• Journal of Pharmaceutical Investigation
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• 제34권3호
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• pp.161-168
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• 2004

5-Fluorouracil (5-FU) is an antimetabolite anticancer agent active against many types of solid tumors. Tegafur (TF), a prodrug of 5-FU, is frequently used in combination with uracil as dihydropyrimidine dehydrogenase (DPD) inhibitory fluoropyrimidine. We studied the stability of 5-FU and TF in biological fluids of rats and determined their bioavailability (BA) and excretion into bile, and urine. The drug concentrations were analyzed by an HPLC method. At room temperature, there was a 14-30% decrease in the concentration of 5-FU and TF in bile, urine, and plasma specimen at 10 and $100\;{\mu}g/ml$ over 240 min. No significant difference was noted among the sample types or between two different concentrations of 10 and $100{\mu}g/ml$. The decrease in drug concentration was significantly less in samples kept on ice (6-12%) for both drugs. These data indicate that biological fluid samples containing 5-FU or TF in plasma, urine, or bile should be placed on ice during the sample collection. Following these storage guidelines, samples were collected after administration 50 mg/kg of each drug via i.v. or oral route. BA was 1.5 folds greater for TF (60%) than that of 5-FU (42%). Approximately 0.52 and 3.3% of the i.v. doses of 5-FU and TF was excreted into bile, respectively. Renal clearance of 5-FU was about 16% of its total body clearance. These results suggest that instability of 5-FU and TF in biological fluids should be considered in pharmacokinetic or pharmacogenomic studies.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제49권1호
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• pp.13-20
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• 2023

Objectives: Ultra-wide implants may be used as a replacement if existing implants fail. This study was conducted to evaluate the factors influencing the prognosis and failure of ultra-wide implants. Patients and Methods: This study evaluated whether sex, age, site, diameter, length, additional surgery, implant stability (primary and secondary), and reason for ultra-wide implant placement affect the 5-year survival and success rates and marginal bone loss (MBL) of ultra-wide implants. Seventy-eight ultra-wide implants that were placed in 71 patients (39 males and 32 females) from 2008 to 2010 were studied. One-way ANOVA analysis was conducted to evaluate the statistical significance of MBL according to the patient's sex, implant site, and diameter. Independent sample t-tests were used to determine the statistical significance of MBL analysis which was used to determine the significance of the 5-year success and survival rates related to the variables. One-way ANOVA was conducted to evaluate the statistical significance of sex, implantation site, diameter, and MBL. Independent sample t-tests were used to evaluate the correlation between implantability and MBL for implantation reasons, while additional surgery, length, and Kaplan-Meier analysis were used to evaluate 5-year survival and success rates. Results: The mean age of patients was 54.2 years with a survival rate of 92.3% and a success rate of 83.3% over a mean 97.8-month period of observation. MBL averaged 0.2 mm after one year of prosthetic function loading and 0.54 mm at the time of final observation. Success rates correlated with primary stability (P=0.045), survival rates correlated with secondary stability (P=0.036), and MBL did not correlate with any variables. Conclusion: Ultra-wide implants can be used to achieve secure initial fixation in the maxillary and mandibular molar regions with poor bone quality or for alternative purposes in cases of previous implant failure.

• 한국의류학회지
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• 제25권3호
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• pp.560-568
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• 2001

The aim of the present study was to measure intra-individual consistency in clothing and fabric evaluation and to examine its relation to the ratings. A sample of 93 female and 97 male university students rated clothing of 4 styles of daytime wear and 2 fabrics on 15 pairs of polar adjectives twice in 7-days interval. Correlation coefficients between the two ratings for each subject, intra-individual consistency in the evaluation, ranged from -0.12 to 0.89 and mean coefficient was 0.63 of female and -0.01 to 0.78 and mean coefficient was 0.54 of male. Based on the coefficients, the subjects were classified into three groups: high, medium, and low intra-individual consistency. Analysis of variance of mean ratings by the three groups revealed that significant difference existed in 24% of female and 23% of male in 90 combinations of 6 clothing and 15 semantic differential scales. Female of subjects with high intra-individual consistency were most likely definite to evaluate clothing, whereas the ones with low were least. But male subjects were not definite. Mean correlation coefficients for style evaluation subscales of female was 0.39, but male was 0.44. Among the semantic differential scales, high stability in the two ratings was observed for the synthetic clothing evaluation. Correlation coefficients for each clothing obtained from the mean score of the subjects in each semantics differential scale were around 0.98, including that the mean scores of the subjects in each scale could yield excellent stability in clothing evaluation.

• Journal of Mechanical Science and Technology
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• 제15권1호
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• pp.1-9
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• 2001

The recent spread of scaled telemanipulation into microsurgery and the nano-world increasingly requires the identification of the possible operation region as a main system specification. A teleoperation system is a complex cascaded system since the human operator, master, slave, and communication are involved bilaterally. Hence, a small time delay inside a master and slave system can be critical to the overall system stability even without communication time delay. In this paper we derive an upper bound of the scaling product of position and force by using Llewellyns unconditional stability. This bound can be used for checking the validity of the designed bilateral controller. Time delay from the sample and hold of computer control and its effects on stability of scaled teleoperation are modeled and simulated based on the transfer function of the teleoperation system. The feasible operation region in terms of position and force scaling decreases sharply as the sampling rate decreases and time delays inside the master and slave increase.

• 한국분말재료학회지
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• 제25권2호
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• pp.126-131
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• 2018

In the present study, we investigate the effects of milling time and the addition of a process control agent (PCA) on the austenite stability of a nanocrystalline Fe-7%Mn alloy by XRD analysis and micrograph observation. Nanocrystalline Fe-7%Mn alloys samples are successfully fabricated by spark plasma sintering. The crystallite size of ball-milled powder and the volume fraction of austenite in the sintered sample are calculated using XRD analysis. Changes in the shape and structure of alloyed powder according to milling conditions are observed through FE-SEM. It is found that the crystallite size is reduced with increasing milling time and amount of PCA addition due to the variation in the balance between the cold-welding and fracturing processes. As a result, the austenite stability increased, resulting in an exceptionally high volume fraction of austenite retained at room temperature.

• 한국임상약학회지
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• 제8권1호
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• pp.54-58
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• 1998

The stability of ceftriaxone sodium 100 mg/ml in the water for injection was tested at two temperature conditions (refrigerator and room temperature) and two storage containers (vitro and syringe). The stability of each sample was determined by high-performance liquid chromatography while storing for 5 days at room temperature and 27 days at refrigerator. The concentration of ceftriaxone sodium was 100 mg/ml which the hospital usually use as a filling preparation for I.V. push or Y-site injection. There was no significant difference between the storage in vials and syringes. There was no significant difference in the change of concentration until storing the reconstituted ceftriaxone sodium injection for 2 days at room temperature and 14 days at refrigerator. In conclusion, the ceftriaxone sodium 100 mg/ml in the water for injection can be stored in vial or syringe for 2 days at room temperature and 14 days at refrigerator after preparation.

• 대한전기학회논문지
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• 제45권1호
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• pp.1-8
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• 1996

Recently, much attention has been paid to problems which is concerned with voltage instability phenomena and much works on these phenomena have been made. In this paper, by substituting d $P_{k}$ d $e_{k}$ ( $v^{\rarw}$= e +j f) for $P_{k}$ in conventional load flow, direct method for finging the limit of voltage stability is proposed. Here, by using the fact that taylor se- ries expansion in .DELTA. $P_{k}$ and .DELTA. $Q_{k}$ is terminated at the second-order terms, constraint equation (d $P_{k}$ d $e_{k}$ =0) and power flow equations are formulated with new variables .DSLTA. e and .DELTA.f, so partial differentiations for constraint equation are precisely calculated. The fact that iteratively calculated equations are reformulated with new variables .DELTA.e and .DELTA.f means that limit of voltage stability can be traced precisely through recalculation of jacobian matrix at e+.DELTA.e and f+.DELTA.f state. Then, during iterative process divergence may be avoid. Also, as elements of Hessian mat rix are constant, its computations are required only once during iterative process. Results of application of the proposed method to sample systems are presented. (author). 13 refs., 11 figs., 4 tab.

• 한국환경과학회지
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• 제28권11호
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• pp.1041-1045
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• 2019

In this study, the KS A ISO Guide 35 was applied to develop analytical standards for heavy metal cadmium using the Korean mussel (Mytilus coruscus) and to evaluate the homogeneity and stability of the sample. Some of the crucial characteristics that reference materials must consist include homogeneity and stability of both intra- and inter-bottles. We tested homogeneity using ANOVA analysis and short-term stability using regression analysis. The variations of cadmium concentrations did not significantly differ between intra- and inter-bottles (F=0.41, p=0.90). For short-term stability verification, cadmium analysis results were not statistically significant as a result of the regression analysis (significance F=0.51, p=0.53). This suggests that we can not dismiss the null hypothesis that there is no significant variation in concentrations of cadmium over time. These results indicated that the cryogenic-milling process has statistically proven the short-term stability for materials from mussels in the chemical analysis of cadmium. Therefore, we propose that the Korean mussel's reference material developed for the proficiency test could be used as a tool to evaluate reliability and consistency in laboratories.

• 분석과학
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• 제15권2호
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• pp.120-126
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• 2002

유도결합 플라스마 질량분석기(ICP-MS)와 유도결합 플라스마 원자방출분광기 (ICP-AES)를 이용하여 상업적으로 유통되고 있는 4 종의 분무기(Meinhard, ESI PFA, Cross-flow, Babington)와 한국표준과학연구원(KRISS)에서 직접 제작한 분무기인 KRISS Inert 분무기와 KRISS conespray 분무기의 성능을 평가하였다. 각 분무기의 압력, 시료주입량의 변화에 따른 시료주입 효율을 조사하였으며 ICP-MS와 ICP-AES에 연결하였을 때 시료주입량의 변화에 따른 감도, 안정성, 바탕선 세기, 산화물과 수소화물의 생성 비율을 조사하였다. 시료의 종류, 시료 양의 제한성, 분석기기의 종류, 분석 원소에 따라 가장 적합한 분무기를 선택해야 높은 감도, 낮은 바탕값, 안정한 신호세기 등의 좋은 분석결과를 얻을 수 있음을 알 수 있었다.

• 천문학회지
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• 제28권2호
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• pp.139-146
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• 1995

The bright part of the halo luminosity function is derived from a sample of the 233 NLTT propermotion stars, which are selected by the 220 km/ see of cutoff velocity in transverse to rid the contamination by the disk stars and corrected for the stars omitted in the sample by the selection criterion. It is limited to the absolute magnitude range of $M_v=4-8$, but is based on the largest sample of halo stars up to now. This luminosity function provides a number density of $2.3{\cdot}10^{-5}pc^{-3}$ and a mass density of $2.3{\cdot}10^{-5}M_{o}pc^{-3}$ for 4 < $M_v$ < 8 in the solar neighborhood. These are not sufficient for disk stability. The kinematics of the sample stars are < U > = - 7 km/sec, < V > = - 228 km/sec, and < W > = -8 km/sec with (${\sigma_u},{\sigma_v},{\sigma_w}$) = (192, 84, 94) km/sec. The average metallicity of them is [Fe/H] = $- 1.7{\pm}0.8$. These are typical values for halo stars which are selected by the high cutoff velocity. We reanalyze the luminosity function for a sample of 57 LHS proper-motion stars. The newly derived luminosity function is consistent with the one derived from the NLTT halo stars, but gives a somewhat smaller number density for the absolute magnitude range covered by the LF from NLTT stars. The luminosity function based on the LHS stars seems to have a dip in the magnitude range corresponding to the Wielen Dip, but it also seems to have some fluctuations due to a small number of sample stars.