• Korean Journal of Environmental Agriculture
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• v.36 no.2
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• pp.97-105
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• 2017

BACKGROUND : Environmental stress has a major effect on the growth and yields of vegetables, and can significantly affect nutritionally important phytochemicals, causing large economic losses. METHODS AND RESULTS : The present study was aimed at exploring the effects of water stress on the carotenoid and proline contents in kale leaves to understand drought tolerance of kale plants. Kale was randomly divided into two groups at 57 days after sowing (DAS). One of the groups was well-watered (WW) and the other was water stressed (WS). Harvesting of kale leaves was started one day after treatment (58 DAS) and continued for 10 days (~67 DAS). We investigated the status of plant growth (leaf number, length, width, fresh weight) of kale throughout the study. Carotenoid (lutein, ${\alpha}-carotene$, zeaxanthin, ${\beta}-carotene$) and proline contents were analyzed by high-performance liquid chromatography (HPLC). Our results showed that the total carotenoid contents ranged from 926.0 to 1,212.0 mg/kg dry wt. (at 3 and 2 days, respectively) in WW treatment and 887.8 to 1,157.4 mg/kg dry wt. (at 10 and 4 days, respectively) in WS treatment. The ratio of individual carotenoid to the total carotenoid contents of kale leaves was 51.4 for lutein, 4.44 for zeaxanthin, 2.76 for ${\alpha}-carotene$, and 41.4% for ${\beta}-carotene$. Total carotenoid contents showed a significant reduction from 7 days (1,037.2 mg/kg dry wt.) to 10 days (887.8 mg/kg dry wt.) in WS treatment. The lutein content did not show a significant difference in WW between 7 and 10 days after treatment but showed a significant difference in WS treatment. The ${\alpha}-carotene$ content showed no significant difference between the treatments. However, zeaxanthin content was higher during 4-10 days and ${\beta}-carotene$ content was lower during 6-10 days in WS than in WW on each harvest day. In WW, the proline content showed no significant difference, but in WS, the proline content started to increase at 7 days and almost doubled in 10 days. CONCLUSION : The marked increase in zeaxanthin and proline contents in kale leaves indicated that the two phytochemicals are associated with drought tolerance in the plant.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.2
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• pp.118-122
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• 2006

This experiment was carried out on plastic pots ($40cm{\times}25cm{\times}30cm$) filled with sand soil at greenhouse using two soybean cultivars with small seed; one was Pungsannamulkong (PSNK) recognized as a tolerant cultivar against excessive water stress and the other one was Sobaeknamulkong (SBNK) recognized as a susceptible cultivar. Seed was sown with 30 plants of 2 hills, and the amount of applied fertilizer was N; 3.0 g, P; 3.0 g, and K; 3.4 g per $m^2$ with all basal fertilizations. Plants were grown under photoperiod of natural light with day temperature of $31{\pm}5^{\circ}C$ and night temperature of $22{\pm}1^{\circ}C$. The flooding treatment was done for 3, 5, 7 and 10 days by filling pots with tap water up to 1 cm above the level of the soil surface when plants were 2 days after emerging. Nitrogen uptake by leaves of soybeans decreased significantly by the flooding after 6 days. This significant reduction of N uptake by flooding was evidently recognized from the chlorosis of leaves. The dry matter of flooded soybean seedlings significantly decreased compared to non-flooded soybean seedlings at 10 days. The dry matter of roots also showed similar result of the shoot. Shoots had more N reduction than roots under the flooding. This N reduction was more pronounce in SBNK than in PSNK. Chlorophyll content of flooded soybeans showed decreasing or non-increasing tendency, and the reduction of chlorophyll content was more in SBNK than in PSNK from the flooding stress. Nitrate content of soybean seedlings with flooding stress showed decreasing tendency in shoot and root parts. Ammonium content, however, was higher in flooding stress compared to the non-flooding. Flooding caused a remarkable change in the AA (amino acid) composition and TAA (total amino acid) concentration in the leaves of soybean seedlings.

• Korean Journal of Agricultural Science
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• v.42 no.3
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• pp.167-175
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• 2015

The present study aimed to investigate the effects of drought stress on the accumulation of glucosinolates (GSLs) in the leaves of Kale cultivated in autumn and spring. HPLC analysis guided to identify seven GSLs including progoitrin, glucoraphanin, sinigrin, gluconapin, glucobrassicin, 4-methoxyglucobrassicin and neoglucobrasscin. Quantification of GSLs revealed that the contents of sigirin was the highest (45%) followed by the level of progoitrin (24%) in terms of total GSLs. The ranges of total GSL contents was 1.16 (84)-15.88 (89 DAS, ${\mu}mol/g$ dry wt. (DW)) in treatment plot and 1.23 (84)-7.05 (74 DAS, ${\mu}mol/g$ dry wt.) in control plot showed the enhancement in the contents of GSLs in treatment than in the control plot. The present results evidenced that the variation of total GSL contents were depending on the harvest period. In 105 DAS, comparatively no differences in the GSL contents on each sample in autumn season, whereas in spring season, although there was decrease in the GSLs tendency from 74 DAS to 84 DAS in both control and treatment plot, the GSL contents of treatment plot was dramatically increased in 89 DAS. In treatment plot, the GSL contents on 89 DAS (1.16) was 15 fold higher to 84 DAS ($15.88{\mu}mol/g$ DW). The variation in the contents of GSL in spring and autumn did not documented significant differences because of their differences in the growth time and cultivation conditions. In conclusion, the GSL contents in kale was likely to be affected by drought stress treatment. Scrutiny and further research for exact relation between drought stress and GSL contents in kale should be needed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.84-85
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• 2005

Dislocations are often found at Shallow Trench Isolation (STI) process after repeated thermal cycles. The residual stress after STI process often leads defect like dislocation by post STI thermo-mechanical stress. Thermo-mechanical stress induced by STI process is difficult to remove perfectly by plastic deformation at previous thermal cycles. Embedded flash memory process is very weak in terms of post STI thermo-mechanical stress, because it requires more oxidation steps than other devices. Therefore, dislocation-free flash process should be optimized.

• Journal of Korean society of Dental Hygiene
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• v.16 no.2
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• pp.277-284
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• 2016

Objectives: The purpose of the study was to investigate the influencing factors of oral health-related quality of life in social workers. Methods: A self-reported questionnaire was completed by 240 social workers in Gwangju by convenience sampling method. The questionnaire consisted of general characteristics of the subjects(age, monthly salary, smoking, alcohol consumption) and systemic health condition(systemic diseases, medication, oral health status, and stress). The factors associated with oral health-related quality of life included skin dryness, eye dryness, lip dryness, and nasal dryness. The subjective dry mouth consisted of 6 questions measured by visual analogue scale(VAS). Cronbach's alpha was 0.868 in the study. The data were analyzed for t-test, one-way ANOVA and multiple regression analysis using SPSS 18.0 program. Results: The oral health-related quality of life in social workers varied by age, oral health status, stress status, and halitosis. The oral health-related quality of life had positive correlations with the subjective perception of dry mouth and whole body dry symptoms. The health status(${\beta}=-0.410$) had the influence on the oral health-related quality of life, nasal dryness(${\beta}=0.230$), age(${\beta}=0.189$), and halitosis (${\beta}=0.162) in order. Conclusions: The oral health-related quality of life was closely related to the health status and nasal dryness. It is necessary to develop the quality of life improvement programs including oral health prevention and care program in the social workers.

• Clean Technology
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• v.10 no.3
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• pp.121-130
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• 2004

Pelletizer of dry ice snow produced by adiabatic expansion of liquid carbon dioxide and their blaster were designed and manufactured. The blaster had a high cleaning power against various contaminants on the surface such as stain, oily dirt, lacquer film and paints with low blasting pressure and low consumption of blasting air. The capacity of hopper for dry ice pellet supply was 12 kg and the mass rate of pellet blasting was controlled in 0 to 1.2 kg/min. The impact of the pellets was independent of standoff distance within a certain limiting distance, and dependent on the impact stress, angle and mass rate of dry ice pellet blasting. On the other hand the cleaning power was influenced by thermal properties and surface roughness of the substrates and decreased in the order of glass, copper, brass, steel and acryl. The power was also affected by hardness and adhesion of the contaminant on the substrate, and decreased in the order of grease, epoxy and paint. The noise was detected during blasting in the range of 85 to 100dBA.

• Korean Journal of Exercise Nutrition
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• v.23 no.4
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• pp.14-22
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• 2019

[Purpose] Here, we aimed to determine the effect of Polygonum cuspidatum stem extract (PSE) on exorbital lacrimal gland-excised rat models and hyperosmotic stress-stimulated human conjunctival cells (HCCs). [Methods] Seven week old male Wistar rats were divided into six groups. Only the rats in the control group (NOR, n=5) did not undergo surgery. Three days after the surgery, the exorbital lacrimal gland-excised rats were randomly allocated to five groups: (1) vehicle-treated dry-eyed rats (DED, n=5); (2) PSE (10 mg/kg) treated DED rats (PSE-10, n=5); (3) PSE (100 mg/kg) treated DED rats (PSE-100, n=5); and (4) PSE (250 mg/kg) treated DED rats (PSE-250, n=5). In addition, the HCC line was co-treated with hyperosmolar media (528 mOsm) and PSE (1-100 μg/ml). [Results] PSE treatment restored the tear volume and goblet cell density by inhibiting severe corneal irregularities and damage. The treatment with PSE significantly attenuated the hyperosmolar stress-induced inflammation and cell death through the suppression of mRNA expression levels of Tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), Interleukin-1β (IL-1β), and Interferon-γ (IFN-γ), and the expression of Bcl-2-associated X protein (Bax) as well as the activation of caspase-3 in vitro. [Conclusion] The inhibitory effects of PSE treatment on dry eye disease indicate the potential of nutritional intervention by PES against inflammatory diseases without adverse effects.

• Journal of the Korea Society of Computer and Information
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• v.27 no.12
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• pp.259-266
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• 2022

In this paper, we propose a study is to prepare basic data for integrated health promotion education by preventing dry mouth and dry eyes through lifestyle management. From October 7 to 17, 2022, a total of 516 respondents who voluntarily agreed and responded through a self-written structured questionnaire were statistically analyzed for university students in their 20s across the country. As for the factor of feeling dry mouth among the living habits of the study subjects, the more smoking per day, the higher(8.41±2.041) and very high(7.75±2.927) felt dry mouth(p=.015), and the time spent using smart phones. The shorter this was, the lower(1.16±0.784) and very low(1.83±1.672) felt dry mouth(p=.022). The main factors contributing to dry mouth and dry eyes were dry eyes (odds ratio 3.651, p=.000), and high smoking(odds ratio 0.916, p=.038), and the more you use your smart phone (odds ratio 0.256, p=.004), the more you feel dry mouth. When feeling dry eyes, they felt dry mouth more(odds ratio 4.002, p=.000), and the more they exercised, the more dry eyes they felt(odds ratio 1.600, p=.009). As a result, since dry mouth and dry eyes appear as common inconveniences, it was found that lifestyle management is necessary to maintain and promote a healthy life. Therefore, it is proposed to build an integrated health platform that can improve the quality of life and implement personalized health management programs.

• Korea-Australia Rheology Journal
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• v.12 no.3_4
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• pp.151-155
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• 2000

A semiconducting poly(naphthalene quinone) radical (PNQR) was synthesized from Friedel-Craft acylation between naphthalene and phthalic anhydride and used as dispersing particles of a dry-base electrorheological (ER) material in silicone oil. Under an applied electric field (E), the dynamic yield stress (${\tau}_{dyn}$) of this ER fluid, obtained from a steady shear experiment with a controlled shear rate mode, was observed to increase with $E^{1.45}$ Based on this relationship, we propose a universal correlation curve for shear viscosity, which is independent of E using a scaling analysis.

• Journal of Korean society of Dental Hygiene
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• v.12 no.5
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• pp.973-985
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• 2012

Objectives : The aim of this study is to investigate the possible impact factors on adults' self-reports of dry mouth and to develop strategies to improve oral health education policy. Methods : This study was conducted on a total of 622 self-administered questionnaires adult above 20 and under 65 years of age living in Seoul and Gyeonggi provinces. The final participants consisted of 443 adults without chronic illness, taking medications and wearing dentures. The Hierarchical Multiple Regression model with three stages was used to assess the association for exposure of interest, such as socio-demographics, health-related behavior, mental health and self-reported of dry mouth. Results : The participants reported mean score of dry mouth($6.32{\pm}4.47$), of which 191 were male($6.81{\pm}4.56$) and 252 were female($5.94{\pm}4.37$). Hierarchical Multiple Regression revealed that the score of dry mouth was shown to be significantly higher for the following people: Males, who were employed, unemployed, negative self-perceived general health, perceived stress, and participants who had no experience awareness of distress in two weeks. The explanatory power was 21.9%. The most powerful impact factor regarding to employment was shown to be negatively associated to dry mouth, and self-perceived general health, experiencing awareness of distressful in two weeks was also important factors. Conclusions : Based on these results in order to develop oral health education policy strategies for the prevention and management of dry mouth, there need to be considered for the employee.