Ab initio MO Study on N-Nitrosoazetidine-2-carboxylic Acid

Cho, Kwang-Hwi Korean Chemical Society 2005 Bulletin of the Korean Chemical Society Vol.26 No.1

A Numerical Analysis on the Heat Transfer Characteristic According to a Number of Distributed Tube Row of Fin-and-Tube Heat Exchanger in Hybrid Solar Collector

Choi Hwi-Ung(최휘웅),Fatkhur Rokhman(파쿠르 로커만),Lyu Nam-Jin(류남진),Son Chang-Hyo(손창효),Yoon Jung-In(윤정인),Choi Kwang-Hwan(최광환) 한국태양에너지학회 2016 한국태양에너지학회 학술대회논문집 Vol.2016 No.10

Tautomerism of Cytosine on Silver, Gold, and Copper: Raman Spectroscopy and Density Functional Theory Calculation Study

Cho, Kwang-Hwi,Joo, Sang-Woo Korean Chemical Society 2008 Bulletin of the Korean Chemical Society Vol.29 No.1

Tautomerism of pyrimidine base cytosine has been comparatively examined on nanoparticle and roughened plate surfaces of silver, gold, and copper by surface-enhanced Raman scattering (SERS). The SERS spectrum was found to be different depending on the metals and their substrate conditions suggesting the dissimilar population of various tautomers of cytosine on the surfaces. The ab initio calculations were performed at the levels of B3LYP, HF, and MP2 levels of theory with the LanL2DZ basis set to estimate the energetic stability of the tautomers with the metal complexes as well as the gas phase state. The amino group and N3-coordinated tautomer was predicted to be more favorable for bonding to Au, whereas the hydroxyl and N1-coordinated zwitter ionic form is most stable with Ag and Cu as a bidentate form from the DFT calculation. The binding energy with the Ag atom is calculated to be smaller than those with the Au and Cu atoms in line with the temperature-dependent SERS spectra of cytosine.

Effects of structurally stabilized EGF and bFGF on wound healing in type I and type II diabetic mice

Choi, Seong Mi,Lee, Kyoung-Mi,Kim, Hyun Jung,Park, Ik Kyu,Kang, Hwi Ju,Shin, Hang-Cheol,Baek, Dawoon,Choi, Yoorim,Park, Kwang Hwan,Lee, Jin Woo Elsevier 2018 Acta Biomaterialia: structure-property-function re Vol.66 No.-

<P><B>Abstract</B></P> <P>Diabetes mellitus comprises a multiple metabolic disorder that affects millions of people worldwide and consequentially poses challenges for clinical treatment. Among the various complications, diabetic ulcer constitutes the most prevalent associated disorder and leads to delayed wound healing. To enhance wound healing capacity, we developed structurally stabilized epidermal growth factor (ST-EGF) and basic fibroblast growth factor (ST-bFGF) to overcome limitations of commercially available EGF (CA-EGF) and bFGF (CA-bFGF), such as short half-life and loss of activity after loading onto a matrix. Neither ST-EGF nor ST-bFGF was toxic, and both were more stable at higher temperatures than CA-EGF and CA-bFGF. We loaded ST-EGF and ST-bFGF onto a hyaluronate-collagen dressing (HCD) matrix, a biocompatible carrier, and tested the effectiveness of this system in promoting wound healing in a mouse model of diabetes. Wounds treated with HCD matrix loaded with 0.3 μg/cm<SUP>2</SUP> ST-EGF or 1 μg/cm<SUP>2</SUP> ST-bFGF showed a more rapid rate of tissue repair as compared to the control in type I and II diabetes models. Our results indicate that an HDC matrix loaded with 0.3 μg/cm<SUP>2</SUP> ST-EGF or 1 μg/cm<SUP>2</SUP> ST-bFGF can promote wound healing in diabetic ulcers and are suitable for use in wound dressings owing to their stability for long periods at room temperature.</P> <P><B>Statement of Significance</B></P> <P>Various types of dressing materials loaded with growth factors, such as VEGF, EGF, and bFGF, are widely used to effect wound repair. However, such growth factor-loaded materials have several limitations for use as therapeutic agents in healing-impaired diabetic wounds. To overcome these limitations, we have developed new materials containing structurally stabilized EGF (ST-EGF) and bFGF (ST-bFGF). To confirm the wound healing capacity of newly developed materials (ST-EGF and ST-bFGF-loaded hyaluronate-collagen dressing [HCD] matrix), we applied these matrices in type I and type II diabetic wounds. Notably, these matrices were able to accelerate wound healing including re-epithelialization, neovascularization, and collagen deposition. Consequentially, these ST-EGF and ST-bFGF-loaded HCD matrix may be used as future therapeutic agents in patients with diabetic foot ulcers.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

적외선 센서를 이용한 다종가스 계측기 구현

최낙진,류정호,강봉휘,이광우,이덕동 경북대학교 센서기술연구소 1997 센서技術學術大會論文集 Vol.8 No.1

The semiconductor gas sensors with a tin oxide as the raw material have been generally used to detect gases in the principle of electrical conductivity variation. However, it was difficult to design the gas detection system due to the non-selectivity, the non-stability and the influence of temperature, humidity etc. Therefore, it was proposed NDIR(non-dispersive infrared) method using pyroelectric infrared sensor to overcome the disadvantage of the semiconductor gas sensors. This method has been recently used to detect various gases in industrial parts. It has the advantages of selectivity, stability and responsibility. The gases used in this paper were CO_(2)(carbon dioxide) and HC(hydrocarbon) series. The system was designed with the Intel MCU i8097BH microprocessor. Main topics were to remove interference effect for other gases and to minimize influence for ambient circumstance by using the software and the hardware techniques.

등방성 이종재료 내의 Ⅴ-노치 균열에 대한 응력강도계수 결정에 관한 연구

조상봉,정휘원,김진광 경남대학교 신소재연구소 1999 論文集 Vol.11 No.-

접합계면 V-노치 균열 문제는 고유치와 고유벡터 문제로 수식화할 수 있다. V-노치 균열첨단에서 응력특이성을 가지는 고유치가 존재한다. 상반일 등고선 적분법(RWCIM)은 고유치와 관련된 고유벡터의 계수를 구하는 한 가지의 방법이다. 상반일 등고선 적분법을 이용하여 접합계면 균열의 응력확대계수를 구하도록 시도하였다. 상반일 등고선 적분법으로 구한 응력확대계수와 경계요소법과 변위외삽법을 이용하여 구한 결과를 비교하였다. An inteiface 17-notched crack problem can be formulated as a eigenvalue problem. there are the eigenvalues which give stress singularities at the V-notched crack tip. The RWCIM is a method of calculating the eigenvector coefficients associated with eigenvalues. Obtaining the stress intensity factors for an interface crack in dissimilar materials was examined by the RWCIM. The results obtained for stress intensity factors using RWCIM were compared with those obtained by using the displacement extrapolation method and the BEM.

고성능 유도 전동기를 위한 퍼지 속도 제어기

권병휘,全光鎬,崔秉淑,鄭雨均 홍익대학교 산업기술연구소 1997 産業技術 Vol.7 No.-

In this dissertation a novel speed control system that implements the fuzzy logic controller(FLC) is proposed. The proposed FLC used the speed error its rate of change, and the drive current as three fuzzy variables. The real command output current is chosen by the defuzzification of fuzzy output extracted from the fuzzy control rules. The flex and the torque of the induction motor are estimated using the dynamic model with an excellent dynamic response over a wide speed range and with the rotor flux field-oriented scheme of the decoupling characteristics The performance of this control system is substantiated by computer simulations.

임상검체에서 분리된 Acinetobacter의 항균제 내성(1991-1997)

송호연,조성란,김휘준,고광균 대한화학요법학회 1998 대한화학요법학회지 Vol.16 No.2

목적 : 최근 원내감염의 중요 원인균으로 대두되고 있는 A. baumannii의 발생 양상 및 병동 별 항균제 내성의 변화 추이를 조사하여 치료시 적절한 항균제를 선택하는데 도움이 되는 자료를 제공하고자 하였다. 방법 : 1991년 1월부터 1997년 12월까지 7년간 한 대학병원의 입원환자로부터 분리 동정된 Acinetobacter의 균종별, 계절별, 임상검체별 분리양상을 조사하고 디스코 확산법에 의한 항균제 내성의 변화 추이 및 중환자실과 일반 병실에서의 항균제 내성 차이를 분석하였다. 결과 : 분리 동정된 Acinetobacter 4,128균주 중 91.5%가 A. baumannii로 연도에 따라 발생율이 증가하는 양상을 보였고 여름철이 호흡기계 검체로부터 가장 많이 분리되었다. A. baumannii로 imipenem과 ciprofloxacin을 제외한 대부분의 항균제에 높은 내성을 나타내었고 많은 항균제에서 내성율이 연도에 따라 점차 증가하였다. 3,777균주의 A. baumannii 중 45.2%가 중환자실 및 신생아실에서 분리되었는데 이는 중환자실 입원 환자수가 일반병동보다 훨씬 적은 것을 고려할 때 매우 높은 발병율임을 알 수 있었다. 또한 중환자실에서 분리된 균주의 다제내성율은 일반병동에서 분리된 균주보다 훨씬 높았다. 결론 : 중환자실에는 일반병동에 비해 다제내성율이 훨씬 높아 감염에 대한 저항력이 저하된 중증환자들의 생명을 끊임없이 위협하고 있는데 이런 다제내성균의 출현 및 원내감염을 줄이기 우한 중환자실만의 집중적인 대책이 수립되어야 할 것으로 사료된다. Background : Acinetobacter baumannii is recognized as an important causative agent of nosocomial infection. Therefore, it is important to understand the changing patterns of antimicrobial resistance to guide for antimicrobial therapy of infection by A. baumannii. So we compared the rate of miltidrug-resistance between ICU and general wards and we analyzed the trends of antimicrobial resistan changes during the past seven years. Methods : Acinetobacter isolated from 1991 to 1997 at a tertiary hospital were classified according to species, wards, seasons and clinical specimens. We tested the antimicrobial resistance by the standard disk diffusion method and compared the multidrug-resistant patterns of A. baumannii isolated from ICU with those from general wards. Results : Among the 4,128 Acinetobacter isolates, A. baymannii was the most common species(91.5%), followed by A. Iwoff??(8.5%), Acinetobacter species were isolated mainly from respiratory specimens during the summer. A. baumannii showed high resistance rates to most of antibiotics except imipenem and ciprofloxacin and resistance rates were increasing year after year. Forty-five percent of A. baumannii was isolated from ICU and neonate room, it showed higher multidrug-resistance rate than those generated from general wards. Conclusion : Multidrug-resistant. A. baumannii was predominant in ICU than general wards. It will contribute to increase of mortality due to nosocomial infection in severly ill patients. In order to reduce occuranc of multidrug-resistant isolates and noscomial infection in ICU, it is necessary to organize the intensive surveillance system in ICU.

자폐아동의 기본운동교육프로그램 참가가 지각운동능력발달에 미치는 영향

이창섭,이명휘,현광석,이창규,조병준 한국특수체육학회 2003 한국특수체육학회지 Vol.11 No.1

The purpose of this study was to examine how the program of basic movement can influence and change the capability of perceptive movement among the children with autism. Four subjects (age3-5) participated in the specially designed program, three times a week for four weeks. For the purpose of this study, Oseretsky's Motor Development Test and PMDT(perception-Movement development Diagnosis Test) were used. The results were as follows; First, the upper limb performance of the children with autism showed significant changes by the movement education program. Second, along with the development of upper limb performance, the motor development index of the children with autism showed significant changes. Third, the Oseretsky spectrum of movement, of the children with autism responded to the order of mono-movement capability, hand-movement and co-operative movement. Fourth, the movement education program was more effective for the children with autism than for the retarded children in view of motor development capability. Fifth, the movement education program was more effective for the child with autism of multi-movement characteristics.

복합형 태양열 가열기에서 열매체 단일운전에 따른 기기성능 평가

최동원(Choi Dong-Won),최휘웅(Hwi-Ung Choi),김영복(Young-Bok Kim),윤정인(Jung-In Yoon),손창효(Chang-Hyo Son),최광환(Kwang-Hwan Choi) 한국태양에너지학회 2014 한국태양에너지학회 학술대회논문집 Vol.2014 No.3