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Study on Young’s Modulus of Geomaterials used in Korean Railway Infrastructures
Sung Jin Lee,Seong Hyeok Lee,Il Wha Lee,Su Beom Hwang,Ki Jae Kim 한국철도학회 2013 International Journal of Railway Vol.6 No.2
In this study, cyclic triaxial tests were carried out with the coarse granular materials used in Korean railway infrastructure (reinforced trackbed, gravel of transition zone, upper subgrade of railway) and Young’s modulus for the target materials in small strain level were suggested. And the result of elastic modulus suggested in this study is expected to be effectively applied to dynamic analysis of the railway embankment structure using similar material, since the grain size distributions and unit weight of the material tested in this study are specified in Korean Railway Design Criteria.
Sang-Eun Park,Min-Yim Park,Po-Keun Han,Sang-Wha Lee* 대한화학회 2006 Bulletin of the Korean Chemical Society Vol.27 No.9
An electrostatic interaction is responsible for the attachment of gold seeds of 1-3 nm onto APTMS (3-aminopropyl trimethoxysilane)-coated silica cores in the formation of gold clusters. A surface plasmon resonance and morphology of gold clusters were significantly affected by the pH of gold colloids prepared by THPC reducing agent. Gold colloids of alkaline pH induced the heterogeneous deposition of gold seeds onto the silica nanoparticles, probably due to the continuous reduction of residual gold ions during the attachment process. Gold colloids of acidic pH induced the monodisperse deposition of gold seeds, consequently leading to the formation of smooth gold layer on the silica nanoparticles surface. The gold nanoshells (core radius = 80 nm) prepared by gold colloids of pH 3.1 exhibited the more red-shift and relatively stronger intensity of plasmon absorption bands, compared with gold nanoshells prepared by alkaline gold colloids of pH 9.7.
Lee, Jung Sook,Song, Young Wha,Kim, Sung Won International Academy of Physical Therapy Research 2012 Journal of International Academy of Physical Ther Vol.3 No.2
Ischemia, the leading cause of strokes, is known to be deeply related to synaptic plasticity and apoptosis in tissue damage due to ischemic conditions or trauma. The purpose of this study was to research the effects of NEES(needle electrode electrical stimulation) in brain cells of ischemia-induced rat, more specifically the effects of Poly[ADP-ribose] polymerase(PARP) on the corpus striatum. Ischemia was induced in SD mice by occluding the common carotid artery for 5 minutes, after which blood was re-perfused. NEES was applied to acupuncture points, at 12, 24, and 48 hours post-ischemia on the joksamri, and at 24 hours post-ischemia on the hapgok. Protein expression was investigated through PARP antibody immuno-reactive cells in the cerebral nerve cells and western blotting. The number of PARP reactive cells in the corpus striatum 24 hours post-ischemia was significantly(p<.05) smaller in the NEES group compared to the global ischemia(GI) group. PARP expression 24 hours post-ischemia was very significantly smaller in the NEES group compared to the GI group. Results show that ischemia increases PARP expression and stimulates necrosis, making it a leading cause of death of nerve cells. NEES can decrease protein expression related to cell death, protecting neurons and preventing neuronal apoptosis.
Lee, Min Jae,Kim, Dong Eun,Zakrzewska, Adriana,Yoo, Young Dong,Kim, Su-Hyeon,Kim, Sung Tae,Seo, Jai Wha,Lee, Young Sook,Dorn, Gerald W,Oh, Uhtaek,Kim, Bo Yeon,Kwon, Yong Tae American Society for Biochemistry and Molecular Bi 2012 The Journal of biological chemistry Vol.287 No.28
<P>The N-end rule pathway is a proteolytic system in which destabilizing N-terminal amino acids of short lived proteins are recognized by recognition components (N-recognins) as an essential element of degrons, called N-degrons. In eukaryotes, the major way to generate N-degrons is through arginylation by ATE1 arginyl-tRNA-protein transferases, which transfer Arg from aminoacyl-tRNA to N-terminal Asp and Glu (and Cys as well in mammals). We have shown previously that ATE1-deficient mice die during embryogenesis with defects in cardiac and vascular development. Here, we characterized the arginylation-dependent N-end rule pathway in cardiomyocytes. Our results suggest that the cardiac and vascular defects in ATE1-deficient embryos are independent from each other and cell-autonomous. ATE1-deficient myocardium and cardiomyocytes therein, but not non-cardiomyocytes, showed reduced DNA synthesis and mitotic activity ~24 h before the onset of cardiac and vascular defects at embryonic day 12.5 associated with the impairment in the phospholipase C/PKC-MEK1-ERK axis of Gα(q)-mediated cardiac signaling pathways. Cardiac overexpression of Gα(q) rescued ATE1-deficient embryos from thin myocardium and ventricular septal defect but not from vascular defects, genetically dissecting vascular defects from cardiac defects. The misregulation in cardiovascular signaling can be attributed in part to the failure in hypoxia-sensitive degradation of RGS4, a GTPase-activating protein for Gα(q). This study is the first to characterize the N-end rule pathway in cardiomyocytes and reveals the role of its arginylation branch in Gα(q)-mediated signaling of cardiomyocytes in part through N-degron-based, oxygen-sensitive proteolysis of G-protein regulators.</P>
Lee, Sang-Wha,Ahn, Kwang-Soon,Zhu, Kai,Neale, Nathan R.,Frank, Arthur J. American Chemical Society 2012 The Journal of Physical Chemistry Part C Vol.116 No.40
<P>We report on the effects of treating TiO<SUB>2</SUB> nanocrystalline films with different concentrations of TiCl<SUB>4</SUB> (5–500 mM) on the film morphology, charge-carrier dynamics, and performance of dye-sensitized solar cells. Transport and recombination in the TiCl<SUB>4</SUB>-treated films were studied by frequency-resolved modulated photocurrent/photovoltage spectroscopies. These studies showed that, at a low TiCl<SUB>4</SUB> concentration (5 mM), the electron diffusion coefficient in the annealed film increased. At intermediate TiCl<SUB>4</SUB> concentrations (15–50 mM), the surface area of the films increased, resulting in an increase of light harvesting and overall power conversion efficiency. At a high TiCl<SUB>4</SUB> concentration (500 mM), light scattering in the film in the long wavelength region of the visible spectrum was enhanced, but the averaged pore size of the film became narrower, resulting in slower transport and loss of cell performance.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2012/jpccck.2012.116.issue-40/jp3079887/production/images/medium/jp-2012-079887_0007.gif'></P>
Lee, Sang Heon,Derby, Richard,Sul, Dong geun,Hong, Jung wha,Kim, Gon Ho,Kang, Seok,Kim, Nack Hwan,Yoo, Seung Han,Lee, Seok Jun,Hong, Young Ki,Lee, Jeong Eun Blackwell Publishing Inc 2011 Pain medicine Vol.12 No.3
<P><B>Abstract</B></P><P><B>Study Design. </B> An institutional, prospective clinical data analysis.</P><P><B>Objective. </B> To evaluate the safety and efficacy of a new navigable percutaneous disc decompression device (L'DISQ) in patients with lumbar disc herniation with radicular pain.</P><P><B>Methods and Outcome Measures. </B> We performed disc decompressions using L'DISQ on 27 patients with persistent disabling back and leg pain for 1 month or longer (average 6.48 months) due to a herniated lumbar intervertebral disc. Baseline data were prospectively gathered before the index procedure and at 1, 4, 12, and 24 weeks post‐procedure. Data included pain intensity (visual analog scale [VAS]), measure of disability (Oswestry Disability Index [ODI] and Rolando–Morris Questionnaire [RM]), health‐related quality of life (Bodily Pain Scale of Short Form‐36 version 2 [SF‐36 BP]), and passive straight leg raising test (SLR).</P><P><B>Results. </B> The VAS fell from 7.08 ± 1.22 to 1.84 ± 0.99 scores at 24 weeks post‐procedure. At 24 weeks, the ODI had fallen from 41.88 ± 10.61 to 16.66 ± 8.55% and the RM from 11.52 ± 3.91 to 2.68 ± 1.97 points. The SF‐36 BP dropped significant improvement from 32.89 ± 5.83 to 49.57 ± 4.96 scales. In the SLR test, the angular change of 24 weeks showed considerable improvement from 60.20 ± 20.02 to 83.00 ± 14.29 degrees. No major complication occurred, although two cases developed a disc reherniation 1 month post‐procedure.</P><P><B>Conclusions. </B> The L'DISQ device is specifically designed to remove herniated disc using a wand that can be navigated into a disc protrusion or extrusion. Following decompression, we measured clinically significant pain improvement and decreased disability for patients with both radicular and axial pain caused by protruded and extruded discs.</P>
Effects of White Radish (Raphanus sativus) Enzyme Extract on Hepatotoxicity
Lee, Sang-Wha,Yang, Kwang-Mo,Kim, Jung-Ki,Nam, Byung-Hyouk,Lee, Chang-Min,Jeong, Min-Ho,Seo, Su-Yeong,Kim, Gi-Yong,Jo, Wol-Soon Korean Society of ToxicologyKorea Environmental Mu 2012 Toxicological Research Vol.28 No.3
Raphanus sativus (Cruciferaceae), commonly known as radish is widely available throughout the world. From antiquity it has been used in folk medicine as a natural drug against many toxicants. The present study was designed to evaluate the hepatoprotective activity of radish (Raphanus sativus) enzyme extract (REE) in vitro and in vivo test. The $IC_{50}$ values of REE in human liver derived HepG2 cells was over 5,000 ${\mu}g/ml$ in tested maximum concentration. The effect of REE to protect tacrine-induced cytotoxicity in HepG2 cells was evaluated by MTT assay. REE showed their hepatoprotective activities on tacrine-induced cytotoxicity and the $EC_{50}$ value was 1,250 ${\mu}g/ml$. Silymarin, an antihepatotoxic agent used as a positive control exhibited 59.7% hepatoprotective activity at 100 ${\mu}g/ml$. Moreover, we tested the effect of REE on carbon tetrachloride ($CCl_4$)-induced liver toxicity in rats. REE at dose of 50 and 100 mg/kg and silymarin at dose of 50 mg/kg were orally administered to $CCl_4$-treated rats. The results showed that REE and silymarin significantly reduced the elevated levels of serum enzyme markers induced by $CCl_4$. The biochemical data were supported by evaluation with liver histopathology. These findings suggest that REE, can significantly diminish hepatic damage by toxic agent such as tacrine or $CCl_4$.
Study on Young's Modulus of Geomaterials used in Korean Railway Infrastructures
Lee, Sung Jin,Lee, Seong Hyeok,Lee, Il Wha,Hwang, Su Beom,Kim, Ki Jae The Korean Society for Railway 2013 International Journal of Railway Vol.6 No.2
In this study, cyclic triaxial tests were carried out with the coarse granular materials used in Korean railway infrastructure (reinforced trackbed, gravel of transition zone, upper subgrade of railway) and Young's modulus for the target materials in small strain level were suggested. And the result of elastic modulus suggested in this study is expected to be effectively applied to dynamic analysis of the railway embankment structure using similar material, since the grain size distributions and unit weight of the material tested in this study are specified in Korean Railway Design Criteria.
Lee, Jung Sook,Song, Young Wha,Kim, Sung Won International Academy of Physical Therapy Research 2014 Journal of International Academy of Physical Ther Vol.5 No.2
The cerebellum is known to control balance, equilibrium, and muscle tone. If the cerebellum becomes damaged, the body is unable to retain its balancing functions or involuntary muscle movement. This is why, in stroke patients, there is a high risk of functional disability, as well as a myriad of other disabilities secondary to stroke. Ischemia was induced in SD mice by occluding the common carotid artery for 5 minutes, after which blood was reperfused. Needle electrode electrical stimulation(NEES) was applied to acupuncture points, at 12, 24, and 48 hours post-ischemia on the joksamri. Protein expression was investigated through caspase-3 antibody immuno-reactive cells in the cerebral nerve cells and Western blotting. The results were as follows: The number of caspase-3 reactive cells in the corpus cerebellum 12 and 24 hours post-ischemia was significantly (p<.05) smaller in the NEES group compared to the GI group. caspase-3 expression 12 and 24 hours post-ischemia was significantly(p<.05) smaller in the NEES group compared to the GI group. Based on these results, NEES seems to have a significant effect on Caspase-3 in the cerebellum in an ischemic state at 12 and 24 hours post ischemia, NEES delays the occurrence of early stage apoptosis-inducing Caspase-3, delaying and inhibiting apoptosis. Further systematic studies will have to be conducted in relation to the application of this study's results on stroke patients.