• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.361-365
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• 2013

To investigate factors determining peach fruit quality, chlorophyll content by leaf positions, chlorophyll content of foliated leaf, change of leaf area, and photosynthetic capacity were monitored. Photosynthetic rate in response to radiation intensity and $CO_2$ concentration, and change of sucrose content after shading treatment also were investigated. Chlorophyll content was similar in $5-12^{th}$ leaves after 10 days of foliation, while young $13-16^{th}$ leaves showed lower chlorophyll contents. Chlorophyll content was 2.56 ${\mu}g/cm^2$ on May $28^{th}$, just after foliation, and rapidly increased up to 6.35 ${\mu}g/cm^2$ on June $12^{th}$. After this point, chlorophyll content gradually increased during two months showing the highest value of 9.03 ${\mu}g/cm^2$ on August $14^{th}$. Leaf area was 27.1 $cm^2$ just after foliation and 37.7 $cm^2$ on $10^{th}$ day of foliation increasing 10.6 $cm^2$ during 10 days. Leaf area slowly increased by 3.9 $cm^2$ during next one month. Photosynthetic capacity increased rapidly until the $30^{th}$ day of foliation showing the highest capacity of 13.8 ${\mu}mol/m^{-2}/sec^{-1}$. After this point, photosynthetic capacity decreased sharply. Photosynthetic rate in response to radiation intensity increased rapidly until the PPFD reached to 600 ${\mu}mol/m^{-2}/sec^{-1}$ and increased gradually from 600 ${\mu}mol/m^{-2}/sec^{-1}$ to 1200 ${\mu}mol/m^{-2}/sec^{-1}$ of PPFD and stayed stable beyond this point. Photosynthetic rate in response to $CO_2$ concentration increased until 600 ppm of $CO_2$. At higher $CO_2$ concentration, photosynthetic rate stayed stable or decreased. Sucrose content in leaves was not significantly different between control and shading group until one hour of shading treatment while decreased in shading group after two hours of treatment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.3
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• pp.308-317
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• 2015

The aim of the present study was to investigate the ear and kernel characteristics of colored waxy corn hybrids during ripening according to different sowing dates. Heukjinjuchal and Eolrukchal 1 were sown at April 20 (first cropping) and July 20 (second cropping) in 2011~2012. The accumulated temperature from silking to harvesting was about $590{\sim}610^{\circ}C$. It takes 23~24 days when Heukjinjuchal and Eolrukchal 1 were sown in April 20, but July 20 sowing takes 32~35 days. Ear weight, ear diameter, 100-kernel weight and starch content of colored waxy corn were increased as ears matured (p<0.05). Growth temperature was getting decreased during the ripening stage of second cropping, the rate of ear and kernel development had slowed. Starch granules started to accumulate in the cells around the pericarp, then developed in the cells around the embryo. In the second cropping, starch granules in the kernel of colored waxy corn were less compact than the first cropping. The contents of total anthocyanins, cyanidin-3-glucoside and pelargonidin-3-glucoside were increased according to ripening (p<0.05). These results will be helpful to farmers for double cropping of colored waxy corn cultivation and management.

• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.234-243
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• 2007

Algal growth potential (AGP) test was performed to evaluate the water quality and changes in phytoplankton communities before and after a heavy rain event at six sampling sites in Cheonggye Stream (St. 1 and 2), Jungnang Stream (St. 3 and 4), and Lower part of Han River System (St. 5 and 6) after rehabilitation of Cheonggye Stream, October 2005. To test AGP on each sampling site, cyanobacterium Microcystis aeruginosa was applied as a standard alga. Total nitrogen (TN) showed high values at Jungnang Stream, while St. 4 recorded highest values in this study. However, TN values of Cheonggye Stream and Lower Part of Han River showed similar levels. Total phosphate (TP) also showed high values at Jungnang Stream, while St. 4 recorded highest. However, TP in Cheonggye Stream were extremely low levels. Although chlorophyll-${\alpha}$ (chi-${\alpha}$) contents before the rain event were similar through the sampling sites, chl-${\alpha}$ after the rain increased dramatically at Jungnang Stream and Lower part of Ban River. In particular, after the rain, TP was the highest at St. 4, where Cyclotella sp. dominated the phytoplankton community. When compared with control, AGP values before the rain were comparatively low in all sites, while those after the rain highly increased with the dose-dependently of field water added, due perhaps to the increased nutrients by rainfall. Similar results were observed in Cheonggye Stream. Therefore, for the aesthetic fostering for the citizens, although Cheonggye Stream was Presently being sustained by treated water supply, they have a potential of outbreak of phytoplankton by the increased nutrients supply when a heavy rain comes.

• Applied Biological Chemistry
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• v.20 no.2
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• pp.188-204
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• 1977

The studies on the saponins of Korean ginseng, Panax ginseng C.A. Meyer, were performed according to the cultivating locations, sampling seasons, plant parts, and growing stages. The changes in saponin content in the course of manufacturing Red ginseng and Ginseng extract were observed. In this paper, a new method for the determination of the total and the individual saponin glucosides was proposed and applied to the samples under study. The method employing Digital Densitorol DMU-33C (Toyo electric Co., Japan) followed the separation of the saponins by means of a preparative thin layer chromatography. The saponin contents and their fractional distribution were summarized as follows: 1. The average concentrations(% plant dry weight) of semi-purified saponins in the roots of Korean ginseng planted in the various locations were 5.0%(Keumsan), 6.0% (Kimpo), and 5.4% (Pocheon), respectively. 2. There were 3.3% saponins in White ginseng(Rhizome) and 12.7% saponins in Ginseng tail (Fibrous root). 3. Regarding the year of growth, the contents of saponins were 90.3mg (2-year-old ginseng), 254.4mg (3-year-old ginseng), 404.2mg (4-year-old ginseng). 999.6mg (5-year-old ginseng), and 1377.1mg (6-year-old ginseng) respectively, and the saponin factions containing panaxatriol as an aglycone increased. 4. Thin layer chromatography revealed that Red ginseng yielded many saponins which Shibata et al. designated as $ginsenoside-Rb_1$ (22.1%), $-Rb_2(15.4%)$, -Rc(12.6%), -Re (15.7%), and $-Rg_1$, (9.3%). 5. 29.9% of crude saponins were isolated from ethanolic extract of Panax ginseng fibrous root and their extraction yield was 94.2% of fibrous root saponin.

• Journal of Distribution Research
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• v.6 no.2
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• pp.1-17
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• 2002

The recent dot-com craze has been one of the main causes that accelerated the growth of internet-related companies in diversity as well as in size. Meanwhile, the domestic market of supplies and equipment for internet businesses has been dominated by major foreign companies. To regain their market positions, the domestic manufacturers had to find the way to build up their competitive advantages, such as meeting their customers needs and reducing overall costs. In this study, one domestic PC server manufacturer, which competes fiercely with foreign manufacturers for the top place, has been chosen as a model to evaluate its current supply chain and to find an area that can be improved for a better performance. System Dynamics is used throughout the study. The central concept to system dynamics is understanding how all the objects in a system interact with one another. It focuses on feedback and secondary effects to think through how a strategy might or might not work, depending on how organizational changes are received, and what kinds of consequences emerge. Then, computerized models were built for simulations, each with different conditions, and, finally, the results were evaluated based on some criteria which are considered to be important and meaningful. The inefficiency that exists in the supply chain was proved to be a thirty-day long purchasing order leadtime, and it was expected that more effective supply chain could be formed if the leadtme were reduced to 14 days or 7 days. The results of simulations showed that the overall expected costs in supply chain was the least with the purchasing leadtime being 7 days. The lower average number of parts held as inventory, along with the reduced lost sales, acted as the factor reducing the expected overall costs. Although there was a slight increase in the average number of final products held as inventory and the total ordering cost, the benefits from lower parts inventory and reduced lost sales were large enough to justify the overall cost reduction.

• Korean Journal of Soil Science and Fertilizer
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• v.5 no.2
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• pp.39-42
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• 1972

A field experiment was conducted in a moderately well drained paddy field doveloped in a narrow strip of a valley in order to observe changes of potassium requirement in paddy production when lime is applied. The results obtained are as follows; 1. The response of paddy to potassium (K) and lime (L) is represented mathematically as follow; $Y=462.78+11.582K-0.058L-0.768K^2-0.000015L^2+0.2204KL$. It is considered that the increase of potassium reqirement when slaked lime is applied, is partially due to the increased growth of plant accomplished by the improvement of soil conditions such as the reduction of respiration inhibitors and cationic balance in soil solution. 2. An economic analysis of the use of potassium and slaked lime applying the costs, 80 won per kg of paddy, 19 won per kg of potassium and 4 won per kg of slaked lime to the response function above, showed that the slaked lime without potssium brought a large loss, whereas the use of the lime together with potassium increased the profit remarkably. The profit increased when 10kg of potassium per 10 a is applied in addition to 200kg slaked limn, per 10kg is amounted 4,685 won. 3. A linear relationship between the economic optimum dose of potassium (y) and the amount of slaked lime (x) in paddy production, is obtained as follow; $$y=7.48+\frac{2.77}{200}x$$ It is, however, considered that the amount of potassium to he used might differ according to the soil conditions such as the potassium content and cation exchange capicity of the soil.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.5
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• pp.584-590
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• 2012

Dried $Compositae$ flowers have traditionally been used for the treatment of anti-inflammatory and anti-oxidative stress in Korea. This paper investigates the effects of $Compositae$ extracts on the inhibition of proliferation and apoptosis of human gastric cancer AGS cells, human breast cancer MDA-MB-231 cells, and SK-BR-3 cells. The proliferation of AGS cells, MDA-MB-231 cells, and SK-BR-3 cells were determined by MTT assay. Several $Compositae$ extracts inhibited proliferation of AGS cells, MDA-MB-231 cells, and SK-BR-3 cells in a dose-dependent manner. To assess the apoptosis of $Compositae$ extracts, the nuclei of MDA-MB-231 cells were stained with DAPI. The presence of chromatin condensation in the $Compositae$ extract-treated cells was detected on a fluorescent microscope (${\times}200$). We conducted Western blot analysis of changes in Bcl-2, Bax, and p53 protein expression levels. Apoptosis by $Chrysanthemum$ $zawadskii$ subsp. coreanum, $Chrysanthemum$ $zawadskii$ var. $tenuisectum$ and $Rudbeckia$ $laciniata$ var. $hortensis$ treatment created a decrease in Bcl-2 expression, whereas the expression of Bax and p53 were increased. These results indicate that $Chrysanthemum$ $zawadskii$ $subsp.$ $coreanum$, $Chrysanthemum$ $zawadskii$ var. $tenuisectum$ and $Rudbeckia$ $laciniata$ var. $hortensis$ inhibit breast cancer cell growth through the induction of apoptosis.

• Korean journal of applied entomology
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• v.57 no.3
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• pp.127-135
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• 2018

Climate change can affect variables related to the life cycle of insects, including growth, development, survival, reproduction and distribution. As it encourages alien insects to rapidly spread and settle, climate change is regarded as one of the direct causes of decreased biodiversity because it disturbed ecosystems and reduces the population of native species. Hypera postica caused a great deal of damage in the southern provinces of Korea after it was first identified on Jeju lsland in the 1990s. In recent years, the number of individuals moving to estivation sites has concerned scientists due to the crop damage and national proliferation. In this study, we examine how climate change could affect inhabitation of H. postica. The MaxEnt model was applied to estimate potential distributions of H. postica using future climate change scenarios, namely, representative concentration pathway (RCP) 4.5 and RCP 8.5. As variables of the model, this study used six bio-climates (bio3, bio6, bio10, bio12, bio14, and bio16) in consideration of the ecological characteristics of 66 areas where inhabitation of H. postica was confirmed from 2015 to 2017, and in consideration of the interrelation between prediction variables. The fitness of the model was measured at a considered potentially useful level of 0.765 on average, and the warmest quarter has a high contribution rate of 60-70%. Prediction models (RCP 4.5 and RCP 8.5) results for the year 2050 and 2070 indicated that H. postica habitats are projected to expand across the Korean peninsula due to increasing temperatures.

• Korean Journal of Agricultural Science
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• v.25 no.2
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• pp.168-175
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• 1998

To evaluate the storage characteristics of pheasant meat products, contents of aerobic, anaerobic and food poisoning bacteria as well as VBN were measured during storage at various temperatures. 1. During the storage Escherichia coli and food poisoning bacteria including Salmonella, Shigella and Staphylococcus were not detected from any of the pheasant meat products. 2. Total plate counts of aerobic and anaerobic bacteria increased with storage temperature, showing more than $10^6CFU/g$ of most pheasant meat products within 5~10 days of storage at $20^{\circ}C$ and $30^{\circ}C$. However, frank sausage, loin ham, pressed ham and salad showed less than $10^5CFU/g$ in 20~30 days of storage at $20^{\circ}C$. 3. When stored at $10^{\circ}C$, smoked product, electric roasted product and pressed ham showed the bacterial counts of more than $10^4CFU/g$ within 10 days of storage. Frank sausage, loin ham and salad, however, showed less than $10^3CFU/g$ in 10 days of storage at $10^{\circ}C$. 4. VBN contents of smoked product, electric roasted product and frank sausage exceeded edible limit of 20 mg%, showing more than 40 mg% and 80 mg% within 5 days and 10 days, respectively, of storage at $10^{\circ}C$. In contrast, loin ham, pressed ham and salad had the VBN of less than 20 mg% in 10 days of storage at $10^{\circ}C$. In summary, while pheasant meat products in general appear to be prone to microbial growth, loin ham and salad are thought to have a longer storage period than others, showing about 10 days of preservation at $10^{\circ}C$. Products other than loin ham and salad are suggested to be stored frozen or refrigerated at below $10^{\circ}C$.

• Journal of Life Science
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• v.27 no.9
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• pp.1070-1077
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• 2017

Chondrocyte apoptosis induced by reactive oxygen species (ROS) plays an important role in the pathogenesis of osteoarthritis. Schisandrin A, a bioactive compound found in fruits of the Schisandra genus, has been reported to possess multiple pharmacological and therapeutic properties. Although several studies have described the antioxidant effects of analogues of schisandrin A, the underlying molecular mechanisms of this bioactive compound remain largely unresolved. The present study investigated the cytoprotective effect of schisandrin A against oxidative stress (hydrogen peroxide [$H_2O_2$]) in SW1353 human chondrocyte cells. The results showed that schisandrin A preconditioning significantly inhibited $H_2O_2-induced$ growth inhibition and apoptotic cell death by blocking the degradation of poly (ADP-ribose) polymerase proteins and down-regulating pro-caspase-3. These antiapoptotic effects of schisandrin A were associated with attenuation of mitochondrial dysfunction and normalization of expression changes of proapoptotic Bax and antiapoptotic Bcl-2 in $H_2O_2-stimulated$ SW1353 chondrocytes. Furthermore, schisandrin A effectively abrogated $H_2O_2-induced$ intracellular ROS accumulation and phosphorylation of histone H2AX at serine 139, a widely used marker of DNA damage. Thus, the present study demonstrates that schisandrin A provides protection against $H_2O_2-induced$ apoptosis and DNA damage in SW1353 chondrocytes, possibly by prevention of ROS generation. Collectively, our data indicate that schisandrin A has therapeutic potential in the treatment of oxidative disorders caused by overproduction of ROS.