• 대한금속재료학회지
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• 제49권2호
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• pp.167-173
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• 2011

Nickel cobalt ferrite($Ni_{0.5}Co_{0.5}Fe_2O_4$) powder was prepared through the ceramic route by the calcination of a stoichiometric mixture of NiO, CoO and $Fe_2O_3$ at $1100^{\circ}C$. The pressed pellets of $Ni_{0.5}Co_{0.5}Fe_2O_4$ were isothermally reduced in pure hydrogen at $800{\sim}1100^{\circ}C$. Based on the thermogravimetric analysis, the reduction behavior and the kinetic reaction mechanisms of the synthesized ferrite were studied. The initial ferrite powder and the various reduction products were characterized by X-ray diffraction, scanning electron microscopy, reflected light microscope and vibrating sample magnetometer to reveal the effect of hydrogen reduction on the composition, microstructure and magnetic properties of the produced Fe-Ni-Co alloy. The arrhenius equation with the approved mathematical formulations for the gas solid reaction was applied to calculate the activation energy($E_a$) and detect the controlling reaction mechanisms. In the initial stage of hydrogen reduction, the reduction rate was controlled by the gas diffusion and the interfacial chemical reaction. However, in later stages, the rate was controlled by the interfacial chemical reaction. The nature of the hydrogen reduction and the magnetic property changes for nickel cobalt ferrite were compared with the previous result for nickel ferrite. The microstructural development of the synthesized Fe-Ni-Co alloy with an increase in the reduction temperature improved its soft magnetic properties by increasing the saturation magnetization($M_s$) and by decreasing the coercivity($H_c$). The Fe-Ni-Co alloy showed higher saturation magnetization compared to Fe-Ni alloy.

• 대한골관절종양학회지
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• 제6권4호
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• pp.163-167
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• 2000

동맥류성 골낭종(aneurysmal bone cyst)은 비종양성 팽륜성 골 병변으로 정확한 병인은 밝혀지지 않았지만 반응성 현상으로 생각되며, 다른 골 병변과 동반되거나 원발성으로 발생한다. 동맥류성 골낭종은 주로 장골과 척추골에 발생하며, 늑골에서 발생하는 경우는 드물다. 저자들은 좌측 첫번째 늑골에서 발생하였으며, 연부조직 악성 종양으로 오인되었던 동맥류성 골낭종 1예를 경험하였기에 보고하는 바이다. 19세 여자 환자가 좌측 견갑부에서 촉진되는 종괴를 주소로 내원하였다. 방사선학적 검사상, 광범위한 연부조직 병소이며 낭성구조로 이루어진 불균일한 양상이었고, 인접한 좌측 첫번째 늑골의 부분적 골소실이 있어, 연부조직에서 발생한 악성 종양 의진하에 절제술을 시행하였다. 절제된 종괴의 육안 소견상, 종괴 변연부를 달걀 껍질같이 얇은 한층의 골조직이 싸고 있는 것이 관찰되어 늑골 기원의 병변이라는 것을 알 수 있었다. 광학 현미경 검사상, 종괴는 큰 동맥류성 공간으로 이루어져 있었고 혈액으로 차 있었다. 동맥류성 공간사이를 피복세포가 없이 섬유성 격이 나누고 있으면서 여기에는 파골세포와 유사한 다핵 거대세포, 단핵세포, 유골과 섬유점액성조직이 관찰되었다. 병리 소견에 따라 재검한 MRI에서, 늑골에서 종괴의 변연부로 이어지는 얇은 골구조가 관찰되어 늑골에서 발생한 동맥류성 골낭종이 연부조직 쪽으로 광범위하게 돌출해 나온 것임을 알 수 있었다.

• 한국방사선학회논문지
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• 제7권2호
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• pp.107-112
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• 2013

발목 병변을 관찰하는 단순 방사선촬영은 여러 가지가 있다. 그 중에서 Ankle Broden법은 발꿈치뼈(Calcaneus) 및 발목뼈(Ankle Joint)의 결합상태와 발목뼈의 발꿈치뼈 골절(Calcaneus Fracture), Subtentaculum Tali Frature를 관찰하기 위하여 촬영을 한다. 이 촬영법은 전 후면과 측면뿐 아니라, 사면 상(oblique view)이나 축 상(axial view)의 촬영을 하며 잦은 부상이 발생하는 목말뼈 발꿈치뼈간, 발꿈치뼈 발배뼈간 결합상을 보기 위해 주로 촬영을 한다. 본 연구는 석고처치 환자들은 발목관절이 영상에 잘 묘출되기가 어렵기 때문에 발목뼈 사이의 관계 및 연부조직의 구조적 변화와 Subtalar joint, Calcaneus Fracture, Subtentaculum Tali Frature에 따른 목말뼈 발꿈치뼈의 골 결합 (talocalcaneal coalition)을 관찰하기 위한 Harris-Beath View($30^{\circ}{\sim}55^{\circ}$) 촬영 시 평가에 유용한 발목뼈의 결합상을 얻을 수 있는 각도를 알아보고자 하였다. 연구의 진행은 40명의 환자에게서 획득한 영상을 평가하였으며, 평가결과 $25^{\circ}$의 촬영상은 목말밑 관절(subtalar joint)이 열려져 분리되지 않았고 또한, Subtentaculum Tali Frature에 중복되어 보였다. $30^{\circ}$의 촬영상은 발꿈치뼈 골절(Calcaneus Fracture), Subtentaculum Tali Frature, 목말밑관절(subtalar joint과 후방 관절면의 앞부분이 가장 잘 나타나고 Calcaneo Navicularcoalition, Talocal Canealcoalition, Naviculo Cuneiform coalition의 결합상태가 명확하게 보였다. $35^{\circ}$의 촬영상은 목말밑관절(subtalar joimt), 목말뼈(talus), 발뒤꿈치뼈의 뒤쪽관절면이 명확하고 발목발꿈치관절(talocalcaneal joint)의 분리정도가 좋고 발목뼈굴(sinus tarsi)이 넓게 나타나며 좋은 평가가 되었다. $45^{\circ}$영역에서는 연부조직과 석고 분리를 판별할 수 있었고 가쪽복사와 뼈 밀도가 명확하게 보였다. $35^{\circ}$에 비해 발꿈치뼈(Calcaneus)이 분리되었지만 영상이 왜곡되어 보였다. Calcaneus, Subtentaculum Tali Frature는 $25^{\circ}$에서 $1.20{\pm}0.414$, $30^{\circ}$에서는 $2.47{\pm}0.516$, $35^{\circ}$에서는 $2.87{\pm}0.352$, $45^{\circ}$에서는 $2.27{\pm}0.458$로 나타났고 통계적으로 유의한 차이가 나타났다(p<0.05). 왜곡의 정도를 포함시키면 $30^{\circ}$영역의 왜곡이 적게 나타났고, $40^{\circ}$ 영역은 심한 왜곡현상을 보였다. 따라서 Ankle(Broden)촬영에서 $30{\sim}35^{\circ}$상이 가장 좋은 영상이었으며, $30{\sim}40^{\circ}$상에서는 Calcaneus Fracture, Subtentaculum Tali Frature의 진단에 가장 좋은 영상을 묘출하였다.

• Imaging Science in Dentistry
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• 제34권1호
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• pp.35-48
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• 2004

Purpose: To investigate the effect of rhBMP-2 on the healing of bone defect in the low calcium diet rat. Materials and Methods: To prepare the experimental model, control group was fed a normal diet and experimental group was fed a low calcium diet for 3 weeks. And then, 4 mm bicortical perforated bone defect was made on mandibular body of each rats. Experimental group was subdivided into two groups; experimental group 1 (rats given a low calcium diet before and after bone defect) and experimental group 2 (rats given a low calcium diet before and after bone defect with rhBMP-2 application). At 1, 3, 5 and 7 weeks after bone defect formation, the rats were terminated. The healing of bone defect was assessed by three-dimensional computerized tomography, soft x-ray radiography, and histopathological examination. Results : The wound healing of the bone defect for control group, experimental group 1, and experimental group 2 showed a increase from 3 weeks after bone defect formation. The experimental group 2 showed a more increase in healing amount than control group and experimental group 1 from 5 weeks after bone defect formation and the experimental group 2 showed a complete recovery of bone defect at 7 weeks after bone defect formation. Conclusion: The healing process of bone defect is accelerated by rhBMP-2 application in the low calcium diet rats.

• 대한세포병리학회지
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• 제1권1호
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• pp.93-97
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• 1990

Two cases of giant cell tumor of bone diagnosed by fine needle aspiration cytology are described. Case 1 was a 28-year-old male who had pain sense for one year at the right distal thigh. His radiologic finding revealed a destructive cortical lesion with soft tissue extension at medial side of epiphysis of the distal femur. Case 2 was a 21-year-old female complaining pain at left distal forearm for eight months and showed a well-demarcated expansile osteolytic lesion with multiseptation, and cortical destruction at epiphysis and metaphysis of the left distal radius on the X-ray. Fine needle aspiration of each lesion was performed. The aspirate of the case 1 revealed moderate cellularity, which was composed of scattered giant cells of osteoclastic type and small round to oval monotonous stromal cells in large areas. Giant cells were evenly distributed in single or small groups and had irregular but abundant cytoplasms with 10 to 20 nuclei in the center. The nuclei showed ovoid shape, fine granular chromatin, and a small but conspicuous nucleolus. Stromal cells were dispersed in isolated pattern or sometimes aggregated in clusters and showed the same nuclei as those of giant cells and scanty cytoplasms. Comparing to case 1, case 2 had a more translucent abundant cytoplasm in the giant cells and more spindled stromal cells. All two cases revealed neither nuclear atypism nor increased abnormal mitoses In both giant and stromal cells, suggesting no evidence of malignancy. Thereafter the lesions were treated with excision and curettage, and histologically confirmed as giant cell tumors of the bone.

• 대한방사선기술학회지:방사선기술과학
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• 제16권1호
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• pp.89-94
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• 1993

However, technical advances in ultrasono imaging have had a remarkable impact on the study of biliary system oral cholecystography is a contrast of the gallbladder which is very frequently performed even with the application of Extra Shock Wave Lithotripsy(ESWL) in clinical use. Oral GB requires a stringent preparation if it is to be fully successful and a considerable amount of time to complete all its procedures and its objects of the radiographs. 1) to obtain a firm diagnosis of the presence of gallstones. 2) to essess function of the gallbladder that is, its ability to concentrate and store bile. After a times sequence of X-ray exposures taken in various positions to show the gallbladder to be satisfactorily filled, the patient is given a fatty meal, for instances two eggs or a cup of milk. The gallbladder which is drained by the cystic duct stores and concentrates the bile and is stimulated to contrast and excrete the bile by hormone "cholecystokinin" secreted in the intestinal mucosa. To evaluate the effect of the fatty meal which caused the gallbladder to constrict and empty, and by so doing the contrast medium passes through the cystic and bile ducts which are shown in radiographs exposed from 15-30 minutes after the variety practice of fattymeal, such as soft-boiled 2 eggs, raw 2 eggs, 100g of peanuts, and 200ml of milk. If the concentration of the opaque medium in the gallbladder is adequate, then not only the size, shape and position of the gallbladder will be shown from firms taken at intervals, the rate of concentration of the opaque medium and of the emptying of gallbladder has been measured and analyzed.

• 천문학회지
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• 제36권1호
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• pp.33-41
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• 2003

Recent observations have shown that coronal magnetic fields in the northern (southern) hemisphere tend to have negative (positive) magnetic helicity. There has been controversy as to whether this hemispheric pattern is of surface or sub-surface origin. A number of studies have focused on clarifying the effect of the surface differential rotation on the change of magnetic helicity in the corona. Meanwhile, recent observational studies reported the existence of transient shear flows in active regions that can feed magnetic helicity to the corona at a much higher rate than the differential rotation does. Here we propose that such transient shear flows may be driven by the torque produced by either the axial or radial expansion of the coronal segment of a twisted flux tube that is rooted deeply below the surface. We have derived a simple relation between the coronal expansion parameter and the amount of helicity transferred via shear flows. To demonstrate our proposition, we have inspected Yohkoh soft X-ray images of NOAA 8668 in which strong shear flows were observed. As a result, we found that the expansion of magnetic fields really took place in the corona while transient shear flows were observed in the photosphere, and the amount of magnetic helicity change due to the transient shear flows is quantitatively consistent with the observed expansion of coronal magnetic fields. The transient shear flows hence may be understood as an observable manifestation of the pumping of magnetic helicity out of the interior portions of the field lines driven by the expansion of coronal parts as was originally proposed by Parker (1974).

• 대한족부족관절학회지
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• 제11권2호
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• pp.198-203
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• 2007

Purpose: To assess the arthroscopic findings in chronic lateral ankle instability and to evaluate the results of modified $Brostr{\ddot{o}}m$ operation and arthroscopic procedures. Materials and Methods: Twenty-nine cases with chronic lateral ankle instability were treated with modified $Brostr{\ddot{o}}m$ operation and ankle arthroscopy from May 2004 to January 2007. There were 19 male and 10 female with the mean age of 29.7 years. Mean follow up period was 15.8 months. All patients were checked preoperative stress anterior drawer and varus test with X-ray. Results: Associated injuries were 28 fat impingement projected into the joint between distal tibio-fibular space, 20 anterior impingement of soft tissue, 19 osteochondral defects and 13 loose body. Preoperative AOFAS score of pain, function and alignment were 28.9, 34.1 and 7.9 each other. They were improved into 38.7, 40.8 and 9.8 postoperatively. Conclusions: Modified $Brostr{\ddot{o}}m$ operation with ankle arthroscopy for chronic lateral ankle instability is believed to be a reliable option to obtain satisfactory results. Careful attention to the associated injuries such as distal fat impingement, anterior impingement, osteochondral defect and loose body is needed during the arthroscopy.

• 대한본초학회지
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• 제22권3호
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• pp.77-83
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• 2007

Objectives : The purpose of this study was to examine the effects of the Hominis placenta extracts on improvement of senile osteoporosis (Type 2) in SAM P6. In traditional Oriental medicine, Placenta (Jahageo) is indicated for insufficiency of blood and tidal fever due to steaming bone disorder. Methods : At 10 weeks after birth, Placenta ex. was given 100 mL, 200 ml/kg/day, i.p. 3 times a week for 4 weeks in SAM P6 mice. And then we measured complete blood cells, blood urea nitrogen, creatinine, inorganic phosphate and total iron. In addition, we tested bone mineral density (BMD) using the soft X-ray. Results : As a result, in SAM P6, injection of Placenta ex. (200 mL) increased in RBC, HB and PLT, in comparison with control group. It was also found that the inorganic phosphate levels increased significantly in the injection groups of the Placenta ex. from that of the control group, but blood urea nitrogen was no significant. Moreover, Placenta ex. were showed a trend of increase in bone mineral density (BMD) of the vertebrae lumbales and tibia in P6 mice. Conclusions : These findings suggest that Placenta ex. are effective in preventing bone loss in SAMP6.

• Archives of Plastic Surgery
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• 제34권6호
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• pp.813-817
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• 2007

Purpose: The zygomatic arch is a key element which composes the facial contour. In many cases of zygomatic arch fracture, it is difficult to fix rigidly the fractured segments. If reduced bone segments were not fixed rigidly, they are proven to be displaced by mastication or unintentional external forces. So, unfixed zygomatic arch fracture after reduction may require a external device of prevention of collapse. We introduce a new protector which stabilizing the fractured segments to prevent for collapse of the reduced zygomatic arch fracture. Methods: After reduction of zygomatic arch with blind approach(Gillies', Dingman or Keen's approach), bone segments was pulled with percutaneous traction suture in medial aspect of zygomatic arch. Then, the suture was fixed with Aqua $splint^{(R)}$, externally. And intraoperative and postoperative X-ray was done. The splint was removed on 14 days after the operation. Results: 5 patients were treated with this method. 4 patients of total patients had no collapse in zygomatic arch. There was minimal collapse in one patient. Postoperative complications such as facial nerve injury, mouth opening difficulty, contour deformity, infection, scar were not observed. Conclusion: In comparison with other techniques, this technique has several advantages which are simple and easy method, short operation time, no scar, less soft tissue injury, and facilitated removal of splint. Therefore, Aqua $splint^{(R)}$ would be a good alternative to prevent for collapse in unstable zygomatic arch fractures