• 대한치과의사협회지
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• 제53권9호
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• pp.644-655
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• 2015

Purpose: This study was conducted to evaluate the effect of the fixture abutment connection type and diameter on the screw joint stability in external butt joint for 2nd surgery and internal cone connected type implant system for 1st and 2nd surgery using ultimate fracture strength. Materials and Methods: USII system, SSII system and GSII system of Osstem Implant were used. Each system used the fixture with two different diameters and cement-retained abutments, and tungsten carbide / carbon coated abutment screws were used. Disc shaped stainless steel metal tube was attached using resin-based temporary cement. The experimental group was divided into seven subgroups, including the platform switching shaped specimen that uses a regular abutment in the fixture with a wide diameter in USII system. A static load was increased to the metal tube at 5mm deviated point from the implant central axis until it reached the compression bending strength at a rate of 1mm/min. Then the deformations and patterns of fracture in threaded connection were compared. Results and Conclusion: 1. In the comparison between the Regular diameter, compression bending strength of SSII system was higher than USII system and GSII system. There was no significant difference between USII system and GSII system. 2. In the comparison between wide diameter, compression bending strength was increased in the order of GSII system, USII system, and SSII system. 3. In comparison between the implant diameter, compression bending strength of the wide diameter was greater than the regular diameter in any system(P<0.05). 4. There was no significant difference between the platform switching (III group) and the regular diameter (I group) in USII system. 5. In USII system, fracture of abutment screw and deformation of both fixture and abutment were observed in I, II and III subgroups. 6. Failure pattern of SSII system, which was the fracture of abutment screw and deformation of the abutment and fixture, was observed in both IV and V subgroups. Fracture of some fixtures was observed in subgroup V. 7. Failure pattern of GSII system, which was the fracture of the abutment screw and deformation of the fixture and the abutment, was observed in both VI and VII subgroups. Apart from other subgroups, subgroup VII demonstrated no bending neither the fracture at the top of the fixture. The compressive deformation of internal slope in the fixture was the only thing observed in subgroup VII.

• Journal of Ecology and Environment
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• 제38권1호
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• pp.85-93
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• 2015

In 2013, the epidemics of pine wilt disease caused by the pine wood nematodes (Bursaphelenchus xylophilus) resulted in damages to the forests of black pine (Pinus thunbergii Parl.) trees in Jeju Island, Korea. Among the affected trees, an old black pine tree at Cave Temple on Mt. Sanbangsan was included and died due to the prevalence of pine wilt disease. The tree was on Mt. Sanbangsan, which was designated as a National Scenic Place with the Number 77 and was believed to be more than 400 years old in age. By examining the disc of the tree stem obtained from the height of 2 m, we counted the tree rings from 4 different directions and cross-dated the readings by comparing the records of drought simulated from the BROOK Model. Our analysis indicates that the tree seems to have grown since late 1860s. Contrary to the belief of the general public, we can conclude that the age of the tree was estimated to be at maximum 150 years, which means that it was not the same old tree as was shown in the painting of the Tam-Ra-Sun-Ryeok-Do (an old painting book for the Inspection Tour of Jeju Island) published in 1702. Discussion was extended to the life history of the tree in growth and leaning and the measures to protect the tree species from the damages of the pine wilt disease caused by pine wood nematodes.

• 한국식품영양과학회지
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• 제42권8호
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• pp.1263-1269
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• 2013

한약재 및 해조류 추출물에 대한 Photobacterium phosphoreum의 항균력을 측정한 결과, 오미자 열수 및 에탄올 추출물과 감태 및 비틀대 모자반 에탄올 추출물이 항균력을 나타내었으며 비틀대 모자반과 감태 에탄올 추출물이 각각 0.015625 mg/mL, 0.125 mg/mL의 최소저해농도를 나타내었다. P. phosphoreum 유래 HDC의 저해 효과를 측정한 결과, 감태와 대황 에탄올 추출물이 1 mg/mL에서 각각 32%, 25%의 높은 저해활성을 나타내었다. P. phosphoreum에 대해 항균력과 HDC 저해 효과를 나타낸 천연물을 고등어육에 첨가한 후 균주를 접종하여 생균수 및 histamine 생성량을 측정한 결과, 저장일차가 증가함에 따라 처리구에서 균수가 크게 감소하였다. Histamine의 함량도 다소 감소하였지만 주로 항균활성에 의해 histamine이 저해된 것으로 나타났다.

• 한국산학기술학회논문지
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• 제18권10호
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• pp.817-822
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• 2017

제동 장치는 기계장치의 사용자나 시스템의 안전관점에서 가장 중요한 요소 중 하나이며, 작동 조건 내에서 신뢰성 있는 제동력이 유지 되어야 한다. 일반적으로 브레이크는 운동에너지를 마찰을 통해 열에너지로 변환하여 회전하는 기계장치를 제동한다. 운동에너지가 열에너지로 전환되는 과정에서 고온의 열이 발생하여 기계적 거동에 영향을 준다. 마찰열은 브레이크 시스템의 열팽창 및 마찰계수 변화 등에 영향을 주고 제어되지 않는 고온은 브레이크 성능을 저하시킨다. 따라서 브레이크의 발열을 예측하고 이를 제어하는 것은 중요하다. 마찰열을 예측하기 위한 다양한 수치해석 연구들이 수행되었지만, 계산의 효율 및 재원의 한계로 수치해석의 경계조건을 다양한 형태로 가정하여 마찰열 예측 연구를 수행하였다. 가정된 마찰열 거동은 실제 열전달 온도 분포 경황과 차이가 있고 이를 이용한 냉각 효과나 열응력 수치해석 결과의 신뢰성이 부족하다. 이러한 한계점을 극복하고 마찰열 예측 시뮬레이션 절차를 정립하기 위하여 본 연구에서는 열-구조 결합 요소를 사용하여 브레이크 시스템의 마찰열 발생을 직접적으로 모사하는 시뮬레이션을 수행하였다. 본 논문은 Finite Element Method(FEM)을 이용하여 브레이크 작동에 따른 마찰열 발생을 모사하고 열분포 특성을 분석하기 위해 브레이크 모델을 대상으로 열-구조 연성요소를 적용한 수치해석 연구를 수행하였다. 이 연구는 마찰열 직접 모사의 필요성을 제안하고 시뮬레이션에 필요한 정보를 제공할 수 있다 판단된다.

• Journal of Korean Neurosurgical Society
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• 제63권6호
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• pp.806-813
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• 2020

Objective : Lumbar disc herniation (LDH) is a common disease, and lumbar discectomy (LD) is a common neurosurgical procedure. However, there is little previous data on return to work (RTW) after LD. This study investigated the period until the RTW after LD prospectively. Clinically, the pain state at the time of RTW also checked. RTW failure rate 6 months after surgery also investigated. Methods : Patients with daily/regular jobs undergoing LD between September 2014 and December 2018 were enrolled. Pain was assessed by the Oswestri Disability Index (ODI) and the Numeric Rate Scale (NRS). Employment type was divided into self-employed, regular and contracted. Monthly telephone interviews were conducted to check RTW status and self-estimated work capability after surgery. Results : Sixty-seven patients enrolled in this study. Three patients failed to RTW, and three others resigned within 6 months after surgery. The preoperative NRS and ODI were 7.2±1.2 and 22.1±7.9, respectively. The average time to RTW was 5.1±6.0 weeks. At RTW, NRS was 1.5±1.8 and ODI was 6.3±3.9. Amongst patients that successfully returned to work were 16 self-employed workers, 42 regular employees, and three contracted workers. The time to RTW of self-employed, regular, and contracted workers were 5.9±8.8, 4.2±4.3 and 13.3±2.3 weeks, respectively (p=0.011). Thirty-six of the patients that returned to work self-reported a 22.8±15.6% reduction in work capability at 6 months. Conclusion : RTW may vary depending on the employment status. In this study, we found that while employment type may affect the length to RTW, most patients were able to RTW and >40% of patients reported no loss of work capabilities 6 months postoperatively, hopefully alleviating some patient hesitation towards LD.

• 한국식품영양과학회지
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• 제44권12호
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• pp.1793-1798
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• 2015

본 연구는 약용 버섯으로 쓰이는 구름버섯을 ethyl acetate, ethanol 및 methanol 등으로 추출하고 각 추출용매에 따른 구름버섯 추출물로부터 총 폴리페놀 및 총 플라보노이드 함량을 측정하였으며, DPPH 라디칼 소거능과 ABTS 라디칼소거능 등의 항산화 활성 및 항균 활성을 조사하였다. 구름버섯의 총 폴리페놀 함량과 총 플라보노이드 함량은 ethyl acetate와 ethanol 추출물에서 methanol 추출물보다 높게 나타났다. DPPH 라디칼 소거능은 methanol 추출물이 대조구로 사용한 1 mM ascorbic acid의 DPPH 라디칼 소거능과 유사한 약 80% 소거능을 보여주었으며, ethanol 추출물과 ethyl acetate 추출물보다 유의적으로 높았다. ABTS 라디칼 소거능은 모든 추출물에서 ascorbic acid의 활성과 유사한 약 90% 소거능이 측정되었다. 결과적으로 추출용매의 종류에 따라 DPPH 라디칼 소거능은 영향을 받지만, ABTS 라디칼은 극성 및 비극성 물질 모두와 반응하여 소거되므로 추출용매의 영향 없이 높은 ABTS 라디칼 소거능을 나타내었다. 그리고 구름버섯의 항균 활성 측정 결과 모든 추출물에서 S. aureus를 제외한 모든 균주에 대한 활성을 확인할 수 있었으며, 다양한 다제내성 균주에 대한 구름버섯의 항균활성은 구름버섯이 천연 항균 소재로서의 가능성이 있음을 보여주는 의미 있는 결과이다. 또한 DPPH 라디칼과 ABTS 라디칼 소거능이 ascorbic acid와 같이 높은 항산화능을 보임으로써 구름버섯이 천연 항산화제로서 이용 가치가 있음을 확인할 수 있었다. 이렇게 항균 및 항산화 활성을 동시에 나타내는 구름버섯은 향후 분야별 허용 추출용매를 이용하여 추출방법 및 추출조건 등을 일부 변형한다면 건강기능성 식품 및 화장품 등에 첨가 가능한 원료소재로 활용될 수 있을 것으로 생각된다.

• 한국산림과학회지
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• 제77권2호
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• pp.199-207
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• 1988

포플러류(類)에 대(對)한 유용유전자(有用遺傳子) 삽입에 관(關)한 기초(基礎) 연구(研究)로서, 북미(北美)의 자연잡종(自然雜種) 포플러, P. alba ${\times}$ P. grandidentata 3 클론을 대상으로 Agrobacterium tumefaciens A281과 A348 strain의 감염력을 조사(調査)하였다. Kanamycin 저항성(低抗性)의 neomycin phosphotransferase (NPT-II) 유전자(遺傳子)를 가진 Agrobacterium binary pGA 472 vector와 이들 조직배양(組織培養)된 세 클론의 잎조각을 함께 배양(培養)하여, 형질전환(形質轉換)된 부위(部位)를 선발(選拔)하기 위해서 kanamycin sulfate의 적정농도(適正濃度)를 조사(調査)하였다. A281과 A348 strain 중(中) A281 strain이 가지고 있는 pTiBo542가 binary vector system의 helper plasmid로서의 역할에 가장 적합한 것으로 나타났다. 비교적 저농도(低濃度)(10mg/l)의 kanamycin sulfate가 잎조각배양으로 부터 식물체(植物體) 유도를 억제하였다. Kanamycin 저항성(低抗性) 유전자(遺傳子)가 내포된 Agrobacterium binary vector와 잎조각을 함께 배양(培養)한 후(後) kanamycin에 대한 저항성(低抗性)을 가진 callus가 kanamycin(60mg/l)이 들어있는 식물체 유도배지에서 선발(選拔)되었다. Kanamycin 저항성(低抗性) 유전자(遺傳子)에 의해 형질전환된 이들 kanamycin 저항성(低抗性) callus와 정상적인 비교 callus를 kanamycin이 들어있는 식물체(植物體) 유도배지에서 배양(培養)했을때 정상적인 비교 callus는 50mg/l의 kanamycin 농도(濃度)에서 생장(生長)이 억제된 반면, 형질전환(形質轉換)된 kanamycin 저항성(低抗性) callus는 200mg/l의 kanamycin 농도(濃度)에서도 생장(生長)을 계속하였다.

• 대한치과교정학회지
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• 제20권2호
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• pp.363-379
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• 1990

The purpose of this study was to evaluate the effects of the mandibular retractive force on the mandibular condyle of growing dog. The experimental animals were six mongrel dogs of two-month old. Their deciduous dentition were completed. Two of them was used as control group, and experimental group was composed of remaining four. Head band and chin cup were made of cotton tape, and hooks are fabricated on the chin cup and had band for closed coil. Mandibular retractive force was 100g/side and chin cap appliance was used for 14 hours/day during night. Experimental group were sacrificed at 2, 4, 6, 8 weeks from beginning of the experiment. Right TMJ was prepared for histologic study and left TMJ was examined grossly for disc, fossa, and condyle. The conclusions are: 1. Two-month old control animal showed active cartilaginous growth on the mandibular condyle, therefore showed thick proliferative and hypertrophic zones. Remodeling process in the condyle head was observed in which there were bone resorption on the anterior surface and bone apposition on the posterior surface. 2. Four-month old control animal showed marked reduction of hypertrophic zone but the condylar bone remodeling was more pronounced. 3. In experimental group, there are marked reduction of hypertrophic zone at 4 weeks from beginning of experiment, and hypertrophic zone disappeared at posterior-superior portion of condyle in 6-week experimental animal. 8 week experimental animal showed slight recovery of hypertrophic zone. 4. In experimental group, bone deposition was increased at anterior surface of condyle, and bone resorption was increased at posterior surface of condyle. 5. In control group, the glenoid fossa and surrounding bone showed mainly bone apposition. But experimental group showed bone resorption at anterior surface of articular eminence and increased bone apposition at posterior surface of postglenoid spine. 6. No marked traumatic change was seen but 4 weeks and 8 weeks experimental animal showed flattening of posterior surperior condylar surface. Bone marrow of condyle showed minute focal bleeding in 2 weeks and 4 weeks experimental animal, and congestion and depression of hematopoietic bone marrow during all experimental period.

• Journal of Korean Neurosurgical Society
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• 제43권5호
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• pp.221-226
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• 2008

Objective : The aim of the present study was to assess the safety and efficacy of the dynamic stabilization system in the treatment of degenerative spinal diseases. Methods : The study population included 20 consecutive patients (13 females, 7 males) with a mean age of $61{\pm}6.98$ years (range 46-70) who underwent decompression and dynamic stabilization with the Dynesys system between January 2005 and August 2006. The diagnoses included spinal stenosis with degenerative spondylolisthesis (9/20, 45%), degenerative spinal stenosis (5/20, 25%), adjacent segmental disease after fusion (3/20, 15%), spinal stenosis with degenerative scoliosis (2/20, 10%) and recurrent intervertebral lumbar disc herniation (1/20, 5%). All of the patients completed the visual analogue scale (VAS) and the Korean version of the Oswestry Disability Index (ODI). The following radiologic parameters were measured in all patients : global lordotic angles and segmental lordotic angles (stabilized segments, above and below adjacent segments). The range of motion (ROM) was then calculated. Results : The mean follow-up period was $27.25{\pm}5.16$ months (range 16-35 months), and 19 patients (95%) were available for follow-up. One patient had to have the implant removed. There were 30 stabilized segments in 19 patients. Monosegmental stabilization was performed in 9 patients (47.3%), 9 patients (47.3%) underwent two segmental stabilizations and one patient (5.3%) underwent three segmental stabilizations. The most frequently treated segment was L4-5 (15/30, 50%), followed by L3-4 (12/30, 40%) and L5-S1 (3/30, 10%). The VAS decreased from $8.55{\pm}1.21$ to $2.20{\pm}1.70$ (p<0.001), and the patients' mean score on the Korean version of the ODI improved from $79.58%{\pm}15.93%$ to $22.17%{\pm}17.24%$ (p<0.001). No statistically significant changes were seen on the ROM at the stabilized segments (p=0.502) and adjacent segments (above segments, p=0.453, below segments, p=0.062). There were no patients with implant failure. Conclusion : The results of this study show that the Dynesys system could preserve the motion of stabilized segments and provide clinical improvement in patients with degenerative spinal stenosis with instability. Thus, dynamic stabilization systems with adequate decompression may be an alternative surgical option to conventional fusion in selected patients.

• Journal of Korean Neurosurgical Society
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• 제56권1호
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• pp.21-27
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• 2014

Objective : Infectious spinal disease is regarded as an infection by a specific organism that affects the vertebral body, intervertebral disc and adjacent perivertebral soft tissue. Its incidence seems to be increasing as a result of larger proportion of the older patients with chronic debilitating disease, the rise of intravenous drug abuser, and the increase in spinal procedure and surgery. In Korea, studies assessing infectious spinal disease are rare and have not been addressed in recent times. The objectives of this study are to describe the epidemiology of all kind of spinal infectious disease and their clinical and microbiological characteristics as well as to assess the diagnostic methodology and the parameters related to the outcomes. Methods : A retrospective study was performed in all infectious spinal disease cases presenting from January 2005 to April 2010 to three tertiary teaching hospitals within a city of 1.5 million in Korea. Patient demographics, risk factors, clinical features, and outcomes were assessed. Risk factors entailed the presence of diabetes, chronic renal failure, liver cirrhosis, immunosuppressants, remote infection, underlying malignancy and previous spinal surgery or procedure. We comparatively analyzed the results between the groups of pyogenic and tuberculous spinal infection. SPSS version 14 statistical software was used to perform the analyses of the data. The threshold for statistical significance was established at p<0.05. Results : Ninety-two cases fulfilled the inclusion criteria and were reviewed. Overall, patients of tuberculous spinal infection (TSI) and pyogenic spinal infection (PSI) entailed 20 (21.7%) and 72 (78.3%) cases, respectively. A previous spinal surgery or procedure was the most commonly noted risk factor (39.1%), followed by diabetes (15.2%). The occurrence of both pyogenic and tuberculous spondylitis was predominant in the lumbar spine. Discs are more easily invaded in PSI. At initial presentation, white cell blood count and C-reactive protein levels were higher in PSI compared to TSI (p<0.05). Etiological agents were identified in 53.3%, and the most effective method for identification of etiological agents was tissue culture (50.0%). Staphyococcus aureus was the most commonly isolated infective agent associated with pyogenic spondylitis, followed by E. coli. Surgical treatment was performed in 31.5% of pyogenic spondylitis and in 35.0% of tuberculous spondylitis cases. Conclusion : Many previous studies in Korea usually reported that tuberculous spondylitis is the predominant infection. However, in our study, the number of pyogenic infection was 3 times greater than that of tuberculous spinal disease. Etiological agents were identified in a half of all infectious spinal disease. For better outcomes, we should try to identify the causative microorganism before antibiotic therapy and make every effort to improve the result of culture and biopsy.