엔진구동형 NiTi 파일의 근관성형능력 비교

김보혜,최경규,박상혁,최기운 大韓齒科保存學會 2010 Restorative Dentistry & Endodontics Vol.35 No.2

The purpose of this study was to compare the root canal shaping ability of 4 rotary NiTi instruments in simulated root canals. For the preparation of thirty two curved root canals, Mtwo instruments using “single length”technique, and Profile, ProTaper Universal, and K3 using crown-down technique (N = 8) were used. All canal samples were prepared by reaching an apical canal size of #30. Pre- and post-instrumentation digital images were recorded and an assessment of canal shape was determined using a computer image analysis program SigmaScan Pro (Systat Software Inc., San Jose, CA, USA). The changes of the dimension of inner walls of canals, (2) the changes of the dimension of outer walls of canals, and (3) the centering ratio were measured at 7 measuring points, and then data were statistically analyzed using one-way ANOVA and Duncan’s test. The results were as below; 1. The root canal shaping ability of Profile was significantly faster than that of other rotary NiTi instruments (p < 0.05). 2. The deformation and fracture of all instruments used for this study were not experienced. 3. In the degree of changes of the dimension of inner walls of canals, Profile demonstrated the lowest changes of the dimension of inner walls of canals except at the measuring points of the 1 and 2 mm (p < 0.05). However, the ProTaper Universal showed the highest changes of the dimension of inner walls of canals at all measuring points (p < 0.05). 4. In the degree of changes of the dimension of outer walls of canals, Mtwo demonstrated the lowest changse of the dimension of outer walls of canals except at the measuring point of the 1 mm (p < 0.05). However, Profile exhibited the highest changes of the dimension of outer walls of canals at the measuring points of 3 and 4 mm and ProTaper Universal and K3 showed the largest changes of the dimension of outer walls of canals at the measuring points of 1, 2, 6, and 7 mm (p < 0.05). 5. In degree of centering ratio, Profile demonstrated the least centering ratio comparing with the centering ratio shown by other NiTi instruments at the measuring points of 1, 4, 5, and 6 mm. Results suggest that in the coronal part of canal preparation, active cutting files such as ProTaper Universal may efficiently flare the canal orifice and form a better taper, and in the apical part of the canal, files which have a better centering ability such as Profile may maintain the original canal curvature and reduce the shaping time. 이 연구의 목적은 4가지 엔진구동형 NiTi 기구의 근관성형력을 비교하는 것이다. 32개의 투명레진모형을 사용하여 파일의 단면도가 S자 형태이고“single length”방법으로 근관성형을 시행하는 Mtwo와 crown-down 방법으로 근관성형을 하는 Profile, ProTaper Universal 및 K3로 근관성형을 하였다 (n = 8). 모든 근관은 한사람의 술자가 근단공 크기가 #30이 될때까지 성형하였다. 기구 사용 전과 후 근관 모양을 디지털 영상을 기록하였고, 컴퓨터 영상 분석 프로그램(Expression Scanner와 Adobe Photoshop CS)으로 평가하였다. 다음과 같은 결론을 얻었다. 근첨으로부터 1, 2, 3, 4, 5, 6, 7 mm 떨어진 부위의 내측과 외측으로 삭제된 레진 양을 측정하였고, 자료는 SPSS법으로 비교 분석하였다. 1. 근관형성 시간은 Mtwo가 84.50초로 가장 짧았으며, 총 작업시간은 K3가 269.37초로 가장 길었다(p < 0.05). 2. 기구의 변형과 파절은 모든 구동형 NiTi 파일에서 발생하지 않았다. 3. 근관 내측 폭경의 변화는 Profile이 1, 2 mm 부위를 제외한 다른 부위에서 가장 적었으며, ProTaper Universal은 모든 부위에서 가장 많았다(p < 0.05). 4. 근관 외측 폭경의 변화는 Mtwo이 1 mm 부위를 제외한 모든 부위에서 가장 적었으며, Profile은 3, 4 mm 부위에서 가장 많았다(p < 0.05). ProTaper Universal와 K3는 1, 2, 6, 7 mm 부위에서 가장 많았다(p < 0.05). 5. 근관중심변위율(centering ratio)은 Profile이 1, 4, 5, 6 mm 부위에서 가장 적었다(p < 0.05). 이상의 결과, 구동성 NiTi 파일을 이용한 만곡 근관의 근관형성은 치경부는 ProTaper와 같은 삭제력이 높은 파일을 사용하는 것이 근관 입구를 효과적으로 넓히고 더 나은 taper를 형성하며, 근단부는 Profile과 같은 근관 중심 변위가 적은 파일을 사용하는 것이 근관형성 시간을 단축하고 근단부의 근관 변형(transportation)을 줄일 수 있다고 판단된다.

풍동실험을 위한 LabVIEW 응용 온라인 계측시스템의 개발

김봉근,장성태,이경용,박운진 한국기술교육대학교 2004 論文集 Vol.10 No.2

On-line measurement systems were newly developed for the performing effective wind tunnel experiments by utilizing the LabVIEW(Laboratory Virtual Instruments Engineering Workbench) system. As a result, instead of post-data-processing procedures based on Fortran programming which was commonly adopted in conventional measurement systems, wind tunnel experiments can be carried out on window-based PC operating systems and thus much time and effort required in analyzing fluid flow field can be successfully reduced. Furthermore, by utilizing the web publishing tool which is provided by the LabVIEW, it is possible to monitor and to control each measurement step via internet web pages from the remote area other than the laboratory in which experiments are carried out.

응급센터에서 기관내 삽관을 시행하지 않은 호흡곤란 환자의 동맥혈 이산화탄소분압과 호기말 이산화탄소분압의 연관성분석

김형국,박승현,오동렬,박규남,이원재,황두영,최승필,이운정,정시경,김세경 大韓應急醫學會 1998 대한응급의학회지 Vol.9 No.4

Background: The end-tidal carbon dioxide tension(ETCO₂) is defined as a partial pressure of carbon dioxide at the end of an exhaled breath. The purpose of this study is to determine the correlation between ETCO₂and arterial carbon dioxide tension(PaO₂) in nonintubated patients with respiratory distress in emergency department(ED). Methods: A prospective non-blind study was performed in ED of our university hospitals. Participants included all nonintubated adult patients with respiratory distress requiring arterial blood gas analysis. ETCO₂was measured with a capnography monitor during tidal volume breathing. ETCO₂were recoreded at the time of arterial blood gas sampling. The correlation between ETCO₂and PaCO₂was analyzed in all patients and in subgroups by simple linear regression. Results: Sixty patients were enrolled. In all patients, ETCO₂was 5.72mmHg lower than PaCO₂and correlated well with PaCO₂(r²=0.716). ETCO₂correlated best with PaCO₂in patients who were either acidotic or non-smoking. Conclusion: ETCO₂correlate well with PaCO₂in nonintubated patients with respiratory distress in ED. ETCO₂may be sufficient to reflect PaCO₂in selected patients and obviate the need for repeat arterial blood gas determination.

표면 딤플 유무에 따른 골프공 주위 유동장의 해석

김봉근,이경용,박운진 한국기술교육대학교 2003 論文集 Vol.10 No.1

To investigate the drag reduction effect of surface dimples on a golf ball, the flow fields around golf ball models with or without dimples at a subcritical Reynolds number of Re=1.4x10⁴ were analyzed experimentally in a wind tunnel as well as numerically by utilizing the commercial CFD program of CFX 5.5. It was proved by hot-wire measurements and flow visualization that the onset of flow separation was obviously delayed by the existence of surface dimples on a golf ball and thus thewake width of the flow field behind a golf ball with dimples became slightly narrower than that without dimple. For both cases, it was hard to identify the Karman type vortex shedding frequency and its harmonics in the wakes. At this relatively high Reynolds number, it was revealed that the implementation of a commercial CFD program to predict the flow field around a 3-D blunt body was not fruitful.

都心地 發破에서의 地盤振動 測定에 關한 硏究

金雄秀,林漢旭,李慶雲,徐栢洙 江原大學校 産業技術硏究所 1983 産業技術硏究 Vol.3 No.-

The blast vibrations were measured from 10 places through Seoul subway area to study their effects on the structures and to establish the safe blasting limits. For purpose of the present study, particle velocity only was recorded and analyzed, because it correlated most directly with damage. The results are as follows: (1) The proagation equation, V=K(D/W1/3)-n was obtained. Typical values could be found for n range from 1.7 to 1.5 and for k range from 48 to 138. (2) From the relationship between schmidt hammer rebound hardness and uniaxial compressive strength, Sc=0.514×(S.H)0.23, the compressive strength at any area can be assumed. (3) The use of AN-FO and other explosives with low detonation pressure may reduce vibration levels generated.

양극화 Al 박 상에 형성된 산화층의 표면적과 밀도

김기철,이경철,안운선,박광자 성균관대학교 기초과학연구소 1992 論文集 Vol.43 No.1

전해 콘덴서를 만드는 데 쓰이는 알루미늄 박은 그 표면을 etching한 다음에 양극 산화를 시켜서 표면에 산화층을 형성시키고 그 금속/산화금속 계면의 넓이를 극대화 시킨 것이다. 이 산화금속 층의 구조와 계면의 넓이를 판단하기 위해서 etching 처리한 박과 etching에 이어서 양극 산화 처리한 알루미늄 박 산화층의 표면적과 밀도를 중량식 BET 흡착 장치를 이용해서 측정하였다. Aluminium foils used for the electrolytic capacitor are usually prodused by etching the metal surface followed by anodization to form dielectric oxide layers on them with the maximum metal/metal oxide interface area. The densities and surface areas of the surface layer on the etched film as well as those on the anodized film are determined with a gravimetric BET apparatus. The interface areas and the structure of the dielectrics are inferred from the results.

음낭외상시 고환파열에 대한 초음파 검사의 진단적 유용성

김경영,한동준,신대은,노준,문형윤,임동훈,김철성,박성운 朝鮮大學校 附設 醫學硏究所 2007 The Medical Journal of Chosun University Vol.32 No.3

Purpose: We determined the use of scrotal ultrasonography in the initial diagnosis and management of testicular injuries due to blunt scrotal trauma. Mateiials and Methods: We reviewed 54 patients of scrotal trauma in the last 8 years. Forty patients were evaluated by ultrasonography preoperatively. A heterogeneous echo pattern of the testicular parenchyma with loss of oval shape, contour definition was the basis for diagnosis of testicular rupture. Among them, 33 cases underwent scrotal exploration and 7 cases were managed conservatively. The remaining 14 patients were evaluated only by physical examination, 8 patients of them were explored immediately because of suspicious testicular mpture. The accuracy of ultrasonography were determined by comparing radiographic interpretations with intraoperative findings. Results: Among the 33 patients who were evaluated by ultrasonography and explored immediately, there were 26 suspected testicular ruptures on ultrasonography. Surgical exploration revealed testicular rupture in 23 and simple hematoma in 10. The testicular rupture was correctly diagnosed by ultrasonography in the 22 cases, and there were 4 false-positive and 1 false-negative diagnoses of testicular rupture. The sensivity and specificity for the diagnosis of testicular rupture are 96% and 60%, and the positive and negative predictive values are 85% and 86%, respectively, Conclusions: Scrotal ultrasonography, with the main radiographic finding of a heterogeneous echo pattern of the testicular parenchyma with loss of oval shape, contour definition, is highly sensitive on the diagnosis of testicular rupture. And it increases the salvage rate for testicular rupture with preservation of the testicular function and prevents delayed complications of chronic pain, atrophy and orchiectomy associated with missed testicular rupture.

중간레진의 친수성이 상아질 접착에 미치는 영향

김용성,박상혁,최기운,최경규 대한치과보존학회 2007 Restorative Dentistry & Endodontics Vol.32 No.5

Coxiella burnetii에 대한 항체의 검출을 위한 Enzyme-Linked Immunosorbent Assay의 정립

이경호,박주영,박윤선,김수기,신운섭,고춘명 대한감염학회 1994 감염 Vol.26 No.4

본 연구에서는 지금까지 진단이 내려지지 않았던 C. burnetii 감염증 환자들을 보다 빠르고 간편하며 정확하면서도 대량으로 검사할 수 있는 방법으로서 C. burnetii 단백항원을 이용한 효소면역측정법을 정립하고자 하였다. 본 실험에서 정립한 효소면역측정법은 간접 방법으로서 C. burnetii phase I에 대한 IgG를 검출하기 위해 고안되었다. C. burnetii 단백질 항원의 적정 농도는 야성 대조혈청의 흡광도와 음성 대조혈청에서의 흡광도의 차이가 가장 크게 나는 농도인 1ug/ml을 적정항원농도로 결정하였으며, 검사 혈청의 적정희석 농도도 역시 양성대조항원의 OD 값과 음성대조항원에서의 OD값의 차이가 가장 크게 나면서 비교적 background activity가 적은 혈청의 희석 농도인 1:300을 적정 혈청 희석 농도로 결정하였다. 이 때 각각의 야성 혈청이 0.185의 흡광도를 가질 수 있는 가장 높은 혈청 희석 농도의 로그값과, 같은 혈청을 1:300으로 희석했을 때의 흡광도 사이에 상관계수 r값이 0.95인 직선적 관계가 성립하여, 하가지 혈청 희석 농도(1:300)에서 결정된 ELISA값이 그 혈청의 항체가를 양적으로 표시하였다. 효소면역측정법의 양성 판정 기준은, IFA에서 C. burnetii에 대한 항체가 음성으로 확인된 혈청 100개를 대상으로 ELISA를 시행하여, 이들의 흡광도의 산술평균치와 표준편차를 구한 결과, 신뢰구간 95%에서 최고치인 0.185를 ELISA 야성 판정의 기준인 cut-off value로 정하였다. 위애서 정한 기준에 의해 ELISA를 시행하엿을 때, IFA에서 양성으로 판명된 혈청 모두에서 양성으로 나타나 민감도가 매우 높은 것으로 나타났다. 다음으로 ELISA 방법의 특이도를 조사하기 위해서, IFA 검사에서 음성으로 확인된 혈청(혈청 희석 농도 1:10에서 음성)을 대상으로 ELISA를 시행한 결과, blocking agent로서 1% BSA를 사용했을 때는 9.3%, 5% NGS는 11.3%, 그리고 blocking을 전혀 하지 않았을 때는 15.3%의 위양성율을 나타내어, BSA와 NGS 상이에는 통계학적으로 차이가 없었으나, blocking을 하지 않는 것 보다는 하는 것이 위양성율이 적은 것으로 나타났다. 그러나, 이것은 어디까지나 IFA기준이며, 절대적인 의미에서의 위양성율을 의미하는 것은 아니다. 결론적으로 본 연구에서 정립한 효소면역측정법은 매우 높은 민감도를 갖고 있으므로 Q fever가 의심되는 환자를 screening하기 위한 적절한 방법으로 사료된다. Currently, the indirect immunofluorescence assay(IFA) is used for detecting antibodies to Coxiella burnetii. Although reliable, this method is time-consuming, and the results are subject to interpretation. To develop an alternative test, we used an enzyme-linked immunosorbent asssy (ELISA) because it was faster, less complicated, and more objective than the IFA. The ELISA, unlike the IFA, can also be automated. In this study an indirect ELISA using C. burnetii protein antigens was developed to detect immunoglobulin G to C. burnetii phase I. A linear relation was found between the logarithms of absorbance values of sera at a dilution of 1/300 and the titres as determined by an end point dilution ELISA. The finding of linear relation (r=0.95) confirmed that an ELISA value determined with a single serum dilution (1:300) can be interpreted quantitatively as the titer of antibody in that serum. A serum dilution of 1:300 was used in all subsequent tests because at this dilution the difference between absorbance values for positive and negative sera was greatest: a serum sample was regarded as positive if the OD? value was ≥0.185 (absorbance threshold) at this dilution. The results obtained by the ELISA were compared with those by the IFA established already. The results indicate that the assay provides a sensitive, alternative method for diagnosing Q fever, but it needs reevaluation for the specificity because of its high false-positive rates.

심장으로 전이된 악성 흑색종의 고식적 절제 1예

이경수,이현희,연태진,남기병,김동운,조명찬 대한순환기학회 2000 Korean Circulation Journal Vol.30 No.9