• Journal of Pharmaceutical Investigation
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• v.40 no.1
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• pp.9-14
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• 2010

Lacidipine used for the treatment of hypertension has low water solubility and is classified as BCS Class II category. Gelucire-based solid dispersions (SD) containing lacidipine were prepared by solvent evaporation method to enhance drug dissolution. The powdered forms of SD showed irregularly spherical shape. Thermal behaviors of SD from differential scanning calorimetry indicated that distinct endothermic peak of lacidipine ($184^{\circ}C$) was shifted to lower region ($150.1^{\circ}C$). Drug was present in a crystalline form. NMR spectra also showed some molecular interaction between drug and Gelucire. There was no significant difference in DSC and NMR behaviors between Gelucire 44/14 and Gelucire 50/13. The initial dissolution rate of SD-loaded tablet linearly increased both in water and in water containing 1% tween 20, and much higher than the commercial tablet, $Vaxar^{(R)}$. When the amount of SD was increased, the release rate was greater. The Gelucire 50/13 showed higher dissolution than the Gelucire 44/14. The produced solid dispersion with various kinds of excipients and making tablets, it was found that solid dispersions can increase the solubility in artificial gastric juice and finally increases dissolution rate.

• Korean Journal of Applied Biomechanics
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• v.30 no.1
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• pp.1-6
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• 2020

Objective: The incidence rate of elbow ulnar collateral ligament injuries is dependent on the throwing speed or pitching type, especially in adolescent baseball players. However, mixed results have been reported due to a lack of controlled biomechanical analysis. Thus, the purpose of this study was to investigate the biomechanical analysis of the elbow in relation to throwing speed and pitching type. Method: Four overhead type high-school baseball players were recruited for this study. The participants were asked to throw balls with different types of pitch and speed. While the throwing speeds were measured, each pitching moment of the elbow was recorded. Descriptive statistics, frequency analysis, mean comparison analysis, and Pearson's correlation analysis were performed in order to examine differences in peak varus and valgus moment during pitching motion in the elbow in all throwing speed and pitching types. Results: There was no significant difference in physical characteristics, throwing speed, and momentum variability among all players. The mean varus moments were 44.38±1.55 Nm, 48.83±1.66 Nm, and 48.94±0.95 Nm, and the moment gaps between varus and valgus were 7.36±3.25 Nm, 7.44±2.02 Nm, and 7.36±2.62 Nm in fastball, curveball, and slider ball, respectively. The varus moment was higher in the curved and slider balls than in the fastballs, and there was no significant differences between the varus moments regarding the pitching type. However, the increase in valgus moment and decrease in moment gap according to throwing speed was significantly increased in the slider ball (r=0.718 and -0.591, respectively). Conclusion: The possibility of elbow injury caused by the valgus moment or moment gapincreases more rapidly in slider balls as the speed increases. Based on our results, appropriate pitching guidelines should be suggested to prevent ulnarligament injuries, especially in adolescent baseball players.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.661-667
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• 2002

Welding-induced buckling distortion is one of the most problematic concerns in both design and fabrication of welded thin-plate structures. This paper deals with experimental and numerical results of the welding-induced longitudinal and/or buckling distortion occurring in welding of 6mm-thick AH36 high strength steel plates. Effects of the heat input and the plate size on the distortion were experimentally evaluated for square plates. Bead-on-plate welding was performed with the submerged arc welding process along the middle line of plate specimens. Experimental results showed that the longitudinal distortion made a single curvature in the plate, and the distortion magnitude along the weld centerline was proportional to the heat input and the plate size. The experimental results were used to examine the validity of the numerical simulation procedure for welding-induced distortion where the longitudinal distortion mode and magnitude were numerically quantified. Three-dimensional, large deformation, welding simulations were performed for selected weld models. Numerical results of the distortion mode and magnitude were in a good agreement with experimental ones. Depending on the presence of halting the distortion growth during the cooling cycle of welding, the condition discriminating buckling distortion from longitudinal distortion was established. Eigenvalue analyses were performed to check the buckling instability of tested plates with different sizes subjected to different heat inputs. The perturbation load pattern for the analysis was extracted from longitudinal inherent strain distributions. Critical buckling curve from the eigenvalue analyses revealed that the buckling instability is manifested when plate size or heat input increases.

• International Journal of High-Rise Buildings
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• v.3 no.1
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• pp.21-33
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• 2014

The tied braced frame (TBF) system was developed to achieve uniform seismic inelastic demand along the height of multi-storey eccentrically braced steel frames. A modular tied braced frame (M-TBF) configuration has been recently proposed to reach the same objective while reducing the large axial force demand imposed on the vertical tie members connecting the link beams together in TBFs. M-TBFs may however experience variations in storey drifts at levels where the ties have been removed to form the modules. In this paper, the possibility of reducing the discontinuity in displacement response of a 16-storey M-TBF structure by introducing energy dissipating (ED) devices between the modules is examined. Two M-TBF configurations are investigated: an M-TBF with two 8-storey modules and an M-TBF with four 4-storey modules. Three types of ED devices are studied: friction dampers (FD), buckling restrained bracing (BRB) members and self-centering energy dissipative (SCED) members. The ED devices were sized such that no additional force demand was imposed on the discontinuous tie members. Nonlinear response history analysis showed that all three ED systems can be used to reduce discontinuities in storey drifts of M-TBFs. The BRB members experienced the smallest peak deformations whereas minimum residual deformations were obtained with the SCED devices.

• Environmental Mutagens and Carcinogens
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• v.19 no.2
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• pp.89-94
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• 1999

Cell proliferation and c-Jun expression pattern in liver exposed by nongenotoxic carcinogens phenobarbital (PB) and clofibrate, and genotoxic carcinogen 2-amino-3-methylimidazo [4,5-f] quinoline (IQ) were investigated to see whether differential effects of genotoxic and non-genotoxic carcinogens on the development of neoplastic foci may be related to differential effect on cell proliferation. Male F344 rats were initially given a single intraperitioneal injection of diethylnitrosamine (200 mg/kg body weight), and 2 weeks later, animals were fed diets containing 0.03% IQ or 0.5% CE or 0.05% PB or basal diet as a control for 6 weeks. All rats were subjected to the two-thirds partial hepatectomy (PH) at week 3. Sequential sacrifice of rats was performed until 8 weeks. Cell proliferation was examined by immunohistochemical staining of bromodeoxyuridine and c-Jun expression was determined by northern blotting. The increase of cell proliferation rate after PH was significant in the rats fed 0.05% IQ and continued until 8 weeks, while the increase was not significant in the rats fed phenobarbital and clofibrate compared to that in the rats fed control diet. mRNA level of c-Jun in the liver treated with IQ was about 7 fold higher than that of control and peak at 5 hours after rH. In the liver treated with CE, mRNA level of c-Jun was 3-4 fold higher than that of control and the highest level of mRNA of c-Jun was seen at 24 hours after PH. These results show that differential effects of genotoxic and non-genotoxic carcinogens on the development of neoplastic foci may be related to differential effect on cell proliferation pattern.

• Korean Journal of Clinical Pharmacy
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• v.20 no.3
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• pp.221-228
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• 2010

In 2009, American Journal of Health-System Pharmacy (AJHP) recommended that targeting vancomycin trough concentrations of 10 mg/L or more because of therapeutic failure and potential risk of developing vancomycin resistance. Therefore, new dosage guidelines that could achieve to these higher target were needed. The aims of this study were to develop dosage guidelines targeting new vancomycin trough concentration and to evaluate the performance of these new guidelines. All data analysis were performed using NONMEM(R). Population pharmacokinetic model was first developed from vancomycin dosage and concentration data collected retrospectively during routine therapeutic drug monitoring in 441 patients, then new vancomycin dosage guidelines were developed by using the model to predict vancomycin trough and peak concentrations in a simulated dataset. The estimates, such as, vancomycin concentration trough level, time to achieve target level, mean error were performed to evaluate and compare difference between conventional dosage and new dosage guidelines. The proposed dosage guidelines were predicted to achieve 43.5% of vancomycin trough level within 10~20 mg/L, which is significantly higher than current guidelines (26.3%). Time to achieve target trough level was 19.4 hours in new guidelines comparing to 93.1 hours in the conventional dosage. Thus, new vancomycin dosage guidelines have been developed to achieve new target trough concentrations earlier and more consistently than conventional guidelines.

• KSBB Journal
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• v.18 no.2
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• pp.100-106
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• 2003

An on-line frontal analysis HPLC system was developed to determine the unbound concentration of (S)-perillyl alcohol, an potential anti-cancer agent, in human serum albumin (HSA) solution, The analysis was performed on a Develosil 100 Diol 5 (10 cm x 4.6 mm I.D.) high-performance frontal analysis (HPFA) column. Sodium phosphate solution was used as the mobile phase (pH 7.4, ionic strength 0.17) at a flow rate of 1 $m\ell$/min. UV wavelength was set at 205 nm. A injection volume of 600${mu}ell$ was chosen to ensure the compound eluted formed a zonal peak with a plateau. By Scatchard analysis, it was found that the binding constant(K) and binding number(n) of (S)-perillyl alcohol to molecular HSA were 2.05 x $10^6$ [$M{-1}$], 0.00428, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.171-174
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• 2004

The stochiometric $AgGaSe_2$ polycrystalline mixture of evaporating materials for the $AgGaSe_2$ single crystal thin film was prepared from horizontal furnace. To obtain the single crystal thin films, $AgGaSe_2$ mixed crystal and semi-insulating GaAs(100) wafer were used as source material and substrate for the Hot Wall Epitaxy (HWE) system, respectively. The source and substrate temperature were fixed at $630^{\circ}C$ and $420^{\circ}C$, respectively. The thickness of grown single crystal thin films is $2.1{\mu}m$. The single crystal thin films were investigated by photoluminescence and double crystal X-ray diffraction(DCXD) measurement. The carrier density and mobility of $AgGaSe_2$ single crystal thin films measured from Hall effect by van der Pauw method are $4.89{\times}10^{17}\;cm^{-3},\;129cm^2/V{\cdot}s$ at 293K, respectively. From the photocurrent spectrum by illumination of perpendicular light on the c - axis of the $AgGaSe_2$ single crystal thin film, we have found that the values of spin orbit splitting ${\Delta}S_o$ and the crystal field splitting ${\Delta}C_r$ were 0.1762 eV and 0.2494 eV at 10 K, respectively. From the photoluminescence measurement of $AgGaSe_2$ single crystal thin film, we observed free excition $(E_X)$ observable only in high quality crystal and neutral bound exciton $(D^o,X)$ having very strong peak intensity And, the full width at half maximum and binding energy of neutral donor bound excition were 8 meV and 14.1 meV, respectively. By Haynes rule, an activation energy of impurity was 141 meV.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.8
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• pp.770-775
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• 2008

Autonomic nervous system of the anesthetized patients can be influenced by the many kinds of stimulations such as intubation, surgical incision and so on. The changes of the heart rates and blood pressures are surrogates of responses of the autonomic system to the external stimulations. Recently, the power spectral analysis of the heart rate variability (HRV) made it easy to know the fractions and changes of sympathetic and parasympathetic autonomic systems. In this study, the changes of pulse transit time, one of the response of vessels to stimulations, was investigated in relation to the HRV. Ten patients were examined and average age is 22.5 $\pm$ 11.04, average weight is 63 $\pm$ 14.4 kg. The patients were anesthetized only by sevoflurane inhalation. Pulse transit time is determined by calculating the difference of the time between the R peak of ECG and the characteristic point of the plethysmography. Power spectral density (PSD) of the HRV was achieved in the frequency of 0.04-0.15 (LF) and 0.15-0.4 (HF). Compared to preanesthetic period the values of LF and LF/HF ratio of HRV were decreased (p<0.05). HF and PTT was increased in anesthetic state with sevoflurane. Otherwise, after intubation, the HF was decreased and LF, LF/HF ratio and PTT were increased. PSD of the HRV is well-known for the index of the autonomic nervous activity. Not only HRV but PTT analysis also is a useful index reflecting the autonomic responses to various stimulations. And this analysis is useful in bed side monitoring because the calculating method is simple and it takes shorter processing time compared to the HRV analysis.

• Biomedical Science Letters
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• v.10 no.4
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• pp.361-366
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• 2004

The purpose of this study was to determine the effect of high voltage pulsed current (HVPC) stimulation on proliferative activities of basal keratinocytes by measured nucleolar organizer region (NOR) expression and thickness of spinous layer in aged rat skin. Fifty-one weeks old twelve male Sprague-Dawley rats (300∼350g) were divided into control and HVPC stimulation groups. Each animal's hair on the back were removed. The HVPC stimulation group received an negative monophasic twin peak pulsed current stimulation with 50 V, while the control group was given the same treatment without electricity. The rats were sacrificed after 3 weeks. The biopsy specimens were fixed in formalin, embedded in paraffin and stained with hematoxyline-eosin and silver nitrate. The thickness of basal to granular layer of the epidennis were measured using a light microscope and computerized image analysis system. The number of argyrophilic nucleolar organizer region (AgNOR) were counted using a light microscope and computerized image analysis system and calculated as the mean number of AgNOR per nucleus in the basal keratinocyte. By using a Student's t-test, an increase in the thickness of basal-spinous layer (P<0.001) of epidermis can be observed in HVPC stimulation rats as compared with the control rats, whereas the thickness of the granular layer is not affected. A Student's t-test showed a significantly higher mean NOR number per nucleus of the basal keratinocyte in the HVPC stimulation rats than control rats (P<0.001). There was significantly positive correlation between the NOR number and the thickness of basal-spinous layer (r=0.80, P<0.05). These results suggest that the HVPC stimulation may increase the thickness of spinous layer in the epidennis due to increased proliferative activities of basal keratinocytes in epidennis in aged rat skin.