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Enhanced ripening behavior of Mg-doped CdSe quantum dots
Sung, Yun-Mo,Kwak, Woo-Chul,Kim, Woong,Kim, Tae Geun Cambridge University Press (Materials Research Soc 2008 Journal of materials research Vol.23 No.7
<P>Pure CdSe and Mg-doped CdSe nanocrystal quantum dots were synthesized into the zinc-blende structure at a low temperature by the inverse micelle technique using paraffin oil and oleic acid as surface capping agents. The ripening behavior of the nanocrystals was monitored using the red shift in ultraviolet (UV)-visible light absorption peaks, and their size variation was estimated using the so-called, quantum confinement theory. The Lifshitz-Slyozov-Wagner (LSW) kinetics analyses were performed based on the variation in size according to the ripening temperature and time period. The activation energy (<I>Q</I>) and reaction rate constant (<I>K</I>o) were determined for the ripening reaction using Arrhenius-type plots. The kinetics analyses reveal that the volume diffusion through the liquid-phase solution is the governing mechanism for the ripening of both nanocrystals. The Mg-doped CdSe nanocrystals showed enhanced ripening kinetics due to the low activation energy for the volume diffusion.</P>
Sung-Mo Choi,Yeo-Sang Yun,Jin-Ho Kim 국제구조공학회 2006 Steel and Composite Structures, An International J Vol.6 No.4
The connection with combined cross diaphragm is developed for the connection of square CFT column and steel beam and proposed to be used for the frame with asymmetric span length. The structural characteristics of this connection lie in the penetration of the beam flange in the direction of major axis through the column for the smooth flow of stress. The purpose of this study is to analyze the dynamic behavior and stress flow of suggested connection and to evaluate the resistance to shock of connection. Four T-type CFT column-to-beam specimens; two with combined cross diaphragm and the others with interior and through diaphragms, the existing connection types, were made for cyclic load test guided by the load program of ANSI/AISC SSPEC 2002. The results show that the proposed connection is more efficient than existing ones in terms of strength, stress flow and energy absorption and satisfies the seismic performance required in the region of weak/moderate earthquakes.
Yun, Beom-Sik,Lee, Mi-Ra,Oh, Chang-Jin,Cho, Jeong-Hee,Wang, Chun-Yan,Gu, Li Juan,Mo, Eun-Kyung,Sung, Chang-Keun The Korean Society of Ginseng 2010 Journal of Ginseng Research Vol.34 No.4
Black ginseng and white ginseng were extracted with 80% ethanol and evaluated for relative ginsenoside composition, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities, and antioxidant properties. As analyzed by HPLC, black ginseng contained a greater proportion of ginsenoside $Rg_3$ compared to white ginseng. White ginseng was characterized by undetectable ginsenoside $Rg_3$ but it contained more total ginsenosides than black ginseng. Black ginseng extract exhibited higher (p<0.05) free radical-scavenging activity, as well as higher antioxidant activities than white ginseng against 2,2-diphenyl-1-picryl-hydrazyl, superoxide dismutase, and xanthine oxidase, despite the fact that the total saponin content was higher in white ginseng than black ginseng. In addition, the black ginseng extract displayed greater AChE and BChE inhibitory activities. These results suggest that black ginseng has stronger effects on anti-oxidation and AChE and BChE inhibition than white ginseng.
p31comet Induces cellular senescence through p21 accumulation and Mad2 disruption.
Yun, Miyong,Han, Young-Hoon,Yoon, Sun Hee,Kim, Hee Young,Kim, Bu-Yeo,Ju, Yeun-Jin,Kang, Chang-Mo,Jang, Su Hwa,Chung, Hee-Yong,Lee, Su-Jae,Cho, Myung-Haing,Yoon, Gyesoon,Park, Gil Hong,Kim, Sang Hoon,L American Association for Cancer Research 2009 Molecular Cancer Research Vol.7 No.3
<P>Functional suppression of spindle checkpoint protein activity results in apoptotic cell death arising from mitotic failure, including defective spindle formation, chromosome missegregation, and premature mitotic exit. The recently identified p31(comet) protein acts as a spindle checkpoint silencer via communication with the transient Mad2 complex. In the present study, we found that p31(comet) overexpression led to two distinct phenotypic changes, cellular apoptosis and senescence. Because of a paucity of direct molecular link of spindle checkpoint to cellular senescence, however, the present report focuses on the relationship between abnormal spindle checkpoint formation and p31(comet)-induced senescence by using susceptible tumor cell lines. p31(comet)-induced senescence was accompanied by mitotic catastrophe with massive nuclear and chromosomal abnormalities. The progression of the senescence was completely inhibited by the depletion of p21(Waf1/Cip1) and partly inhibited by the depletion of the tumor suppressor protein p53. Notably, p21(Waf1/Cip1) depletion caused a dramatic phenotypic conversion of p31(comet)-induced senescence into cell death through mitotic catastrophe, indicating that p21(Waf1/Cip1) is a major mediator of p31(comet)-induced cellular senescence. In contrast to wild-type p31(comet), overexpression of a p31 mutant lacking the Mad2 binding region did not cause senescence. Moreover, depletion of Mad2 by small interfering RNA induced senescence. Here, we show that p31(comet) induces tumor cell senescence by mediating p21(Waf1/Cip1) accumulation and Mad2 disruption and that these effects are dependent on a direct interaction of p31(comet) with Mad2. Our results could be used to control tumor growth.</P>
Sung-Il Hwang,Seung Hyup Kim,Young Jun Kim,Ah Young Kim,Jung Yun Cho,Joon Woo Lee,Hyung-Seok Kim,Kyung Mo Yeon The Korean Society of Radiology 2000 Korean Journal of Radiology Vol.1 No.3
Objective: The purpose of this study was to compare the effectiveness of MR urography (MRU) with that of ultrasonography (US) in the evaluation of urinary tract when this failed to opacify during excretory urography (EXU). Materials and Methods: Twelve urinary tracts in 11 patients were studied. In each case, during EXU, the urinary system failed to opacify within one hour of the injection of contrast media, and US revealed dilatation of the pelvocalyceal system. Patients underwent MRU, using a HASTE sequence with the breath-hold technique; multi-slice acquisition was then performed, and the images were reconstructed using maximal intensity projection. Each set of images was evaluated by three radiologists to determine the presence, level, and cause of urinary tract obstruction. Results: Obstruction was present in all twelve cases, and in all of these, MRU accurately demonstrated its level. In this respect, however, US was successful in only ten. The cause of obstruction was determined by MRU in eight cases, but by US in only six. In all of these six, MRU also successfully demonstrated the cause. Conclusion: MRU is an effective modality for evaluation of the urinary tract when this fails to opacify during EXU, and appears to be superior to US in demonstrating the level and cause of obstruction.
Torque control during lingual anterior retraction without posterior appliances
Sung-Seo Mo,Seong-Hun Kim,Sang-Jin Sung,Kyu-Rhim Chung,Yun-Sic Chun,Yoon-Ah Kook,Gerald Nelson 대한치과교정학회 2013 대한치과교정학회지 Vol.43 No.1
Objective: To evaluate the factors that affect torque control during anterior retraction when utilizing the C-retractor with a palatal miniplate as an exclusive source of anchorage without posterior appliances. Methods: The C-retractor was modeled using a 3-dimensional beam element (0.9-mm-diameter stainless-steel wire) attached to mesh bonding pads. Various vertical heights and 2 attachment positions for the lingual anterior retraction hooks (LARHs) were evaluated. A force of 200 g was applied from each side hook of the miniplate to the splinted segment of 6 or 8 anterior teeth. Results: During anterior retraction, an increase in the LARH vertical height increased the amount of lingual root torque and intrusion of the incisors. In particular, with increasing vertical height, the tooth displacement pattern changed from controlled tipping to bodily displacement and then to lingual root displacement. The effects were enhanced when the LARH was located between the central and lateral incisors, as compared to when the LARH was located between the lateral incisors and canines. Conclusions: Three-dimensional lingual anterior retraction of the 6 or 8 anterior teeth can be accomplished using the palatal miniplate as the only anchorage source. Using LARHs at different heights or positions affects the quality of torque and intrusion.