• Journal of Pharmaceutical Investigation
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• v.28 no.1
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• pp.1-5
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• 1998

The effect of synthetic polymer membranes on the permeation rate of dideoxynucleoside-type anti-HIV drugs through hairless rat skin was studied using ethylene/vinyl acetate copolymer (EVA) and ethylene/methyl acrylate copolymer (EMA) membranes fabricated by solvent casting method. In vitro skin permeation kinetics study of DDC (2',3'-dideoxythymidine), DDI (2',3'-dideoxyinosine) and AZT (3'-azido-3'-deoxythymidine) across the (membrane/skin) composite was conducted for 24 hours at $37^{\circ}C$ using the Valia-Chien skin permeation system. The results showed that skin permeation rate of each drug across the (skin/membrane) composite was mainly dependent on the property of the membrane. Proper selection of the polymeric membrane which resembles hydrophilicity/lipophilicity of the delivering drug was important in controlling the skin permeation rate.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.8 s.185
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• pp.64-71
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• 2006

In this paper, a uniform speed controller for an ultrasonic rotary motor is developed using the phase-difference method. The phase difference method uses traveling waves to drive the ultrasonic motor. The traveling waves are obtained by adding two standing waves that have a different phase to each other. A compact phase-difference driver system is designed and integrated by combining VCO(Voltage Controlled Oscillator) and phase shifter. Theoretically the relationship between the phase difference in time and the rotational speed of the ultrasonic motor is sine function, which is verified by experiments. Then a series of experiments under various loading conditions are conducted to characterize the motor's performance that is the relationship between the speed and torque. Proportional-integral control is adopted for the uniform speed control. The proportional control unit calculates the compensating phase-difference using the rotating speed which is measured by an encoder and fed back. Integral control is used to eliminate steady-state errors. Differential control for reducing overshoot is not used since the response of ultrasonic motor is prompt due to its low inertia and friction-driving characteristics. The developed controller demonstrates reasonable performance overcoming disturbing torque and the changes in material properties due to continuous usage.

• Journal of Microbiology and Biotechnology
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• v.17 no.9
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• pp.1460-1468
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• 2007

In this study, an approx. 2.5-kb gene fragment including the catalase gene from Rhodospirillum rubrum S1 was cloned and characterized. The determination of the complete nucleotide sequence revealed that the cloned DNA fragment was organized into three open reading frames, designated as ORF1, catalase, and ORF3 in that order. The catalase gene consisted of 1,455 nucleotides and 484 amino acids, including the initiation and stop codons, and was located 326 bp upstream in the opposite direction of ORF1. The catalase was overproduced in Escherichia coli UM255, a catalase-deficient mutant, and then purified for the biochemical characterization of the enzyme. The purified catalase had an estimated molecular mass of 189 kDa, consisting of four identical subunits of 61 kDa. The enzyme exhibited activity over a broad pH range from pH 5.0 to pH 11.0 and temperature range from $20^{\circ}C$ to $60^{\circ}C$C. The catalase activity was inhibited by 3-amino-1,2,4-triazole, cyanide, azide, and hydroxylamine. The enzyme's $K_m$ value and $V_{max}$ of the catalase for $H_2O_2$ were 21.8 mM and 39,960 U/mg, respectively. Spectrophotometric analysis revealed that the ratio of $A_{406}$ to $A_{280}$ for the catalase was 0.97, indicating the presence of a ferric component. The absorption spectrum of catalase-4 exhibited a Soret band at 406 nm, which is typical of a heme-containing catalase. Treatment of the enzyme with dithionite did not alter the spectral shape and revealed no peroxidase activity. The combined results of the gene sequence and biochemical characterization proved that the catalase cloned from strain S1 in this study was a typical monofunctional catalase, which differed from the other types of catalases found in strain S1.

• Journal of the Korean Geographical Society
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• v.41 no.4 s.115
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• pp.435-456
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• 2006

This study examines the long-term spatial patterns and recent trends of seasonal onsets and durations defined by daily temperatures in South Korea for the period 1973-2004. Spatially, spring and winter onset dates show approximately 44 day and 63 day maximum difference respectively between south and north (Seongsanpo to Daegwallryeong) attributable to the impacts of latitudes and altitudes. In contrast, summer onset, which is more affected by proximity to oceans and altitudes than by latitudes, begins earlier in interior low elevated areas than in the coastal areas but earliest at higher latitudes than Jeiu Island. Five climatic types regarding the seasonal cycles in South Korea are spatially clustered according to the combination of longer seasonal durations. As a reflection of recent climate changes on seasonal cycles in South Korea, winter duration was shortened by 10 days during the post-1988 period due to a late winter onset of 4 days and an early spring onset of 6 days. The winter reduction began in the southern regions of the Korean Peninsula in the mid-1980s and spread northward during the 1990s period, ultimately appearing everywhere. In urbanized cities, where much of the surface is covered with asphalt or concrete, the winter reduction was intensified and summer duration was locally incremented. The reduced winter duration in recent decades shows significant teleconnections with variations of geopotential height (925hPa) in the eastern Arctic region ($0-90^{\circ}E$, $65-85^{\circ}N$) during the cold season. The reduction in winter duration in South Korea agrees with results in overall global warming trends as a climate change signal.

• Proceedings of the KSCN Conference
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• 2005.10a
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• pp.33-38
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• 2005

During the 20th century, humankind went through the most significant changes in history, from industrial and agricultural revolutions to the invention of the personal computers and the internet, and changes continue to come at an even faster rate. One of notable change is emerging multicultural societies. People tended to live in a monocultural society and new cultures were infused in controlled and confined manners, however, people now live and eat in a continuously changing multicultural society Multicultural societies are emerged from the translocation of people (immigration) and, in a larger sense, globalization. Immigrants are faced with various and different cultures from their own, resulting in excitements and agonies in finding balance among many cultures. People who have not translocated themselves must also deal with various imported foreign cultures from fastfood restaurants to food beliefs. This lecture will use Korean Americans as an example to discuss how immigrants navigate different cultures and environments and how acculturation, the process of adaptation, affects their diet and health. In addition, how globalization has changed people's eatery will be briefly discussed. Understanding impacts of living and eating in a multicultural society is meaningful and useful to find effective approaches to promote healthy lifestyles to people in this fast changing times.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.9
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• pp.4603-4624
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• 2016

In this paper, a new reversible watermarking algorithm with adaptive embedding threshold matrix is proposed. Firstly, to avoid the overflow and underflow, two flexible thresholds, TL and TR, are applied to preprocess the image histogram with least histogram shift cost. Secondly, for achieving an optimal or near optimal tradeoff between the embedding capacity and imperceptibility, the embedding threshold matrix, composed of the embedding thresholds of all blocks, is determined adaptively by the combination between the composite chaos and the average energy of Integer Wavelet Transform (IWT) block. As a non-liner system with good randomness, the composite chaos is suitable to search the optimal embedding thresholds. Meanwhile, the average energy of IWT block is calculated to adjust the block embedding capacity, and more data are embedded into those IWT blocks with larger average energy. The experimental results demonstrate that compared with the state-of-the-art reversible watermarking schemes, the proposed scheme has better performance for the tradeoff between the embedding capacity and imperceptibility.

• Journal of Community Nutrition
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• v.5 no.4
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• pp.246-253
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• 2003

With globalization taking place at a rapid speed, more and more people move from one place to another and more people with diverse cultural backgrounds are now living together than ever before. As a result, more people go through the process of acculturation. Dietary acculturation, a part of overall acculturation, is a series of changes that occur in food and nutrient consumption and dietary behaviors. This paper examined dietary acculturation in Korean Americans through a critical literature review. The current diet quality of Korean Americans is fair, and the areas in need of improvement include sodium, calcium, and fiber intakes. Korean Americans had different diet profiles by acculturation status； however, whether dietary acculturation leads to a lower diet quality is not conclusive at this time. This paper also suggests areas that warrant consideration in future research： 1) acculturation measures, 2) dietary measures, 3) possible factors affecting dietary acculturation, 4) health consequences of dietary acculturation, and 5) study design issues. Studying dietary acculturation among immigrants and their offspring is important because it will provide useful insights for designing health and nutrition interventions in both original and new countries. Quality research in dietary acculturation requires collaborations among researchers from different nations because it deals with diverse cultures.

• Journal of Community Nutrition
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• v.5 no.4
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• pp.209-217
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• 2003

The food and nutrition system is a network of processes linking agriculture, food, eating, nutrition, and health. The system includes a series of nine stages (production, processing, distribution, acquisition, preparation, consumption, digestion, transport, and utilization) and two types of contexts (biophysical and sociocultural). Analysis of whole food and nutrition systems provides information about the structure and processes involved in the complete scope of food and nutrition, assisting in the identification of ″upstream″ influences and ″downstream″ consequences in the system. The current analysis gathered existing data about the food and nutrition system in South Korea from public sources and professional publications, and interpreted that information to consider how different elements of the system contribute to health. The findings revealed that South Korea has substantial domestic food production and processing supplemented by imports, widespread food distribution in markets and a growing number of Korean and Western restaurants, a relatively low percentage of household income spent on food, growing use of new food preparation methods such as microwave ovens, a rice/vegetable/fish based three-meal consumption pattern, few recorded digestive problems, increasing calorie storage as body fat, and a relatively low chronic disease prevalence compared to other developed societies. Examination of the full scope of the food and nutrition system provides a broad perspective using whole system thinking that can identify potential strategies for future research and intervention.

• Advances in concrete construction
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• v.7 no.4
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• pp.249-262
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• 2019

In this study, high strength aluminum alloys (AA) plates are proposed as a new construction material for strengthening reinforced concrete (RC) beams. The purpose of this investigation is to evaluate AA plate's suitability as externally bonded reinforcing (EBR) materials for retrofitting shear deficient beams. A total of twenty RC beams designed to fail in shear were strengthened with different spacing and orientations. The specimens were loaded with four-points loading till failure. The considered outcome parameters included load carrying capacity, deflection, strain in plates, and failure modes. The results of all tested beams showed an increase up to 37% in the load carrying capacity and also an increase in deflection compared to the control un-strengthened beams. This demonstrated the potential of adopting AA plates as EBR material. Finally, the shear contribution from the AA plates was predicted using the models available in the ACI440-08, TR55 and FIB14 design code for fiber reinforced polymer (FRP) plates. The predicted results were compared to experimental testing data with the ratio of the experimentally measured ultimate load to predicted load, range on the average, between 93% and 97%.

• Korean Journal of Adult Nursing
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• v.25 no.2
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• pp.157-169
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• 2013

Purpose: This study was to examine the impact of acculturation and social support on the mental health among Korean-American registered nurses. Methods: Data were collected with a convenience sample of 203 Korean-American registered nurses living in New York state and New Jersey state from 8th May to 25th August in 2012. The structured questionnaires measured the degree of acculturation, social support, and mental health. Data analysis was conducted using t-test, ANOVA, Pearson correlation efficient, and Stepwise multiple regression. Results: Lower level of integration and higher level of marginalization were associated with the lower mental health. Social support was also positively related to mental health and had mediating effect on the relationship between acculturation and mental health. The five variables, including participants' educational background, work shift, integration, marginalization, and social support were significant to predict the level of mental health among Korean-American registered nurses, accounting for 41% of the variability. Conclusion: The results imply that higher level of social support and strong identity of both home and host culture will enable Korean-American registered nurses to maintain sound mental health.