• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.202-207
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• 2022

The study on electrode degradation of Proton Exchange Membrane Fuel Cell (PEMFC) was mainly studied on the particle growth and active area reduction of Pt on the electrode. The degradation of the electrode catalyst Pt in contact with the membrane affects the deterioration of the polymer membrane, but there are not many studies related to this. In this study, the phenomenon of the deposition of deteriorated Pt inside the polymer membrane during the accelerated electrode catalyst degradation test and its effects were studied. The voltage change (0.6 V ↔ 0.9 V) was repeated up to 30,000 cycles to accelerate the platinum degradation rate. When the voltage change cycle was repeated while oxygen was introduced into the cathode, the amount of Pt deposited inside the film was larger than when nitrogen was introduced. As the number of voltage change cycles increased, the amount of Pt deposited inside the membrane increased, and Pt dissolved in the cathode moved toward the anode, showing a uniform distribution throughout the membrane at 20,000 cycles. In the process of the accelerated electrode catalyst degradation test, the hydrogen crossover current density of the membrane did not change, and it was confirmed that the deposited Pt did not affect the durability of the membrane.

• Animal Bioscience
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• v.35 no.2
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• pp.184-195
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• 2022

Objective: In this study we aimed to evaluate the effect of dietary live yeast supplementation on ruminal pH pattern, fermentation characteristics and associated bacteria in beef cattle. Methods: This work comprised of in vitro and in vivo experiments. In vitro fermentation was conducted by incubating 0%, 0.05%, 0.075%, 0.1%, 0.125%, and 0.15% active dried yeast (Saccharomyces cerevisiae, ADY) with total mixed ration substrate to determine its dose effect. According to in vitro results, 0.1% ADY inclusion level was assigned in in vivo study for continuously monitoring ruminal fermentation characteristics and microbes. Six ruminally cannulated steers were randomly assigned to 2 treatments (Control and ADY supplementation) as two-period crossover design (30-day). Blood samples were harvested before-feeding and rumen fluid was sampled at 0, 3, 6, 9, and 12 h post-feeding on 30 d. Results: After 24 h in vitro fermentation, pH and gas production were increased at 0.1% ADY where ammonia nitrogen and microbial crude protein also displayed lowest and peak values, respectively. Acetate, butyrate and total volatile fatty acids concentrations heightened with increasing ADY doses and plateaued at high levels, while acetate to propionate ratio was decreased accordingly. In in vivo study, ruminal pH was increased with ADY supplementation that also elevated acetate and propionate. Conversely, ADY reduced lactate level by dampening Streptococcus bovis and inducing greater Selenomonas ruminantium and Megasphaera elsdenii populations involved in lactate utilization. The serum urea nitrogen decreased, whereas glucose, albumin and total protein concentrations were increased with ADY supplementation. Conclusion: The results demonstrated dietary ADY improved ruminal fermentation dose-dependently. The ruminal lactate reduction through modification of lactate metabolic bacteria could be an important reason for rumen pH stabilization induced by ADY. ADY supplementation offered a complementary probiotics strategy in improving gluconeogenesis and nitrogen metabolism of beef cattle, potentially resulted from optimized rumen pH and fermentation.

• Journal of Pharmaceutical Investigation
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• v.39 no.3
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• pp.207-216
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• 2009

Fluconazole is used as an orally administrated antifungal drug for the treatment of tinea corporis, candidiasis including skin mycotic pneumonia infections. The dosage of fluconazole varies with indication ranging from 50 mg/day to 400 mg/day. The fluconazole capsule 50 mg (3 capsules daily) is already available in Korean market. To improve the patient compliance, a fluconazole tablet 150 mg (once a day administration) was developed recently. The purpose of this study was to evaluate the bioequivalence of three doses of fluconazole capsule 50 mg (Diflucan 50 mg, Pfizer Korea Inc., as a reference drug) and a single dose of fluconazole tablet 150 mg (Plunazol 150 mg, Daewoong Pharm. Co., Korea) according to the guidelines of the Korea Food and Drug Administration (KFDA). The bioequivalence for three capsules of Diflucan 50 mg and a single tablet of Plunazol 150 mg was investigated in twenty-four healthy male volunteers under a randomized 2${\times}$2 crossover trial design. The average age of twenty-four volunteers was 24.78${\pm}$3.27 year-old, average height was 175.56${\pm}$5.45 cm and average weight was 67.24${\pm}$6.86 kg. After three capsules of Diflucan 50 mg or a single tablet of Plunazol 150 mg were orally administered, blood was taken at predetermined time intervals and the plasma concentrations of fluconazole in plasma were determined using LC-MS-MS. The 90% confidence intervals for the main parameters of statistical results after logarithmic transformation were AUCt 0.9272-1.0084 and Cmax 0.8423-0.9544 respectively, which are in the range of log 0.8 to log 1.25 and the statistical results of additional parameters (AUClast, t1/2 and MRT) were also in the 90% confidence interval that is in the range of log 0.8 to log 1.25. Therefore, the results of this study confirm the bioequivalence of three capsules of Diflucan 50 mg to one tablet of Plunazol 150 mg.

• Journal of Pharmaceutical Investigation
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• v.38 no.4
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• pp.269-275
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• 2008

The purpose of the present study was to evaluate the bioequivalence of two levofloxacin tablets, Jeil $Cravit^{TM}$ tablet (Jeil Pharm. Co., Ltd., Korea, reference drug) and $Lesacin^{TM}$ tablet (Ilhwa. Co., Ltd., Korea, test drug), according to the guidelines of Korea Food and Drug Administration (KFDA). Twenty-four healthy male Korean volunteers received two tablets containing levofloxacin 200 mg in a $2{\times}2$ crossover study. There was a one-week washout period between the doses. Plasma concentrations of levofloxacin were monitored for over a period of 24 hr after administration by using a high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The area under the plasma concentration-time curve from time zero to 24 hr ($AUC_t$), maximum plasma drug concentration ($C_{max}$) and time to reach $C_{max}\;(T_{max})$ were complied from the plasma concentration-time data. Analysis of variance (ANOVA) test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t$ and $C_{max}$. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{max}$ ratio for $Lesacin^{TM}$/Jeil $Cravit^{TM}$ were $\log\;0.9527{\sim}\log\;0.9981$ and $\log\;0.8712{\sim}\log\;1.0556$, respectively. These values were within the acceptable bioequivalence intervals of $\log\;0.80{\sim}\log\;1.25$, recommended by KFDA. In all of these results, we concluded that $Lesacin^{TM}$ tablet was bioequivalent to Jeil $Cravit^{TM}$ tablet, in terms of rate and extent of absorption.

• Journal of Digital Convergence
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• v.10 no.9
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• pp.409-416
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• 2012

This study aimed to compare the effectiveness of action-observational training and task-oriented training on upper limb function and activities of daily living in patients with post-stroke hemiparesis. This study included 12 voluntary participants with post-stroke hemiparesis. Subjects were randomly assigned to either group 1 or group 2, with 6 in each group. Each subject completed the crossover experiment that comprised of action-observational training (A) and task-oriented training (B). The intervention sequence was A-B for the group 1 and B-A for the group 2. Each training was performed for 30 min a day, 5 times a week for 2 weeks (total experimental period of 4 weeks). Assessments were made using the Wolf Motor Function Test (WMFT) and Modified Barthel Index (MBI) thrice: at baseline, after 2 weeks of intervention, and after 4 weeks of intervention. The results showed that the WMFT and MBI scores significantly improved after the completion of each training (p<.05). Therefore, a determination of the superior training method was difficult. The effect sizes of both groups were greater when performed the action-observational training. The findings suggest that both the action-observational training and task-oriented training may be helpful in improving the upper limb function and activities of daily living for patients with post-stroke hemiparesis, and support the clinical feasibility of the action-observational training.

• Journal of the Korean Geographical Society
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• v.43 no.6
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• pp.894-913
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• 2008

This study examines scale issues in the contemporary feminist migration literature. Scale appears as important, yet poorly understood concept in this field of study. The increasing attention to the feminization of migration requires not only gendered, but also scalar-sensitive approaches. Feminists criticize the conventional approach to the migration as a gender-blind approach that privileges national scale around which migration processes are organized. Claiming multiscalar and interscalar analyses, they propose investigations ranging from macro to micro processes which include globalized gendered division of labor, transnational family networks, and reproduction which takes place in and through the bodies and homes of migrant women. The migrant women, the major actors in recent transnational migration, cross various borders: the national boundaries and the public and private divides, in particular. This crossover can unsettle patriarchal gender relations which have been established based on the physical and symbolic division of nation-states and public/private spheres. Blurring these divisions accompanies social construction of various scales. The transnational family networks of migrant women, for example, show the construction of a transnational scale by migrant women as well as globalization from below. This paper points out misunderstandings of scale in the feminist migration literature and attempts to fill the gaps by introducing the meanings and implications of scales developed mostly by feminist geographers. In so doing, it promotes the interdisciplinary communication.

• Journal of Ecology and Environment
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• v.43 no.2
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• pp.104-116
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• 2019

Background: The composition of wild bird populations in temperate zones greatly varies depending on phenological changes rather than other environmental factors. Particularly, wild birds appearing in wetlands fluctuate greatly due to the crossover of species arriving for breeding during the summer and for wintering. Therefore, to understand the changes to species composition related to phenology, we conducted this basic analysis of populations to further the cause of the protection of wetland-dependent wild birds. Methods: It is wrong to simply divide a wild bird population investigation into seasons. This study identifies species composition and indicator species that change along with seasons. Wetlands to be surveyed are protected by natural monuments and wetland inventory and are in a state close to nature. In order to identify as many species as possible in wetlands, a survey was conducted in both shallow and deep wetlands. The water depth varied in these areas, ranging from 0.2 to 2.0 m, allowing for both dabbling and diving ducks to inhabit the area. Surveys were conducted using line-transect and distance sampling methods and were conducted at intervals of 2 weeks. The survey was conducted under the following three categories: the eco-tone and emergent zone, the submergent zone, and the water surface. The survey was conducted along a wetland boundary by observing wild birds. A PC-ord program was used for clustering, and the SAS program was used to analyze the changes in species composition. The data strongly indicates that day length is the main factor for seasonal migration periods, despite the fact that climate change and increasing temperatures are often discussed. Results and conclusions: The indicator species for determining seasons include migrant birds such as Ardea cinerea, Alcedo atthis, Anas penelope, and Poiceps ruficollis, as well as resident birds such as Streptopelia orientalis and Emberiza elegans. Importantly, increases in local individual counts of these species may also serve as indicators. The survey results of seasonal fluctuations in temperate zones shows that spring (April to June), summer (July to September), autumn (October), and winter (November to March) are clearly distinguishable, even though spring and summer seasons tend to overlap, leading to the conclusion that additional research could more clearly identify fluctuation patterns in species composition and abundance in the study area.

• Sleep Medicine and Psychophysiology
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• v.23 no.2
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• pp.61-67
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• 2016

Objectives: We aimed to evaluate the effects of mattress type on both objective and subjective sleep quality in healthy good sleepers. Methods: Fifteen healthy good sleepers with a mean age of 30.8 years participated in this study. A randomized crossover trial was carried out using two different mattress types: a standard mattress and a contour coil mattress. After a night of adaptation, all participants were randomized to either a standard mattress or a contour coil mattress. Then, nocturnal polysomnography was conducted for two consecutive nights. Subjective evaluations were obtained using a self-report questionnaire before and after the polysomnographic recording sessions. Results: The polysomnographic showed no differences in total sleep time, sleep stage, or wake time after sleep onset between the two mattress conditions. Of the polysomnographic variables, only sleep onset latency was significantly reduced for the contour coil mattress. Additionally, participants reported better subjective sleep quality when sleeping on the contour coil mattress, according to the questionnaires. Conclusion: The type of mattress might affect not only subjective, but also objective sleep quality, including sleep onset latency.

• Journal of Music and Human Behavior
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• v.10 no.2
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• pp.1-33
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• 2013

The aim of this study was to systematically review the latest clinical trials in music medicine and medical music therapy for pediatric patients. Thirteen databases were searched to obtain randomized controlled/crossover design studies published between the year 2000 and 2012 in English language. Out of 1012 articles retrieved in the initial search, fifteen studies were identified based on an exclusion criteria. Overall, selected articles involved children 1 month to 18 years, sample size of 11 to 150, and total participants of 987. Studies were classified and compared as music medicine or music therapy studies through a systematic synthesis assessing general characteristics, methodological quality, measured outcomes, types of interventions and the study results. Seven music medicine and eight music therapy studies measured seven dependent variables using thirty-six different measurement tools with a large heterogeneity in the selection, type, and method of music interventions. Evaluation of the methodological quality revealed that many studies did not provide a full report of the research method, and did not meet some or most methodological standards, such as randomization, allocation concealment, double or partial blinding, and intention to treat analysis. Although overall research results were positive if not significant, poor methodological quality and heterogeneity in design and intervention strategies raise the question of research bias and trustworthiness issues. The systematic review concluded that music may have a valuable clinical effect in addressing the physical and psychosocial needs of hospitalized children, although more rigorous, homogeneous and replicable studies are greatly needed.

• Journal of Pharmaceutical Investigation
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• v.34 no.5
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• pp.413-418
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• 2004

A bioequivalence of $Melax^{TM}$ capsules (Chong Kun Dang Pharm., Korea) and $Mobic^{TM}$ capsules (Boehringer Ingelheim Korea) was evaluated according to the guideline of Korea Food and Drug Administration (KFDA). Single 15 mg dose of meloxicam of each medicine was administered orally to 24 healthy male volunteers. This study was performed in a $2\;{\times}\;2$ crossover design. Concentrations of meloxicam in human plasma were monitored by a high-performance liquid chromatography. $AUC_t$ (the area under the plasma concentration-time curve from time zero to 72 hr) was calculated by the linear trapezoidal rule method. $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{max}$) were compiled from the plasma concentration-time data. Analysis of variance was performed using logarithmically transformed $AUC_t$ and $C_{max}$. No significant sequence effect was found for all of the bioavailability parameters. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{max}$ ratio for $Melax^{TM}/Mobic^{TM}$ were 0.95 - 1.04 and 0.98 - 1.14, respectively. This study demonstrated a bioequivalence of $Melax^{TM}$ and $Mobic^{TM}$ with respect to the rate and extent of absorption.