• Bulletin of the Korean Chemical Society
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• v.34 no.5
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• pp.1503-1507
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• 2013

The two major symptoms characterizing Alzheimer's disease are the formation of amyloid-${\beta}$ extracellular deposits in the form of senile plaques and intracellular neurofibrillary tangles (NFTs) that consist of pathological hyperphosphorylated tau protein aggregated into insoluble paired helical filaments (PHFs). Neurons of the central nervous system have appreciable amounts of tau protein, a microtubule-associated protein. To maintain an optimal operation of nerves, the microtubules are stabilized, which is necessary to support cell structure and cellular processes. When the modified tau protein becomes dysfunctional, the cells containing misfolded tau cannot maintain cell structure. One of the pathological hallmarks of Alzheimer's disease is hyperphosphorylated tau protein. This paper shows that the small heat shock protein from humans (Hsp27) reduces hyperphosphorylated tau and prevents hyperphosphorylated tau-induced cell death of the human neuroblastoma cell line SH-SY5Y.

• Metals and materials international
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• v.24 no.6
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• pp.1327-1332
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• 2018

In this study, a novel approach to the explosive synthesis of titanium carbide (TiC) is discussed. Nonstoichiometric $TiC_x$ powder was produced via the underwater explosion of a Ti powder encapsulated within a spherical explosive charge. The explosion process, bubble formation, and synthesis process were visualized using high-speed camera imaging. It was concluded that synthesis occurred within the detonation gas during the first expansion/contraction cycle of the bubble, which was accompanied by a strong emission of light. The recovered powders were studied using scanning electron microscopy and X-ray diffraction. Submicron particles were generated during the explosion. An increase in the carbon content of the starting powder resulted in an increase in the carbon content of the final product. No oxide byproducts were observed within the recovered powders.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.39.2-39.2
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• 2019

Diffuse radio emissions at the outskirt of merging galaxy clusters called radio relics provide a unique channel to understand the merger history. We present a recent discovery of double radio relics in the cluster merger ZwCL1447+2619 from our recent Giant Metrewave Radio Telescope observations. Both Band 3 (300-500 MHz) and Band 4 (550-850 MHz) data reveal a large (~1Mpc) and thin (~40kpc) radio relic ~1Mpc from the cluster X-ray center and a small radio relic (~0.3 Mpc) on the opposite side. These remarkable radio data together with Subaru weak-lensing analysis and Chandra X-ray observations enable us to reconstruct the merger scenario. Our preliminary analysis suggests that the cluster ZwCL J1447+2619 is a post-merger near its returning phase. In addition, using Keck DEIMOS spectroscopy, we find many "green" and "blue" member galaxies are located between the radio relics, a possible indication of merger shock-driven star formation activities.

• Childhood Kidney Diseases
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• v.27 no.2
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• pp.127-132
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• 2023

Cystinuria, a genetically inherited disorder, is a rare cause of kidney stones. It is characterized by impaired transport of cystine and amino acids in the proximal renal tubule and the small intestine. Most patients develop cystine stones throughout their lifetime. Recurrent renal stones need to be extracted by repeated urologic interventions. Treatment options of cystinuria for preventing stone recurrence are limited and poorly tolerated. In this study, we report a pediatric case of cystinuria with a heterozygous SLC3A1 mutation diagnosed by stone analysis, measurement of urine cystine excretion, and genetic analysis. There were recurrent renal stones despite repetitive shock wave lithotripsy and retrograde intrarenal surgery. However, the rate of stone formation seemed to be slower after D-penicillamine was added into adequate hydration and urinary alkalinization.

• Journal of Energy Engineering
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• v.11 no.1
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• pp.26-33
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• 2002

In this paper, incompressible and compressible flow characteristics around the butterfly valve have been investigated. In order to simplify the problem, a flat disk valve with various valve disk angles and pressure ratios is considered in the present calculations. It was found that as the disk angle increases, the stagnation point on the front surface of the disk moves to the center of the surface and the inflow velocity decreases. The maximum flow velocity occurs at the downstream of throat because of the formation of vents contracta. As the pressure ratio decreases, compressibility effects increase and the jet formed between the throttle body wall and the disk edge becomes supersonic. This flow also builds up as a shock cell structure. The increase of disk angle and pressure ratio makes the mass flow at the inlet decrease, while the increase of disk angle and the decrease of pressure ratio make the pressure loss coefficient increase.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.10
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• pp.791-797
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• 2018

In this work, the high-altitude environment simulation study was carried out at an altitude of 65 km exceeding Mach number of 6 after the launch of Korean Space Launch Vehicle using a shock tunnel. To minimize the flow disturbance due to the strut support of test model as much as possible, a few different types of strut configurations were considered. Using the configuration with minimum disturbance, the high-altitude environment simulation experiment including a propulsion system with a single-plume, was conducted. From the thruster test through flow visualization, not only a shockwave pattern, but a general flow-field pattern from the mutual interaction between the exhaust plume and the free-stream undisturbed flow, was experimentally observed. The comparison with the computation fluid dynamic(CFD) results, showed a good agreement in the forebody whereas in the afterbody and the nozzle the disagreement was about ${\pm}7%$ due to unwanted shockwave formation emanated from the nozzle-exit.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.2
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• pp.127-135
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• 2006

Objectives: The extent of bone formation that occurs at the interface of metallic implants and bone is determined by the number and activity of osteoblastic cells. Stress proteins may be contributing determinants of cell viability in altered environments. Hsp27 is a small Mr hsp which is known as a molecular chaperone. Methods: To better understand how heat shock protein 27 contributes to endosseous implant - associated metal ions affects on osteoblastic cell viability, the effect of chromium and titanium ions were compared to effects of cadmium ions in the ROS17/2.8 osteoblastic cell line. Results: ROS17/2.8 osteoblastic cell line demonstrated ion - specific reductions in growth; reductions were significantly greater for cadmium than for chromium or titanium. Chromium impaired growth of cultures without altering cell viability measured using the MTT assay. A stable transformed cell line expressing additional hsp27(clone "A7") was resistant to the toxic effects of titanium and partially protected from cadmium toxicity. Conclusions: A role for hsp27 in protection of osteoblastic cells from metal ion toxicity is supported by the chromium - induced elevations in hsp27 abundance and the behavior of the A7 cell line in response to metal ions in culture. Similar biochemical responses to altered cellular environments may contribute to the fate of tissues adjacent to select metallic implants.

• Journal of Mushroom
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• v.4 no.1
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• pp.39-42
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• 2006

Cauliflower mushroom(Sparassis crispa) contains much amount of ${\beta}$-glucan, which make lots of farmer want to cultivate the mushroom. Since a practical cultivation method is not provided yet, the mushroom is considered as a difficult crop to deal with. In this study, we tried to develope a simple method to cultivate the mushroom by use of coniferous sawdust-based medium with wheat flour and molasses. There was no significant differences between the sawdust spawn and the liquid spawn for the mycelial growth of the mushroom. The cold shock in $4^{\circ}C$ for a day was thought to be the best way to seduce primordium formation. The sawdust medium of Pseudotsuga menziesii mixed with wheat flour, corn chip, cottonseed meal and 10% molasses was showed the best yield with 41% followed by that of Larix leptolepis mixed with the same additives with 37% of yield. There was good relations between the fruit-body production and the weight loss of the sawdust substrate.

• Journal of Astronomy and Space Sciences
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• v.29 no.2
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• pp.181-189
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• 2012

To broaden the understanding of classical Cepheid structure, evolution and atmospheres, we have extended our continuing secret lives of Cepheids program by obtaining XMM/Chandra X-ray observations, and Hubble space telescope (HST) / cosmic origins spectrograph (COS) FUV-UV spectra of the bright, nearby Cepheids Polaris, ${\delta}$ Cep and ${\beta}$ Dor. Previous studies made with the international ultraviolet explorer (IUE) showed a limited number of UV emission lines in Cepheids. The well-known problem presented by scattered light contamination in IUE spectra for bright stars, along with the excellent sensitivity & resolution combination offered by HST/COS, motivated this study, and the spectra obtained were much more rich and complex than we had ever anticipated. Numerous emission lines, indicating $10^4$ K up to ${\sim}3{\times}10^5$ K plasmas, have been observed, showing Cepheids to have complex, dynamic outer atmospheres that also vary with the photospheric pulsation period. The FUV line emissions peak in the phase range ${\varphi}{\approx}0.8-1.0$ and vary by factors as large as $10{\times}$. A more complete picture of Cepheid outer atmospheres is accomplished when the HST/COS results are combined with X-ray observations that we have obtained of the same stars with XMM-Newton & Chandra. The Cepheids detected to date have X-ray luminosities of log $L_X{\approx}28.5-29.1$ ergs/sec, and plasma temperatures in the $2-8{\times}106$ K range. Given the phase-timing of the enhanced emissions, the most plausible explanation is the formation of a pulsation-induced shocks that excite (and heat) the atmospheric plasmas surrounding the photosphere. A pulsation-driven ${\alpha}^2$ equivalent dynamo mechanism is also a viable and interesting alternative. However, the tight phase-space of enhanced emission (peaking near 0.8-1.0 ${\varphi}$) favor the shock heating mechanism hypothesis.

• Journal of Korean Society of Forest Science
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• v.79 no.3
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• pp.322-329
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• 1990

A group of Pinus densiflora trees attacked by Rhizina root rot were observed at Kangnung. Diseased roots are characterized by rot patches, radial rot traces or formation of adhesive soil masses. The damage has proceeded about 6m per annum, and the pathogen in the infected soil was detected by trap logs. Ascospores of Rhizina undulata was germinated by heat shock at $37^{\circ}C$ for 24 hours or at $40^{\circ}C$ for 17 hours. The mycerial growth was optimum on PDA medium at $25-30^{\circ}C$and pH 5.6-6.3. Coniferous trees were more susceptible than non-coniferous trees in inoculation test in vitro.