표면처리가 장석도재의 굴곡강도에 미치는 영향

정성화,임범순,김철위 서울대학교 치과대학 치과생체재료학교실 1995 치과생체재료학 논문집 Vol.3 No.1

Dental ceramics exhibits excellent esthetic, compressive strength and chemical durability, good tissue compatibility and transulcency comparable to natural teeth. Dental ceramics, however, have brittleness as ell as low tensile and shear strength and are extremely sensitive to brittle fracture initiated at surface defects. Glazing and polishing treatments can reduce the influence surface flaws, which lead to an increase in strength of the porcelain. And the other method of strengthening the porcelain is to generate a state of residual compression in the surface, which can be accomplished either by ion exchange treatment or thermal tempering. The object of this study was to compare the effect of various surface treatments on the flexural strength of feldspathic porcelain. Bars of feldspathic porcelain specimen (3×3×30㎜) were prepared from Vintage (Shofu) body procelain by condensing slurries into a platinum foil mould , then sintered in a furnace (Master Splint 120) according to the manufacturer's recommendations under vacuum. The bars were divided into the seven groups : self-glazing (control), over glazing subsequent to ion exchange, and ion exchange subsequent to over-galzing. The ion exchange treatment consisted of applying Ceramicoat past (GC) as evenly as possible to the porcelain using a paintbursh. The coating material was dried for 20 minutes at 150℃, followed by firing at 450℃ for 30 minutes. To evaluate the effect of ion exchange temperature, the same drying cycle was followed by 30-minute heat treatments at 350℃, 400℃, 500℃, and 550℃. Each specimen was loaded to failure on a universal testing machine with a crosshead speed of 0.02 ㎝/min. 7∼10 specimens in each groups were test and the mean value for flexural strength was calculated. The fracture surfaces were examined by a scanning electron microscope. For qualitative analysis of the relative changes in potassium and sodium concentrations after ion exchange treatment, energy dispersive x-ray analysis was performed on the surface and bulk section of the fractured surface. Quatitative chemical analyses were performed on the cross section of the specimen after ion exchange treatment by a scanning elecron microscope equipped with a wavelength dispersive x-ray analyzer. Analyses were made in 10∼20 ㎛ below the treated surface. From the experiment, the following results were obtained: 1. The flexural strength was increased by 37% using over-laze treatment, but polishing or heat treatments of feldspathic did not show significant difference (p>0.05) relative to the self-glaze control group. 2. Relative to the control group (self-glaze), the mean flexural strengths of specimen were increased by ion exchanged treatment : 20% at 350℃, 28% at 400℃, and 56% at 450℃ and 500℃. 3. The effect of ion exchange treatment was lost if the porcelain was subsequently treated by self-glaze. The group with ion exchange treatment subsequent to over-glaze treatment showed the highest flexural strength among the experimental groups. 4. The fracture surface of the specimen with ion exchange treatment showed the hackle region, which could imply the degree of fracture resistance in the ion exchanged layer. 5. The chemical analysis (EDX and WDX) results showed that the effect of ion exchange was extended to 50 ㎛ below the ion treated surface.

구급일지를 통한 병원 전 환잔 분류 및 처치의 적절성 평가 연구

민순식,김재광,이근,박철완,양혁준,류일,현성열,이훈규,정환모,김윤 대한응급의학회 2000 대한응급의학회지 Vol.11 No.4

Background: Recently, patients' demands for emergency medicine are increasing, and most of prehospital medical care, including basic life support, cardiopulmonary resuscitation and triage, are provided by paramedics or emergency medical technicians. Evaluation of the adequacy of prehospital management and triage has become important for improving the quality and the effectiveness of the emergency medical system. Methods: The 202 patients who were transferred by ambulance with paramedics, nurses, or emergency medical technicians to the Emergency Department in Gil Medical Center from July 1, 1999, to September 31, 1999, were enrolled. This study was conducted prospectively by using the emergency physician,s log and newly devised protocols recorded by paramedics or nurses. Results: 1) Male to female ratio was 1: 0.8, and the peak age of the patients were the 4th(18.8%) and 6th decade(15.3%). 2) Of the 202 patients, 84 patients were transferred for trauma and 118 for medical problems. The mean transfer time was 6±1.73 minutes. 3) The validities of prehospital triage and decisions using the trauma severity measure and the disease severity measure, were 33.3% in trauma patients and 57.6% in medical patients.4) The results for the adequacy rate in prehospital management analyzed by using the rate of necessity of treatment. performance of treatment, and adequate treatment were as follows: oxygen supply.38.1/41.6/93.8 ; wound dressing. 19.3/71.8/92.9 ; immobilization of the cervical spine, 15.8/56.3/92.9 ; application of a spinal board. 12.9/42.3/72.7 ; application of a splint, 9.9/50.0/60.0 ; manual maintenance of an airway. 9.9/55.0/63.6 ; and CPR, 4.5/66.7/0. 5) Kind of ALS(Advanced Life Support) were not conducted(peripheral IV, EKG. intubation, medical administration. defibrillation, pacing). The rates of necessity of treatment were as follows: peripheral IV, 40.6%; ECG monitoring, 23.3% ; endotracheal intubation, 8.9% ; medical administration, 8.9% ; defibrillation. 3.5%; and pacing. 1.5% Conclusion: The adequacy of prehospital triage and decisions using trauma and disease severity measures was relatively low. To improve the adequacy of BLS(Basic Life Support) and to increase the performance of ALS(Advanced Life Support), we must create challenges to develop new protocols and to supplement new equipment.

인천시관내 고1 건강검진 결과분석

임순철,안상용,김기성,황옥분,고봉순,박대정 한국건강관리협회 2000 건협 Report Vol.3 No.-

Histochemistry에 의한 Muscle Study와 임상적 의의

張淳喆,李載澤,金柱鎬,鄭鶴仁 대한임상병리사협회 1984 임상병리사회지 Vol.16 No.1

크롬(Ⅵ)의 체내 흡수와 소실속도에 관한 연구

김현영,이성배,임철홍,이권섭,정용현,이종성,한정희,전윤석,황호순,이용묵 한국산업위생학회 2003 한국산업보건학회지 Vol.13 No.1

The CrO3 mostly used in plating. metal surface disposal, leather, cosmetic manufacturing, as an experiment material by repeatedly inhaling and exposure the male S.D. rats at a 0.00, 0.2., 0.50, 1.25 mg/㎡ concentration(particle size: 0.5-0.5 aerosol)6hours a day, 5day a week in 13weeks comparing with 2weeks, 8weeks of recovery group about the noxiousness of the experiment animal and the reduce scale of the CrO3 in the internal organ especially in blook and respiratory organ with the period of convalescent and clearance. The experiment results which we received are as follows. 1. In blood the RBC, HGB and HCT experiment, rats with 0.20, 0.50 mg/㎡ concentration showed that there were some decreases but not dependent. The kidneys absolute weight compared with control group was reduced intentionally(p〈0.05) and the lungs absolute weight compared with control group showed intentional increase(p〉0.05). 2. After the exposure of the experiment material, the whole blook, l\blood plasma and red blood cell in blood by (x): the period of convalescent, per (y); the decreasing of Cr concentration, was y=66.51 e -0.057x, y=67.2 e-0.101x, y=70.01 e-0.030 in 0.50 mg/㎡ exposure concentration by calculating the clearance coefficient of correlation, and the half life (day)was estimated 12.0, 6086, 23.0 each. 3, After the exposure of the experiment material, the experiment animals lung, liver and kidneys by(x); the period of convalescent, per (y); the decreasing of Cr conentration, was y=1808 e-0.00493x, y=12.02e-0.0297x, y=67.61 e-0.0292x in 0.50mg/㎡ exposure concentration by calculating the clearance coefficient of correlation, and the half life(day)was estimated 140.6, 23.3, 23.7, each, and including lung, liver with all of the experiment internal organs, the Cr clearance decreased as the exposure concentration increased.

Methotrexate 치료를 받고 있는 활동성 류마티스 관절염 환자에서 etanercept의 유효성과 안전성에 관한 연구

최병렬,강태영,정청일,이혜순,엄완식,김태환,전재범,유대현,배상철 대한내과학회 2004 대한내과학회지 Vol.66 No.5

목적 : 류마티스 관절염을 앓고 있는 한국인 중에 기존 DMARDs로 치료 실패하였고, 고정용량의 MTX를 복용하고 있는 환자들에 있어서 etanercept의 유효성과 안전성을 평가하고자 하였다. 방법 : 기존 DMARDs로 치료 실패한 활동성 류마티스 관절염 환자 76명을 대상으로 하여 단일군, 공개시험을 하였다. 대상 환자들은 고정용량의 MTX를 복용하면서 etanercept 25 mg을 1주일에 두 번 피하 주사하였으며 12주간 투여하였다. 유효성은 ACR 20, ACR 50,조조강직 시간으로 평가하였고, 약제의 안전성은 이상반응 등으로 평가하였다. 결과 : 대상 환자는 총 76명으로 평균 연령은 45.2세, 남자 5명, 여자 71명이었다. 84.4%인 54명이 12주째에 ACR 20을 만족하였고, 53.1%인 34명이 12주째에 ACR 50을 만족하였다. 조조 강직 시간은 치료 전 203.3분에서 치료 12주째 42.6분을 평균 74.5% 호전되었다. 가장 흔한 이상반응은 주사부위 반응이었다. 이외에도 상기도 감염, 오심, 안면부종 등이 발생하였으나 심각한 부작용은 없었다. 결론 : etanercept는 효과적이고, 안전한 류마티스 관절염 치료 방법이며 특히 MTX치료에도 불구하고 활동성인 류마티스 관절염에 기대되는 치료라고 할 수 있다. Background : This study was performed to investigate the efficacy and safety of etanercept in active rheumatoid arthritis patients with stable dose of methotrexate in Korean. Methods : In a 12 week, single arm, open trial, we assigned 76 patients with active rheumatoid arthritis who had an inadequate response to disease-modifying antirheumatic drugs. Patients received twice-weekly subcutaneous injections of etanercept 25 ㎎ while containing to receive methotrexate at a stable dose of 7.5~25 ㎎ per week. The clinical response was defined as the percent improvement in disease activity according to the criteria of the American Collage of Rheumatology (ACR) at 12 weeks. Results : Etanrecept led to significant improvements in disease activity and was safe and well tolerated. At 12 week, 84.4% of the patients receiving 25 ㎎ of etanercept achieved a 20% ACR response, and 53.1% of those receiving etanercept achieved a 50% ACR response. The most common adverse event was injection-site reaction. Other advanse events were upper respiratory infection, nausea, and facial edema, but there were no serious adverse events associated with etanercept. Conclusion : In active rheumatoid arthritis patients, etanercept was safe, well tolerated, and provided rapid clinical improvements.

화상 환자에서 발생한 외과적 중재술을 요하는 감염성 심내막염 2예

김근숙,이태유,정연손,최창순,최민호,류제헌,김철홍,조구영,우흥정 대한감염학회 2003 감염과 화학요법 Vol.35 No.3

감염성 심내막염은 화상 후에 발생할 수 있는 치명적인 합병증이다. 임상 증상은 일반적으로 없는 경우가 대부분이고 지속되는 발열과 양성 혈액 배양 검사가 유일하다. 감염의 다른 확실한 원인 없이 발열과 양성 혈액 배양 검사가 있을 때는 감염성 심내막염을 강력하게 의심해야 하며 심장 초음파로 진단 가능하다. 감염성 심내막염은 사망률은 높지만 초기에 진단하면 항생제 정주를 지속하는 것으로 치료할 수 있다. 저자들은 화상환자에서 발생한 수술적 처치를 필요로 하는 감염성 심내막염 2예를 경험하였기에 보고하는 바이다. Infective endocarditis is a rare but fatal complication following burn injury. The clinical presentation is silent, but with persistent fever and positive blood culture. The manipulation of clinical care as well as the burn wound itself and immunosuppression caused by extensive bums puts the burn patients at risk of bacteremia. Staphylococcus aureus and Gram-negative bacilli are most common pathogens of infective endocarditis following burns. We report herein two cases of infective endocarditis in the burn patients who requires surgical intervention. The first case was caused by Pseudomonas aeruginosa with complication of multifocal pneumonia, and the second case by coagulase-negative stapylococcus with cerebral hemorrhage.

An fMRI Study of Cognitive Function during Hyperoxia

Chung Soon-Cheol,Kim Ik-Hyeon,Tack Gye-Rae,Lee Soo Yeol,Sohn Jin-Hun The Korean Society of Medical and Biological Engin 2005 의공학회지 Vol.26 No.1

This study aimed to investigate the hypothesis that administration of the air with 30% oxygen compared with normal air (21% oxygen) enhances cognitive functioning through increased activation in the brain. Seventeen college students (right­handed, average age of 24.3) were selected as subjects for this study. An oxygen supply equipment that provides 21% and 30% oxygen at a constant rate of 8L/min was developed. In order to measure the performance level of visuospatial and verbal cognition, two psychological tests were developed. The experiment consisted of two runs, one for cognition task with normal air (21% oxygen) and the other for cognition task with hyperoxic air (30% oxygen). Visuospatial and verbal tasks were presented while brain images were scanned by a 3T fMRI system using the single-shot EPI method. The results showed that there was an improvement in performance and also increased activation in several brain areas in the higher oxygen condition. These results suggest that while performing cognitive tasks, high concentrations of oxygen administration make oxygen administration sufficient, thus making neural network activate more, and the ability to perform cognitive tasks increase.

Development and Verification of Real Time Subjective Sensibility Evaluation System

Chung, Soon-Cheol,Min, Byung-Chan The Korean Society of Medical and Biological Engin 2003 의공학회지 Vol.24 No.4

본 연구에서는 인간의 주관적 감성 변화를 실시간으로 측정할 수 있는 시스템을 개발하였다. 본 시스템은 펜 마우스와 디지타이저론 이용하여 인간의 감성 변화론 실시간으로 입력 받을 수 있는 입력 부분과. 쾌도 및 긴장도의 감성 변화즐 실시간으로 측정하고 평가할 수 있는 감성평가 및 디스플레이 부분으로 구성되어있다. 본 연구에서는 된 시스템의 유효성을 검증하기 위하여 하나의 실험을 수행하였다. 20명의 20대 남녀 피험자를 대상으로 긍정 감성과 부정 감성을 유발시킬 수 있는 사진을 각각 1장식 제시하면서 실시간 주관적 감성 평가와 함께 Galvanic Skin Response (GSR)를 실시간으로 측정하였고, 실험이 종료된 후 설문지를 이용하여 비 실시간 주관적 감성 평가를 실시하였다. 이를 통해 실시간 및 비 실시간 주관적 감성 평가, 생리 신호 평가의 결과들을 비교하였다. 상관관계 계수의 비교로부터 긍정 사진 자극으로 유발된 실시간 주관적 감성 변화는 부정 사진 자극으로 유발된 GSR 반응과, 부정 사진 자극으로 유발된 실시간 주관적 감성 변화는 부정 사진 자극으로 유발된 GSR 반응과 더 밀접한 관계가 있었다. 또한 설문지를 이용한 비 실시간 주관적 감성 평가 결과는 실시간 주관적 감성 평가의 누적된 평균 감성 값과 유사하였다. 이러한 결과로부터, 본 시스템의 가장 큰 특징은 시간에 따라 시시각각으로 변하는 인간의 주관적 감성 크기 변화를 관찰할 수 있다는 것과 자극제시 기간 동안의 평균적인 감성 평가가 가능하다는 것이다. In the present study, a new Real Time Subjective Evaluation (RTSSE) system was developed. The system is composed of two parts: a sensibility input part and sensibility evaluation part. The sensibility input part receives values, which are recorded on an input board using a stylus and digital tablet, from each subject's evaluation of his/her own subjective sensibility towards a particular stimulus. The sensibility evaluation part displays the level of pleasantness and arousal on one or two dimensions in real time. An experiment was conducted in order to investigate the feasibility and effectiveness of the RTSSE system. The present study compared Galvanic Skin Response (GSR) with the RTSSE by presenting 28 subjects in their 20s with pictures arousing either positive or negative sensibility. Following the experiment, an off-line subjective assessment using a questionnaire was given to the same subjects. According to the correlation coefficients, changes in subjective sensibility caused by the positive visual stimulus were related more closely to GSR, from the positive visual stimulus, and changes in subjective sensibility caused by the negative visual stimulus were related more closely to GSR from the negative visual stimulus. The questionnaire results showed marked similarity to the average responses of the RTSSE. In conclusion, the most remarkable characteristic of the present system is that it not only assesses the average sensibility when stimuli are presented, but also shows the changing strength of sensibility over time.

THE EFFECT OF OXYGEN ADMINISTRATION ON VISUOSPATIAL COGNITIVE PERFORMANCE: TIME COURSE DATA ANALYSIS OF fMRI

CHUNG, SOON-CHEOL,LEE, BONGSOO,TACK, GYE-RAE,YI, JEONG-HAN,YOU, JI-HYE,SON, SANG-HEE Taylor Francis 2006 INTERNATIONAL JOURNAL OF NEUROSCIENCE - Vol.116 No.2

<P>This study investigated the effects of 30% oxygen administration on visuospatial cognitive ability using time course data analysis of fMRI. A visuospatial task was presented while brain images were scanned by a 3T MRI system. The results showed that there was an improvement in performance and also increased BOLD intensity in the parietal lobe in the higher oxygen condition. There was positive relation between behavior performance and BOLD intensity in the right parietal lobe. This result supports the conclusion that the increase in the cognitive processing ability due to highly concentrated oxygen can be explained by the increase in the BOLD intensity.</P>