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한지숙,박금수,조철호,고윤웅,윤진우,전상일 대한내과학회 1986 대한내과학회지 Vol.30 No.1
We retrospectively analyzed clinical and laboratory features of 58 patients with SLE for the survival and the factors which may have influenced the outcome from 1970 through 1983. The survival was calculated using the method of Merill and Shulman, taking the time of diagnosis and the onset of symptom as the starting point. We divided 58 patients with SLE into 2 groups, those whose survival was less than or equal to 2 years and those greater than 2 years, and compared clinical and laboratory features between them with particular emphasis on those factors which may have influenced the outcome. The results obtained as follows: 1) The estimated survival from diagnosis was 76.7% in 1 year, 62.3% in 2 years, 62.3% in 3 years, 59.6% in 4 years, 53.8% in 5 years and 50.6% in 10 years. The estimated survival from the onset of symptom was 65.5%, in 1 years, 59.54% in 2 years, 56.2% in 3 years, 52.2% in 4 years, 52.5% in 5 years, and 46.l% in 10 years. 2) There was a statisticaly significant difference in prognosis between 2 groups with regard to CNS involvement, serositis, and increased serum creatinine level(≥3.0mg/dl).
Preparation and in vivo evaluation of immediate-release pellet containing celecoxib solid dispersion
Park, Chun-Woong,Tung, Nguyen-Thach,Son, Dao-Danh,Kim, Ju-Young,Rhee, Yun-Seok,Kang, Seung-Yeop,Park, Shin-Ae,Hwang, Kyu-Mok,Oh, Tack-Oon,Ha, Jung-Myung,Chi, Sang-Cheol,Park, Eun-Seok 한국약제학회 2012 Journal of Pharmaceutical Investigation Vol.42 No.3
The aim of this study was to make use of small size of immediate-release (IR) pellet and amorphous state of solid dispersion to increase solubility of celecoxib (CLX), a drug in BCS class II. Primary, binary and ternary solid dispersions were developed to choose the final components for solid dispersion. A ternary novel solid dispersion was prepared by incorporation of one aqueous soluble polymer (povidone k17; PVP 17PF), Methacrylate copolymer-based gastric soluble polymer ($Eudragit^{(R)}$ EPO) and one pH modulator (MgO). This combination was effective to increase solubility in pH 1.2 up to 25-30 %. The mechanism of solubility enhancement was proven by DSC, PRXD, and FT-IR. Accordingly, hydrogen bonding or electrostatic interaction of CLX with PVP/$Eudragit^{(R)}$ EPO was the main cause to form the amorphous state of CLX within polymer cluster which increasing solubility of drug. Besides, MgO played an important role to change microenviroment for solid dispersion. Pellets containing this solid dispersion were prepared by extrusion and spheronization technique. Effect of four kinds of additive (calcium hydrogen phosphate dihydrate,$NaHCO_3$, crospovidone, and sodium dodecyl sulfate) on dissolution of CLX from IR pellet was also determined. Because of highest dissolution rate, formulation using sodium dodecyl sulfate was used for pharmacokinetics study. Solid dispersion-IR pellet formulation presented bioequivalence and lower variability in comparison with reference product.
Park, Chun-Woong,Kim, Ju-Young,Rhee, Yun-Seok,Oh, Tack-Oon,Ha, Jeong-Myung,Park, Eun-Seok Informa Healthcare 2012 Drug development and industrial pharmacy Vol.38 No.10
<P>The objective of this study was to achieve an optimal formulation of spray dried matrix type controlled-release (MTCR) microparticles containing tamsulosin hydrochloride for orally disintegrating tablet. To control the release rate of tamsulosin hydrochloride, Acrylate-methacrylate copolymer (Eudragit<SUP>®</SUP> L-100 or Eudragit<SUP>®</SUP> S-100) and ethylcellulose were employed on the composition of MTCR microparticles. Physicochemical properties of MTCR microparticles such as particle size and SEM were characterized. Pharmacokinetic parameters of tamsulosin hydrochloride were evaluated in the rats after oral administration. MTCR microparticles were spherical microparticles of around 10 µm diameter with a corrugated surface. ODTs containing MTCR microparticles were disintegrated within 30 s and MTCR microparticles were able to control the release rate of tamsulosin hydrochloride following Fickian diffusion mechanism. The <I>in vitro</I> release rates of tamsulosin hydrochloride from MTCR microparticles were proportional to the ratio of Acrylate-methacrylate copolymer to ethylcellulose. Moreover, MTCR microparticles retarded the <I>in vivo</I> release rate of tamsulosin hydrochloride without reducing the bioavailability. Our results suggest that MTCR microparticles may be potential oral dosage forms to control the release and to improve the bioavailability of tamsulosin hydrochloride.</P>
Park, Chun-Woong,Rhee, Yun-Seok,Go, Byung-Wook,Kam, Sung-Hoon,Lee, Kyu-Hyun,Lee, Hye-Suk,Park, Eun-Seok 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.9
A simple and sensitive HPLC method for the analysis of rabeprazole in plasma is described using UV detection in the presence of lorazepam as the internal standard. Rabeprazole and lorazepam were extracted with ethyl ether and quantitated using a reverse-phase $C_{18}$ column. The method was specific as there were no interfering peaks in the human plasma eluting at the retention times of rabeprazole and lorazepam. The method was fully validated in human plasma for the concentration range of 20.0-1000.0 ng/ml. The correlation coefficients were greater than 0.999. Extraction recoveries were 72.3% for the drug and 79.1% for the internal standard. The method was simple, reliable, and accurate for the quantitation of rabeprazole in human plasma. The same plasma samples, which were collected in healthy male volunteers administered a 20 mg tablet of $Pariet^{(R)}$, were analyzed by HPLC and LC/MS/MS. As a result of that, there was no significant difference between pharmacokinetic parameters. The suitability of HPLC method for pharmacokinetic studies was verified by determining the relevant pharmacokinetic parameters.
Scaling Down Characteristics of Vertical Channel Phase Change Random Access Memory (VPCRAM)
Chun Woong Park,Chongdae Park,Woo Young Choi,Dongsun Seo,Cherlhyun Jeong,Il Hwan Cho 대한전자공학회 2014 Journal of semiconductor technology and science Vol.14 No.1
In this paper, scaling down characteristics of vertical channel phase random access memory are investigated with device simulator and finite element analysis simulator. Electrical properties of select transistor are obtained by device simulator and those of phase change material are obtained by finite element analysis simulator. From the fusion of both data, scaling properties of vertical channel phase change random access memory (VPCRAM) are considered with ITRS roadmap. Simulation of set reset current are carried out to analyze the feasibility of scaling down and compared with values in ITRS roadmap. Simulation results show that width and length ratio of the phase change material (PCM) is key parameter of scaling down in VPCRAM. Thermal simulation results provide the design guideline of VPCRAM. Optimization of phase change material in VPCRAM can be achieved by oxide sidewall process optimization.
Park, Woong-Sup,Lee, Chi-Seung,Chun, Min-Sung,Kim, Myung-Hyun,Lee, Jae-Myung Elsevier 2011 Materials science & engineering. properties, micro Vol.528 No.25
<P><B>Highlights</B></P><P>• A modified constitutive model for the behaviors of cryogenic material is presented. • A novel material parameter identification method is suggested. • A damage model is applied to the proposed model for a description of material failure. • Test results suggested in a previous study are simulated using the proposed method.</P> <P><B>Abstract</B></P><P>Austenitic stainless steel (ASS), aluminum alloy, and nickel steel alloy are strong temperature- and strain-rate-dependent materials. They exhibit very complicated nonlinear behaviors during plastic deformation. While the typical characteristics of their nonlinear behaviors, including second hardening and strain-rate sensitivity, can be easily identified through experimental investigation, a useful numerical model is not available. The unavailability of such a model is because of the wide variance in the nonlinearities of the materials. In the present study, a unified constitutive model is proposed for representing the temperature- and strain-rate-dependent material nonlinearities in ASS and aluminum and nickel steel alloys. Based on the Bodner model, a strain-hardening function was developed for expressing second hardening as well as strain-rate sensitivity. To provide unified material parameters for the hardening exponent and strain-rate control, a new type of material parameter identification method is proposed. Based on the proposed constitutive model, in conjunction with both a damage model and the material parameters, a verification study is conducted. The experimental results of both Park et al. <ce:cross-ref refid='bib0005'>[1]</ce:cross-ref> and Tomita and Iwamoto <ce:cross-ref refid='bib0010'>[2]</ce:cross-ref>, which are valid within a temperature range of 80–345K and a strain-rate range of 0.0005–500/s, are compared with the numerical results of this study.</P>
The Synthesis and Photocatalytic activity of Carbon Nanotube-mixed TiO<sub>2</sub> Nanotubes
Park, Chun Woong,Kim, Young Do,Sekino, Tohru,Kim, Se Hoon The Korean Powder Metallurgy Institute 2017 한국분말재료학회지 (KPMI) Vol.24 No.4
The formation mechanism and photocatalytic properties of a multiwalled carbon nanotube (MWCNT)/$TiO_2$-based nanotube (TNTs) composite are investigated. The CNT/TNT composite is synthesized via a solution chemical route. It is confirmed that this 1-D nanotube composite has a core-shell nanotubular structure, where the TNT surrounds the CNT core. The photocatalytic activity investigated based on the methylene blue degradation test is superior to that of with pure TNT. The CNTs play two important roles in enhancing the photocatalytic activity. One is to act as a template to form the core-shell structure while titanate nanosheets are converted into nanotubes. The other is to act as an electron reservoir that facilitates charge separation and electron transfer from the TNT, thus decreasing the electron-hole recombination efficiency.
Chun, Young Jin,Kim, Dae In,Park, Kee Woong,Jeong, Soon-Chun,Park, Sangkyu,Back, Kyoungwhan,Kim, Chang-Gi The Ecological Society of Korea 2013 Journal of Ecology and Environment Vol.36 No.1
The expression of transgenic traits in genetically modified crops is sometimes associated with decreases in crop performance or fitness. These decreases in performance or fitness of transgenic plants in unfavourable conditions may provide valuable information about the ecological consequences of transgene escape. In a glasshouse trial, we tested the cost associated with resistance to herbicides by comparing the growth, yield, and competitive ability of transgenic rice with its parental non-transgenic line. This new line was developed for constitutive overexpression of protoporphyrinogen oxidase (PPO) to increase resistance to herbicides. We evaluated nine agronomic traits of transgenic and non-transgenic rice grown in a replacement series design over four densities. Competitive ability was also assessed between transgenic and non-transgenic plants by analyzing their relative yields based on biomass and seed weight data. Our results indicated that non-transgenic plants showed greater performance than did the transgenic plants when those genotypes were grown in mixtures. The non-transgenic rice plants exhibited superior competitive ability at certain combinations of planting densities and genotype proportions. These results suggest that PPO-herbicide resistance incurs some costs in plant performance and competitive ability.
Park, Chun Woong,Choi, Woo Young,Lee, Jong-Ho,Cho, Il Hwan Institute of Physics 2013 Semiconductor science and technology Vol.28 No.11
<P>Ambipolar characteristics of tunneling FETs have been improved by introducing a novel structure which contains dielectric sidewall in the gate region. In the ambipolar operation mode, gate field effect on intrinsic-drain junction region can be reduced with dielectric sidewall. As a result, ambipolar state tunneling probability is decreased at the intrinsic-drain junction. Since the sidewall region is located near the drain region, tunneling probability of source-intrinsic region is not affected by dielectric sidewall. This asymmetric characteristics means only ambipolar current of tunneling FETs can be prohibited by dielectric sidewall. Reduction of ambipolar characteristic of proposed structure has been evaluated with dimension and location of dielectric sidewall. Quantitative analysis of ambipolar characteristics is also investigated with tunneling.</P>