• Bulletin of the Korean Chemical Society
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• v.28 no.6
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• pp.921-928
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• 2007

Three different phosphonated trisbipyridine ruthenium complexes, [(4-CH3-4'-CH2PO(OH)2-2,2'-bipyridine)- (bpy)2Ru]·(PF6)2 (Ru-P1), [(4-CH3-4'-CH2PO(OH)2-2,2'-bipyridine)3Ru]·(PF6)2 (Ru-P2), and [(4,4'-CH2PO- (OH)2-2,2'-bipyridine)3Ru]·(PF6)2 (Ru-P3) were synthesized and their photochemical and electrochemical properties were studied. These ruthenium complexes were strongly adsorbed on the surface of the layered metal oxide semiconductor K4Nb6O17 that was partially acid-exchanged and sensitized up to pH 10, while the carboxylated ruthenium complex, (4,4'-COOH-2,2'-bipyridine)3Ru·Cl2 (Ru-C) that was previously studied was sensitized only below pH 4. The visible light water reduction at K4Nb6O17 that was internally platinized and sensitized by these phosphonated Ru-complexes was comparatively studied using a reversible electron donor iodide.

• Bulletin of the Korean Chemical Society
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• v.14 no.2
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• pp.188-191
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• 1993

The reaction between methyl 2,3-di-O-benzyl-4,6-di-O-mesyl-${\alpha}$-D-glucopyranoside (1b) and potassium superoxide resulted in hydrolysis, and gave methyl 2,3-di-O-benzyl-${\alpha}$-D-glucopyranoside (1) as a sole product. When the reaction was performed with a vicinal dimesylate, methyl 4,6-O-benzylidene-2,3-di-O-mesyl-${\alpha}$-D-altropyranoside (4b), again the hydrolysis product, methyl 4,6-O-benzylidene-${\alpha}$-D-altropyranoside (4) was obtained. However, the reaction of potassium superoxide with another vicinal dimesylate, methyl 4,6-O-benzylidene-2,3-di-O-mesyl-${\alpha}$-D-glucopyranoside (3b), nucleophilic displacement took place to afford methyl 4,6-O-benzylidene-${\alpha}$-D-altropyranoside (4). Apparently different results from two trans vicinal dimesylates, 3b and 4b are explained by the transient formation of epoxides, methyl 2,3-anhydro-4,6-O-benzylidene-${\alpha}$-D-allopyranoside (8) and methyl 2,3-anhydro-4,6-O-benzylidene-${\alpha}$-D-mannopyranoside (9) by $KO_2$. The reaction between the allo epoxide 8 and $KO_2$ gave altro 4. The manno epoxide 9 also afforded altro 4 as the major product. Facile epoxide formation by the reaction of a vicinal dimesylate and superoxide was also observed with 3-O-benzyl-1,2-O-isopropylidene-5,6-di-O-mesyl-${\alpha}$-D-glucofuranose: 5,6-anhydro-3-O-benzyl-1,2-O-isopropylidene-${\beta}$-L-idofuranose was obtained.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.4
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• pp.381-387
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• 2007

The excellent dielectric properties of $SF_6$(sulfur hexafluoride) have lead to its wide range of application in the field of high voltage insulation. Because there has been some recent concern regarding the environmental impacts of $SF_6$ binary gas mixtures, with $SF_6$ as the main component, have been the subject of active research. Scientists have long been interested in the possible use of gaseous fluorocarbons, including $CF_4$ (Carton Tetrafluoride), in high voltage applications due to their inert character and high dielectric strength. This paper presents experimental results concerning the AC breakdown characteristics lot various mixtures of $SF_6/CF_4$ in a test chamber and 25.8 kV GIS (Gas Insulation Switchgear) at practical pressures (0.1-04 MPa) and gap lengths (0.5 mm, 1 mm) in a test chamber. In the result, it was observed that an increase in the dielectric strength is attained through the addition of $SF_6$ to $CF_4$. It is possible to make an environment friendly gas insulation material while maintaining the dielectric strength by combing $SF_6$ and $CF_4$ which generates a lower level of the "global warming" effect.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.165-166
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• 2007

In these days $SF_6$ mixtures and alternative gas have been studied because of global warming and liquefying at low temperature and high pressure. At present work the breakdown characteristics of $SF_6/CF_4$ mixture in non-uniform field was performed. The experiments were carried out under positive and negative standard lightning impulse (SLT) voltages. The point-plane electrode was used with 3 mm gap distance in the test chamber. The $SF_6/CF_4$ mixture which contain 20% of $SF_6$ was compared with pure $SF_6$ and $CF_4$ gas. Experimental gas pressure ranged from 0.1 to 0.4 MPa. The breakdown voltage under negative SLI is higher than the breakdown voltage under positive voltage. And the breakdown voltage of $SF_6$ 20%, $CF_4$ 80% mixture is similar to that of pure $SF_6$.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.3
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• pp.103-107
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• 2005

Impossible differential attacks on AES have been proposed up to 6-round which requires $2^{91.5}$ chosen plaintexts and $2^{122}$ 6-round AES encryptions. In this paper, we introduce various 4-round impossible differentials and using them, we propose improved impossible differential attacks on 6-round AES. The current attacks require $2^{83.4}$ chosen plaintexts and $2^{105.4}$ 6-round AES encryptions to retrieve 11 bytes of the first and the last round keys.

• Journal of Embryo Transfer
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• v.25 no.1
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• pp.15-20
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• 2010

This study was performed to identify the optimal timing for oocyte donor replacement during OPU procedure. OPU was carried out to collect oocytes from every donor at an interval of $3{\sim}4$ days (2 times a week). The collected oocytes were matured in vitro in TCM-199 supplemented with 10% FBS, 10 mg/ml of FSH and 1 mg/ml of estradiol for 24 h. After 24 h of exposure to sperm, the presumptive zygotes were cultured in CR1aa medium supplemented with 4 mg/ml of BSA for 3 days before being changed to CR1aa medium with 10% of FBS for another $3{\sim}4$ days. The mean numbers of retrieved oocytes were remained constantly up to 3 months ($6.0{\pm}0.5$, $6.2{\pm}0.7$, $5.2{\pm}0.6$), but significantly decreased at over 4 to 6 months ($3.7{\pm}0.5$, $2.8{\pm}0.4$, $1.2{\pm}0.2$) (p<0.05). The blastocyst development potential was also very similar rate from 1 to 3 months (37.2%, 40.4% and 44.6%), but significantly decreased from 4 to 6 months (24.8%, 29.3% and 28.6%, respectively) (p<0.05). The production of OPU derived embryos in periods of 1 to 3 months ($2.2{\pm}0.3$, $2.5{\pm}0.3$ and $2.3{\pm}0.4$) were significantly higher than those in 4 to 6 months ($0.9{\pm}0.2$, $0.8{\pm}0.2$ and $0.3{\pm}0.2$, respectively) (p<0.05). In conclusion, the efficient periods for the production of OPU derived embryos was until 4 months, twice per week to produce over 64 transferable embryos and then replace new donor after 3 months use. The best replacement time is 3 months and could be maximized production of OPU derived embryos.

• The Korean Journal of Physiology and Pharmacology
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• v.27 no.4
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• pp.417-426
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• 2023

The TRPM4 gene encodes a Ca²⁺-activated monovalent cation channel called transient receptor potential melastatin 4 (TRPM4) that is expressed in various tissues. Dysregulation or abnormal expression of TRPM4 has been linked to a range of diseases. We introduced the hemagglutinin (HA) tag into the extracellular S6 loop of TRPM4, resulting in an HA-tagged version called TRPM4-HA. This TRPM4-HA was developed to investigate the purification, localization, and function of TRPM4 in different physiological and pathological conditions. TRPM4-HA was successfully expressed in the intact cell membrane and exhibited similar electrophysiological properties, such as the current-voltage relationship, rapid desensitization, and current size, compared to the wild-type TRPM4. The presence of the TRPM4 inhibitor 9-phenanthrol did not affect these properties. Furthermore, a wound-healing assay showed that TRPM4-HA induced cell proliferation and migration, similar to the native TRPM4. Co-expression of protein tyrosine phosphatase, non-receptor type 6 (PTPN6 or SHP1) with TRPM4-HA led to the translocation of TRPM4-HA to the cytosol. To investigate the interaction between PTPN6 and tyrosine residues of TRPM4 in enhancing channel activity, we generated four mutants in which tyrosine (Y) residues were substituted with phenylalanine (F) at the N-terminus of TRPM4. The YF mutants displayed properties and functions similar to TRPM4-HA, except for the Y256F mutant, which showed resistance to 9-phenanthrol, suggesting that Y256 may be involved in the binding site for 9-phenanthrol. Overall, the creation of HA-tagged TRPM4 provides researchers with a valuable tool to study the role of TRPM4 in different conditions and its potential interactions with other proteins, such as PTPN6.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.7 no.1
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• pp.1-6
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• 2014

Purpose: In order to know the effectiveness of ultrasonographic examination in diagnosis and follow-up evaluation for the frozen shoulder, we compared those with contralateral side in initial and after steroid injection. Materials and Methods: For the 20 unilateral frozen shoulder from July 2012 to July 2013, ultrasonographic examination was tried using reference line 1 (CBT: distance from coracoid process to LHB tendon) and line 2 (CBG: distance from coracoid process to bicipital groove). We tried 1 time steroid injection and compared the improvement in gross motion and reference line with 2 month, 4 month, and 6 month's serial ultrasonographic examination. Results: The differences on CBT line between lesion side and normal side were -5.6 mm, -5.0 mm, and -4.3 mm in neutral (Neut), external rotation (ER) and internal rotation (IR), respectively. The differences on CBG line were -6.1 mm, -4.7 mm, and -5.0 mm respectively (p<0.05). The changes in the reference line after steroid injection were evaluated at 2 month (CBT: -4.8 mm, -3.5 mm, -2.6 mm / CBG: -4.7 mm, -4.0 mm, -3.6 mm), 4 month (CBT: -4.7 mm, -3.2 mm, -1.7 mm / CBG: -4.3 mm, -3.7 mm, -1.2 mm), and 6 month (CBT: -1.1 mm, -2.9 mm, -0.5 mm / CBG: -1.2 mm, -0.7 mm, -0.9 mm). The gross motion was improved at 4 month after injection, from elevation $108^{\circ}$, ER $32^{\circ}$, IR L5 in initial to $133^{\circ}$, $42^{\circ}$, L3 respectively (p<0.05). Pain improved from 7.5 in initial to 3.0 at 2 month on visual analog scale (VAS). Conclusion: The serial examination after steroid injection revealed that the delayed improvement on reference line (6 month) compared with pain (2 month) or gross motion (4 month). Dynamic ultrasonogram was useful in diagnosis and follow-up evaluation of frozen shoulder.

• Biomolecules & Therapeutics
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• v.30 no.6
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• pp.529-539
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• 2022

Rheumatoid arthritis (RA) is a multifactorial immune-mediated disease, the pathogenesis of which involves different cell types. T-cell activation plays an important role in RA. Therefore, inhibiting T-cell activation is one of the current therapeutic strategies. Cytotoxic T-lymphocyte antigen 4-immunoglobulin (CTLA4-Ig), also known as abatacept, reduces cytokine secretion by inhibiting T-cell activation. To achieve a homeostatic therapeutic effect, CTLA4-Ig has to be administered repeatedly over several weeks, which limits its applicability in RA treatment. To overcome this limitation, we increased the number of sialic acid-capped antennas by genetically engineering the CTLA4 region to increase the therapeutic effect of CTLA4-Ig. N-acetylglucosaminyltransferase (GnT) and α2,6-sialyltransferase (α2,6-ST) were co-overexpressed in Chinese hamster ovary (CHO) cells to generate a highly sialylated CTLA4-Ig fusion protein, named ST6. The therapeutic and immunogenic effects of ST6 and CTLA4-Ig were compared. ST6 dose-dependently decreased paw edema in a mouse model of collagen-induced arthritis and reduced cytokine levels in a co-culture cell assay in a similar manner to CTLA4-Ig. ST6- and CTLA4-Ig-induced T cell-derived cytokines were examined in CD4 T cells isolated from peripheral blood mononuclear cells after cell killing through irradiation followed by flow- and magnetic-bead-assisted separation. Interestingly, compared to CTLA4-Ig, ST6 was substantially less immunogenic and more stable and durable. Our data suggest that ST6 can serve as a novel, less immunogenic therapeutic strategy for patients with RA.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1541-1543
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• 2003

The microwave dielectric properties of $0.6Mg_4Ta_2O_9-0.4TiO_2$ ceramics were investigated. All sample of $0.6Mg_4Ta_2O_9-0.4TiO_2$ ceramics were prepared by the conventional mixed oxide method, and sintered in the temperature of $1350^{\circ}C{\sim}1450^{\circ}C$. The structural properties of $0.6Mg_4Ta_2O_9-0.4TiO_2$ ceramics were investigated by the X-ray diffraction meter. According to the X-ray diffraction patterns of $0.6Mg_4Ta_2O_9-0.4TiO_2$ ceramics, the major phase of the hexagonal $0.6Mg_4Ta_2O_9-0.4TiO_2$ were presented, In the case of $0.6Mg_4Ta_2O_9-0.4TiO_2$ ceramics sintered at $1400^{\circ}C$ for 5hr., the dielectric constant, quality factor and temperature coefficient of resonant frequency were 12.19, 109.411GHz, -17.21ppm/$^{\circ}C$, respectively.