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임신여성을 제외한 성인에서의 B군 연쇄구균 감염에 관한 임상적 고찰
고경식,권선희,안우석,이원욱,김구엽,서환조 대한감염학회 1995 감염 Vol.27 No.4
목적:B군 연쇄구균은 최근 보고에 의하면 만성 기저질환(당뇨병, 악성종양등)이 있는 성인에서 감염빈도 및 사망률, 이환율이 증가하고 있는 추세이며 그 중요성이 대두되고 있다. 이에 저자들은 B군 연쇄구균 감염의 임상양상, 기저질환(위험인자)을 알아보고, B군 연쇄구균 항균제 감수성등을 규명하고자 하였다. 방법:1986년 1월부터 1993년 12월까지 경희대학교 부속병원에서 B군 연쇄구균이 배양된 274예를 대상으로 의무기록지를 검토하였다. 결과: 1) 전체 연구대상은 274예로 98예(35.8%)가 남자였고, 176예(64.2%)가 여자였다. 이들의 연령분포를 보면 신생아군에서 감염이 많이 발생하였다 이후 감소추세를 보이다가 20대 이상에서 다시 증가 하는 추세를 보였다. 2) 감염 양상은 274명중 명확한 감염이 156명(56.9%), 추정감염이 55명(20.1%), 비감염이 63명(23.0%)이었다. 임신을 제외한 18세 이상의 성인은 231명으로 남자가 83명, 여자가 148명이었고 남여 비율은 1:1.78이었다. 이중 133예(57.6%)에서 명확한 감염이었고, 46명(19.9%)에서 추정 감염, 52명(22.5%)에서 비감염이었다. 명확한 감염환자 133명중 31명(23.3%)이 병원내 감염이였다. 3) 18세 이상의 성인 231명에서 Group B Streptococcus가 분리 동정된 감염 부위는 자궁 경부 77예(33.3%), 요 73예(31.6%), 객담및 상기도 39예(16.9%), 농 24예(10.4%)등이었다. 4) 명확한 감염을 가지고 있었던 성인 133명의 임상양상은 요로 감염 37명(28%), 자궁 경부염 37명(28%), 피부, 연조직 감염 23명(17%), 폐렴 10명(8%), 패혈증 8명(6%)등이었다. 5) 명확한 감염을 가지고 있었던 성인 133명중 92명(69%)에서 한가지 이상의 만성 기저질환이 있었으며, 이중 당뇨병 32%, 뇌 혈관 질환 21%, 고혈압 19%, 신부전 12%, 악성종양 5%등을 차지하였다. 6) 항균제 감수성 검사(251예)에서 penicillin 98.4%, cephalothin 99.6%, cefamandol 98.8%, erythromycin 96.0%, clindamycin 89.4%, oxacillin 88.8%, lincomycin 87.8%, methicillin 86.8%, minocycline 49.4%, trimethoprim-sulfamethoxazole 15.5%의 감수성을 보였다. 7) 명확한 성인 감염 133명중 6명(4.5%)이 사망하였다. 결론:B군 연쇄구균은 만성 기저질환이 있는 성인에서 감염 빈도가 높고, 치명적인 결과를 초래할수 있으므로 감염 예방 및 조기 발견, 적절한 항균제 감수성 검사에 따라 조기 치료로 사망률을 줄여야 할것으로 생각된다. Background: Several reports have suggested that the incidence of diseases caused by Group B streptococcus is increasing in nonpregnant adults, particularly those with serious underlying diseases. The objectives of this study were to define the clinical manifestations, underlying conditions(risk factors) of definite group B streptococcal diseases in nonpregnant adults and to obtain antimicrobial sensitivity of these infections. Methods: We analyzed the records of 274 cases of the Group B streptococcus isolated in Kyung-Hee University hospital between 1986 and 1993. Results: 1) Total Group B streptococcal isolates were 274 cases : Of these cases, 7 percent were 1 month of age or younger, 3 percent were older than 1 month but younger than 18 years of age, and 91 percent were 18 or older. 2) Men and nonpregnant women accounted for 87 percent (n=231) : 133 cases (57.6%) with definite infection, 46 cases(19.9%) with possible infection, and 52 cases(22.5%) with no infection. 31 cases of 133 (23.3%) nonpregnant adult with definite infection apeared to have acquired the disease nosocomially. 3) In the 133 nonpregnant adult patients, the most common clinical diagnosis were urinary tract infection(28%), and cervicitis(28%). 4) In the 133 nonpregnant adult patients, the underlying diseases or conditions were diabetes mellitus(32%), cerebrovascular accident(21%), hypertension(19%), renal failure(12%), and malignant neoplasm(5%), Sixty-nine percent of the cases had one or more underlying diseases. 5) In the antimicrobial sensitivity tests, 98.4% of isolates were sensitive to penicillin, 99.6% to cephalothin, 98,8% to cefamandol, 96.0% to erythromycin, 89.4% to clindamycin, and 49.4% to minocycline. 6) The case mortality rate was 4.5%(6 of 133). Conclusion:We found group B streptococcal infection to be a significant and apparently increasing cause of definite diseases in nonprognant adults, particularly in those with serious underlying diseases. Recognizing these infections early in the groups with serious underlying diseases will be helpful in lowering mortality.
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Study on the Defects Detection in Composites by Using Optical Position and Infrared Thermography
Koo-Ahn Kwon,Hee-Sang Park,Man-Yong Choi,Jeong-Hak Park,Won Jae Choi 한국비파괴검사학회 2016 한국비파괴검사학회지 Vol.36 No.2
Non-destructive testing methods for composite materials (e.g., carbon fiber-reinforced and glass fiberreinforced plastic) have been widely used to detect damage in the overall industry. This study detects defects using optical infrared thermography. The transient heat transport in a solid body is characterized by two dynamic quantities, namely, thermal diffusivity and thermal effusivity. The first quantity describes the speed with thermal energy diffuses through a material, whereas the second one represents a type of thermal inertia. The defect detection rate is increased by utilizing a lock-in method and performing a comparison of the defect detection rates. The comparison is conducted by dividing the irradiation method into reflection and transmission methods and the irradiation time into 50 mHz and 100 mHz. The experimental results show that detecting defects at 50 mHz is easy using the transmission method. This result implies that low-frequency thermal waves penetrate a material deeper than the high-frequency waves.
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Koo-Ahn Kwon,Hee-Sang Park,Man-Yong Choi,Jeong-Hak Park,Won-Jae Choi 한국비파괴검사학회 2017 한국비파괴검사학회지 Vol.37 No.2
Many composite materials are used in the aerospace industry because of their excellent mechanical properties. However, the nature of aviation exposes these materials to high temperature and high moisture conditions depending on climate, location, and altitude. Therefore, the molecular arrangement chemical properties, and mechanical properties of composite materials can be changed under these conditions. As a result, surface disruptions and cracks can be created. Consequently, moisture-impregnating defects can be induced due to the crack and delamination of composite materials as they are repeatedly exposed to moisture absorption moisture release, fatigue environment, temperature changes, and fluid pressure changes. This study evaluates the possibility of detecting the moisture-impregnating defects of CFRP and GFRP honeycomb structure sandwich composite materials, which are the composite materials in the aircraft structure, by using an active infrared thermography technology among non-destructive testing methods. In all experiments, it was possible to distinguish the area and a number of CFRP composite materials more clearly than those of GFRP composite material. The highest detection rate was observed in the heating duration of 50 mHz and the low detection rate was at the heating duration of over 500 mHz. The reflection method showed a higher detection rate than the transmission method.
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Study on the Defects Detection in Composites by Using Optical Position and Infrared Thermography
Kwon, Koo-Ahn,Park, Hee-Sang,Choi, Man-Yong,Park, Jeong-Hak,Choi, Won Jae The Korean Society for Nondestructive Testing 2016 한국비파괴검사학회지 Vol.36 No.2
Non-destructive testing methods for composite materials (e.g., carbon fiber-reinforced and glass fiber-reinforced plastic) have been widely used to detect damage in the overall industry. This study detects defects using optical infrared thermography. The transient heat transport in a solid body is characterized by two dynamic quantities, namely, thermal diffusivity and thermal effusivity. The first quantity describes the speed with thermal energy diffuses through a material, whereas the second one represents a type of thermal inertia. The defect detection rate is increased by utilizing a lock-in method and performing a comparison of the defect detection rates. The comparison is conducted by dividing the irradiation method into reflection and transmission methods and the irradiation time into 50 mHz and 100 mHz. The experimental results show that detecting defects at 50 mHz is easy using the transmission method. This result implies that low-frequency thermal waves penetrate a material deeper than the high-frequency waves.
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Kwon, Koo-Ahn,Park, Hee-Sang,Choi, Man-Yong,Park, Jeong-Hak,Choi, Won-Jae The Korean Society for Nondestructive Testing 2017 한국비파괴검사학회지 Vol.37 No.2
Many composite materials are used in the aerospace industry because of their excellent mechanical properties. However, the nature of aviation exposes these materials to high temperature and high moisture conditions depending on climate, location, and altitude. Therefore, the molecular arrangement chemical properties, and mechanical properties of composite materials can be changed under these conditions. As a result, surface disruptions and cracks can be created. Consequently, moisture-impregnating defects can be induced due to the crack and delamination of composite materials as they are repeatedly exposed to moisture absorption moisture release, fatigue environment, temperature changes, and fluid pressure changes. This study evaluates the possibility of detecting the moisture-impregnating defects of CFRP and GFRP honeycomb structure sandwich composite materials, which are the composite materials in the aircraft structure, by using an active infrared thermography technology among non-destructive testing methods. In all experiments, it was possible to distinguish the area and a number of CFRP composite materials more clearly than those of GFRP composite material. The highest detection rate was observed in the heating duration of 50 mHz and the low detection rate was at the heating duration of over 500 mHz. The reflection method showed a higher detection rate than the transmission method.
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광 적외선열화상을 이용한 풍력 블레이드의 결함 크기 정량화 연구
권구안(Koo-Ahn Kwon),최만용(Man-Yong Choi),박희상(Hee-Sang Park),박정학(Jeong-Hak Park),허용학(Yong-Hak Huh),최원재(Won Jae Choi) 한국비파괴검사학회 2015 한국비파괴검사학회지 Vol.35 No.1
풍력발전기의 핵심 부품인 풍력 블레이드는 예상치 못한 풍 하중과 공력 특성으로 인해 불안전한 상태에 놓여 있다. 그에 따라 필연적으로 발생하는 내부 결함을 검출하기 위해 초음파탐상을 이용한 비파괴 검사가 주로 진행되어 왔다. 하지만 블레이드의 소재 특성으로 인해 음향 신호 분석에 따른 문제점이 발생한다. 따라서 본 연구에서는 풍력 블레이드 인공결함시험편을 제작후, 능동적 광 적외선열화상 비파괴검사 방법을 이용하여 결함의 크기를 정량화하기 위한 실험을 진행하였다. 100 kW 급 블레이드 내부의 결함 크기 정량화를 위해 알루미늄 켈리브레이션 테이프를 사용하였으며, 게재물(inclusion), 디본딩(debonding), 주름(wrinkle) 결함을 삽입하였다. 실험 결과 모두에서 뚜렷한 결함 검출이 가능하였으며, 결함 크기 정량화 결과 debonding 인공 결함 (φ50.0 mm)에서 최대 98.0%의 정확성을 보였다. A wind turbine blade is an important component in wind-power generation, and is generally exposed to harsh environmental conditions. Ultrasonic inspection is mainly used to inspect such blades, but it has been difficult to quantify defect sizes in complicated composite structures. Recently, active infrared thermography has been widely studied for inspecting composite structures, in which thermal energy is applied to an object, and an infrared camera detects the energy emitted from it. In this paper, a calibration method for active optical lock-in thermography is proposed to quantify the size. Inclusion, debonding and wrinkle defects, created in a wind blade for 100 kW wind power generation, were all successfully detected using this method. In particular, a φ 50.0 mm debonding defect was sized with 98.0% accuracy.
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안종건,장영호,권일경,고준수,권명구 한국낙농학회 1991 韓國酪農學會誌 Vol.13 No.3
1, 초유에 L. acidophilus를 배양한 결과 젖산균의 증가로 인한 pH 감소로 대장균의 사멸, 총균수의 감소가 일어났으며 특히 25℃에서 효모와 곰팡이의 억제 효과가 좋았다. L. casei와 S. thermophilus를 배양한 경우 15℃ 이상에서 젖산균의 증가로 대장균수는 감소하였으나 총균수 및 효모와 공팡이수는 감소하지 않았다. 젖산 발효 후 안식향산 및 솔빈산 가리의 첨가는 모든 저장 온도에서 효모와 곰팡이의 억제에 효과적이었으나 안식향산은 젖산균을 비롯한 전체 미생물에도 영향을 주어 성장이 약간 감소하였다. 2. 초유를 L. acidophilus 및 L. casei와 S. thermophilus로 배양할 경우 저장중 크림 분리가 일어났으나 안식향산과 솔빈산 가리 첨가구에서는 크림분리가 일어나지 않았으며 유청분리는 L. casei와 S. thermophilus로 발효구에서만 일어났다. L. casei와 S. thermophilus로 발효할 경우 15℃ 이상에서는 효모와 곰팡이의 수가 많아 조직내 gas가 발생하였고 안식향산과 솔빈산 가리 첨가구도 25℃에서 gas가 발생하였다. 또한 표면에서는 곰팡이 성장은 L. acidophlus 발효구에서 일어났다. This study was carried out to elucidate the influence of lactic acid bacteria, and food additives added after lactic fermentation on preservation of colostrum during fermentation at various temperatures to increase availability of surplus colostrum. 1. In colostrum fermented with L. acidophilus, coliforms count and total bacteria count were reduced at 15℃ and 25℃ due to rapid decrease in pH and reduced yeast and mold count at 25℃. In colostrum fermented with L. casei and S. thermophilus, coliforms count was reduced but total bacetria count and yeast and mold count were not. Addition of sodium benzoate and potassium sorbate after lactic fermentation reduced yeast and mold count effectively at various temperatures but addition with sodium benzoate slightly reduced lactic bacteria count and total bacteria count, also. 2. Physical characteristics of colostrum fermented with lactic acid bacteria revealed cream layer formation but colostrums added with sodium benzoate and potassium sorbate after lactic fermentation were not. Separation of whey was shown only in the colostrum fermented with L. casei and S. thermophilus and those added with food preservatives at 25℃. The mold growth on the surface of colostrum was appeared in the colostrum fermented with L. acidophilus at 25℃.
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