• Molecules and Cells
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• v.23 no.1
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• pp.57-63
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• 2007

Leukotrienes (LTs) are produced by several biosynthetic enzymes including cytosolic phospholipase $A_2$ ($cPLA_2$), 5-lipoxygenase (5-LO), and 5-lipoxygenase activating protein (FLAP) in the perinuclear area. In the present study, we showed that pretreatment with methyl-${\beta}$-cyclodextrin (MβCD), a cholesterol-depleting agent, dramatically reduced the synthesis of LTs in response to A23187 in mast cells. A23187-induced LT synthesis was inhibited by pretreatment with M${\beta}$CD, and this effect was reversed when cholesterol was added. In an approach to identifying the $M{\beta}CD$-sensitive protein(s), we observed that FLAP co-localized with flotillin-1, a lipid raft marker protein, in the lipid raft-rich low-density region of sucrose gradients. In addition, electron microscopic analysis revealed that FLAP co-localized with flotillin-1. Together, these results suggest that FLAP is present in cholesterol-rich lipid raft-like domains and that its localization in these domains is critical for LT synthesis.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.491-494
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• 2002

The real-time industrial network often referred to as fieldbus, is an important element for building automated manufacturing systems. Thus, in order to satisfy the real-time requirements of field devices such as sensors, actuators, and controllers. numerous standard organizations and vendors have developed various fieldbus protocols such as Profibus, WorldFIP and Foundation Fieldbus. However, the application of fieldbus has been limited due to the high cost of hardware and the difficulty in interfacing with multi-vendor products. In order to solve these problems, the computer network technology, especially Ethernet (IEEE 802.3), is being adopted lo the industrial environment. The crucial technical obstacle for Ethernet is that its non-deterministic behavior makes it inadequate for industrial applications where real-time data such as control command and alarm signal hale to be delivered within a certain time limit. Recently, the development of switched Ethernet shows a very promising prospect for industrial application due to the elimination of uncertainties in the network operation resulting in much improved performance. This paper focuses on the application of the switched Ethernet for industrial comm unications.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.3
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• pp.162-168
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• 1991

Iterbicide resduc. cauicd ~rljul-y to ovcrsown pasture grasses \\hen herbicide appliccl for use in pasturc est;~blish~nt~nt lo gro~vth contro! ol n;rtivc ~r ~:cds and shrubs. 'l'hih L~sperirnel~t was conducted to cv;lluati. (he herbicidr residue anti its ph!:totosical ~riiiuence on the growth of introtluccd pasturts species. Esperimcmtal soils was treated with buthitlazolc, ~ o d l ~ l m chlorate, glyphosatc. U-46 anti paraquat each at twt) applici~tion rates. Lhcf~1i.s glowl~mlc~ including othrr pasture grasses and le~urnes were evaluatrd for tolerance to herbicide. IIerbicide residue in the amount ot injury caused to introduced pasture grasses was found in order of buthidazole, sodium chlorate, U-46 and glyphosate. Euthidazole was not available for use in pasture establishment because of their long persist of toxic herbicide residues. A great stand redl~ction of subseq ~ ~ c n t oversown pastures was also observed In sodium chlorate treatment. However, normal vegetative stand and grass production was obtained, when thc pasture grasses seeded 45-60 days later herbicide treatments. Glyphosate did not affect subsequent oversown pasture species in both grasses and legumes. fistuccr arundinc~cea and Pou pratensis were the most tolerant pasture species to herbicide residue while 7'rzfi,lium pyatense and Medicugo suti~u showed a wsceptible response regardless of herbicide.

• Fashion & Textile Research Journal
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• v.16 no.2
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• pp.319-325
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• 2014

This article describes a method for producing chitosan non-woven fabrics by just hot pressing without the use of a binder. A study has been made of the wet spinning of chitosan fiber. The fibers were rinsed thoroughly in running water and chopped wet into staples of with a length of approximately 5-10 mm. The chopped chitosan staples were dispersed uniformly in water and fabricated using a non-woven making machine. This study examined the formation and the characteristics of chitosan non-woven fabrics manufactured by hot pressing without the use of a binder. The effects of the non-woven fabrication conditions on the thermal, morphological, structural, and physical properties of chitosan non-woven fabric with and without water as a plasticizer were studied. The temperature of the exothermic peak, decomposition of chitosan fibers increased with increasing heating rate. Water in the chitosan fiber effectively plasticized the chitosan fiber. The thermal bonded structure of the wet chitosan fiber with water as a plasticizer was clearly found in many parts of the non-woven fabric at a fabrication temperature of $200^{\circ}C$. The intensity and profile of the (100) plane($2{\theta}=10.2^{\circ}$) and (040) plane($2{\theta}=20.9^{\circ}$) in the chitosan non-woven fabric decreases and became smooth in the non-woven fabric formation by melting.

• Journal of the Korean Society for information Management
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• v.17 no.4
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• pp.171-186
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• 2000

The slody examined whethcr academe libraries deliver web~hased electronic relerencc services lo remole users. Amo~~g 178 acadclnlc lihraies. only 25.5% prolide reference services of inlroducing eleclronic reference materials and 20.8% o f h electron~c rdel-coce mquq rcwices. However, the use oi electronic access to reference inquuy was weak. One acarlcmic llbrarr reccived on avn-agc 3.2 queslions pcr monlh ovw elecmnic reference inquiries Irom remo~e users. Among the 1,128 questions i-cccived eleclroo~ci~lly, oldy 19.8% were reyardcd as real rekrencc queslmns.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4C
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• pp.380-387
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• 2002

In this paper, the effect of the phase noise of a local oscillator on the ACPR of a transmitter and the reception sensitivity of a receiver to meet the TIA/EIA/IS-98-D for the CDMA mobile station was analyzed. And the optimum condition for performance of the local oscillator was suggested. It was found that the phase noise level of the local oscillator in a receiver and a transmitter should be below -138.3dBc/Hz and -120dBc/Hz, respectively, at 900kHz offset. It was confirmed that the reception sensitivity and ACPR efficiency were satisfactory when the signal of the local oscillator to the down-converter of a receiver with the phase noise level of less than -138.3dBc/Hz is supplied to the up-converter of the transmitter.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6C
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• pp.532-540
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• 2005

In this paper, a sequential detection scheme is proposed as a combination of a novel weak-signal and a locally optimum(LO) detection schemes. In Part 1, we propose a novel sequential detection scheme for weak signals and show some interesting threshold properties and examples. In Part 2, the performance of the proposed sequential detection scheme is compared with that of the fixed sample size(FSS) test, sequential probability ratio test (SPRT), and truncated sequential probability ratio test(TSPRT).

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.487-488
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• 2015

In type Ia supernovae (SNe Ia) cosmology, a well-established correlation exists between the mass of host galaxies and the Hubble residual (HR) of SNe Ia. In order to investigate the origin of this correlation, we used low-resolution spectroscopic data of early-type host galaxies obtained from our YOnsei Nearby Supernovae Evolution Investigation (YONSEI) project. We measured velocity dispersions and Lick/IDS absorption line indices from these fully calibrated spectra. These indices were used to estimate the luminosity-weighted mean age, metallicity and mass of host galaxies. We found a tight correlation between host mass and population age, which is consistent with the "downsizing" trend in early-type galaxies. This suggests that the well-established correlation between HR and host mass is most likely due to the difference in population age. More observations, which are in progress, are required to understand the impact of luminosity evolution on SNe Ia cosmology.

• Journal of fish pathology
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• v.25 no.3
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• pp.199-210
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• 2012

It can be hypothesized that dietary fatty acids can modulate immune responses in fish by inducing apoptosis of immune cells since dietary polyunsaturated fatty acid (PUFA) increase apoptosis by oxygen radicals generated by peroxidation. Thus we examined the effects of deferent dietary lipid sources such as squid liver oil (FO), linseed oil (LO) and soybean oil (SO) on oxidation (Cytochrome C oxidase; COS), apoptosis (TNF-${\alpha}$ Scinderin like) and immune (IL-$1{\beta}$ and NKEF) gene expression in the main immune organ (head kidney) in olive flounder (Paralichthys olivaceus) by Q-PCR analysis after feeding diets containing each oil (5%) for 15 weeks. Linseed oil and soybean oil were chosen to compare n-3 or n-6 enriched vegetable oils, respectively. Consequently, COS, TNF-${\alpha}$ and Scinderin like gene expression was increased in SO group, indicating the induction of oxidation and apoptosis. Meanwhile, no significant difference was found in immune gene expression. In conclusion vegetable oils containing n-3 PUFA like linseed oil seems to be more suitable lipid source than soybean oil for replacement of fish oil in flounder since n-6 PUFA in SO leads to activation of apoptosis pathways within the cellular damage in head kidney.

• Journal of The Korean Astronomical Society
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• v.55 no.6
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• pp.207-213
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• 2022

The Seoul Radio Astronomy Observatory (SRAO) operates a 6.1-meter radio telescope on the Gwanak campus of Seoul National University. We present the efforts to reform SRAO to a Very Long Baseline Interferometry (VLBI) station, motivated by recent achievements by millimeter interferometer networks such as Event Horizon Telescope, East Asia VLBI Network, and Korean VLBI Network (KVN). For this goal, we installed a receiver that had been used in the Combined Array for Research in Millimeter-wave Astronomy and a digital backend, including an H-maser clock. The existing hardware and software were also revised, which had been dedicated only to single-dish operations. After several years of preparations and test observations in 1 and 3-millimeter bands, a fringe was successfully detected toward 3C 84 in 86 GHz in June 2022 for a baseline between SRAO and KVN Ulsan station separated by 300 km. Thanks to the dual frequency operation of the receiver, the VLBI observations will soon be extended to the 1 mm band and verify the frequency phase referencing technique between 1 and 3-millimeter bands.