• Journal of Life Science
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• v.29 no.1
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• pp.9-17
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• 2019

As tumors develop, they encounter microenvironmental stress, such as hypoxia and glucose depletion, due to poor vascular function, thereby leading to necrosis, which is observed in solid tumors. Necrotic cells are known to release cellular cytoplasmic contents, such as high mobility group box 1 (HMGB1), into the extracellular space. The release of HMGB1, a proinflammatory and tumor-promoting cytokine, plays an important role in promoting inflammation and metabolism during tumor development. Recently, HMGB1 was shown to induce the epithelial-mesenchymal transition (EMT) and metastasis. However, the underlying mechanism of the HMGB1-induced EMT, invasion, and metastasis is unclear. In this study, we showed that noninvasive breast cancer cells MCF-7 formed tightly packed, rounded spheroids and that the cells in the inner regions of a multicellular tumor spheroid (MTS), an in vitro model of a solid tumor, led to necrosis due to an insufficient supply of O2 and glucose. In addition, after 7 d of MTS culture, the EMT was induced via the transcription factor Snail. We also showed that HMGB1 receptors, including RAGE, TLR2, and TLR4, were induced by MTS culture. RAGE, TLR2, and TLR4 shRNA inhibited MTS growth, supporting the idea that RAGE/TLR2/TLR4 play critical roles in MTS growth. They also prevented MTS culture-induced Snail expression, pointing to RAGE/TLR2/TLR4-dependent Snail expression. RAGE, TLR2, and TLR4 shRNA suppressed the MTS-induced EMT. In human cancer tissues, high levels of RAGE, TLR2, and TLR4 were detected. These findings demonstrated that the HMGB-RAGE/TLR2/TLR4-Snail axis played a crucial role in the growth of the MTS and MTS culture-induced EMT.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.243-249
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• 2006

Porous polymer gel electrolytes (PGEs) based on poly(vinylidenefluoride-co-hexafluoropropylene) (P(VdF-co-HFP)) as a polymer matrix and polyvinylpyrolidone (PVP) as a pore-forming agent were prepared and electrochemical properties were investigated for an electric double layer capacitor (EDLC) in order to increase a permeability of an electrolyte into the PGE. Propylene carbonate (PC) and ethylene carbonate (EC) as plasticizers, and tetraethylammonium tetrafluoroborate ($TEABF_4$) as a supporting salt for the PGE were used. EDLC unit cells were assembled with the PGE and electrode comprising BP-20 and MSP-20 as activated carbon powders, Super P as a conducting agent, and P(VdF-co-HFP)/PVP as a mixed binder. Ion conductivity of PGEs increased with an increased PVP content and was the best at 7 wt% PVP, whereas electrochemical characteristics such as AC-ESR of unit cell were better in 3 wt%. And electrochemical characteristics of the unit cell with PGE were the best at a 33 : 33 weight ratio of PC to EC. Specific capacitance of a mixed plasticizer system of PE and EC was higher than that of pure PC. Ion conductivity of PGEs with a film thickness of $20{\mu}m$ was higher, but electrochemical characteristics of unit cells were higher for a $50{\mu}m$ membrane thickness. Also, the unit cell has shown the highest capacitance of 31.41 F/g and more stable electrochemical performance when PGE and electrode were hot pressed. Consequently, the optimum composition ratio of PGE for EDLCs was 23 : 66 : 11 wt% such as P(VdF-co-HFP) : PVP = 20 : 3 wt% and PC : EC = 44 : 22 wt%. In this case, $3.17{\times}10^{-3}S/cm$ of ion conductivity was achieved at the $50{\mu}m$ thickness of PGE for EDLCs. And the electrochemical characteristics of unit cells were $2.69{\Omega}$ of DC-ESR, 28 F/g of specific capacitance, and 100% of coulombic efficiency.

• The Korean Journal of Soil Zoology
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• v.5 no.2
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• pp.101-112
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• 2000

Spiders usually have poor vision but not the jumping spiders. Their eight eyes are located on its distinctive box-shaped head and relatively well developed. The Spiders were fixated with 3% glutaraldehyde and thin section was performed with ultra-microtome. The specimens were observed with light microscopy, transmission and scanning electron microscopy. Eye area of jumping spider is competed of three rows. The first eye row comprise four eyes. Among them, two anterior median eyes are the largest and two anterior lateral eyes are relatively small. The former are main-eyes and have excellent vision. The second row, which has the two smallest eyes, is located about midway between the first and third rows. The third row is about half-way back on the thorax and eyed of which are middle size. To investigate ultrastructure of salticid spiders'eye, Menemerus fulvus was chosen. All of Menemerus fuvus's eyes are composed of cornea, lens, vitreous body and retina in histologically. Cornea layer, linked to exocuticle of exoskeleton. is regular layer structure without any cell tripe. Lenses are biconvex type. Retinas comprise well developed microvilli-shape rhabdomeres, unpigmented supporting cells, and pigmented cell. Retinas of anterior median eyes are surrounded by circular cylinder-shaped vitreous body, photoreceptor, i.e. rhabdomeres, of it is irregularly arranged compared to the other eyes.

• Journal of Broadcast Engineering
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• v.18 no.2
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• pp.215-224
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• 2013

With the rising popularity of smart-phones, the supply of Internet protocol television is largely increased and it causes the wireless communication network load to be increased. To overcome such an overloading problem, 3GPP is now working on the standardization of MBMS since LTE Release 6 specification. MBMS has good performance in bandwidth efficiency by sharing the same bandwidth with the mulitple MBMS users having the same content. According to the proposed algorithm, in heterogeneous networks having a dispersed Single-cell MBMS where 3GPP network and Wi-Fi network are mixed, if the number of MBMS users, who are belonging to cells supporting a dispersed Single-cell MBMS, is more than a specified threshold, the MBMS priority policy is operated. Otherwise, the Wi-Fi priority policy is executed. As the simulation results show both the increase of total available bandwidth ratio and the decrease of network usage cost, it is confirmed that the proposed scheme allows the network efficiency to be maximized.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.4 no.2
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• pp.101-110
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• 2011

To describe the background, mechanism, clinical results and complications of prolotheapy based on the literature review. Prolotherapy is a minimally invasive injection-based treatment of chronic musculoskeletal pain, including ligament and joint laxity. The mechanism of this injection-based technique is to initiate a local inflammatory response with resultant tissue healing. The used proliferants are classified by bio-mechanism to act in three different ways as osmotic, irritants, and chemotatics. The most commonly used proliferant is hyperosmolar (10~25%) dextrose to act by osmotic rupture of cells. High resolution ultrasound imaging of musculoskeletal structure provide a more accurate diagnosis. Also ultrasound-guided intervention provides a more high efficacy and low rate of complications. The most common complication is local pain at the injected site, that is self-limited and good responsive to anti-inflammatory agents. Other complications are rare. It is reported that prolotherapy appears safe when performed by an experienced clinician. Prolotherapy has grown in popularity and has received significant recent attention. However there are limited evidence-based data supporting the indication and efficacy of prolotherapy in the treatment of chronic musculoskeletal pain or soft tissue injuries. Future studies are necessary to determine whether prolotherapy can play an independent and definitive role in a treatment for chronic musculoskeletal pain.

• Journal of Embryo Transfer
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• v.16 no.1
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• pp.53-60
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• 2001

This study was conducted to evaluate whether \"Royal jelly\" (RJ) added to Tris-buffer dilute contributed to supporting post-thaw viability and longevity of frozen canine spermatozoa. Two Japanese spitzs (2 to 4 years of age) were used as a semen donor. Semen was collected by manual masturbation and separated into 3 fractions. Only the sperm-rich fraction having sperm motility of more than 70%, containing sperm concentration of 2~4$\times$10$^{8}$ cells/ml and having dead or abnormal spermatozoa of less than 15% was used for the experiment. Each ejaculated semen was centrifuged at 400 $\times$ g for 5 min and then diluted in a Tris-buffer supplemented with 20 ml egg yolk (Ext I), 4% glycero1 and 1% Equex STM Paste (Ext II) or g1ycero1, Equex STM paste and RJ of various concentrations (Ext II-RJ). After freezing and thawing, viability of spermatozoa in Ext II -RJ containing 1% RJ immediately after thawing (67.5$\pm$9.6) was significantly lower than that of Ext II , Ext II -RJ containing 0.01 or 0.1% RJ (77.5$\pm$12.5, 78.7$\pm$8.2 and 80.0$\pm$6.3). However, Ext II-RJ containing 0.1% RJ yielded higher viability than Ext II, Ext II-RJ containing 0.01% at or 1% 1 h after thawing (69.5$\pm$8.1 vs. 55.0$\pm$12.9, 57.5$\pm$9.6 and 41.5$\pm$12.6; P<0.05). At 1 h after thawing, the viability of spermatozoa thawed in 7$0^{\circ}C$ (68.8$\pm$12.5) was significantly higher than that of spermatozoa thawed in 38$^{\circ}C$ (48.8$\pm$16.3), although there was no difference in the viability between both groups immediately after thawing (77.5$\pm$9.6 and 81.3$\pm$8.1). Post-thaw viability and longevity of post-thaw spermatozoa in Ext II-RJ containing 0.1% RJ was higher in those in Ext II at 1 h (65.0$\pm$12.9 vs. 42.5$\pm$12.6), 2 h (52.5$\pm$12.6 vs. 27.5$\pm$17.1) and 3 h (40.0$\pm$14.1 vs. 20.0$\pm$12.1) after thawing. These results indicated that addition of 0.1% af to Tris-buffer enhanced post-thaw viability and longevity of canine spermatozoa and this additive can be used for increasing the possibility of collision between spermatozoa and ova during insemination.emination.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.5
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• pp.239-246
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• 2017

Communications for mobile sink groups such as rescue teams or platoons bring about a new challenging issue for handling group mobility in wireless sensor networks. Recently, a group region-based approach has been proposed to send data to a mobile sink group. However, it uses excessive flooding for 3 steps (group region discovery, region information notification, and data dissemination) to support mobile sink group. Thus, it causes high energy consumption and data delivery failure. Moreover, its per-sink mobility supporting scheme makes energy consumption and data delivery failure more serious. Thus, this paper proposes an Energy-efficient and Reliable Mobile Group communication protocol (ERMG) to support a mobile sink group, which exploits a virtual grid structure. For the group region discover and notification and the data dissemination, ERMG uses communications with only cell heads of grid cells that manages group sinks. ERMG also uses a per-grid based scheme to support sink mobility. Simulation results show that ERMG has 30% less energy consumption and 6% more desired delivery deadline success ratio than the existing protocols.

• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.641-646
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• 2018

Sodium borohydride, $NaBH_4$, shows a number of advantages as hydrogen source for portable proton exchange membrane fuel cells (PEMFCs). Properties of $NaBH_4$ hydrolysis reaction using activated carbon supported Co-B/C, Co-P-B/C catalyst were studied. BET surface area of catalyst, yield of hydrogen, effect of $NaBH_4$ concentration and durability of catalyst were measured. The BET surface area of carbon supported catalyst was over $500m^2/g$ and this value was 2~3 times higher than that of unsupported catalyst. Hydrogen generation of activated carbon supported catalyst was more stable than that of unsupported catalyst. The activation energy of Co-P-B/C catalyst was 59.4 kJ/mol in 20 wt% $NaBH_4$ and 14% lower than that of Co-P-B/FeCrAlloy catalyst. Catalyst loss on activated carbon supported catalyst was reduced to about 1/3~1/2 compared with unsupported catalyst, therefore durability was improved by supporting catalyst on activated carbon.

• KSBB Journal
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• v.24 no.2
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• pp.113-121
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• 2009

As one of the new areas of 'omics' technology, there is increasing interest in metabolomics, which involves the analysis of low-molecular-weight compounds in cells, tissues, and biofluids, and considers interactions within various organisms and reactions of external chemicals with those organisms. However, metabolomics research is still at a fundamental stage in Korea. Therefore, the purpose of this study was to establish a strategic long-term plan to revitalize the national metabolomics approach and obtain the elementary data necessary to determine a policy for effectively supporting metabolomics research. These investigations clarified the state of metabolomics study both in Korea and internationally, from which we attempted to find the potentiality and fields where a metabolomics approach would be applicable, such as in medical science. We also discuss strategies for developing metabolomics research. This study revealed that promoting metabolomics in Korea requires cooperation with metabolomics researchers, acquisition of advanced technology, capital investment in metabolomics approach, establishment of metabolome database, and education of metabolome analysis experts. This would reduce the gap between the national and international levels of metabolomics research, with the resulting developments in metabolomics having the potential to greatly contribute to promoting biotechnology in Korea.

• Journal of Ginseng Research
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• v.33 no.2
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• pp.155-159
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• 2009

Sudden idiopathic sensorineural hearing loss is a disease that develops within several hours to several days. Its etiology has not yet been verified, but the disturbance of the circulation of blood in the inner ear, inner-ear hydrops, and viral infection are considered possible causes of the disease. This study was conducted to evaluate the effect of Panax ginseng extract, which is known to have a vasodilatory effect, on sudden sensorineural hearing loss. Sixty-nine patients suffering from sudden sensorineural hearing loss were admitted to Korea University Anam Hospital from March to December 2008. They were divided into the experimental (30 ears) and control (39 ears) groups. Ginseng extract (2700 mg/day, 4 weeks) was added to the therapeutic regimen in the experimental group. The effect of ginseng extract therapy was analyzed according to the factors relating to the prognosis. A considerable hearing improvement was documented in both groups (32.2 dB in the experimental group and 25.8 dB in the control group). However, there was little beneficial effect of ginseng extract on additional hearing improvement compared with control. The total recovery rate of the experimental group (80.0%) was better than that of the control group (58.9%), and the experimental group's high-tone hearing gain at 3 kHz (29.7 dB) was better than that of the control group (21.7 dB). The results of the study suggest that the effects of ginseng therapy tend to be superior to those of the conventional therapy, but the difference between the two is not statistically significant. The hearing gains tend to be in the higher frequencies and may be due to the promotion of cellular differentiation from the supporting cells.