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Won K.Y.,Kyung Hee University | Lim S.-J.,Kyung Hee University | Kim G.Y.,Kyung Hee University | Kim Y.W.,Kyung Hee University | And 3 more authors.
Human Pathology | Year: 2012

Cancer cells show a higher rate of anaerobic respiration than normal cells. The exact mechanisms for this higher glycolysis rate in cancer cells remain to be elucidated. The results of recent studies have indicated that p53, the most commonly mutated tumor suppressor gene, may have important functions in the regulation of energy-generating metabolic pathways that switch from oxidative phosphorylation to glycolysis via the synthesis of cytochrome c oxidase 2 (SCO2), p53-transactivated TP53-induced glycolysis (TIGAR), and apoptosis regulator. We evaluated the expression of p53, SCO2, TIGAR, and COX in 113 cases of invasive breast cancer using immunohistochemistry. A high expression of p53, SCO2, TIGAR, and COX was noted in 27.5% (31 cases), 84.1% (95 cases), 74.3% (84 cases), and 73.4% (83 cases) of the breast tumors, respectively. A high p53 expression was significantly associated with low expression levels of SCO2 (P =.008), COX (P <.0001), and TIGAR (P =.007). On the survival analysis, the low SCO2-expressing breast cancer patients showed a significantly poorer prognosis than that of the high SCO2-expressing breast cancer patients (P =.0078). These results suggest that p53 can modulate the metabolic pathways via the proteins SCO2 and TIGAR in human breast cancer. © 2012 Elsevier Inc. All rights reserved.


Park S.-Y.,Korea University | Lee S.-W.,Korea University | Lim J.-Y.,Korea University | Um B.J.,Sejong Science High School | Shin D.-M.,Korea University
Journal of Nanoscience and Nanotechnology | Year: 2016

A series of new red emitting phosphorescent iridium(III) complexes, (MN-TFP)2Ir(tmd), (MN-TFP)2Ir (dpd), (MN-MQ)2Ir(tmd), (MN-MQ)2Ir(dpd), (MN-Q)2Ir(tmd), and (MN-Q)2Ir(dpd), were synthesized for phosphorescent organic light-emitting diodes (PhOLEDs). The emitters consist of electron-rich and deficient aromatic rings, such as 1-methylnaphthalene (MN), 4-(trifluoromethyl)pyridine (TFP), 4-methylquinoline (MQ), and quinoline (Q). The ancillary ligands were 2,2,6,6-tetramethylheptane-3,5-dione (tmd) and 1,3-diphenylpropane-1,3-dione (dpd). The main ligands were synthesized by the Suzuki coupling reaction. The red emitting complexes were synthesized by the Nonoyama reaction. The optical properties were characterized by UV-visible absorption and photoluminescence (PL) spectroscopy. OLED devices with the structure of indium tin oxide (ITO)/PEDOT: PSS (40 nm)/HTL (17 nm)/RH-35:red dopant (5%, 40 nm)/HCL (5 nm)/SNABH 205:6s-12 (5%, 15 nm)/TPBi (20 nm)/LiF (1 nm)/Al (100 nm) were manufactured. These OLED devices were characterized by an investigation of current density-voltage-luminance, current efficiency, power efficiency, EQE, and EL spectrum. The red emitting iridium(III) complexes will be used as a solution process dopant for the hybrid OLED devices. Copyright © 2016 American Scientific Publishers All rights reserved.


Kim G.,Sejong University | Kang S.-H.,Kyung Hee University | Lim C.-Y.,Sejong Science High School | Kwon Y.-K.,Kyung Hee University
Chemical Physics Letters | Year: 2012

Using density functional theory, we examine the effects of a nitrogen atom adsorbed onto an anionic golden cage (Au16-) on the properties of the nanocage. For the exohedral adsorption that is more stable than the endohedral doping, the bridge and hollow sites have larger binding energies than the atop sites by ∼1 eV. When the N atom is adsorbed on the cage, electrons are transferred to nitrogen from Au16-. The nitrogen atom may move thermally from the exterior to the interior through a bridge site. In infrared spectra, exohedral doping causes greater intensities at higher frequencies than endohedral doping. © 2012 Elsevier B.V. All rights reserved.


Jeon S.H.,Sejong Science High School | Kim H.S.,Sejong Science High School | Han Y.J.,Sejong Science High School | Kim M.-Y.,Sejong Science High School | Um I.-H.,Ewha Womans University
Bulletin of the Korean Chemical Society | Year: 2014

A kinetic study on aminolysis of 2-chloro-4-nitrophenyl X-substituted-benzoates (2a-k) in 80 mol % H2O/20 mol % DMSO at 25.0 oC is reported. The Brønsted-type plot for the reactions of 2-chloro-4-nitrophenyl benzoate (2g) with a series of cyclic secondary amines curves downward (e.g., β1 = 0.25, β2 = 0.85 and pKa o = 10.3), which is typical of reactions reported to proceed through a stepwise mechanism with a change in ratedetermining step (RDS). The Hammett plot for the reactions of 2a-k with piperidine consists of two intersecting straight lines, while the corresponding Yukawa-Tsuno plot exhibits an excellent linear correlation with ρX = 1.15 and r = 0.59. Thus, it has been concluded that the nonlinear Hammett plot is not due to a change in RDS but is caused by stabilization of substrates through resonance interactions between the electron-donating substituent and the C=O bond. Substrates possessing a substituent at the 2-position of the leaving aryloxide deviate negatively from the curved Brønsted-type plot for the reactions of Y-substituted-phenyl benzoates (3ai), implying that the steric hindrance exerted by the substituent at the 2-position is an important factor which governs the reactivity of Y-substituted-phenyl benzoates.


Jeon S.H.,Sejong Science High School | Kim H.S.,Sejong Science High School | Han Y.J.,Sejong Science High School | Kim M.-Y.,Ewha Womans University | Um I.-H.,Ewha Womans University
Bulletin of the Korean Chemical Society | Year: 2013

Second-order rate constants (kN) have been measured spectrophotometrically for the reactions of 4-chloro-2- nitrophenyl X-substituted-benzoates (1a-1h) with a series of cyclic secondary amines in 80 mol % H2O/20 mol % DMSO at 25.0 ± 0.1 °C. The Hammett plot for the reactions of 1a-1h with piperidine consists of two intersecting straight lines, while the Yukawa-Tsuno plot exhibits an excellent linear correlation with ρX = 1.25 and r = 0.58, indicating that the nonlinear Hammett plot is not due to a change in the rate-determining step (RDS) but is caused by ground-state stabilization through resonance interactions for substrates possessing an electron-withdrawing group in the benzoyl moiety. The Brønsted-type plot for the reactions of 4-chloro-2- nitrophenyl benzoate (1d) with a series of cyclic secondary amines curves downward with β2 = 0.85, β1 = 0.24, and pKao = 10.5, implying that a change in RDS occurs from the k2 step to the k1 process as the pK a of the conjugate acid of the amine exceeds 10.5. Dissection of kN into the microscopic rate constants k1 and k 2/k-1 ratio associated with the reaction of 1d reveals that k2 is dependent on the amine basicity, which is contrary to generally held views.

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