• Radiation Oncology Journal
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• 제30권3호
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• pp.146-151
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• 2012

Purpose: This treatment planning study was undertaken to evaluate the impact of beam angle configuration of intensity-modulated radiotherapy (IMRT) on the dose of the normal liver in hepatocellular carcinoma (HCC). Materials and Methods: The computed tomography datasets of 25 patients treated with IMRT for HCC were selected. Two IMRT plans using five beams were made in each patient; beams with equidistance of $72^{\circ}$ (Plan I), and beams with a $30^{\circ}$ angle of separation entering the body near the tumor (Plan II). Both plans were generated using the same constraints in each patient. Conformity index (CI), homogeneity index (HI), gamma index, mean dose of the normal liver (Dmean_NL), Dmean_NL difference between the two plans, and percentage normal liver volumes receiving at least 10, 20, and 30 Gy (V10, V20, and V30) were evaluated and compared. Results: Dmean_NL, V10, and V20 were significantly better for Plan II. The Dmean_NL was significantly lower for peripheral (p = 0.001) and central tumors (p = 0.034). Dmean_NL differences between the two plans increased in proportion to gross tumor volume to normal liver volume ratios (p = 0.002). CI, HI, and gamma indices were not significantly different for the two plans. Conclusion: The IMRT plan based on beams with narrow separations reduced the irradiated dose of the normal liver, which would allow radiation dose escalation for HCC.

• Journal of the Korean Geotechnical Society
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• 제20권6호
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• pp.85-94
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• 2004

In the companion paper, a constitutive model was proposed in order to represent brittleness and dilatancy for cohesionless soils. An optimized design methodology was proposed on the basis of real-coded genetic algorithm in order to determine parameters fir the proposed model systematically. The material parameters were then determined by that algorithm. In order to verify the proposed model, triaxial tests were peformed under $K_0$ conditions for weathered soils. In addition, the results of istropic compressed triaxial tests for granular materials verified the proposed model. For those results the brittle stress-strain relationship and the dilatancy could be modeled reasonably by the proposed model. As a result it was found that the proposed model can appropriately represent the behavior on weathered soil and granular soil.

• Journal of Yeungnam Medical Science
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• 제28권1호
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• pp.77-83
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• 2011

Non-islet cell tumor-induced hypoglycemia (NICTH) is associated with mesenchymal tumor types, including hemangiopericytoma, fibrosarcoma, mesothelioma, and neurofibroma, as well as carcinoma of the liver, adrenal glands, and kidneys. Non- islet cell tumors induce hypoglycemia by overproducing an abnormal form of insulin-like growth factor II (IGF m. Complete removal of the tumor or reduction of the tumor mass is a successful therapeutic strategy in cases of NICTH. However, if the tumor re-grows, curative resection is nearly impossible, and hypoglycemia occurs repeatedly. Glucocorticoids are effective in terms of long-term relief from hypoglycemia through promotion of gluconeogenesis in the liver, tumor suppression, production of 'big'-IGF-II, and correction of the attendant biochemical abnormalities involving the growth hormone (GH)-IGF axis. We found that administration of corticosteroid therapy to a patient suffering from NICTH resulted in improvement of hypoglycemia associated symptoms.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제37권5호
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• pp.380-385
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• 2011

Introduction: Hydroxyapatite ($Ca_{10}(PO_4)_6(OH)_2$, HA) is the main inorganic phase of human hard tissue that is used widely as the repair material for bones. When HA is applied to a bony defect, however, it can be encapsulated with fibrous tissue and float in the implanted area due to a lack of consolidation. Bioceramics as allogenic graft materials are added to HA to improve the rate and bone healing capacity. Fluoridated hydroxyapatite ($Ca_{10}(PO_4)_6(OH,F)_2$, FHA), where F- partially replaces the OH- in hydroxyapatite, is considered a good alternative material for bone repair owing to its solubility and biocompatibility. Materials and Methods: This study was designed to determine the bone healing capacity of FHA newly produced as a nanoscale fiber in the laboratory. HA and FHA with bioglass was implanted in a rabbit cranium defect and the specimen was analysed histologically. Results: 1. At 4 weeks, fibrous connective tissue and little bone formation was observed around the materials of the experimental group I implanted HA and bioglass. Newly formed bone was observed around the materials in the experimental group II implanted FHA and bioglass. 2. At 8 weeks, the amount of newly formed and matured bone was higher in experimental group II than in experimental group I and the control group. Conclusion: These results suggest that FHA and bioglass is a relatively favorable bone substitute with biocompatibility and better bone healing capacity than pure HA and bioglass.

• Korea-Australia Rheology Journal
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• 제17권3호
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• pp.117-123
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• 2005

Background: Reduced deformability of red blood cells (RBCs) may play an important role on the pathogenesis of chronic vascular complications of diabetes mellitus. However, available techniques for measuring RBC deformability often require washing process after each measurement, which is not optimal for day­to-day clinical use at point of care. The objectives of the present study are to develop a device and to delineate the correlation of impaired RBC deformability with diabetic nephropathy. Methods: We developed a disposable ektacytometry to measure RBC deformability, which adopted a laser diffraction technique and slit rheometry. The essential features of this design are its simplicity (ease of operation and no moving parts) and a disposable element which is in contact with the blood sample. We studied adult diabetic patients divided into three groups according to diabetic complications. Group I comprised 57 diabetic patients with normal renal function. Group II comprised 26 diabetic patients with chronic renal failure (CRF). Group III consisted of 30 diabetic subjects with end-stage renal disease (ESRD) on hemo-dialysis. According to the renal function for the diabetic groups, matched non-diabetic groups were served as control. Results: We found substantially impaired red blood cell deformability in those with normal renal function (group I) compared to non-diabetic control (P = 0.0005). As renal function decreases, an increased impairment in RBC deformability was found. Diabetic patients with chronic renal failure (group II) when compared to non-diabetic controls (CRF) had an apparently greater impairment in RBC deformability (P = 0.07). The non-diabetic cohort (CRF), on the other hand, manifested significant impairment in red blood cell deformability compared to healthy: control (P = 0.0001). Conclusions: The newly developed slit ektacytometer can measure the RBC deformability with ease and accuracy. In addition, progressive impairment in cell deformability is associated with renal function loss in all patients regardless of the presence or absence of diabetes. In diabetic patients, early impairment in RBC deformability appears in patients with normal renal function.

• Weed & Turfgrass Science
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• 제2권3호
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• pp.306-311
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• 2013

Pythium blight occurred by Pythium aphanidermatum on chewing fescue cv. "Jamestowm II" from early June, 2010 and 2011 at the test field in Daegu University in Gyeongbuk Province, Korea. Disease symptoms on the turfgrass were leaf blights dying from the leaf tip and root rot, which appeared patches of brown to dark brown color or gray brown color in the field. The pathogens (40-1 isolate) of Pythium blight was isolated from the diseased leaf and crown tissue and cultured on potato-dextrose agar (PDA) for identification. Lobulate sporangia were inflated, complex structures, and filamentous sporangia were usually indistinguishable from vegetative hyphae. Sequences of ribosomal RNA gene of the fungus were homologous with similarity of 100% to those of P. aphanidermatum isolates in GenBank database. Pathogenicity was also confirmed on the chewing fescue, creeping betgrass and Kentucky bluegrass by Koch's postulates. This is the first report of Pythium blight on chewing fescue caused by P. aphanidermatum in Korea.

• Korean Journal of Pharmacognosy
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• 제25권1호
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• pp.51-58
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• 1994

The studies were conducted to investigate the anti-diabetic activities on the hyperglycemia induced by streptozotocin in rats, anti-hypertensive activities in SHR, anti-fatigue and decrease of body weight activities in mice by Kyung Ok-Ko water extract and drink, which is a traditional preparation in Korea. 1. The blood glucose levels of streptozotocin-induced hyperglycemic rats were dose-dependently decreased by administrations of various doses(300, 600, 1200 mg/kg) of Kyung Ok-Ko water extract. Particularly, administration of 600, 1200 mg/kg were significantly shown to decrease glucose levels comparing with control group. 2. The serum total cholesterol levels of streptozotocin-induced hyperglycemic rats were dose-dependently decreased by administrations of various doses(300, 600, 1200 mg/kg) of Kyung Ok-Ko water extract. Particularly, administration of 600, 1200 mg/kg were significantly shown to decrease total cholesterol levels comparing with control group. 3. The serum triglyceride levels of streptozotocin-induced hyperglycemic rats were dose-dependently decreased by administrations of various doses(300, 600, 1200 mg/kg) of Kyung Ok-Ko water extract. Particularly, administration of 600, 1200 mg/kg were significantly shown to decrease triglyceride levels comparing with control group. 4. The blood pressure in SHRs were dose-dependently lower descended by administration of Kyung Ok-Ko water extract 300, 600, and 1200 mg/kg, respectively. 5. The swimming time of Kyung Ok-Ko water extract(100, 200, 400 mg/kg) and drink(0.7, 1.4, 2.1 ml/kg) were significantly extended to all experimental group dose-dependantly. 6. The decrease of body weight of Kyung Ok-Ko water extract(100, 200, 400 mg/kg) and drink(0.7, 1.4, 2.1 ml/kg) were significantly evaluated dose-dependently in all experimental group.

• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.2064-2068
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• 2007

합류식 하수도는 오수와 우수를 동시에 배제하는 하수관거 시스템으로 시공이 쉽고 건설비용이 저렴한 반면에 강우시 차집되지 않고 월류되는 유출량으로 인해 수체에 악영향을 초래한다. 관거에서 유출되는 유출수는 강우 초기에 유역에서 집중적으로 유출되는 비점오염원과 하수 및 관거내 오염물질 등을 동반하여 수질 개선을 어렵게 하고 수질 악화를 가중시킨다. 본 연구에서는 기존 유역에 설치된 합류식 하수관거를 분류식으로 개선하고 강우시 초기 세척에 의해 유입하는 비점오염원을 삭감하기 위한 초기우수 처리시설 설치에 따른 M 저수지 수질개선 효과를 수치모델을 사용하여 모의하였다. 저수지의 수질예측은 횡방향 평균 2차원 저수지 수리 및 수질모델인 CE-QUAL-W2를 사용하였다. 저수지 유입량은 군산기상대에서 관측한 일별 강우량 자료를 이용하여 일별 유출량을 산정하였고, 댐 방류량 자료는 M저수지의 2006년 일별 관측수위를 이용하여 유입량과 수위-체적 곡선으로부터 산정하였다. 모델의 보정은 2005년 5월과 8월에 측정한 수질자료를 이용하여 수행하였으며, 저수지의 관측값과 모의결과는 저수지 중앙부 대표지점에서 이루어졌으며, 모델은 관측값을 잘 반영하였다. 모의 결과 M 저수지의 연평균 BOD농도는 합류식(1.25 mg/L)에 비해 분류식 하수 관거(0.91 mg/L)를 도입할 경우 27.2% 개선되었으며, 초기우수 처리시설(0.84 mg/L)을 추가 할 경우 32.8%까지 개선효과가 상승하였다. 기존 합류식 하수관거의 경우 연간 유출부하량은 7,713 kg/yr이었으며, 분류식으로 전환할 경우 2,256 kg/yr, 초기우수처리시설을 추가할 경우 902 kg/yr로 삭감되는 것으로 예측되었다. 분류식하수관거와 초기우수처리를 모두 이행할 경우, BOD와 COD 기준이 호수 수질 기준 II등급 이내로 유지되며, T-P 농도는 0.02mg/L 이하로 유지되어 6월 이후 여름철에 저수지내 조류성장 억제에 효과가 클 것으로 예측되었다. 하수관거 정비사업을 통해 M 저수지는 기존의 농업용 저수지의 목표수질뿐만 아니라, 친수공간으로써 적합한 II등급 수질을 유지할 수 있을 것으로 판단되었다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권4호
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• pp.240-247
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• 2009

Purpose: The purpose of this study was to evaluate marginal bone loss to the bone crest functionally loaded for up to eighteen months and also with regard to other variables of interest. Material and Methods: 135 endosseous implants(GS II, Osstem, South Korea) were placed in 35 patients. The design of GS II implant is straight with the microthread. Radiographic examinations were conducted at baseline (implant loading) and 3, 6, 9, 12 and 18 months after loading. Marginal bone level measurement was made from the reference point to the lowest observed point of contact of the marginal bone with the fixture. The reference point of the fixture was the border between the blasted surface and machined surface of the fixture. Results: Implants were on function for a mean 12.7 months(range, 3?18 months). For the 56 maxillary and 79 mandibular implants, mean marginal bone loss was 0.68 mm and 0.70 mm. Implants placed maxillary posterior area displayed more crestal bone loss than the other position. The difference between mesial and distal bone levels was statistically significant (p<0.05) with respective means of 0.51 mm and 0.62 mm. Also, The difference between bone graft group and no-bone graft group was statistically significant(p<0.05) with respective means of 0.38 mm and 0.66 mm. But no statistically significant influence of sex, type of surgery(one or two stage surgery), the implant length was observed(p>0.05). Conclusion: This study indicates the amount of marginal bone loss around implant has maintained a relative stable during follow-up periods.

• The Transactions of the Korean Institute of Electrical Engineers C
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• 제49권2호
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• pp.92-97
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• 2000

The mechanical and electrical properties of the hot-pressed and annealed $\beta$-SiC+39vol. %ZrB2 electroconductive ceramic composites were investigated by adding 1, 2, 3wt% Al2O3+Y2O3(6:4wt%) of the liquid forming additives. In this microstructures, no reactions were observed between $\beta-SiC$ and ZrB2. The relative density is over 90.8% of the theoretical density and the porosity decreased with increasing Al2O3+Y2O3 contents. Phase analysis of the composites by XRD revealed $\alpha-SiC(6H, 4H)$, ZrB2 and $\beta-SiC$(15R). Flexural srength showed the highest of 315.5MPa for composites added with 3wt% Al2O3+Y2O3 additives as room temperature. Owing to crack deflection and crack bridging of fracture toughness mechanism, the fracture toughness showed 5.5MPa.m1/2 and 5.3MPa.m1/2 for composites added with 2wt% and 3wt% Al2O3+Y2O3 additives respectively at room temperature. The area fraction of the elongated SiC grain in the etched surface of sample showed 65% and 65.1% for composite added with 2wt% and 3wt% Al2O3+Y2O3 additives respectively. The electrical resistivity at room temperature. The electrical resistivity of the composites wall all positive temperature coefficient(PTCR) against temperature up to $700^{\circ}C$.