Three-Dimensional Porous Collagen/Chitosan Complex Sponge for Tissue Engineering

Kim, Sung Eun,Cho, Yong Woo,Kang, Eun Jung,Kwon, Ick Chan,Lee, Eunhee Bae,Kim, Jung Hyun,Chung, Hesson,Jeong, Seo Young The Korean Fiber Society 2001 Fibers and polymers Vol.2 No.2

A three-dimensional, porous collagen/chitosan complex sponge was prepared to closely simulate basic extracellular matrix (ECM) constitutes, collagen and glycosaminoglycan. The complex sponge was prepared by a lyophilization method and had the regular network with highly porous structure, suitable for cell adhesion and growth. The pores were well interconnected, and their distribution was fairly homogeneous. The complex sponge was crosslinked using 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) to increase its boilogical stability and enhance its mechanical properties. The crosslinking medium has a great effect on the inner structure of the sponge. The homogeneous, porous structure of the sponge was remarkably collapsed in an aqueous crosslinking medium. However, the morphology of the sponge remained almost intact in a water/ethanol mixture crosslinking milieu. Mechanical properties of the collagen/chitosan sponge were significantly enhanced by EDC-mediated crosslinking. The potential of the sponge as a scaffold for tissue engineering was investigated using a Chinese hamster ovary cell (CHO-K1) line.

2003년 국내 중증급성호흡기증후군 진료 현황 및 문제점 분석

이진수,김은실,정문현,백제중,정선화,안주희,최영화,이선희,고철우,김성범,김민자,박승철,기현균,송재훈,최상호,김양수,이상오,조용균,박영훈,정숙인,김연숙,이흥범,손창희,장성희,정희진,김우주 대한감염학회 2004 감염과 화학요법 Vol.36 No.3

목적 : 2002년 말 중국에서 SARS가 발생한 이후 국내에서도 2003년 10월까지 총 3명의 추정환자, 17명의 의심환자가 보고되었다. 향후 추가적인 SARS의 유행이 우려되는 상황에서, 그간의 SARS 환자 진료에 있어서의 실질적인 준비사항, 진료 현황 등에 대한 조사를 통해 문제점을 파악하여, 향후 더 나은 대비가 될 수 있도록 개선점을 제시하고자 하였다. 재료 및 방법 : SARS로 의심되는 환자를 진료 경험이 있는 병원의료진을 대상으로 2003년 10월에 설문조사를 실시하였다. 설문에는 SARS 환자 진료 시의 실질적인 조치, 진료 현황, 병실, 응급실 및 외래에서의 격리 시설과 준비사항, 보건당국의 관리와 지원에 관한 사항을 포함하였다. 결과 : 대상이 되는 22개 병원 중 17개(17/22, 77.2%) 병원이 설문에 응하였다. SARS 환자를 위한 격리실은 응급실, 외래, 일반병실 및 중환자실에서 각각 9개(9/17, 52.9%), 5개(5/17, 29.4%), 15개(15/16, 93.7%), 4개(4/16, 25%) 병원에서 음압처리가 되어있지 않은 일인실 혹은 다인실이 사용되었고, 1개(1/16, 6.3%) 병원에서만 일반병실에서 음압격리실이 운영되었다. 입원환자의 진찰 시 개인보호구의 착용은 거의 모든 의료기관에서 이루어졌다. 보건당국에서 SARS지정병원의 시설 등을 사전에 확인한 곳은 1곳(1/12, 8.3%)이였고, 14개 병원(14/15, 93.3%)에서는 보건당국에 의뢰한 검사결과를 통하 받지 못하였다. 결론 : 의료기관에서 SARS 환자용 격리실뿐만 아니라 기존의 격리실 설비 등이 미흡하였으며, 특히 중환자실 및 외래의 준비가 더욱 부족하였다. 보건당국의 의료기관에 대한 종합적인 지원이 부족하였고, 병원과의 원활한 연계가 잘 이루어지지 않았다. SARS 만이 아닌 격리를 필요로 하는 질환의 적절한 진료를 위해 향후 병원 시설의 정비와 정부차원에서의 보다 구체적이고 실질적인 대책마련이 필요하다. Background : There was an worldwide outbreak of the Severe Acute Respiratory Syndrome (SARS) originated from China in late 2002. During that period three cases of suspected SARS and 17 cases of probable SARS were reported in Korea. With the concerns about the reemergence of SARS-coV transmission, it is important to be prepared for any possibility. So, this study is aimed to analysis the past measures in managing SARS and propose the amendatory plans to improve the preparedness. Materials & Methods : Questionnaires were collected among clinicians with any experience in managing the probable or suspected SARS cases in Oct. 2003. 17 out of 22 hospitals responded to the questionnaire. The contents in the questionnaire were practical activities, personal equipments, response plans, isolation facilities in emergency centers, outpatient clinics, general wards and intensive care units, and relationship with the public health department. Results : The dedicated isolation rooms in emergency centers, outpatient clinics, general wards, and intensive care units were prepared in 9 (9/17, 52.9%), 5 (5/17, 29.4%), 15 (15/16, 93.7%), and 4 (4/16, 25.0%) hospitals, respectively. Except for one hospital that newly made negative pressure room for SARS, single or multi-bed rooms without airborne infection control were used in all the other hospitals. The personal precaution principles were kept quite well in general wards. Before the designation of SARS hospital by the public health department prior evalution to see if the hospital was suitable for managing SARS was conducted in only 1 (1/12, 8.3%) hospital. The results of laboratory diagnosis were reported back in 1 (1/15, 6.6%) hospital. Conclusions : The isolation facilities which can control airborne infection were almost deficient not only for SARS but also for other respiratory transmissible diseases. For the infection control of transmissible diseases including SARS, more investment is needed on medical facilities and comprehensive support from the public health department required.

한국인 직무 스트레스 측정도구의 개발 및 표준화

장세진,고상백,강동묵,김성아,강명근,이철갑,정진주,조정진,손미아,채창호,김정원,김정일,김형수,노상철,박재범,우종민,김수영,김정연,하미나,박정선,이경용,김형렬,공정옥,김인아,김정수,박준호,현숙정,손동국 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4

Background and Purposes: Over the past three decades, numerous studies performed in Korea have reported that job stress is a determinant risk factor for chronic diseases and work disability. Every society has its own culture and occupational climate particular to their organizations, and hence experiences different occupational stress. An occupational stress measurement tool therefore needs to be developed to estimate it objectively. The purpose of this study is to develop and standardize the Korean Occupational Stress Scale (KOSS) which is considered to be unique and specific occupational stressors in Korean employees. Subjects and Methods: Data were obtained from the National Study for Development and Standardization of Occupational Stress (NSDSOS Project: 2002-2004). A total of 12,631 employees from a nationwide sample proportional to the Korean Standard Industrial Classification and the Korean Standard Occupational Classification were administered. The KOSS was developed for 2 years (2002-2004). In the first year, we collected 255 items from the most popular job stress measurement tools such as JCQ, ERI, NIOSH and OSI, and 44 items derived from the a qualitative study (depth interview). Forty-three items of KOSS, in the second year, were retained for use in the final version of the KOSS by using Delphi and factor analysis. Items were scored using conventional 1-2-3-4 Likert scores for the response categories. Results: We developed eight subscales by using factor analysis and validation process: physical environment (3 items), job demand (8 items), insufficient job control (5 items), interpersonal conflict (4 items), job insecurity (6 items), organizational system (7 items), lack of reward (6 items), and occupational climate (4 items). Together they explained 50.0% of total variance. Internal consistency alpha scores were ranged from 0.51 to 0.82. Twenty-four items of the short form of the KOSS (KOSS-SF) were also developed to estimate job stress in the work setting. Because the levels of the subscales of occupational stress were gender dependent, gender-specific standard norms for both the 43-item full version and the 24-item short form using a quartile for the subscales of KOSS were presented. Conclusion: The results of this study suggest that KOSS might be an appropriate measurement scale to estimate occupational stress of Korean employees. Further and more detailed study needs to be conducted to improve the validity of this scale.

DSP 인버터에 의한 편측식 선형 유도전동기의 비간섭제어

우정인,신동률,조용길,노인배,정영일 東亞大學校 附設 情報通信硏究所 1998 情報通信硏究所論文誌 Vol.6 No.1

We proposed the speed control of the inverter-fed SLIM(Single-sided Linear Induction Motor) for conveyance system by the decoupled thrust control with DSP board. The voltage equations of SLIM are expressed on the suitable α-β axis by the proposed equivalent circuits, which can analyze the characteristics of the thrust and the normal force and so on. These control methods, which are the slip angular frequency control and the decoupling control for the thrust and normal force by analyzing these parameters can be successfully driven without interfering of each axis. These results exemplified the linear drive of SLIM with the reference value.

영구자석 동기발전기의 정주파수 정전압 출력에 관한 연구

우정인,조용길,황정원,송호신 동아대학교 공과대학 부설 한국자원개발연구소 1994 硏究報告 Vol.18 No.2

The permanent magnet machines have the advantages of high efficiency and power density, features very improtant for air-borne applications with their requiement of no external dc supply for rotor excitation, in addition, a very lower synchronous reactance thus making it a stiff source of power with a higher steady state and more transient capability than ist counterpart, the wound rotor type. In this paper, The permanent magnet synchronous machine is taken as a power source in the variable speed constant frequency power conversion scheme with converter-inverter system. All digital routines are excuted in the sampling time of 100 micro second by a DSP Board (TMS320c25) with A/D converters, which is detect the load current, capacitor current and DC link voltage at a sudden load change and to compute the predicted current. In one sampling interval, two optimal space voltage vectors as well as tow zero voltage vectors are employed so that the capacitor current may follow the reference. As a result, sinusoidal output constant voltage is obtained while swiching frequency is constant, and experimental results are presented, which shows the effectiveness of the proposed control method.

영구자석형 선형동기전동기의 위치제어를 위한 가변구조 벡터제어 시스템에 관한 연구

우정인,신동률,허태원,조광승 東亞大學校 2000 東亞論叢 Vol.37 No.-

OA, FA기기 등에 에너지 밀집도를 높일 수 있는 영구자석형 선형동기전동기(PMLSM)를 적용하고자하는 연구가 활발하게 진행되고 있다. PMLSM은 파라메터의 변동과 외부의 외란에 매우 민감하다. 이러한 PMLSM의 구동에 있어서 요구되는 것은 파라미터 변동과 부하 토크 외란에 견실하면서 빠른 응답속도를 가지는 제어기이다. 따라서, 본 논문에서는 PMLSM의 위치제어를 위한 가변구조 벡터제어시스템을 제안하고자 한다. 파라메터 변동과 외부외란의 변화에 강인한 가변구조 기법을 이용한 슬라이딩 모드제어의 타당성을 시뮬레이션을 통하여 검증하고자 한다.

교류여자방식 브러시리스 동기전동기의 공간벡터에 의한 토오크제어

우정인,정영일,노태균,조용길,신동률 東亞大學校 附設 情報通信硏究所 1997 情報通信硏究所論文誌 Vol.5 No.1

In the paper, a vector control method for a AC-excited BLSM(Brushless Synchronous Motor) is proposed. The BLSM has a feature that separate exciter is not needed for excitation. The proposed method is described in two parts as follow, one is the design of drive and the other is a modeling for its imlpementation. Rotor flux is estimated using inditect sensing method based on voltage equation in the synchronously rotation reference frame. And rotor position os calculated from rotor angular velocity and stator current. Through computer simulation results of this prorosed system, it is shown that the BLSM drive has a ability of precision torque control from the static and dynamic performances.

반송용 편측식 선형기기의 추력제어에 의한 특성해석

우정인,신동률,조용길,노태균 東亞大學校 大學院 1999 大學院論文集 Vol.24 No.-

본 논문에서는 PWM 인버터 구동 편측식 선형유도 전동기(이하 SLIM)의 공간백터 제어와 PI 제어를 통한 추력 제어를 행한다. 1차측 권선과 SLIM의 2차측 구조 사이에서 발생하는 공극길이의 떨림은 빠른 응답특성을 얻기위해서 최소화 되어야 한다. 먼저, SLIM의 전압방정식이 추력과 수직력 특성을 해석하기 위하여 d-q축 등가회로로서 나타내어진다. 또한, d-q축 등가회로의 모델링과 해석은 등가회로상에서 전류변동에 따른 강인한 과도 추력특성을 얻을 수 있다. 지령속도와 추력에 의한 SLIM의 직접구동 결과는 실험을 통해서 확인된다.

태양광 발전전력을 입력으로한 DC/DC 컨버터의 일정출력제어

조용길,허태원,신동률,조광승,우정인 東亞大學校 大學院 2000 大學院論文集 Vol.25 No.-

In this paper, it is proposed to constant power control of solar power system. The solar power system has disadvantage that low power density and variable power output. Proposed strategy is controled by DC/DC converter using phase shift PWM and I-PD type control applying type 1 digital system. The validity of proposed control strategy is verified from simulations results using PSIM.

슬라이딩 관측기를 이용한 유도전동기의 센서리스 제어

우정인,조용길,신동률,박지호 東亞大學校 附設 情報通信硏究所 1999 情報通信硏究所論文誌 Vol.7 No.1

In this paper, the robust vector control method of Induction Motor for the purpose of improving the system performance deterioration caused by parameter variations is proposed. The full order state observer estimates the stator surrent and the rotor flux by using the state prediction of state variables. And, the motor speed is estimated without without speed using the full order state observer. Also, the parameter variation is compensate by the Sliding Observer. By using this method, speed sinsorless control and current contol with no affection of the parameter variation can be obtained simultaneously.