreversible damage to the marginal portion.

• 대한소아치과학회지
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• 제23권3호
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• pp.746-763
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• 1996

An alternative design to conventional class II cavity preparation for proximal carious lesions is the tunnel preparation. It preserves the marginal ridge intact, thus making it possible to maintain the natural contact relationship with the adjacent tooth and minimize tooth reduction. This in vitro study was purposed to evaluate the effect of the materials' elastic constants and shear-bond strength on the marginal ridge fracture resistance of teeth restored by the tunnel technique, and to find the materials of choice for tunnel restorations. $Resinomer^{(R)}$, $Ketac-silver^{(R)}$, $Miracle-Mix^{(R)}$, and Tytin were used as restorative material. The elastic constants of each restorative material were evaluated by ultrasonic pulse measurement. Young's modulus and bulk modulus of the restorative materials were evaluated in three specimens for each material type. The shear-bond strength of the restorative materials to the dentin surface was measured after thermocycling 400 times between 6 and $60^{\circ}C$, using ten specimens for each material type. For measuring marginal ridge strength, 60 sound extracted molar teeth were distributed into six groups by size. Sound molar teeth were used as a Control group and unfilled prepared teeth were grouped as Unrestored. Another four groups were named Resinomer group, Ketac-Silver group, Miracle Mix group, and Tytin group by type of restorative material. Tunnel cavity preparation was done with ' 1/2, 2, and 4 round burs in sequence. Initial access to proximal surface was made through an occlusal access preparation started at least 2mm from the marginal ridge, and the proximal opening was formed about 2.5mm below the marginal ridge. After restoration and thermocycling, marginal ridge strength was measured using a universal testing machine. The results were as follows: 1. The Young's modulus of $Tytin^{(R)}$ was 63.95 GPa, followed by $Ketac-Silver^{(R)}$ 27.60 GPa, $Miracle-mix^{(R)}$ 18.48 GPa, and $Resinomer^{(R)}$ 10.74 GPa showing significant differences between the groups(P<0.05). The bulk modulus of the materials showed the same order as Young's modulus. The value of $Tytin^{(R)}$ showed 59.57 GPa indicating that it will deform less than other materials under the same stress. It was followed by $Ketac-Silver^{(R)}$ 23.57 GPa, Miracle $Mix^{(R)}$ 12.50 GPa, and $Resinomer^{(R)}$ 11.60 GPa. 2. The Resinomer group had a shear-bond strength of 7.41 MPa which was significantly higher than those of the Ketac-Silver group (1.80 MPa) and the Miracle Mix group (2.84 MPa) (P<0.01). All the specimens of Tytin group detatched from the dentin surface during thermocycling. 3. The mean marginal ridge strength of the Unrestored group(46.14 kgf) was significantly lower than that of the Control group (84.24 kgf) (P<0.01). The marginal ridge strength of teeth restored by the tunnel technique was, in order, Ketac-Silver group 74.06 kgf, Miracle Mix group 73.36 kgf, Resinomer group 63.47 kgf, and Tytin group 58.76 kgf. The Ketac-Silver, Miracle Mix, and Resinomer groups showed no significant difference with the Control group (P>0.05), but the Tytin group showed significantly lower strength compared to the Control group(P<0.05). The results showed that the marginal ridge strength of the teeth restored by the tunnel technique was not significantly lower than that of sound teeth. They also demonstrated that the bonding strength of the restorative material to the tooth surface should be high and the modulus of elasticity should not be lower than that of the tooth in order to restore the marginal ridge strength to its natural condition.