• Bulletin of the Korean Chemical Society
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• v.22 no.3
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• pp.276-280
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• 2001

The self-assembled formation of octadecanethiol (CH3(CH2)17SH) on a gold substrate was studied using a quartz crystal microbalance (QCM) and a scanning tunneling microscope (STM). From the QCM measurements at vario us concentrations of octadecanethiol solutions in hexane and alcohol, the adsorption process of octadecanethiol onto Au was confirmed to consist of two steps as follows: (i) fast but disordered adsorption and (ii) a thermodynamically controlled rearrangement for uniform packing of octadecanethiol. Also, it was revealed that the adsorption rate became faster in ethanol than in hexane since less solubility of octadecanethiol in ethanol could help the formation of the monolayers. At 5 ${\times}$10-7 M solution, the monolayer formation was monitored by STM. The morphology of monolayer region was initially circular (diameter size: 7.26 $\pm$ 2.1 nm) and gradually changed to a stripe type after several minutes. At higher concentration, the self-assembled monolayer was formed immediately after the solution was introduced to a substrate.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.221.3-222
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• 2003

Adenophorae Radix, the roots of Adenophora triphylla var. japonica Hara (Campanulaceae) is known to be an anti-inflammatory and antitussive drug used for the treatment of lung disease. However quality control method is not established yet. This study is to establish the quality control method of Adenophorae Radix.From the roots of this plant, we isolated (6R,7R)-E,E-tetradeca-4,12-diene-8,10-diyne-1,6,7-triol (1) as a marker compound for the quality control and determined its content by HPLC-UV detector. (omitted)

• Korean Journal of Plant Taxonomy
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• v.52 no.4
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• pp.214-218
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• 2022

Eleocharis R. Br. (Cyperaceae) is characterized by unbranched culms, one terminal spikelet, bisexual flowers, and bristly perianths, occurring mainly in circumboreal marshes and wetlands. There are about 250 species worldwide, and 15 taxa in Korea have been recognized. Chromosomes in Cyperaceae are known to be holocentric, missing constricted centromeres during cell division. For the first time, we report the chromosome counts of Eleocharis from Korean populations of E. attenuata f. laeviseta (Nakai) H. Hara (2n = 20); E. parvula (Roem. & Schult.) Link ex Bluff, Nees & Schauer (2n = 10); E. ussuriensis Zinserl. (2n = 16); and E. valleculosa var. setosa Ohwi (2n = 16). The populations exhibit variations in their chromosome sizes from ca.1.7 ㎛ to ca. 6 ㎛, categorized as gradient and bimodal karyotypes. The karyotypes observed are congruent with previous phylogenetic groups proposed. To clarify the traditional and phylogenetic classification of Korean Eleocharis, further taxonomic and chromosomal investigations with additional taxon sampling efforts are required.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.1
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• pp.52-57
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• 1997

The paper deals with kinematic evaluation of performance of a hydraulic shovel arm for deburrinhg task. First, a new criteria for evaluation is derived to evaluate accuracy of an ene-effector at each position with- in the movable area of the hydraulic shovel arm. Secondly a graphic evaluation system that displays a map of the criteria for evaluation and a map of the manupulability measure is build. Thirdly, by using by using the sas- tem, a hydraulic shovel arm is kinematically evaluated. Finally, from the comparison of the result obtained from the computer simulation and an experimental result, it is indicated that the derived criteria for evalu- ation and the graphic system are useful.

• Clinical Endoscopy
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• v.56 no.2
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• pp.261-261
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• 2023

• Clinical Endoscopy
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• v.57 no.2
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• pp.175-180
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• 2024

Therapeutic endoscopic ultrasonography (EUS) procedures using the forward-viewing convex EUS (FV-EUS) have been reviewed based on the articles reported to date. The earliest reported procedure is the drainage of pancreatic pseudocysts using FV-EUS. However, the study on drainage of pancreatic pseudocysts focused on showing that drainage is possible with FV-EUS rather than leveraging its features. Subsequently, studies describing the characteristics of FV-EUS have been reported. By using FV-EUS in EUS-guided choledochoduodenostomy, double punctures in the gastrointestinal tract can be avoided. In postoperative modified anatomical cases, using the endoscopic function of FV-EUS, procedures such as bile duct drainage from anastomosis, pancreatic duct drainage from the afferent limb, and abscess drainage from the digestive tract have been reported. When a perpendicular puncture to the gastrointestinal tract is required or when there is a need to insert the endoscope deep into the gastrointestinal tract, FV-EUS is considered among the options.

• Anatomy and Cell Biology
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• v.57 no.1
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• pp.147-151
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• 2024

Atlanto-occipital assimilation is an osseous embryological anomaly of the craniovertebral junction in which the atlas (C1) is fused to the occiput of skull. Embryologically, this assimilation may happen due to failure of the segmentation and separation of the caudal occipital and the cranial cervical sclerotome. The segmentation clock is maintained by NOTCH and WNT signalling pathways along with Hox genes and retinoic acid. This condition is likely to be a consequence of mutation in above mentioned genes. The knowledge of this assimilation may be crucial for the clinicians as it may lead to various neurovascular symptoms. The present case report involves the analysis of atlanto-occipital assimilation with its clinical significance and embryological basis.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.913-920
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• 2010

This study was conducted to improve the seed germination by low temperature and $GA_3$ in $Orostachys$ $japonicus$ A. Berger (Jirisan) and $O.$ $iwarenge$ (Mak.) Hara (Jejuyeonhwa), Korean native plants. Observation of the seeds using a stereo microscope showed that all seeds of the two species have wrinkled surface and oblong shape. Seed size ranged 0.77-1.00/0.25-0.37 mm (length/width), indicating that the seeds are minute seeds. When the seeds of two $Orostachsis$ species were sown into petri-dish and placed in a plant growth chamber of 10, 15, 20, or $25^{\circ}C$, 'Jirisan' showed seed germination below 20% at all temperatures and 'Jejuyeonhwa' 80% at only $10^{\circ}C$. Seed germination of 'Jirisan' increased up to 44% at $10^{\circ}C$ by low temperature ($4^{\circ}C$) storage for 10 days, but decreased again at storage for more than 20 days. The seeds of 'Jejuyeonhwa' showed a large increase in seed germination by low temperature for 20-30 days, which was 95% at $10^{\circ}C$, but low temperature for more than 40 days significantly decreased seed germination. Dipping treatment in GA3 solution of $50-400mg{\cdot}L^{-1}$ for different periods (3, 6, 12, and 24 hrs) remarkably improved germination rate and speed in both species, 80-100% in 'Jirisan' and 90-100% in 'Jejuyeonhwa' at all concentrations and dipping times used in this study.

• Korean Journal of Medicinal Crop Science
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• v.3 no.3
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• pp.217-225
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• 1995

In this study the essential oil and pharmacologically active components of different valerian species (Valeriana fauriei var. dasycarpa Hara and V. officinalis L. from Korea and V. wallichii DC from Nepal) were analyzed to search for native plant resources that can be used for medicinal herb and tobacco flavoring. The oil contents in dry roots of V. fauriei, V. officinalis and V. walhchii were 1. 71%, 0. 82% and 0. 83 %, respectively. The composition of the essential oil among different valerian species was compared. In V. fauriei 47 compounds were identified, while 21 and 25 compounds were identified in V. officinalis and V. wallichii. The major compounds in the oil of V. fauriei were bornyl acetate (33.8%) and camphene (10.8%), cedrol (4. 1 %), -pinene (3. 2%) and unidentified sesquiterpene alcohol (3. 0%). The major compounds were borneol (62. 5%) and ${\beta}-sesquiphelandrene$(6. 8%) and spathulenol (2. 1%) in V. officinalis, and borneol (74. 3%) and ${\alpha}-elemene$ (2.7%) and -sesquiphellandrene (2. 3%) in V. wallichii. Among the components known as major pharmacologically active compounds in European or Japanese valerian roots, valeranone, valerenal and -kessyl acetate was detected in a small amount in V. fauriei, but kessoglycol diacetate was not detected in V. faudei and V. officinalis Among the valepotrate compounds, major pharmacologically active components in V. wallichii, valtrate was detected in a small amount in V. fauriei and V. officinalis., and detected 1. 42% in V. wallichii. Didrovaltrate was also detected in the three valerian species tested, but acevaltrate was not detected except V. wallichii. On the other hand, antioxidative activity was slightly higher in V. fauriei than those of V. officinalis.

• Journal of Life Science
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• v.30 no.11
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• pp.965-972
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• 2020

Sambucus sieboldiana var. miquelii (Nakai) Hara is distributed in Korea, China, and Japan, and has been used as an anti-rheumatic in folk medicine in oriental countries. The present study aims to investigate the potential use of this species in health functional foods, cosmetics, and food preservatives. Methanol extracts of leaves and branches from this plant were prepared to quantitatively analyze the total phenol and flavonoid contents, and to investigate the antioxidative and enzyme inhibitory activities, and the inhibition of nitric oxide (NO) production activity. The results showed that the total polyphenol and flavonoid contents of the crude extract were 1.52±0.1 mg/g and 1.73±0.1 mg/g, respectively. S. sieboldiana polyphenols exhibited potent scavenging activity shown by 2, 2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and 2, 2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation assay. The crude extract also exhibited significant α-glucosidase and tyrosinase inhibitory activity with IC₅₀ values of 183.5 ㎍/ml and 323.9 ㎍/ ml, respectively. Additionally, the crude extract exhibited strong anti-inflammatory activity determined through the nitric oxide inhibition assay in a dose-dependent manner with an IC₅₀ value of 36.7 ㎍/ml and no cytotoxic effect on the macrophages. Therefore, we demonstrated that the leaves and branches of S. sieboldiana extract possess antioxidant, anti-diabetic, depigmentation potential, and NO production inhibitory activities. According to recent research, S. sieboldiana has great potential as a source of the bioactive compound which could be used as food, cosmetics, and pharmaceutical agents.