• Journal of Food Hygiene and Safety
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• v.32 no.5
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• pp.434-442
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• 2017

The UV light in sunlight breaks down the chemical bonds in a polyolefin polymer through a process called photodegradation, ultimately causing cracking, chalking, colour changes, and loss of physical properties such as impact strength, tensile strength, elongation, and others. UV absorbers are used to prevent or terminate the oxidation of plastics by UV light. They are receptive to UV radiation and dissipate the energy harmlessly as heat. Benzotriazoles and benzophenones are used mainly in polyolefins such as polyethylene and polypropylene. In this study, we have developed a method for the analysis of 12 UV absorbers, which are Uvinul 3000, Cyasorb UV 24, Uvinul 3040, Tinuvin 312 and P, Seesorb 202, Chimassorb 81, Tinuvin 329, 234, 326, 328 and 327, migrated from the food packaging materials into four food simulants for aqueous, acidic, alcoholic and fatty foods. The UV absorbers in food simulants were determined by reversed-phase high performance liquid chromatograph-ultraviolet detector with 310 nm after solid-phase extraction with a hydrophilic-lipophilic balance (HLB) cartridge or dilution with isopropanol. The analytical method showed a good linearity of coefficient ($R^2{\geq}0.99$), limits of detection (0.049~0.370 mg/L), and limits of quantification (0.149~1.120 mg/L). The recoveries of UV absorbers spiked to four food simulants ranged from 70.05% to 110.13%. The developed method would be used as a reliable tool to determine concentrations of the migrated UV absorbers.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.29 no.2 s.43
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• pp.205-232
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• 2003

Ursolic acid (UA) and Oleanolic acid (ONA), known as urson, micromerol and malol, are pentacyclic triterpenoid compounds which naturally occur in a large number of vegetarian foods, medicinal herbs, and plants. They may occur in their free acid form or as aglycones for triterpenoid saponins, which are comprised of a triterpenoid aglycone, linked to one or more sugar moieties. Therefore UA and ONA are similar in pharmacological activity. Lately scientific research, which led to the identification of UA and ONA, revealed that several pharmacological effects, such as antitumor, hepato-protective, anti-inflammatory, anticarcinogenic, antimicrobial, and anti-hyperlipidemic could be attributed to UA and ONA. Here, we introduced the effect of UA and ONA on acutely barrier disrupted and normal hairless mouse skin. To evaluate the effects of UA and ONA on epidermal permeability barrier recovery, both flanks of 8-12 week-old hairless mice were topically treated with either 0.01-0.1 mg/ml UA or 0.1-1 mg/ml ONA after tape stripping, and TEWL (Transepidermal water loss) was measured . The recovery rate increased in those UA or ONA treated groups (0.1 mg/ml UA and 0.5 mg/ml ONA) at 6 h more than $20\%$ compared to vehicle treated group (p<0.05). Here, we introduced the effects of UA and ONA on acute barrier disruption and normal epidermal permeability barrier function. For verifying the effects of UA and ONA on normal epidermal barrier, hydration and TEWL were measured for 1 and 3 weeks after UA and ONA applications (2mg/ml per day). We also investigated the features of epidermis and dermis using electron microscopy (EM) and light microscopy (LM). Both samples increased hydration compared to vehicle group from f week without TEWL alteration (p<0.005). EM examination using RuO4 and OsO4 fixation revealed that secretion and numbers of lamellar bodies and complete formation of lipid bilayers were most prominent $(ONA{\geq}UA>Vehicle)$. LM finding showed that thickness of stratum corneum (SC) was slightly increased and especially epidermal thickening and flattening was observed (UA>ONA>Veh). We also observed that UA and ONA stimulate epidermal keratinocyte differentiation via $PPAR\;\alpha$. Protein expression of involucrin, loricrin, and filaggrin increased at least 2 and 3 fold in HaCaT cells treated with either $ONA\;(10{\mu}M)$ or UA $(10{\mu}M)$ for 24h respectively. This result suggested that the UA and ONA can improve epidermal permeability barrier function and induce the epidermal keratinocyte differentiation via $PPAR\;{\alpha}$. Using Masson-trichrome and elastic fiber staining, we observed collagen thickening and elastic fiber elongation by UA and ONA treatments. In vitro results of collagen and elastin synthesis and elastase inhibitory activity measurements were also confirmed in vivo findings. These data suggested that the effects of UA and ONA related to not only epidermal permeability barrier functions but also dermal collagen and elastic fiber synthesis. Taken together, UA and ONA can be relevant candidates to improve epidermal and dermal functions and pertinent agents for cosmeseutical applications.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.4
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• pp.489-495
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• 1996

Seedling emergences of four rice varieties (Dongjinbyeo, Dadajo, Galsaekggarak-sharebyeo, and Italiconaverneco) and three barnyardgrass species(Echjnochloa oryzjcola, E. crus-gali var. crus gali E. crus-gali var. praticola) were evaluated in relation to soil strength. Soil strength was varied by compressing the entire volume of soil with a hydraulic jack so as to be 0.5, 1, 2, 3, 6kg /$\textrm{cm}^2$. Soil strength was measured with a penetrometer (Yamanaka type) and soil covering above the seed was 4cm deep. Experiments were conducted at two air temperature conditions of 17 and $25^{\circ}C$. At a soil strength of up to 2kg/$\textrm{cm}^2$, little or no decrease in seedling emergence occurred in all rice varieties and barnyardgrasses tested. Above that value, seedling emergence decreased progressively as the soil strength increased. The degree of decrease was greatest in Dongjinbyeo and smallest in Dadajo among tested rice varieties, and greatest in Echinochloa oryzicola among barnyardgrasses, being greater in barnyardgrasses than rice. Seedling emergence was delayed almost linearly as the soil strength increased. The delay was greatest in Dongjinbyeo among rice varieties and in Echinochloa oryzicola among barnyardgrasses. Mesocotyl length increased as soil strength increased up to 2 to 3kg / $\textrm{cm}^2$ in Dongjinbyeo and Dadajo in 17$^{\circ}C$ and $25^{\circ}C$, and up to 6kg/$\textrm{cm}^2$ in Galsaekggaraksharebyeo and Italiconaverneco in $25^{\circ}C$. Dongjinbyeo showed the least elongation of mesocotyl among rice varieties in any soil strength. The total length of mesotyl, first internode and incomplete leaf showed little variation with soil strength. The total length was longer than the 4cm covering depth in other varieties except Dongjinbyeo. This might have caused the lower emergence rate in Dongjinbyeo than other varieties in higher soil strength.

• Journal of Plant Biotechnology
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• v.38 no.4
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• pp.285-292
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• 2011

In plants, heteroblasty reflects the morphological adaptation during leaf development according to the external environmental condition and affects the final shape and size of organ. Among parameters displaying heteroblasty, leaf index is an important and typical one to represent the shape and size of simple leaves. Leaf index factor is eventually determined by cell proliferation and cell expansion in leaf blades. Although several regulators and their mechanisms controlling the cell division and cell expansion in leaf development have been studied, it does not fully provide a blueprint of organ formation and morphogenesis during environmental changes. To investigate genes and their mechanisms controlling leaf index during leaf development, we carried out molecular-genetic and physiological experiments using an Arabidopsis mutant. In this study, we identified macrophylla (mac) which had enlarged leaves. In detail, the mac mutant showed alteration in leaf index and cell expansion in direction of width and length, resulting in not only modification of leaf shape but also disruption of heteroblasty. Molecular-genetic studies indicated that mac mutant had point mutation in ROTUDIFOLIA3 (ROT3) gene involved in brassinosteroid biosynthesis and was an allele of rot3-1 mutant. We named it mac/rot3-5 mutant. The expression of ROT3 gene was controlled by negative feedback inhibition by the treatment of brassinosteroid hormone, suggesting that ROT3 gene was involved in brassinosteroid biosynthesis. In dark condition, in addition, the expression of ROT3 gene was up-regulated and mac/rot3-5 mutant showed lower response, compare to wild type in petiole elongation. This study suggests that ROT3 gene has an important role in control of leaf index during leaf expansion process for proper environmental adaptation, such as shade avoidance syndrome, via the control of brassinosteroid biosynthesis.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.4
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• pp.359-365
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• 1985

The four rice varieties, Kwanak, Nongbaek, Pungsan and Nampung-byo were cultivated to examine the growth conditions and grain yield in a Gyuam SiL paddy field irrigated with cold water around $17^{\circ}C$. Water temperatures for various distances from the inlet were measured. The results were summerized as follows. 1. Culm length, panicle exertion, diameter of the 3rd internode stem, heading date, fertilization rate, ripeness rate, no. of grains per panicle and grain yield were sensitive to water temperature. Panicle length, flag-leaf length, diameter of spike-neck and no. of panicles, however, were negligibly sensitive and there were no differences among varieties. 2. Elongations of the 2nd and 3rd internode steam were unsensitive to water temperature. 1st internode elongation and 4th internode development, however, were sensitive which was major factor in the culm length. 3. Ratios of partial dry weight to total dry weight were closely correlated with water temperature, Therefore, dry weight of grain was increased with water temperature while that of plant and root decreased. 4. Chlorophyll contents were decreased with the increment of water temperature and the highest at $20^{\circ}C$. 5. There was no grain yield at $17^{\circ}C$, Increases of grain yield to water temperature per unit were order at Pungsan > Kwanak > Nongbaek > Nampung. 6. The critical temperature in grain yield was $21^{\circ}C$. Optimum temperatures of Japonica ${\times}$ Indica types were higher than those of Japonica types.

• Journal of Life Science
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• v.19 no.5
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• pp.581-586
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• 2009

Bell pepper plants (Capsicum annuum cv. Plenty) were grown under low night temperatures (LNT: day/night temperature of $28/13^{\circ}C$) and optimum night temperatures (ONT: day/night temperature of $28/20^{\circ}C$) in growth chambers. Pollen grains were collected from plants in the growth chamber and incubated at 10, 15, 20, 25, and $30^{\circ}C$. After 24 hr incubation, in both ONT and LNT, the highest percent pollen germinations were observed at $25^{\circ}C$ followed by germinations at $30^{\circ}C$. Percent pollen germination at $25^{\circ}C$ was 42% in ONT - two times higher than in LNT at 21%. Pollen tube length was much longer at ONT than at LNT, regardless of incubation temperature. Compared with other treatments, earlier and quicker pollen tube elongation was observed in ONT pollen grains incubated at $25^{\circ}C$. To find pollen viability in plant growing conditions, pollen grains were incubated in LNT ($28/13^{\circ}C$) and ONT ($28/20^{\circ}C$) growth chambers for 24 hr. Petri-dishes with pollen grains were put in the growth chambers at the beginning of the night condition. Pollen grains in the LNT growth chamber did not germinate at night ($13^{\circ}C$), but began to germinate when the day condition ($28^{\circ}C$) started. Pollen grains in the ONT condition, however, started germinating from the early night ($20^{\circ}C$) and germination continued during the day ($28^{\circ}C$). Plants in LNT showed increased flower stalk length, ovary diameter, stamen length, flower weight, and fruit length. LNT conditions did not impair seed set. There were no differences in seed sets between fruits at LNT and ONT. Normal seed sets in LNT show that fertilization may be completed during daytime. However, further investigation is needed to find what extent of temperature stress causes malformed and/or parthenocarpic fruits in this bell pepper.

• Horticultural Science & Technology
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• v.33 no.3
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• pp.409-419
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• 2015

This study was conducted to establish an efficient screening method for watermelon plants resistant to Fusarium wilt (FW), which is caused by Fusarium oxysporum f. sp. niveum (Fon). An HA isolate was prepared from a wilted watermelon plant in Haman-gun and identified as F. oxysporum f. sp. niveum based on morphological characteristics, molecular analyses of ITS (internal transcribed spacer) and TEF (translation elongation factor $1{\alpha}$) sequences, and host specificity on cucurbits including watermelon, melon, oriental melon, and cucumber. The assay for disease response of watermelon differentials indicated that the HA isolate was race 0. Among seven liquid media tested, the highest amount of Fon spores was produced from V8-juice broth, which was selected as a medium for mass production of Fon. The disease assay for 21 watermelon and 11 watermelon-rootstock cultivars demonstrated that 20 watermelon cultivars except for 'Soknoranggul' were susceptible; 'Soknoranggul' was moderately resistant. All the tested rootstock cultivars were highly resistant to the HA isolate. The evaluation of disease development depending on various conditions suggested that an efficient screening method for FW resistance in watermelon plants is to dip the roots of 10-day-old seedlings in spore suspension of $1.0{\times}10^5-1.0{\times}10^6conidia{\cdot}mL^{-1}$ for 30 min., to transplant the seedlings to plastic pots with a fertilized soil, and then to cultivate the plants at $25^{\circ}C$ for 3 weeks.

• Korean Journal of Organic Agriculture
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• v.16 no.1
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• pp.127-142
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• 2008

This study was carried out to germination characteristics by temperature conditions and allelopathic effects of aqueous extracts on Amaranthus spinosus L. in order to investigate the competitive dominant in plant ecosystem and possibility application of natural herbicide. A. spinosus L. sprouted after 24 hour from seeding in $30{\sim}45^{\circ}C$ treatment. The germination ratio of A. spinosus L. was the highest estimated at 63.3(${\pm}2.9$)% in $40^{\circ}C$ treatment, followed by 33.3(${\pm}2.9$)% in $35^{\circ}C$, 1.7(${\pm}2.9$)% in $30^{\circ}C$ and 5.0(${\pm}0.0$)% in $45^{\circ}C$ treatment. It was generally decreased the Relative Germination Ratio(RGR), the Relative Elongation Ratio(RER), the Relative Fresh weight Ratio(RFR) of receptor plants by the aqueous extracts of concentration of A. spinosus L. but it was differently inhibited the kind of receptor plant species. And it was different effected among growing regions that aqueous extracts of concentration of A. spinosus L. inhibited more root than shoot. The total phenolic compounds content of A. spinosus L. was decreased gradually middle, first and last of growth stage, and gradually decreased to leaves, roots and stems. We think that A. spinosus L. appeared high germination ratio at a short period and showed allelopathic effects on other plants. Therefore A. spinosus. L. hold the competitive dominant of plant ecosystem in Jeju Island and possibility application of natural herbicide.

• Food Science and Preservation
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• v.16 no.2
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• pp.179-185
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• 2009

To develop an Enoki mushroom packaging method, mushrooms were stored at $1^{\circ}C$ for 12 days after passive MAP packaging(PM), vacuum packaging(VM), and gas flushing packaging(AM), after investigation of film thickness influences on respiration rates and gas compositions(LDPE films 20, 40, and 60 m in thickness were tested). Enoki mushrooms had respiration rates of 26.4 mL $CO_2/kg/hour$ at $0^{\circ}C$, 80.0 mL $CO_2/kg/hour$ at $10^{\circ}C$, 130.9 mL $CO_2/kg/hour$ at $20^{\circ}C$, and 130.9 mL $CO_2/kg/hour$ at $30^{\circ}C$. A film thickness of 20 m was chosen for further tests to maintain the oxygen concentration above the minimum growth level; the thinnest film offered a higher gas transmittance rate than did the thicker films. No anaerobic respiration was evident over 12 days of storage using any packaging method, with the exception of VM. AM, using a high concentration of $CO_2$, restricted respiration rate. Mushrooms packaged using the VM method showed the greatest weight loss and extent of discoloration among the packaging methods tested, followed by AM mushrooms using 50% $CO_2/10%\;O_2/40%\;N_2$. Mushrooms packaged by the VM and PM methods developed a serious off-flavor after 2 days of storage, and a high stipe elongation rate after 5 days of storage, respectively. However, AM using 50% $CO_2/10%\;O_2/40%\;N_2$ of various gas ratios tested, allowed Enoki mushrooms to be maintained for up to 12 days without development of off-flavor, discoloration, or moldiness.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.17 no.1
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• pp.10-18
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• 2006

Objective : The aims of this study were to explore the relations of internet addiction to depression, impulsivity, and obsessive-compulsivity in adolescents. Methods : 1410 high school students (male=611, female=799 : mean age=$16.2{\pm}0.7$) were included in this study. The questionnaire consisted of items on demographic characteristics and internet use pattern. We assessed the level of internet addiction using Young's internet addiction scale (IAS) Barratt impulsiveness scale (BIS) and Maudsley obsessive compulsive inventory (MOCI) were also self-rated. In this study, We defined upper 25% of IAS as 'addiction group' and lower 25% as 'non-addiction group'. Results : The results were as follows ; 1) Male students had significantly higher mean scores on Internet addiction scale than females and there was significantly higher rate of male students in addiction group. 2) The addiction group spent more time for internet use, especially for games than non-addiction group. 3) The addiction group showed significantly higher total scores on BDI, BIS, and MOCI than non-addiction group. 4) Significant associations have been found between the level of internet addiction and depression, impulsivity, and obsessive-compulsivity, respectively. Conclusion : Depression, impulsivity, and obsessive-compulsivity could be significant factors predicting internet addiction. Especially, direct effect of impulsivity could be the most significant to explain internet addiction. Adolescents with high impulsivity may be vulnerable to internet addiction.