• International Journal of Aeronautical and Space Sciences
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• v.18 no.1
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• pp.17-27
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• 2017

The treatment of rotor wake has been a critical issue in the field of the rotor aerodynamics. This paper presents a new free wake model for the unsteady analysis for a wind turbine. A blade-wake-tower interaction is major source of unsteady aerodynamic loading and noise on the wind turbine. However, this interaction can not be considered in conventional free wake model. Thus, the free wake model named Finite Vortex Element (FVE hereafter) was devised in order to consider the interaction effects. In this new free wake model, the wake-tower interaction was described by dividing one vortex filament into two vortex filaments, when the vortex filament collided with a tower. Each divided vortex filaments were remodeled to make vortex ring and horseshoe vortex to satisfy Kelvin's circulation theorem and Helmholtz's vortex theorem. This model was then used to predict aerodynamic load and wake geometry for the horizontal axis wind turbine. The results of the FVE model were compared with those of the conventional free wake model and the experimental results of SNU wind tunnel test and NREL wind tunnel test under various inflow velocity and yaw condition. The result of the FVE model showed better correlation with experimental data. It was certain that the tower interaction has a strong effect on the unsteady aerodynamic load of blades. Thus, the tower interaction needs to be taken into account for the unsteady load prediction. As a result, this research shows a potential of the FVE for an efficient and versatile numerical tool for unsteady loading analysis of a wind turbine.

• Journal of Life Science
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• v.17 no.10
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• pp.1381-1386
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• 2007

To elucidate the changes in physiological activities of Scutellariae baicalensis by heating, composition analysis with HPLC and evaluation of physiological activities of extracts were conducted. HPLC analysis of CW(water extract at room temperature) and CHW(heat treated CW) indicated that two distinctive peaks in the HPLC chromatogram were disappeared after boiling and additional peak was newly observed. This observation suggested that certain chemical changed in the extract occurred by heat treatment. In the estimation of physiological activities, CW showed higher ACE inhibiting activity than CHW. In the case of cytotoxic activity against cancer cells, CW exhibited higher activity than CHW against CCL-185. On the other hand, CHW showed higher activity than CW against HeLa, SNU-601 and HepG2. In addition, CHW showed the inhibitory effect on melanogenesis (80% inhibition) while CW did not show any activity.

• Journal of Korean Critical Care Nursing
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• v.14 no.2
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• pp.1-11
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• 2021

Purpose : The aim of this study was to propose appropriate nurse staffing of adult intensive care units considering patients' nursing care needs according to the Workload Management System for Critical Care Nurses (WMSCN). Methods : In a cross-sectional survey conducted in September 2017, 1,786 patients' WMSCN scores, surveys from 2,145 nurses, and administrative data from 118 units in 41 hospitals were analyzed. The means (standard deviations) of the aforementioned scores and nursing hours per patient day were presented. Nurse-to-patient ratios and nurse-to bed ratios for staffing to meet patients' nursing care needs were calculated. Results : The mean WMSCN scores were 109.50±17.17 in tertiary hospitals and 96.38±19.26 in general hospitals. Nursing hours per patient day were 12.47±2.80 in tertiary hospitals and 11.01±2.45 in general hospitals. Nursing hours per patient day correlated with WMSCN scores. Nurse-to-bed ratios required for the provision of ICU nursing care ranged from 1: 0.36 to 1: 0.48. Conclusion : Our findings provide evidence that current ICU nurse staffing is insufficient for meeting patients' nursing care needs. We suggest adjusting the legal standards for adequate nurse staffing considering these needs.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.5
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• pp.710-718
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• 2007

This study was designed to investigate the effects of plum(Prunus salicina Lindl. cultivars 'Oishiwase', 'Formosa', and 'Soldam') extracts on the proliferation as well as inhibition of human epithelial cells(HaCaT), human cervical carcinoma (HeLa, SiHa, and C33A) cells, and human stomach adenocarcinoma(SNU 638) cells. Dried plum was sequentially extracted and fractionated by hexane(KC-01), chloroform(KC-02), ethyl acetate(KC-03), n-butanol(KC-04), water(KC-05), methanol(KC-6), and hot water extract(KC-07). The epithelial and cancer cells were exposed for 48 h to $50{\mu}g/mL$ of plum extract in vitro, and were then analysed by a sulforhodamin B(SRB) staining assay. The methanol extract(KCP-6) of 'Formosa' proliferated not only the HaCaT cells(147.3%), but also the cervical carcinoma C33A cells(167.8%). The ethyl acetate extract of 'Soldam'(KCJ-3) significantly reduced the proliferation rate of the HPV positive conical carcinoma cells, at 61.5% for the SiHa cells and 70.5% for the HeLa cells. In the C33A cells, which are HPV negative cervical carcinoma cells, the hexane fractions of 'Formosa'(KCP-1) and 'Oishiwase'(KCD-1) markedly suppressed proliferation activity at 20.4% and 61.7%, respectively. However, the proliferation rate of the normal epithelial cells(HaCaT cell) was not reduced the proliferation rate by KCJ-3, KCP-1, or KCD-1, There were no significant effects on proliferation of the stomach cancer cells(SNU 638) by any of the extracts or fractions of the plum cultivars. These results suggest that the anti-proliferative effects of the plum cultivars were selective to the cancer cell origin. In conclusion, we found that several plum cultivar extracts, especially, the ethyl acetate fraction of 'Soldam" and the hexane fraction of "Formosa', have anti-proliferative activity toward human cervical carcinoma cells. However, further investigation is needed to assess the molecular mechanisms that mediate the antiproliferation activities of the plum cultivars.

• Korean small business review
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• v.40 no.3
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• pp.1-24
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• 2018

The purpose of this study is verifying with corporate financial data that the required investment amount flow shows a similar pattern as times passed, in new product development by start-up company. In the previous paper, the same authors proposed the required investment amount flow as a 'New Product Investment Curve (NPIC)'. In this study, we have studied further in various types of companies. The samples used are accounting data of 462 companies selected from 5,873 Korean companies which were finished external audit in 2015. The results of this study are as follows; The average investment period was 3 years for the listed companies, while 6 years for the unlisted companies. The investment payback period was 6 years for listed companies, while 17 years for unlisted companies. The investment payback period of the company supported by big affiliate company (We call 'greenhouse company') was 14~15 years, while 17 years for real venture companies. When we divide all companies into 4 groups in terms of R&D cost and variable cost ratio, NPIC explanatory power of 'high R&D and high variable cost ratio group (Automobile Assembly Business) is best. Among the eight investment cost indexes proposed to estimate the investment amount, the 'cash 1' (operating cash flow+fixed asset excluding land & building+intangible asset, deferred asset change)/year-end total assets) turned out to be the most effective index to estimate the investment flow patterns. The conclusion is that NPIC explanatory power is somewhat reduced when we estimate all companies together. However, if we estimate the sample companies by characteristics such as listed, unlisted, greenhouse, and venture company, the proposed NPIC was verified to be effective by showing the required investment amount pattern.

• Journal of Veterinary Clinics
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• v.29 no.1
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• pp.38-42
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• 2012

To determine the prevalence of the primary glaucoma (PG) and occurrence of primary glaucoma in initially non-affected normal eye. Medical records of 7751 dogs presented to the Veterinary Medical Teaching Hospital (VMTH) of Seoul National University (SNU) between January 2006 and December 2009 were examined. Among 7751 dogs, forty three dogs (0.55%) developed PG. The following breeds were included in the study: 18 American Cocker Spaniels, 17 Shih Tzus, 3 Mixed Breeds, 2 Malteses, 2 Pekingeses, and 1 Chow Chow. The mean onset age of PG in the first eyes was $7.1{\pm}2.3$ years in the all breeds. Compared with Mixed Breed (0.54%), American Cocker Spaniel (3.16%, p = 0.004) and Chow Chow (20%, p = 0.001) had a higher risk of developing glaucoma. Twenty six of 43 dogs (60.1%) were females with male-to-female ratio of 1:1.53. Twenty nine of 33 eyes (87.9%) developed glaucoma in the fellow eye within mean ${\pm}SD$ time of $17.5{\pm}2.7$ months. From this study, American Cocker Spaniel and Shih Tzu were the most frequent PG breed in Korea. Also, unilateral PG dogs developed glaucoma in the non-affected normal eye within approximately 17 months. The results indicate that prophylactic medical therapy with antiglaucoma agents should be considered to delay or prevent developing glaucoma in non-affected normal eye.

• Journal of Veterinary Clinics
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• v.33 no.3
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• pp.155-159
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• 2016

Four dogs were brought to the Veterinary Medicine Teaching Hospital of Seoul National University (VMTH SNU) with a history of hind limb ataxia, three with pain, one without pain. Three of the four showed weak to absent femoral pulses and cold extremities. Thromboembolism was identified by ultrasonography in the external and/or internal iliac arteries. A thrombolytic agent, recombinant tissue plasminogen activator (rt-PA), was administered (0.5-1 mg/kg, every 60-120 min, 3-5 doses). Two dogs (Cases 2 and 3), which were instantly provided rt-PA treatment, survived 6 and 17 months, respectively, although hematemesis and hematochezia were observed during treatment. In the other two dogs (Cases 1 and 4), rt-PA was administered 4 and 28 days after the appearance of pelvic limb symptoms, which may have limited the benefits of the treatment. When rt-PA treatment is instituted instantly and the side effects are monitored thoroughly during treatment, a good prognosis might be expected in canine aortic thromboembolism. For this reason, we suggest that rt-PA treatment should be initiated immediately if thromboembolism is identified.

• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.4
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• pp.299-306
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• 1996

This experiment was conducted from 1991 to 1993 at the forage experimental field, College of Agriculture and Life Sciences, SNU, Suweon to investigate the effects of previous crop residues on growth and yield of succeeding corn(2ea mays L.) and also to determine the best double cropping system necessary to maximize the total dry matter yield of winter forage crops plus corn for silage. In this experiment, treatments consisted of no crop as a control, late maturing Kodiak rye(Seca1e cereale L.), Bamapoli forage rape(Brassica napus Subsp. oleifera L.), G-sprinter oats(Avem sativa L.), Chief crimson clover(Trifolium incarnatum L.), Jackson Italian ryegrass(lo1ium rnultiJlorum L.), Vantage vetch(Vicia sativa L.) and early maturing Koolgrazer rye(Seca1e cereale L.). Corn leaf number and silking date were not significantly affected by previous crop residues, but the leaf number of corn following Italian ryegrass was reduced by 1.9 relative to no previous crop. The plant height and LA1 were significantly reduced during early development when corn followed Italian ryegrass and late maturing Kodiak rye (p<0.05). The dry matter and estimated TDN yields of corn were significantly reduced when corn followed Italian ryegrass and late maturing Kodiak rye. The yield reductions for corn following Italian ryegrass, late maturing Kodiak rye and early maturing Koolgrazer rye, relative to com when no previous crops were planted, were 34, 17 and 8%, respectively. Therefore, the reduction in corn growth and yield in this experiment could be explained by an allelopathic effect resulting from the Italian ryegrass and rye residues. The highest total dry matter yield of 30,509kg/ha was obtained from an early maturing rye-corn double cropping sequence in combination among the eight cropping systems.

• Korean Journal of Head & Neck Oncology
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• v.17 no.1
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• pp.3-7
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• 2001

Objectives: New photosensitizer 9-hydroxypheophorbide-$\alpha$(9-HpbD-$\alpha$) was derived from chlorophyll in water with peak absorption at 660nm. 9-HpbD-$\alpha$ was tested with 660 nm diode laser for the anticancer effect of photodynamic therapy. Materials and Methods: Human SNU 1041 cells were seeded into 96 well plate at a density of $$ cells/well for 24 hours. Cells were washed with media containing various concentration of 9-HpbD-$\alpha$ ranging from $0{\mu}g/ml\;to\;3.75{\mu}g/ml$. Then, laser treatment was done with 660nm diode laser ($10mW/cm^2$) at various time setting (0, 30, 60, 90, 120 minutes) and with various time interval (0, 1, 4, 6, 18 hours). The treated cells were incubated 48 hours and MTT assay was done to measure the viability of cells. Results: The viability of cells was more than 90% after laser treatment in control group. The viability of cells was decreased with increasing concentration of 9-HpbD-$\alpha$ and laser treatment time in experimental groups. The viability of cells was decreased significantly as the interval time between addition of 9-HpbD-$\alpha$ and laser irradiation was increased. Conclusion: This study shows the anticancer effect of photodynamic therapy using 9-HpbD-$\alpha$ and 660nm Diode laser on carcinoma cell line. 9-HpbD-$\alpha$ is considerd as one of new photo sensitizers in the field of photodynamic therapy.

• BMB Reports
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• v.40 no.1
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• pp.95-99
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• 2007

Bovine coding region single nucleotide polymorphisms located proximal to quantitative trait loci were identified to facilitate bovine QTL fine mapping research. A total of 692,763 bovine SNPs was extracted from 39,432 UniGene clusters, and 53,446 candidate SNPs were found to be a depth >3. In order to validate the in silico SNPs experimentally, 186 animals representing 14 breeds and 100 mixed breeds were analyzed. Genotyping of 40 randomly selected candidate SNPs revealed that 43% of these SNPs ranged in frequency from 0.009 to 0.498. To identify non-synonymous SNPs and to correct for possible frameshift errors in the ESTs at the predicted SNP positions, we designed a program that determines coding regions by protein-sequence referencing, and identified 17,735 nsSNPs. The SNPs and bovine quantitative traits loci informations were integrated into a bovine SNP data: BcSNPdb (http://snugenome.snu.ac.kr/BtcSNP/). Currently there are 43 different kinds of quantitative traits available. Thus, these SNPs would serve as valuable resources for exploiting genomic variation that influence economically and agriculturally important traits in cows.