• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.799-806
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• 1995

The steady shear and small amplitude oscillatory dynamic rheological properties of citrus pectin $([\eta]=3.75\;dL/g)$ were characterized for a wide range of pectin concentrations $({\sim}6%)$. The typical power-law flow was observed above 2.0% concentration, and the shear rate dependence of viscosity increased with pectin concentration. The transition from dilute to concentrated regime, determined from the double logarithmic plot of ${\eta_{sp.o}}\;vs\;C[\eta]$, occurred at a critical coil overlap parameter $C^{*}[\eta]\approx4.0$, at which ${\eta_{sp.o}}$ corresponded to approximately 10.0. The slopes of ${\eta_{sp.o}}\;vs\;C[\eta]$, at $C[\eta]\;at\;C[\eta]C^{*}[\eta]$were 1.1 and 4.5, respectively. The steady viscosity $(\eta)$ displayed a good superposition at ${\eta}/{\eta}_o\;vs\;{\gamma}/{\gamma}_{0.8}$ relation with an exception of high concentration (6%), which arised from the significant deviation of flow behavior index (n values of $\eta_{a}=K\gamma^{n-1}$) at high concentration. Dynamic measurements showed that the loss modulus $(G^{\prime\prime})$ was much higher than the storage modulus $(G^\prime)$for all concentrations studied, indicating predominant viscoelastic liquid-like behavior of pectin solutions. The frequency dependence of $G^\prime$ was higher than that of $G^\prime\prime$ at the same concentration, whose trend was more pronounced with decreasing pectin concentration. The shear viscosity $(\eta)$ was almost identical to the complex viscosity $(\eta^{*})$ at low concentration, following the Cox-Merz rule, but they became increasingly different at high concentration.

• Journal of The Korean Association For Science Education
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• v.38 no.5
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• pp.739-751
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• 2018

The purpose of this study is to identify the differences of argumentation discourses for Socio-Scientific Issues in the types of decision-making and personality traits of pre-service biology teachers. For this study, SSI discussion topics were selected according to four types of decision making: logical reasoning, suggestion of complement, emotional base, and internal conflict. Three groups were constructed based on personality traits such as extroversion, acceptability, and integrity. Each three group used the workbook specially developed and freely used the smart device for discussion. A recorder and a camcorder were used to record each group, their behavior was recorded and the written materials during the discussion were collected for the results. Using Walton's analysis framework, the collected data analyzed in terms of the source of utterance, the process of dialogue shift, and the critical movements that can judge the reasoning of utterance. As a result of the study, it was confirmed that the decision-making type of SSI topics and learners' personalities were influential in the decision-making process of SSI small group discussions. This research shows that there is a need to develop instructional materials considering decision-making types and learners' personality types of students as well as pre-service teachers for SSI discussion.

• Food Science and Preservation
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• v.21 no.1
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• pp.69-74
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• 2014

We tested for residual pesticide levels in school foodservice agricultural products in Seoul, Korea from 2010 to 2012. A total of 316 samples of 23 different types of agricultural products were analyzed via gas chromatography-nitrogen phosphate detector (GC-NPD), an electron capture detector (GC-${\mu}ECD$), a mass spectrometry detector (GC-MSD), and a high performance liquid chromatography-ultraviolet detector (HPLC-UV). We used multi-analysis methods to analyze 185 different pesticide types. Among the selected agricultural products, residual pesticides were detected in 26 samples (8.2%), of which 6 samples (1.9%) exceeded the Korea Maximum Residue limits (MRLs). We detected pesticide residue in more than 65% of the Chwinamul, while 6 among 9 analyzed samples contained pesticide residue, and 1 sample exceeded the Korea MRLs. Among the 185 kinds of pesticides that we have tested, 18 were detected, while 7 of them were detected more than twice. Data obtained were then used for estimating the potential health risks associated with the exposures to these pesticides. The most critical commodity is carbofuran in the perilla leaves, which has contributed 3.8% to the hazard index (HI). These results showed that the detected pesticides could not be considered as a serious public health problem. Nevertheless, constant supervision is recommended.

• Journal of Korean Society of Forest Science
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• v.87 no.4
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• pp.611-619
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• 1998

This study was carried out to examine the effects of soil acidification on growth and nutrient status of 2 - year - old Pious densiflora Sieb. et Zucc. seedlings grown for 120 days in brown forest soils acidified with $H_2SO_4$ solution with or without leaching rations from the soil. The concentrations of A1 in the acidified soils increased with increasing amount of $H^+$ added to the soil. The total dry weight of the seedlings was decreased by the addition of the $H_2SO_4$ solution. The increase of Al concentration in the belowground part resulted from the decreased concentration of essential mineral elements such as Ca and Mg in the aboveground part. In addition, a strong positive correlation(r=0.96, p<0.001) was observed between the dry weight of the seedlings and the molar (Ca+Mg+K)/A1 ratio of the soil solution. When the molar (Ca+Mg+K)/Al ratio was approximately 7.0, the dry weight of the seedlings began to decrease compared with that of the seedlings in the control treatment. The seedlings with the molar (Ca+Mg+K)/Al ratio of 1.0 resulted from approximately 40% growth reduction compared with the control value. The results suggest that the molar (Ca+Mg+K)/Al ratio of the soil solution may be a useful indicator for assessing the critical load of acid deposition.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.554-557
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• 2016

Recently, supercomputer has been increasingly adopted as a computing environment for scientific simulation as well as education, healthcare and national defence. Especially, supercomputing system with heterogeneous computing resources is gaining resurgence of interest as a next-generation problem solving environment, allowing theoretical and/or experimental research in various fields to be free of time and spatial limits. However, traditional supercomputing services have only been handled through a simple form of command-line based console, which leads to the critical limit of accessibility and usability of heterogeneous computing resources. To address this problem, in this paper, we provide the design and implementation of web-based HPC (High Performance Computing) job management framework for computational scientific simulation. The proposed framework has highly extensible design principles, providing the abstraction interfaces of job scheduler (as well as bundle scheduler plug-ins for LoadLeveler, Sun Grid Engine, OpenPBS scheduler) in order to easily incorporate the broad spectrum of heterogeneous computing resources such as cluster, computing cloud and grid. We also present the detailed specification of HTTP standard based RESTful endpoints, which manage simulation job's life-cycles such as job creation, submission, control and status monitoring, etc., enabling various 3rd-party applications to be newly created on top of the proposed framework.

• Journal of Life Science
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• v.22 no.12
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• pp.1600-1607
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• 2012

The matrix metalloproteinase (MMP) family plays essential roles in physiological processes such as embryonic development, angiogenesis, wound healing, and tissue homeostasis as a consequence of MMPr capacity for breaking down many types of extracellular matrix proteins. Imbalanced regulation of MMP expression can also lead to pathological conditions such as tumor progression. We recently reported that the Drosophila Mmp1 gene is highly expressed in the digestive tract and is required for the maintenance of intestinal homeostasis such as by restriction of uncontrolled intestinal stem cell proliferation. However, the regulatory mechanisms of MMP gene expression in the intestine remain unclear. In this study, we determined that the expression of Mmp1 is regulated by the homeodomain transcription factor Caudal. Experiments using the targeted expression of Caudal under the regulation of Gal4-UAS system indicated that endogenous Caudal is required for the Mmp1 gene expression in the adult Drosophila intestine and that exogenous Caudal induces Mmp1 expression. Transient transfection experiments indicated that Caudal can activate the promoter activity of Mmp1 and that several putative Caudal binding sites in the 5'-flanking region of the Mmp1 gene may be critical to the upregulation by Caudal. Our data suggest that Mmp1 is one of the target genes of Caudal in physiological normal condition and in tumorigenesis.

• Journal of Life Science
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• v.24 no.6
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• pp.700-706
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• 2014

Doxorubicin (trade name adriamycin), an anthracycline antibiotic, is commonly used in the treatment of a wide range of cancers, including hematological malignancies, many types of carcinoma, and soft tissue sarcomas. It is closely related to the natural product daunomycin, and like all anthracyclines, it works by intercalating DNA. Its most serious adverse effect is life-threatening heart damage. Its anti-metastatic mechanisms in human prostate carcinomas are not fully understood. In this study, we used LNCap human prostate carcinoma cells to investigate the inhibitory effects of doxorubicin on cell motility and invasion, two critical cellular processes that are often deregulated during metastasis. Doxorubicin treatment inhibited cell migration and invasiveness of LNCap cells without showing any toxicity. Doxorubicin treatment also suppressed the activity and expression of matrix metalloproteinase (MMP)-2 and MMP-9, which were associated with up-regulated expression of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in LNCap cells. Doxorubicin treatment also attenuated the expression levels of claudin family members (claudin-1, -2,-3 and -4), major components of tightening of tight junctions (TJs) and increased the tightening of TJs, as demonstrated by an increase in transepithelial electrical resistance. The present findings demonstrate that doxorubicin reduces the migration and invasion of prostate carcinomas LNCap cells by modulating the activity of TJs and MMPs.

• Korean Chemical Engineering Research
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• v.44 no.6
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• pp.623-630
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• 2006

The slag viscosity is an important factor determining the operation temperature of entrained flow type of gasifiers. The temperature of critical viscosity, $T_{cv}$, for 5 crystalline slags was predicted by empirical models and FactSage equilibrium calculations, and the validity of each method was tested. Two empirical models were employed: one using $T_h$ from the ash fusion test, and the other using the concentrations of 5 major components. The first model using $T_h$ over-predicted $T_{cv}$ by $20{\sim}100^{\circ}C$, while the model based on the slag composition under-predicted $T_{cv}$ by $80{\sim}120^{\circ}C$. In the equlibrium calculations, $T_{cv}$ was obtained from the liquidus temperature. When the 4-major component concentrations were used in the calculation, the predicted temperatures were higher than the observed. The liquidus temperature was very sensitive to the concentrations of minor components, and the addition of MgO and $Na_2O$ lowered the liquidus temperature. The results with 4 major and 3 minor components most closely described experimentally observed $T_{cv}$. In the case that a chromia refractory was used, it was shown that $Cr_2O_3$ concentration in the slag also needs to be included for more accurate prediction of $T_{cv}$.

• Journal of Educational Research in Mathematics
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• v.26 no.3
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• pp.403-420
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• 2016

Some of the critical changes in the revised 2015 Korean Mathematics curriculum were that direct proportion and inverse proportion were moved from elementary school to middle school and that supplementary content related to correlation was included. These decisions were based on comparative studies of international curriculum. Therefore in this study, we selected countries for comparison; United States, England, France, Finland, Australia, Japan, Singapore, China and Taiwan. We looked into the timing and scope for direct/inverse proportion and correlation in curricula of these countries. Along with this, we established four criteria; vertical sequence, horizontal sequence, external connection, and internal connection for an analysis framework. Then we compared and analysed the direct/inverse proportion and correlation in each curriculum. As a result, in most of these curricula, the direct/inverse proportions are introduced at middle school or are introduced at elementary school and then developed further at middle school. Most of curriculums on direct/inverse proportion and correlation match the four criteria. Correlation is introduced in high school mathematics in all counties except Finland and it is dealt in diverse context introducing related concepts, for example, correlation coefficient, regression straight line, and least square. We suggested that it is necessary to refer these international trends for the next revision of curriculum.

• Journal of Crop Science and Biotechnology
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• v.11 no.3
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• pp.199-204
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• 2008

Seed dormancy behavior of weed seeds is a critical determinant of their survival rates in a given cropping system as it helps the weeds to evade herbicides and other weeding practices. We investigated the effects of red light, alternating temperature, stratification duration and different doses of nitrogen containing compounds alone or in combination with red light on breaking seed dormancy of Chenopodium album L. The application of red light(80 ${\mu}mols^{-1}m^{-2}$) significantly increased seed germination of C. album in all treatments. Germination rates of 12 h incubated seeds were highest under 20 min of red light irradiation than 1 min, 5 min and 10 min treated seeds. Germination rate was significantly higher at alternating temperatures of $25^{\circ}C\;and\;5^{\circ}C$ for 12 h each with an irradiation of red light(80 ${\mu}mols^{-1}m^{-2}$) for 10 min than other treatments. Stratification period of 15 days significantly stimulated germination percentage of seeds incubated in dark, although 5 days of stratification along with red light application for 10 minutes exhibit similar effects on seeds. Seed germination was also enhanced by nitrogen containing compounds like $NaNO_2,\;KNO_3,\;NH_4Cl\;and\;NH_4NO_3$. We observed that seed germination increased significantly with 25 mM $KNO_3$ and 10 mM $NH_4NO_3$ in dark condition, while $NaNO_2$ and $NH_4Cl$ enhanced seed germination under red light irradiation. It was concluded that red light alone or synergized with alternating temperatures, stratification and nitrogen compounds, especially nitrite and ammonium enhanced seed germination of C. album. Thus, the red light can play a vital role in present and future weed management strategies.