Expression of Fungal Phytase on the Cell Surface of Saccharomyces cerevisiae

김대혁,박승문,양문식,Ae-Young Mo,Yun-Sik Kim 한국생물공학회 2005 Biotechnology and Bioprocess Engineering Vol.10 No.6

Phytase improves the bioavailability of phytate phosphorus in plant foods to humans and animals, and reduces the phosphorus pollution of animal waste. We have engineered the cell surface of the yeast, Saccharomyces cerevisiae, by anchoring active fungal phytase on its cell wall, in order to apply it as a dietary supplement containing bioconversional functions in animal foods and a whole cell bio-catalyst for the treatment of waste. The phytase gene (phyA) of Aspergillus niger with a signal peptide of rice amylase 1A (Ramy1A) was fused with the gene encoding the C-terminal half (320 amino acid residues from the C-terminus) of yeast a-agglutinin, a protein which is involved in mating and is covalently anchored to the cell wall. The resulting fusion construct was introduced into S. cerevisiae and expressed under the control of the constitutive glyceraldehydes-3-phosphate dehydrogenase (GPD) promoter. Phytase plate assay revealed that the surface-engineered cell exhibited a catalytically active opaque zone which was restricted to the margin of the colony. Additionally, the phytase activity was detected in the cell fraction, but was not detected in the culture medium when it was grown in liquid. These results indicate that the phytase was successfully anchored to the cell surface of yeast and was displayed as its active form. The amount of recombinant phytase on the surface of yeast cells was estimated to be 16,000 molecules per cell.

Cultural Characteristics and Extraction ofthe Fungal Pigment Phleichrome from thePhytopathogenic Fungus Cladosporium phlei

김대혁,박승문,김범태,양문식,황기준,Joong-Keun Lee,Jung-Ae Kim,Hea-Jong Chung 한국생물공학회 2007 Biotechnology and Bioprocess Engineering Vol.12 No.5

The cultural characteristics of the fungus Cladosporium phlei were assessed in order to develop an improved method for the production of the fungal pigment, phleichrome, which is an intermediate in the production of a photodynamic therapeutic agent. The growth of C. phlei, as measured by the hyphal growth rate and increase in biomass, varies significantly depending on the culture media utilized (V8 juice-based medium proved optimal for both growth rate and biomass increase). However, even on a V8 juice plate, the growth of C. phlei occurred slowly and in a limited fashion, in that the colony covered only 75% of the agar surface after more than 4 weeks of cultivation at 20℃. Supplementations of glucose, fructose, galactose, and sucrose increased both hyphal expansion and mass production, whereas supplementations of other carbon sources, including glycerol and sorbitol, exerted no detectable effects. The effect of inorganic nitrogen supplementation was negligible, whereas organic nitrogen evidenced significant effects, with enhanced growth with malt extract and growth inhibition with yeast extract and tryptone. Sporulation was enhanced under conditions of continuous light, and a minimum of 103 spores per mL of liquid media was found to be necessary for the optimal mass increase. A simple extraction procedure was established in order to isolate the deep red pigment which was subsequently identified as phleichrome via NMR analysis. When C. phlei was cultured on V8 medium containing 5% glucose and 2% malt extract, the quantity of mycelial mass was estimated as 20.6 g (dry weight) per liter of culture. The expected phleichrome yields from the mycelia and culture filtrates were estimated to be 43 and 2 mg/L, respectively.

텔레매틱스 기반 DSRC 시스템에서 노변기지국과 서버 간 무선 네트워크 구축

김대혁(Daehyuk Kim),김학재(Hakjae Kim),김동현(Donghyun Kim),윤동원(Dongweon Yoon),박상규(Sang Kyu Park) 한국통신학회 2005 한국통신학회 학술대회논문집 Vol.2005 No.6

주익이 손상된 전익형 무인기를 위한 신경회로망 적응제어기법에 관한 연구

김대혁(DaeHyuk Kim),김낙완(Nakwan Kim),석진영(Jinyoung Suk),김병수(Byungsoo Kim) 한국항공우주학회 2013 韓國航空宇宙學會誌 Vol.41 No.5

무인항공기가 외형손상을 입는 경우, 비행역학 특성이 변하기 때문에 손상 이전 설계된 제어기는 더 이상 안정적인 제어성능을 보장하지 않는다. 본 논문에서는 주익의 손상이 일어난 무인항공기에 대해서도 강건한 제어성능을 보장하는 신경회로망 적응제어기법을 소개한다. 구동기의 특성에 의한 제어기의 성능저하를 방지하기 위해 Pseudo Control Hedging(PCH)를 추가적으로 사용하였다. 기체고정좌표계의 중심이 항공기의 무게중심에 위치하지 않는 비대칭 동역학을 사용하였으며, 전익형 무인기를 대상 비행체로 하였다. 날개가 손상되지 않은 모델과 손상된 모델의 풍동시험을 통해 얻은 공력데이터를 이용하여 시뮬레이션을 수행하였다. 시뮬레이션의 결과를 통해 제안된 제어기법이 주익의 손상이 발생한 항공기에 대해서도 여전히 안정적인 조종성능을 보장하는 제어기법임을 검증하였다. A damage imposed on an unmanned aerial vehicle changes the flight dynamic characteristics, and makes difficult for a conventional controller based on undamaged dynamics to stabilize the vehicle with damage. This paper presents a neural network based adaptive control method that guarantees stable control performance for an unmanned aerial vehicle even with damage on the main wing. Additionally, Pseudo Control Hedging (PCH) is combined to prevent control performance degradation by actuator characteristics. Asymmetric dynamic equations for an aircraft are chosen to describe motions of a vehicle with damage. Aerodynamic data from wind tunnel test for an undamaged model and a damaged model are used for numerical validation of the proposed control method. The numerical simulation has shown that the proposed control method has robust control performance in the presence of wing damage.

심실 빈맥의 임상양상 및 예후

김진배 ( Jin Bae Kim ),정보영 ( Bo Young Joung ),김종윤 ( Jong Youn Kim ),김대혁 ( Dae Huyk Kim ),안신기 ( Shin Ki Ahn ),이문형 ( Moon Hyoung Lee ),김성순 ( Sung Soon Kim ) 대한내과학회 2006 대한내과학회지 Vol.71 No.3

목적: 심실 빈맥의 원인 질환으로 허혈성 심질환이 가장 흔하다고 보고되고 있으나 우리나라의 경우 허혈성 심질환에 의한 심실 빈맥의 빈도나 임상양상 및 예후에 대하여 국내 보고가 미흡한 상태였다. 따라서 본 연구를 통해 우리나라에서 발생한 심실 빈맥의 임상적 특징과 예후에 대해 알아보고자 하였다. 방법: 1999년 1월부터 2002년 12월까지 본원에서 심실 빈맥으로 진단된 환자 136명을 대상으로 하였으며 내원 당시 ECG의 특징과 임상적 특징, 추적 결과을 분석하여 예후을 조사하였다. 결과: 남자는 100명(73.5%), 여자는 36명(26.5%)으로 남녀 비는 2.76:1였다. 환자의 발작 시 증상 중 가장 많이 호소하였던 것은 심계 항진(50.8%)이었으며 흉통(17.6%), 졸도가 15예(11.0%), 호흡곤란 7예(5.1%), 심장 돌연사 7예(5.1%)였으며 무증상인 경우가 2예(1.5%), 기타 다른 증상이 4예(2.9%)였다. 심실 빈맥의 발생에 특별한 유발 인자가 없었던 경우가 제일 많았으며(58.1%), 물리적인 활동(33.1%), 감정적인 스트레스(7.4%)가 유발인자로 관찰되었다. 심전도상의 특징을 살펴보면 기저 심박수는 74.8±17.5회, QRS폭은 101.1±18.5 ms였으며 전기축은 정상축이 가장 많았으며 V1 유도의 QRS 모양으로 분류해 보면 우각 차단형이 54예(39.7%), 좌각 차단형이 44예 (32.4%), 다형 심실 빈맥이 15예(11.0%)였으며 V1유도가 기록되지 않았던 경우가 23예(16.9%)있었다. 심실 빈맥의 원인 질환으로는 특발성 심실 빈맥이 74예(54.4%)로 가장 많았으며 허혈성 심질환이 29예(21.3%)로 그 다음이었다. 특발성 심근병증이 16예(11.8%)였으며 심판막증이 6예(4.4%)있었고, 그 밖에도 선천성 심질환(3예), Long QT 증후군(4예), Brugada 증후군(4예)있었다. 추적관찰되었던 119예 중에서 재발되었던 환자는 31예(22.8%)였으며 사망한 환자는 12예(10.1%)였다. 추적 관찰에서 재발 및 사망 여부가 확인되지 않은 환자는 17명(13.9%)였다. 재발하기까지의 기간이나 사망률로 환자의 예후를 판별하였는데, 여타 질환에 비해 특발성 심실 빈맥의 경우가 통계적으로 유의하게 좋은 예후를 보여 주었으며 허혈성 심질환인 경우가 가장 좋치 못한 결과를 보여 주었다(p<0.05). 특발성 심실 빈맥의 치료법 중 전극 도자 절제술가 가장 좋은 예후를 보여 주었으며 득발성 심실 빈맥의 경우 사망 환자는 없었다(p<0.05). 결론: 국내 심실 빈맥의 환자는 서구와는 달리 특발성인 경우가 가장 많았고 특발성 심실 빈맥의 경우가 다른 심실 빈맥에 비하여 예후가 가장 좋았으며 특발성 심실 빈맥의 치료 방법 중 전극 도자 절제술의 효과가 가장 좋았다. Background: Although the determination of etiology is crucial for the management of ventricular tachycardia (VT), there have been few studies on the epidemiology and clinical characteristics of patients with ventricular tachycardia in Korea. Previous studies on Western populations have shown that ischemic VT is the most common type arrhythmia; however, the incidence of ischemic heart disease in Korea is lower than in Western culture. The purpose of this study was to determine the clinical characteristics and prognosis of Korean patients with VT. Methods: From January 1999 to December 2002 patients who were diagnosed with VT by ECG or confirmed by electrophysiological studies were enrolled. Hospital records were reviewed for the clinical characteristics which included: demographic features, underlying disease, clinical presentation, ECG features and prognosis in 136 patients who visited our emergency room or out patient clinic. Results: There were 100 men and 36 women (mean age 51.517.6). The most common presenting symptom was palpitation (56.6%), which was followed by chest pain and syncope. The most common type of VT was idiopathic VT (54.4%); ischemic VT was found in 29 cases (21.3%) and dilated or hypertrophic cardiomyopathy in 16 cases (11.8%). For all types of VT, the idiopathic VT showed the best prognosis and cardiac function (p<0.05). RFCA (Radiofrequency catheter ablation) was the best treatment option for treatment of idiopathic VT (p<0.05). Conclusions: These findings suggest that idiopathic VT may be the most common type of VT in Korean patients; it usually originates form either the right ventricular outflow tract (RVOT) or the LV. The response to treatment and prognosis was poor in VT patients who had underlying heart disease; however, the prognosis was excellent for those with idiopathic VT.(Korean J Med 71:276-284, 2006)

콘크리트 충전 강관의 휨 강도 실험분석

김대혁(Dae Hyeok Kim),한상윤(Sang Yoon Han),신성진(Sung Jin Shin),강영종(Young Jong Kang) 한국철도학회 2015 한국철도학회 학술발표대회논문집 Vol.2015 No.10

원형 CFT 단면의 기하학적 특성에 따른 부재의 휨 거동

김대혁 ( Kim Dae Hyeok ),한상윤 ( Han Sang Yun ),신성진 ( Shin Sung Jin ),강영종 ( Kang Young Jong ) 한국복합신소재구조학회 2016 복합신소재구조학회논문집 Vol.7 No.4

The present study analyzes the flexure behavior of the circular CFT member through experiment and numerical analysis. Through comparison between experimental and numerical results, whether or not the member was a full composite have little effect on the behavior. There circular CFT’s flexure behavior when considering pure moment is almost similar regardless of the interface characteristics between the steel and concrete. This is because there is no difference in the neutral axis of the full-composite and non-composite circular CFT member.

강합성 플레이트 거더 복부판의 전단 좌굴 강도를 평가하기 위한 매개변수 해석

김대혁(Dae-Hyeok Kim),한상윤(Sang-Yun Han),장민서(Min-seo Jang),마이타이항(Mai-Thi Hang),강영종(Young-Jong Kang) 대한토목학회 2019 대한토목학회 학술대회 Vol.2019 No.10

이동식 에어컨의 연속운전 향상을 위한 응축기 경로 연구

김대혁(Dae Hyeok Kim),이재원(Jae Won Lee),정대권(Dae Kwon Jeong),강용태(Yong Tae Kang) 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.4

CFT Pile이 적용된 일체식 교량의 실물실험

김대혁(Dae-Hyeok Kim),한상윤(Sang-Yun Han),신성진(Sung-Jin Shin),강영종(Young-Jong Kang) 한국철도학회 2016 한국철도학회 학술발표대회논문집 Vol.2016 No.10

사용성 및 유지보수에 유리한 장점을 가지는 일체식 교량의 상부구조물을 효율적으로 설계하기 위하여 CFT Pile을 하부구조물에 적용하는 연구가 진행되었다. 본 연구는 하부구조물에 CFT Pile이 적용된 일체식 교량의 현장 적용을 위한 연구로써, 30m의 실물 실험체를 제작하여 정적 재하 실험을 수행하였으며, 재하 되는 하중에 따라 일체식 교량의 거동을 분석하여 구조물의 성능을 평가하였다. This study was carried out in order to economically design the upper structure of the integral bridge by applying the CFT pile to the lower part of the structure. The integral bridge has favorable usability and maintenance. A static loading experiment was conducted by making a full-scale specimen to study the CFT Pile on the lower part of the structure applied to the integral bridges. The behavior of the integral bridge structures and their performance was evaluated.