Novel Repair Technique for Articular Cartilage Defect using a Fibrin and Hyaluronic acid Mixture

( Jae Deog Jang ),( Young Seok Moon ),( Yong Sik Kim ),( Nam Yong Choi ),( Hyun Su Mok1 ),( Young Ju Kim1 ),( Asode Ananthram Shetty ),( Seok Jung Kim ) 한국조직공학·재생의학회 2013 조직공학과 재생의학 Vol.10 No.1

We evaluated the cartilage repair potential of a hyaluronic acid and fibrin mixture when transplanted into cartilage defects. Circular, articular, cartilage defects 4-mm in diameter were made in the trochlear region in 21 New Zealand white rabbits divided into three groups. The seven rabbits in the control group underwent microfracture (M group), the seven rabbits in the experimental group underwent microfracture with subsequent injection of hyaluronic acid mixed with fibrin (MH group), and seven rabbits in the other experimental group underwent microfracture followed by injection of bone marrow concentrate and hyaluronic acid mixed with fibrin (MBH group). At week 12 following surgery, the cartilage was observed and histologically compared in the three groups. The surface of the newly generated cartilage was very smooth and even, and we noticed that the entire area was completely regenerated in both experimental groups. The control group showed incomplete and irregular cartilage formation in the defect. In histologic scoring, comparison of the MBH group (M= 2.333) and the M group (M= 9.000) differed significantly (P= 0.046). Therefore, injection of a mixture of bone marrow concentrate, hyaluronic acid and fibrin to treat articular cartilage defects of the knee appears to be an effective method of cartilage regeneration.

모 제약회사 근로자들의 직업성 천식 유병률과 약제 분말 노출수준

오성수,최용휴,김은아,이영목,장재길,유장진,박승현,김태균,정수영,김규상,강성규 大韓産業醫學會 2006 대한직업환경의학회지 Vol.18 No.2

목적: 제약회사에서 직업상 천식의 유병 규모를 파악하고 작업공정에 대한 작업환경 측정을 통해 제약회사의 약제 분말에 대한 노출수준을 평가하고자 하였다. 방법: 제약회사에서 약제 분말에 노출되는 근로자를 대상으로 천식을 선별하기 위하여 설문조사 및 진찰, 혈액검사, 폐기능 검사 그리고 피부단자시험을 실시하였고, 각 부서별 공정에 따라서 총분진과 항생제 또는 효소제 분말에 대한 작업환경 측정을 실시하였다. 직업상 천식이 의심되는 근로자에 대하여 기관지과민성에 대한 검사(메타콜린을 이용한 비특이 기관지유발시험)와 약제 분말 기관지유발시험을 실시하여 확진하였다. 결과: 설문조사 및 진찰에서 작업 관련 천식 증상이 있는 근로자는 11명(34.4%)이었고, 약제 분말을 이용한 피부단자시험에서 1+ 이상 반응을 보인 근로자 10명(31.2%)이었다. 비특이 기관지유발시험 결과 8명(25.0%)이 양성(PC20 ≤16 mg/ml)이었다. 약제 분말 기관지유발시험을 통해 직업상 천식으로 확진된 근로자는 5명(15.6%)이었다. 작업환경 측정에서 원료를 충진하거나 투입하는 작업 그리고 정립작업에서 약제 분말에 대한 노출이 많았다. 결론: 제약회사에서 직업상 천식은 주로 제조공정 중 약제 분말에 노출된 근로자에서 발생하여, 증상 및 직업성 천식의 유병률이 높았다. 따라서 원료를 충진 또는 투입하는 작업과 정립작업 등 제조과적에서 약제 분말 노출을 줄이기 위한 세심한 주의가 필요하여, 약제 분말을 취급하는 근로자에 대해서는 천식 증상 조사뿐 아니라 정기적으로 피부단자시험, 비특이 기관지유발시험 등을 실시하여야 할 것이다. Objectives: After the investigation of one worker with occupational asthma, we surveyed the preva- lence of occupational asthma and the exposure level of pharmaceutical dust of 32 workers in a pharmaceutical company. Methods: Thirty-two of the 90 employees participated in the survey which consisted of questionnaire, blood sampling, spirometry and skin prick tests with 8 common allergens as well as 9 antibiotics and 2 enzymes. Various indices of the working environment were also measured. Subjects who had a symptom suggestive of work-related asthma or positive skin prick test were further investigated by PC20 methacholine. Nine subjects who had a PC20 result of 16 mg/ml or less (n=7) or had work-related symptoms and positive skin prick test (n=2) were referred to undergo a specific bronchial provocation test to phar- maceutical dust in an academic allergic disease center. Results: Eleven of 32 workers (34.4%) had a work-related symptom suggestive of occupational asthma. Ten (31.2%) showed positive skin prick test. 8 (25.0%) had a PC20 result of 16 mg/ml or less (indicative of significant bronchial hyperresponsiveness), and 5 (15.6%) had a positive result on the specific bronchial provocation test. Exposure levels of stuffing, input of raw materials and screening process were relatively high. Conclusions: This survey showed that pharmaceutical workers have an increased risk of occupational asthma. Although pharmaceutical factories maintain a relatively good working environment, careful control of respiratory tract exposures, especially during stuffing, input or raw materials and screening process, is important to prevent occupational asthma. Pharmaceutical workers need to undergo regular skin prick and methacholine bronchial provocation tests, as well as asthmatic symptom survey, to ensure the early detection and prevention of occupational asthma.

바닥판의 모드질량산정에 관한 연구

김장윤,황재승,홍성목 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.2(구조계)

Modal mass is essential to analyze structural response under disturbance and to design the vibration control devices used to enhance the serviceability of structure. Modal mass differs from that of analytic mathematical model due to the error generated from analytical assumption and construction. Therefore, the objective of this study is to proposed to calculate the modal mass of structure based on the system identification. And the proposed method is applied to two examples, the single DOF system and the slab of apartment.

ZSM-5제올라이트 합성에 관한 연구

홍장후,정택서,강경묵,김운겸 서울産業大學校 1998 논문집 Vol.47 No.1

A pentasil zeolite. ZSM-5 was succesfully synthesized at low temperature and atmospheric pressure. The experinments were carried out in four different methods 1, 2 and 3 depending on the concentrations of water, organic template. TPABr (tetrapropy-lammonium bromide) and the presence or absence of seed, the overall molar composition used in this study was 7.83 Na₂O-0.25 Al₂O₃-100SiO₂-xTPABr-yH₂o where x is 1 and 3 mol, and y is 3000mol, 3500mol, and 4000mol. 2³factorial experiments were performed with the results of kinetics studies Na₂O, TPABr and H₂O as main factors, The result showed that the concentration of H₂O is the most important.

Mesoporous Titanium Oxo-Phosphate에 의한 살균제 Chlorothalonil의 광분해

최충렬,김병하,이병묵,최정,이인구,김장억 한국환경농학회 2003 한국환경농학회지 Vol.22 No.4

Mesoporous titanium oxo-phosphate(Ti-MCM)은 기존의 유기성 오염물질의 광분해제로 널리 이용되고 있는 TiO₂에 비해 표면적이 매우 넓은 장점이 있다. 그러므로 본 연구에서는 Ti-MCM에 의한 chlorothalonil의 흡착 및 광분해 특성을 TiO₂와 비교하였다. 합성된 Ti-MCM은 hexagonal 형태로 d-spacing이 4.1 ㎚이었다. 암조건에서 TiO₂에 의한 chlorothalonil의 흡착은 거의 일어나지 않았으나, Ti-MCM에 의한 흡착은 반응 1시간까지 28%로 급격히 증가하여 흡착평형에 도달하였다. UV조사 하에서 반응 9시간 후의 TiO₂와 Ti-MCM에 의한 chlorothalonil의 제거율은 각각 88%와 100%로 나타났다. 그러나 정치상태에서의 광분해 속도는 chlorothalonil과 Ti-MCM사이의 낮은 접촉에 의한 반응성의 감소로 느린 경향을 나타내었다. 또한 Ti-MCM에 의한 chlorothalonil의 분해효율은 용액의 초기 농도가 낮을수록, pH 7까지 반응용액의 pH가 높을수록 증가하였다. Titanium mesoporous materials have received increasing attention as a new photocatalyst in the field for photocatalytic degradation of organic compounds, The photocatalytic degradation of chlorothlonil by mesoporous titanium oxt-phosphate (Ti-MCM) was investigated in aqueous suspension for comparison with TiO₂ (Degussa, P25) using as an effective photocatalyst of organic pollutants. Mesoporous form of titanium phosphate has been prepared by reaction of sulfuric acid and titanium isopropoxide in the presence of n-hexadecy(trimethylammonium bromide. The XRD patterns of Ti-MCM are hexagonal phases with d-spacings of 4.1 nm. Its adsorption isotherm for chlorothalonil reached at reaction equilibrium within 60 min under dark condition with 28% degradation efficiency. The degradation ratio of chlorothalonil after 9 hours under the UV radiation condition (254 nm) exhibited 100% by TI-MCM and 88% by TiO₂. However, these degradation kinetics in static state showed a slow tendency compared to that of stirred state because of a low contact between titanium matrices and chlorothalonil. Also, degradation efficiency of chlorothalonil was increased with decreasing initial concentration and with increasing pH of solution. As results of this study, it was clear that mesoporous titanium oxo-phosphate with high surface area and crystallinity could be used to photocatalytic degradation of various organic pollutants.

Current measurement and control method of HVAC integration systems through DC link single current sensor

Kim, Hyeong-Jin,Kim, Jae-Man,Kim, Jang-Mok The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.5

The HVAC (Heating, Ventilation & Air Conditioning) system of an electric vehicle consists of an electric compressor including PMSM (Permanent Magnet Synchronous Machine) and a PTC (Positive Temperature Coefficient) heater. Each of these systems is configured independently. This paper proposes an HVAC system that integrates the compressor control system and the heater control system. The system shares an input noise filter, DC link capacitors, and a controller that includes an MCU. In addition, several of the current sensors in each system are replaced with a single current sensor in the DC link. In a typical cooling sequence that uses only a compressor, the integration system can use conventional single shunt control to restore the three-phase current and to control the speed of the compressor. However, the system cannot be controlled by the conventional method of only measuring current in the effective vector in operation, where the compressor and the heater are used together to increase heating performance. The proposed method measures the DC link current in the zero vector as well as the effective vector, and separates the compressor current and the heater current. Therefore, the compressor and the heater can be simultaneously controlled by one current sensor even in operation using the compressor and the heater. The effectiveness of the proposed system and control method are verified through experiments.

Large anomalous Hall current induced by topological nodal lines in a ferromagnetic van der Waals semimetal

Kim, Kyoo,Seo, Junho,Lee, Eunwoo,Ko, K.-T.,Kim, B. S.,Jang, Bo Gyu,Ok, Jong Mok,Lee, Jinwon,Jo, Youn Jung,Kang, Woun,Shim, Ji Hoon,Kim, C.,Yeom, Han Woong,Il Min, Byung,Yang, Bohm-Jung,Kim, Jun Sung Springer Science and Business Media LLC 2018 NATURE MATERIALS Vol.17 No.9

Ultra Precise Position Estimation of Servomotor using Analog Quadrature Encoder

Kim Ju-Chan,Hwang Seon-Hwan,Kim Jang-Mok,Kim Cheul-U,Choi Cheol The Korean Institute of Power Electronics 2006 JOURNAL OF POWER ELECTRONICS Vol.6 No.2

This paper describes the ultra precise position estimation of a servomotor using a sinusoidal encoder based on Arcsine Interpolation Method for the cost reduction of circuit design. The amplitude and offset errors of the sinusoidal encoder output signals, from the encoder itself and analog signal processing procedures, are effectively compensated and on-line tuned by utilizing a low cost programmable differential amplifier without any special expensive equipment. For a theoretical evaluation of the practical resolution of this system, the relationship between the amplitude of ADC(Analog to Digital Converter) input signal errors and the anticipated resolution is also addressed. The performance of the proposed method is verified by comparing it with speed control characteristics of the servomotor driving system using a digital incremental 50,000ppr encoder in the experiments.

Maximum Torque Operation of Interior Permanent Magnet Synchronous Motor in Flux-Weakening Control

Jang-Mok Kim,Hong-Woo Rhew,Jung-Lock Kwon,Seung-Ki Sul 한국정보과학회 1998 Journal of Electrical Engineering and Information Vol.3 No.1

A new flux-weakening scheme for an Interior Permanent Magnet Synchronous Motor (IPMSM) is proposed. This control scheme enables the maximum torque operation for the fast acceleration in the constant power region according to the current and voltage limit condition. Especially the dynamic performance of the braking in the flux-weakening region is improved with the compensation of the stator resistance. Also since the onset of the flux weakening operation is adjusted according to the load conditions, the machine parameters. and whether motoring or braking region. the stable and precise transition operation into or out of the flux weakening region can be achieved. The effectiveness of the proposed scheme is verified through experiments with an IPMSM drive system.

A Control Method for Power-Assist Devices using a BLDC Motor for Manual Wheelchairs

Kim, Dong-Youn,Kim, Yong-Hyu,Kim, Kwang-Sik,Kim, Jang-Mok The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

This paper proposes a new operation and control strategy for Power-Assisted Wheelchairs (PAW) using one brushless DC (BLDC) motor. The conventional electrical wheelchairs are too heavy and large for one person to move because they have two electric motor wheels. On the other hand, the proposed PAW system has a small volume and is easy to move due to the presence of a single wheel motor. Unlike the conventional electric wheelchairs, this structure for a PAW does not have a control joystick to reduce its weight and volume. To control the wheelchair without a joystick, a special control system and algorithm are needed for proper operation of the wheelchair. In the proposed PAW system uses only one sensor to detect the acceleration and direction of PAW's movement. By using this sensor, speed control can be achieved. With a speed control system, there are three kinds of operations that can be done on the speed of a PAW: the increment of PAW speed by summing external force, the decrement of PAW speed by subtracting external force, and emergency breaking by evaluating the time duration of external force. The validity of the proposed algorithm is verified through experimental results.