• 대한치과보철학회지
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• 제41권2호
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• pp.128-135
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• 2003

Statement of problem : Implant screw loosening remains a problem in implant prosthodontics. Some abutment screws with treated surfaces were introduced to prevent screw loosening and to increase preload. DLC(Diamond Like Carbon) film has similar properties on hardness, wear resistance, chemical stability, biocompatibility as real diamond materials. Purpose : The purpose of this study was to investigate the effect of lubricant layer on abutment screw and to discriminate more effective method between soft lubricant and hard lubricant to prevent screw loosening. Material and method : In this study, $1{\mu}m$ thickness DLC was used as protective, lubricating layer of titanium screws and 3 times removal torque was measured on the abutment screws to investigate the difference in 10 coated and 10 non-coated abutment screws. Results : The results indicated that the implants with DLC coating group were not more resistant to the applied force in screw loosening. At 32Ncm, the 3 times removal torque in DLC group were $27.75{\pm}2.89,\;25.85{\pm}2.35$ and $26.2{\pm}2.57$. The removal torque in no-coated abutment screws were $27.85{\pm}4.23,\;27.35{\pm}2.81$ and $27.9{\pm}2.31$, respectively. Conclusion : The lubricant layer used in this study was Diamond Like Carbon(DLC) and it have a properties of hard and stable layer. The DLC coating layer was hard enough to prevent distortion of screws in the repeated unscrewing procedure in clinical situation. The reduced friction coefficient in hard DLC layer was not effective to prevent screw loosening.

• 한국콘텐츠학회논문지
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• 제21권8호
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• pp.367-375
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• 2021

의료의 질은 효과, 효율, 적절성, 과학적-기술적 측면 등과 같은 4가지로 정의할 수 있다. 과학적-기술적 측면의 질 관리를 위해 의료기관에서는 매년 보수교육의 형태로 최신 지견을 현장에 보급하고 있다. 하지만 최신 지견이 가장 빠르게 보급되는 연구 결과들을 단발성인 보수교육만으로 임상 현장에 충분히 보급하는 것에는 명백한 한계가 존재한다. 빅데이터, 인공지능과 같은 지능정보처리 기술이 의료 분야에 적용될 경우 기존에 문헌 조사 등으로 연구되어 적은 정보만으로 연구를 수행해야 했던 한계를 극복할 수 있다. 본 논문은 기존 약재 처방 적응증을 확장할 수 있는 근거가 되는 데이터베이스를 구축한다. 이를 위해 한의학 관련 국내외 논문 정보를 수집, 저장 관리, 분석하는 작업을 수행한다. 약재 처방전의 확장 적응증 콘텐츠 구축을 위한 한의학 근거문헌 데이터의 처리 및 분석 기법을 설계한다. 본 연구를 통해 한의학 의사결정지원시스템에서 근거기반 약재처방 주치 정보의 기본 콘텐츠로 활용할 수 있을 것이라 기대한다.

• 한국토양비료학회지
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• 제46권5호
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• pp.386-390
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• 2013

Recently, special attention has been given to acid rain and its problem to environment such as acid precipitation and air pollution in East Asia. In the present study, rainwater samples were collected from Apr to Nov in 2012. The samples were chemically characterized for the assessment of emission sources. Suwon and Yeoju regions, typical agricultural areas in South Korea, were chosen for study sites. Ion composition and cation-affected neutralization were determined to evaluate the contribution of cations to the acidity of rainwater. Ion and electrical conductivity between the measured and the estimated showed high correlation. The cations observed in Suwon and Yeoju were $Na^+$ > $NH_4{^+}$ > $K^+$ > $Ca^{2+}$ > $Mg^{2+}$ > $H^+$ and $Na^+$ > $K^+$ > $NH_4{^+}$ > $Ca^{2+}$ > $Mg^{2+}=H^+$, respectively. The anions of all sites were $SO{_4}^{2-}$ > $NO_3{^-}$ > $Cl^-$. While the amounts of sulfate, one of the major dissolved components of rainwater, were 77.6 and 75.6 ueq $L^{-1}$ in Suwon and Yeoju, the ones of NSS-$SO{_4}^{2-}$ (Non-Sea Salt sulfate) were 83 and 82% in Suwon and Yeoju, respectively. The comparison of observed pH values ($pH_{obs}$) with the theoretical pH values ($pH_{the}$) showed that the neutralization of rain water considerably went along during the study periods. The highest amounts of rainfall throughout the year in Suwon and Yeoju were 572.3 and 484.6 mm in July, and its corresponding nitrogen loadings in Suwon and Yeoju were 5.28 and 3.50 kg $ha^{-1}$, respectively. The major ion contents for crop growth with $SO{_4}^{2-}$, $Ca^{2+}$, $K^+$ and $Mg^{2+}$ were 51.7, 5.2, 11.8 and 1.8 kg $ha^{-1}$ in Suwon and 34.2, 4.0, 4.2 and 1.1 kg $ha^{-1}$ in Yeoju.

• 대한치과보철학회지
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• 제38권2호
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• pp.169-177
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• 2000

The purpose of this study was to compare the retention of complete cast crown over amalgam ores, composite resin cores, and cast gold cores when cemented with three different luting agents. Eighteen core specimens each of amalgam(Bestaloy, Dong Myung, Seoul, Korea), composite resin (Z100, 3M Dental product, st. Paul, Minn) and type IV gold alloy (Ba-4, Heesung Engelhard Corp., Korea) were made in a customized milling stainless steel die. A wax pattern with a loop attached to occlusal surface was made for each core and a type II gold alloy casting was fabricated. The castings which had clinically acceptable marginal fit were used as test samples. The following luting cements were used to cement cast crowns on each core material : (1) zinc phosphate cement (Confi-dental Products Co., USA) (2) glass-ionomer cement (Fuji Plus, GC Industrial Corp., Tokyo, Japan) (3) resin cement (Panavia 21, Kuraray Co., USA). All cements were mixed according to manufacturers' instructions. A static load of 5kg was then applied for 10 minutes on the crowns. All specimens were stored in saline solution for 24 hours at $37^{\circ}C$ and thermocycled for 500 cycles. After storage and cycling, the tensile bond strengths were measured by using a universal testing machine (Instron Corp., Canton, Mass.) at a crosshead speed of 0.5mm/min. The results were as follows 1. The retentive strength of resin cement was the highest of alt three types of cement for resin core (p<0.05). 2. There was no statistical difference among the retentive strengths of three cements for amalgam core (p>0.05). 3. The retentive strength of resin cement was higher than that of zinc phosphate for cast core, but there was no difference between the retentive strength of glass ionomer cement and those of rein and zinc phosphate cement. 4. The retentive strength of the zinc phosphate cement for amalgam core was the highest of all type of cores.

• 대한치과보철학회지
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• 제37권5호
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• pp.545-566
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• 1999

The use of pure titanium and titanium alloys have been increased recently in fixed, removable prosthodontics and implant fields as a framework. But when they were used for superstructures of implant or metal framework of removable prosthesis, welding is necessary to reconnect the fracture site to control the casting distortions. To overcome the difficulties in soldering the titanium due to high oxidation property, much effort have been devoted. In this study, some of mechanical properties were compared between pure titanium and Ti-6Al-4V alloy by using after welding, electron beam welding technique and tungsten arc welding. Mechanical properties such as tensile strength, yield strength, elongation and microhardness were measured. And, in order to compare the effect of welding site and surrounding metal tissue according to the welding condition, SEM photographs were taken and element distribution was observed by Wave Dispersion Spectroscopy. Through analyses of the data, following results were obtained; 1. In items such as tensile strength, yield strength and elongation according to the welding techniques of pure titanium, only tungsten arc welded group showed significant lower value than other groups(P<0.05). 2. In items such as tensile strength and yield strength according to the welding techniques of Ti-6Al-4V alloy, control group and tungsten arc welded group showed significant difference among all the groups(P<0.05). 3. Ti-6Al-4V alloy exhibited significantly greater elongation than control group when the laser welding method and electron beam welding method were used, and elongation showed increasing tendency. 4. Pure titanium specimens exhibited increasing tendency of microhardness regardless of the weld-ing technique applied, and especially tungsten arc welded group demonstrated a great increase of microhardness than parent metal. 5. There was no hardness change in laser welded group and electron beam welded group of Ti-6Al-4V alloy, but in tungsten arc welded group, hardness changed greatly from parent metal to weld seam. 6. Through the metallographic examination and scanning electron microscopy, laser welding caused central fusion and recristallizations were formed and tungsten arc welding caused localized fusion to 0.3-0.7mm from the surface.

• Journal of Plant Biotechnology
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• 제43권2호
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• pp.151-156
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• 2016

약용 식물 자원은 천연 화장품 소재, 제약 산업 그리고 인간의 건강을 위한 기능성 식품의 개발로 확대 된 이후 중요한 자산이 되고 있다. 그러나 세계적으로 약용 식물의 명칭을 각각 다르게 표기하고 있으며 계통 발생학적 기원이 명확하지 않다는 단점을 지니고 있다. 이 때문에 소비자들은 매우 큰 혼란을 겪고 있으며 특히 형태학적으로 유사한 식물의 말린 뿌리로 유통될 때에는 전문가들도 그들의 기원을 구별하기가 매우 어렵다. 이러한 이유때문에 이처럼 광범위하고 다양한 작물의 기원을 식별하기 위해 분자표지 기법을 적용하여 활용되고 있다. 이 리뷰에서 본 연구자들은 Angelica종의 분화에 관한 적합한 '기원정립'을 위한 현재의 연구 성과들을 정리했다. 결론적으로 Angelica종의 식별을 위해 개발된 분자적 연구에 대해 설명하고 약용작물의 유전체 정보를 활용하여 그들의 기원정립 및 판별에 대해 논의할 것이다.

• 대한수의학회지
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• 제55권1호
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• pp.9-12
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• 2015

Brachyspira (B.) hyodysenteriae is a causative agent of swine dysentery that is responsible for death and economic losses in the pig industry. It is imperative that clinical samples be delivered fresh for accurate diagnosis. The viability and DNA detection of B. hyodysenteriae using lab-made (phosphate buffered saline and modified tryptic soy broth) or commercial transport media (C, D, and E) were compared by culturing and real-time PCR at $4^{\circ}C$ or room temperature (RT), respectively. B. hyodysenteriae grown in D (Anaerobe Systems, USA) and E (Starplex Scientific, Canada) media was viable for 4 days at $4^{\circ}C$ and RT. However, B. hyodysenteriae in A, B, and C (culture swab; BD Biosciences, USA) media were not recovered after 2 days at RT. Ct values for real-time PCR at $4^{\circ}C$ and RT ranged from $27.2{\pm}2.1$ (C) to $29.6{\pm}0.5$ (B), and $28.0{\pm}0.9$ (E) to $30.2{\pm}1.5$ (B), respectively. Considering the field conditions, it is important that transport media is used for specimen isolation and PCR to obtain an accurate diagnosis of swine dysentery.

• Journal of Periodontal and Implant Science
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• 제27권4호
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• pp.767-783
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• 1997

Guided tissue regeneration, bone graft procedures, and application of growth factors have been used to regenerate lost periodontal tissues. Recently, enamel matrix derivative has been introduced into periodontal regeneration procedures in expectation of promoting new bone and cementum formation. The purpose' of this study was to evaluate the effect of enamel matrix derivative in 1-wall intrabony defects in beagle dogs. For this purpose, each dog was anesthesized using intravenous anesthesia and mandibular 1st, 3rd premolars were extracted. 2 months later, the 1-wall intrabony defects(mesio-distal width: 4mm, depth: 4mm) were created on the distal side of 2nd premolars and mesial side of 4th premolars. The control group was treated with debridement alone, and experimental group was treated with debridement and enamel matrix derivative application. The healing processes were histologically and histometrically observed after 8 weeks and the results were as follows : 1. The length of junctional epithelium was $0.94{\pm}0.80mm$ in the control group, $0.57{\pm}0.42mm$ in the experimental group, with no statistically significant difference between groups. 2. The connective tissue attachment was $1.36{\pm}0.98mm$ in the control group. $0.38{\pm}0.43mm$ in the experimental group, with statistically significant difference between groups(P<0.05). 3. The new cementum formation was $2.49{\pm}1.06mm$ in the control group, $3.59{\pm}0.74mm$ in the experimental group. with statistically significant difference between groups(P<0.05). 4. The new bone formation was $1.92{\pm}0.97mm$ in the control group, $2.32{\pm}0.59mm$ in the experimental group. with no statistically significant difference between groups. Within the limitation to this study protocol, enamel matrix derivative application in 1-wall intrabony defect enhanced new cementum formation. Although there was no statistically significant difference, enamel matrix derivative also seems to be effective in inhibition of apical migration of junctional epithelium and new bone formation.

• Asian Pacific Journal of Cancer Prevention
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• 제15권20호
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• pp.8699-8703
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• 2014

18-fluoro-2-deoxyglucose positron emission tomography-computed tomography ($^{18}F$-FDG PET/CT) scans are commonly used for the staging and restaging of various malignancies, such as head and neck, breast, colorectal and gynecological cancers. However, the value of FDG PET/CT for detecting prostate cancer is unknown. The aim of this study was to evaluate the clinical value of incidental prostate $^{18}F$-FDG uptake on PET/CT scans. We reviewed $^{18}F$-FDG PET/CT scan reports from September 2009 to September 2013, and selected cases that reported focal/diffuse FDG uptake in the prostate. We analyzed the correlation between $^{18}F$-FDG PET/CT scan findings and data collected during evaluations such as serum prostate-specific antigen (PSA) levels, digital rectal examination (DRE), transrectal ultrasound (TRUS), and/or biopsy to confirm prostate cancer. Of a total of 18,393 cases, 106 (0.6%) exhibited abnormal hypermetabolism in the prostate. Additional evaluations were performed in 66 patients. Serum PSA levels were not significantly correlated with maximum standardized uptake values (SUVmax) in all patients (rho 0.483, p=0.132). Prostate biopsies were performed in 15 patients, and prostate cancer was confirmed in 11. The median serum PSA level was 4.8 (0.55-7.06) ng/mL and 127.4 (1.06-495) ng/mL in the benign and prostate cancer groups, respectively. The median SUVmax was higher in the prostate cancer group (mean 10.1, range 3.8-24.5) than in the benign group (mean 4.3, range 3.1-8.8), but the difference was not statistically significant (p=0.078). There was no significant correlation between SUVmax and serum PSA, prostatic volume, or Gleason score. $^{18}F$-FDG PET/CT scans did not reliably differentiate malignant or benign from abnormal uptake lesions in the prostate, and routine prostate biopsy was not usually recommended in patients with abnormal FDG uptake. Nevertheless, patients with incidental prostate uptake on $^{18}F$-FDG PET/CT scans should not be ignored and should be undergo further clinical evaluations, such as PSA and DRE.

• 생명과학회지
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• 제30권2호
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• pp.169-177
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• 2020

본 연구는 어성초와 야관문의 메탄올 추출물의 순차적 유기용매 분획물을 제조하고, 분획물의 기능성 성분 분석과 항산화, ACE 저해활성, α-glucosidase 저해활성 등 다양한 생리활성을 연구하였다. DPPH radical 소거 활성 분석 결과 ethyl acetate 분획물에서 어성초 90.8%, 야관문 91.2%로 소거활성이 가장 높았다. ABTS 분석 결과 어성초는 ethyl acetate 분획물에서 86.1%로 가장 높았고 야관문은 chloroform 분획물에서 95.6%로 가장 높았다. FRAP assay 결과 ethyl acetate 분획물에서 어성초 360.1 mg TE/g, 야관문 239.2 mg TE/g로 가장 높았다. ACE 저해활성의 경우 chloroform 분획물이 어성초 13.2%, 야관문 35.2%로 가장 높았다. α-glucosidase 저해활성은 어성초는 ethyl acetate 분획물이 56.3%, 야관문은 water 층에서 93.6%로 가장 높았다. 어성초와 야관문에서 확인한 개별성분에 의한 DPPH radical 소거활성을 측정한 결과, 페놀산 개별 성분의 활성은 caffeic aicd가 93.4%로 가장 높았으며, 플라보노이드 개별 성분의 활성은 quercetin이 96.3%로 가장 높았다. 종합적으로 본 연구는 어성초와 야관문의 기능성 성분 분석과 다양한 생리활성을 이해하는데 도움을 줄 것으로 사료된다.