Pacemaker-mediated Tachycardia 증례 보고 1례

안효용,고영관 대한응급의학회 1999 대한응급의학회지 Vol.10 No.4

Pacemaker-mediated tachycardia(PMT) is a circus movement tachycardia that can occur in patients with dual chamber pacemaker with atrial sensing(VDD or DDD), when a ventricular depolarization, either spontaneous or paced, causes retrograde activation of the atrium. Recently, a number of pacemaker manufactures have incorporated in their devices a variety of relatively complex algorithms to prevent PMT. Despite these measures, PMT may still occur because of inappropriate programming or unpredictable variations of ventriculoatrial conduction. We report one case of PMT in a 78-year-old male who received DDD type pacemaker due to sick sinus syndrome. In this case, PMT was disappeared after reprogramming parameters of pacemaker and the application of PMT protection algorithm.

경량 고강도 Mg-Zn계합금의 조직과 내식성에 관한 연구

안효준,남태현,임수근,안인섭,허보영,김기원 慶尙大學校 1995 論文集 Vol.34 No.1

The purpose in this study is to develope of high strength and corrosion reistant Mg-Zn system alloys by controlling microstructures and by adding of Cu elements. To produce optimum tesile strength,it is imperative to obtain effective grain refinment during casting. Optimal condition for grain size refining effect was obtained at the minmum composotion of 2wt% Cu or 1.5wt%So addition to Mg-6wt%Zn alloy.Age hardening behavior was experimented at the optimal compositions of the Mg-6wt%Zn, Mg-6wt%Zn-2wt%Cu and Mg-6wt%Zn-1.5wt%Si. The hardeness increment due to age hardening was at the Mg-Zn-Si alloy system. The improvement of corrosion resistanece by the addition with Cu is related to and increasing Zn/Cu ration in the intermatallic particles in the Mg-Zn system.Further improvements obtained by T6 treatment are related to the properties of the Mg-Zn phase,whih acts as a corrosion barrier by precipitating along the grainboundaries.Filiform corrosion observed soon after pit initiation and cellular form of pit propagation later in chloride media are explained in terms of solid solution matrix structure and the properties of air formed oxide.The information obtained from the fundamental research work is utilized in suggesting ways of improving the corrosion resistance of commercial AZ91.

조혈모세포이식 환자에서의 기계 환기의 위험 인자 : Assessment of Risk Factors

안중경,이홍기,황정혜,박세훈,이효락,송서영,이순일,박준오,김기현,김원석,정철원,임영혁,강원기,박근칠 대한조혈모세포이식학회 2002 대한조혈모세포이식학회지 Vol.7 No.1

연구배경: 조혈모세포이식을 시행한 환자에서 집중 치료 시 예후가 매우 나쁜 것으로 알려져 있고, 기계 환기는 강력한 사망 예측 인자로서 보고되고 있다. 그러나 현재까지 이식 환자에서 기계 환기의 위험 인자를 밝힌 연구는 매우 드물다. 따라서 기계 환기를 시행한 조혈모세포이식 환자의 임상적 특징을 살펴보고 기계 환기에 대한 위험 인자를 알아보고자 하였다. 방법: 삼성서울병원에서 조혈모세포이식을 시행한 환자 중 기계 환기를 시행한 23명과 기계 환기를 시행하지 않은 142명을 대상으로 후향적 연구를 시행하였다. 기계 환기에 대한 위험 인자의 여부에 관해서는 chi-square 또는 Fisher's exact 검정을 시행하였으며 기계 환기에 대한 각 위험 인자의 영향에 관해서는 다중로지스틱 회귀분석을 시행하였다. 결과: 기계 환기를 시행한 23명의 환자 중 30일째 생존자는 1명이었고 6개월째 생존율은 0%였다. 생존자와 사망자 모두에서 다기관 기능부전이 관찰되었으며, APACHE II 점수와 SAPS II 점수에 의한 예측 사망률은 각각 56%, 59%였다. 조혈모세포이식 후 기계 환기의 위험 인자로는 선행 질환이 혈액질환, 부분불일치 동종이식, 간정맥폐색성질환, 이식 전 질병 상태가 재발하였거나 약물에 반응하지 않는 경우였다. 다중로지스틱 회귀분석 결과 기계 환기의 위험 인자로 통계적으로 유의한 차이를 나타낸 것은 단지 부분불일치 동종이식을 시행한 경우였다. 결론: 현재까지 조혈모세포이식 환자에서 집중 치료의 역할에 대해서는 확실히 정립되어 있지는 않으며, 이식 환자에서 기계 환기는 강력한 사망 예측 인자이다. 따라서, 조혈모세포이식을 시행한 환자에서 기계 환기의 위험 인자와 불량한 예후 인자를 고려하여 기계 환기 여부에 대한 신중한 결정을 내려야 한다. Background: Respiratory failure requiring mechanical ventilation is a frequent, critical complication of hematopoietic stem cell transplantation (HSCT). Patients who require mechanical ventilatory support after HSCT generally have a very poor prognosis. Mechanical ventilation in HSCT recipients is a strong predictive factor of mortality. The objectives of this study are to describe clinical characteristics of HSCT recipients undergoing mechanical ventilation and to identify the risk factors for mechanical ventilatory support after HSCT. Methods: We performed a retrospective chart review of all patients >15 yrs old who received HSCT at Samsung Medical Center and subsequently required mechanical ventilatory support between 1996 and 2001. Results: Thirty-day mortality rate in HSCT recipients undergoing mechanical ventilation was 95.6%. The mean predictive mortality rates of APAHCE II score and SAPS II score were 56% and 59%, respectively. Reasons for mechanical ventila-tion were sepsis (47.8%) followed by fungal infection (13%) and diffuse alveolar hemorrhage (8.7%). Univariate analysis identified relapsed or refractory diseases at HSCT, hematologic disease, hepatic venoocclusive disease and allogeneic or HLA-mismatched transplant as significant risk factors for mechanical ventilation. On multivariate logistic regression analysis, only allogeneic mismatched transplant remained significant. Conclusion: Overall outcome of HSCT recipients undergoing mechanical ventilation is very poor. Therefore, the risk factors and the poor prognostic factors for mechanical ventilation should be taken into account in making further treatment decision for HSCT recipients requiring mechanical ventilation.

부산 지역 해수 중 금속 농도 분석

안영애,탁효정,황인철 고신대학교보건과학연구소 2003 보건과학연구소보 Vol.13 No.-

Lead, chromium, cadmium, copper, arsenic, mercury and zinc of sea water sampled in 17 sites of Busan coast were analyzed. The results were as follows: 1. The pH values of samples were in the ranges of 8.65-9.28 (mean 9.13), and basic. And the mean salinity was 2.57% (1.57∼2.75%). 2. The mean levels of lead, cadmium, arsenic, mercury were 0.073mg/L, 0.076mg/L, 0.085mg/L and 0.012mg/L, respectively. These relatively high concentrations were estimated resulting from industry waste. 3. The mean zinc level of samples was 0.131mg/L, and near the same as of ocean. 4. The mean copper of samples was 0.018mg/L and seemed to be low. 5. Lead was significantly correlated with arsenic (r=0.378) and zinc (r=0.456), while arsenic also was correlated with zinc (r=0.49). And pH was highly correlated with salinity (r=0.881). Lead, cadmium, arsenic, mercury, and zinc level of 7 metals exceeded the legal requirements of seawater quality, which seemed to be due to sewage and ship wastes. Therefore the comprehensive strategies to keep clean seawater should be carried out.

안검하수의 치료

안기영,백봉수,박효천 大韓成形外科學會 1985 Archives of Plastic Surgery Vol.12 No.1

The aim of this thesis is to study 20 cases of blepharoptosis who were followed-up among many patients who received ptosis surgery at Kyungpook National University Hospital from Jan. 1980 to April 1984. To obtain the best surgical results in blepharoptosis, it was necessary to select the appropriate operation form each case according to levator function, the amount of ptosis, its etiology, as well as other factors. In cases of 4.1mm or more levator function, the author attempted to resect the levator muscle, but in cases of between 3mm and 4mm, the combination of levator muscle resection and frontalis sling was selected. On the other hand, in cases of 3mm or less levator function the fontalis sling was selected combined with fascia lata. The results were as follows; 1. The ratio of congenital versus acquired ptosis was 17 : 3. 2. Among 17 cases of congenital ptosis, male versus female was 11 : 6, and monocular versus bi-ocular was 9 : 8. Among 9 cases of congenital monocular ptosis, Lt. versus Rt. eye incidence was 5 : 4. 3. Among 3 cases of acquired ptosis, the causes were traumatic, neurofibromatosis, and birth injury respectively in each separate case. 4. In 5 of the congenital cases, blepharophimosis was combined, and in 4 strabismus was observed. 5. In the amount of ptosis, 7 cased were belew 2mm, 3 cases between 2.1∼4,9mm, and 10 cases above 5mm. In the measurement of the lavator muscle function, 7 cases were belew 3.0mm, 2 cases between 3.1∼4mm, and 11 cases above 4.1mm. 6. The best results were obtained by the levator muscle resection: Which was done for the patients with more than 4.1mm of levator muscle function. Good to excellent results were obtained in 8 cases among 10 cases. 7. The combination of levator muscle resection and frontalis sling was done for the patients with levator muscle function of 3.1mm∼4mm, and gave poor results. 8. Undercorrection and lid fold deformity were the most common types, except for lid lag and lagophthalmos in sleeping.

원자력현미경 측정정보를 이용한 미세접촉 현상 분석

안효석,장동영 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-

In micro/nano-scale contacts in MEMS and NEMS, capillary and van der Waals forces generated around contacting micro-asperities significantly influence the performance of concerning device as they are related to adhesion and stiction of interacting surfaces, In this regard, it is of prime importance to accurately estimate the magnitude of surface forces so that an optimal solution for reducing friction and adhesion of micro/nano-surfaces may be obtained. We introduce an effective method to calculate these surface forces based on topography information obtained from an atomic force microscope

Self-etching primer를 이용하여 접착된 교정용 브라켓의 전단결합강도

안윤표,김효영,전영미,김정기 대한치과교정학회 2003 대한치과교정학회지 Vol.33 No.1

본 연구는 6세대 교정용 접착 시스템인 Transbond Plus Self-Etching Primer(3M/Unitek Dental Products, Monrovia, Calif)를 이용하여 법랑질면에 브라켓을 접착하는 방법과, 통상적인 산부식 방법에 의해 브라켓을 접착한 경우의 전단결합강도 차이를 비교·평가하고, self etching primer를 이용하여 브라켓을 접착할 때 치면에 존재하는 수분이 브라켓의 전단결합강도에 미치는 영향에 관하여 조사하였다. 37% 인산용액과 Self-Etching Primer를 잉용하여 법랑질을 표면 처리하고 Transbond XT를 이용하여 브라켓을 치면에 부착하였다. 또한 수분의 존재에 따른 전단결합강도의 차이를 평가하기 위해 인공타액을 치면에 도포후 Self-Etching Primer를 사용하여 브라켓을 부착한 후 30분과 24시간에 따른 전단결합강도를 비교 평가하여 다음과 같은 결론을 얻었다. 1. Self-etching primer군에서 건조군과 습윤군의 전단결합강도는 37%인산처리군의 결합강도보다 낮았다(p<0.05). 그러나 Self-etching primer군의 전단결합강도는 임상적으로 유용한 수준의 이상이었다. 2. 모든군에서 24시간군의 전단결합강도가 30분군의 전단결합강도보다 높았으며(p<0.05), 이는 브라켓 접착후 일정시간의 경과가 결합강도를 증가시켜 줌을 알 수 있었다. 3. Self-etching primer군에서 습윤군의 전단결합강도는 건조군보다 높은 경향이었으나 통계적 유의성은 인정되지 않았다(p<0.05). 4. ARI 점수의 비교결과 인산처리군에서는 0점과 1점의 빈도가 높았으며, Self-etching primer 건조군과 습윤군에서는 2점과 3점의 빈도가 높아(p<0.05) Self-etching primer군이 인산처리군보다 법랑질-레진 접착계면부위에서의 파절이 많이 일어남을 알 수 있었다. The purpose of this study was to evcaluate the effects of a self-etching primer on the shear bond strength of orthodontic brackets and on the failure pattern of bracket-adhesive interfaces in dry or wet condition. Brackets were bonded to extracted human teeth according to one of three experimental protocols. In the Group P, teeth were etched with 37% phosphoric acid. After the Transbond XT Primer was applied onto the etched surfaces, the brackets were bonded with Transbond XT(3M, Unitek, Monrovia, Calif) and light cured for 40 seconds. In the Group SD, a self-etching primer(3M, Unitek, Monrovia, Calif) was placed on the enamel for 3 seconds and gently evaporated with air, as suggested by the manufacturer. The brackets were then bonded with Transbond XT as in the Group P. In the Group SW, artificial saliva was applied to the enamel surface for 10 seconds to allow complete hydration of the surface before application self-etching primer. The brackets were then bonded following the procedures of Group SD. Each group was divided into 2 sub-groups(0.5h, 24h) according to debonding time shear bond strengths were measured by Instron universal testing machine. After debonding, the teeth and brackets were examined under scanning electron microscope and assessed with the adhesive remnant index. The result obtained were summarized as follows ; 1. The shear bond strengths were high enough to use clinically in all testing groups, but the shear bond strengths of group SD and SW were significantly lower than Group P(p<0.05). 2. With respect to comparison of debonding time, 24h debonding samples exhibited heigher shear bond strength than 0.5h debonding samples in Group P, SD and SW(p<0.05). 3. In the self etching primer groups(Group SD and Group SW), there was no significant difference in mean shear bond stredifference in mean shear bond strength between under dry and wet state(p>0.05). 4. There was a greater frequency of ARI score of 0 and 1 with the Group P. On the other hand, there was a higher frequency of ARI scores of 2 and 3 with Group SD and Group SW(p<0.05).,

폴리카보네이트 수지의 압출가공 특성

안영철,김효준,박인수 慶南大學校 附設 工業技術硏究所 1998 硏究論文集 Vol.15 No.3

본 연구에서는 단축 압출기 내 수지 이동 현상을 이론적으로 해석하고, 구조와 물성을 알고 있는 비스페놀-A계 폴리카보네이트에 대하여 스크루우 회전속도와 유량을 측정하여 이론식으로부터 통로와 길이에 따른 압력의 분포 등을 계산하여 비교하였다. 그 결과, 같은 수평균 분자량을 가질 때 분자량분포가 넓은 것은 유리전이온도가 낮아 연화하기가 쉬울 뿐만아니라, 토출량이 많음에도 불구하고 압출기 내 고체층의 압력분포가 낮게 나타났다. 또한, 완전용융길이도 상대적으로 짧아짐을 보였다. 따라서, 폴리카보네이트의 화학적 구조나 수평균분자량이 같을 때 분자량분포가 넓은 것이 가공성이 우수하다고 판단된다. The transport phenomena of a plastic resin in a single screw extruder has been analyzed theoretically and from the theoretical formulas the pressure distributions along the screw channel were computed and compared with each other by measuring the screw revolution speed and the flow rate for some bisphenol-A polycarbonates for which the structure and properties are known. The results showed that when the number average molecular weights are equal, a polymer having higher molecular weight distribution not only has a lower glass transition temperature ans softens more easily by heating, but also has a lower pressure distribution in the screw in spite of the increased flow rate. It also had a shorter melting length than a polymer having narrow molecular weight distribution. Therefore, it can be said that when the chemical structure ans number average molecular weights are same, a polycarbonate resin having higher molecular weight distribution has a better processability than a polymer having narrow molecular weight distribution.

귓바퀴에 발생한 Spitz 모반 1예

고나영,박준하,안효현,계영철,김수남 대한피부과학회 2006 大韓皮膚科學會誌 Vol.44 No.4

개선된 탄성지반상 보의 휨해석

鄭熺孝,安光列,李承烈,朴泳珏 경상대학교 생산기술연구소 2002 工學硏究院論文集 Vol.2 No.-

The BEF(Beam on Elastic Foundation) analogy was first noted by Vlasov and then utilized for the distortional analysis of box girders by Wright et al., but it was limited only to prismatic straight box girders. With the development of this study, a more generalized element in a stiffness matrix form was presented. With this element, which is "equivalent" to the BEF(Beam on Elastic Foundation) analogy, more complicated configurations can be resulted. In this study, it compares analysis results using the traditional trigonometric function to solve a BEF(Beam on Elastic Foundation) problem with analysis results using stiffness matrix form to solve a EBEF(Equivalent Beam on Elastic Foundation).