Showing papers by "Pusan National University published in 1999"
TL;DR: A novel family of postsynaptic density proteins, termed Shank, that binds via its PDZ domain to the C terminus of PSD-95-associated protein GKAP, and may function as a scaffold protein in the PSD, potentially cross-linking NMDA receptor/PSD- 95 complexes and coupling them to regulators of the actin cytoskeleton.
958 citations
TL;DR: Very large-scale motions in the form of long regions of streamwise velocity fluctuation are observed in the outer layer of fully developed turbulent pipe flow over a range of Reynolds numbers.
Abstract: Very large-scale motions in the form of long regions of streamwise velocity fluctuation are observed in the outer layer of fully developed turbulent pipe flow over a range of Reynolds numbers. The premultiplied, one-dimensional spectrum of the streamwise velocity measured by hot-film anemometry has a bimodal distribution whose components are associated with large-scale motion and a range of smaller scales corresponding to the main turbulent motion. The characteristic wavelength of the large-scale mode increases through the logarithmic layer, and reaches a maximum value that is approximately 12–14 times the pipe radius, one order of magnitude longer than the largest reported integral length scale, and more than four to five times longer than the length of a turbulent bulge. The wavelength decreases to approximately two pipe radii at the pipe centerline. It is conjectured that the very large-scale motions result from the coherent alignment of large-scale motions in the form of turbulent bulges or packets of...
853 citations
TL;DR: Results indicate that S1P induces angiogenesis predominantly via G(i) protein-coupled receptors in endothelial cells and suggest that S 1P may act as an important modulator of platelet-induced angiogenicity.
376 citations
TL;DR: Characterizing Shank cDNA clones and RT-PCR products suggests that alternative splicing in the Shank family may be a mechanism that regulates the molecular structure of Shank and the spectrum of Shank-interacting proteins in the PSDs of adult and developing brain.
277 citations
TL;DR: In this paper, a series of strength tests are carried out on aluminum honeycomb-cored sandwich panel specimen in three point bending, axial compression and lateral crushing loads and simplified theories are applied to analyze bending deformation, buckling/ultimate strength and crushing strength of honeycomb sandwich panels subject to the corresponding load component.
Abstract: Aluminum sandwich construction has been recognized as a promising concept for structural design of lightweight transportation systems such as aircraft, high-speed trains and fast ships. The aim of the present study is to investigate the strength characteristics of aluminum sandwich panels with aluminum honeycomb core theoretically and experimentally. A series of strength tests are carried out on aluminum honeycomb-cored sandwich panel specimen in three point bending, axial compression and lateral crushing loads. Simplified theories are applied to analyze bending deformation, buckling/ultimate strength and crushing strength of honeycomb sandwich panels subject to the corresponding load component. The structural failure characteristics of aluminum sandwich panels are discussed. The test data developed are documented.
262 citations
TL;DR: This paper considers how to allocate storage space for import containers in cases where the arrival rate of import containers is constant, cyclic, and dynamic, and mathematical models and solution procedures are suggested for obtaining the optimal solution.
214 citations
TL;DR: A simulation model for container terminal system analysis is proposed which is a reduced system of a real terminal in Pusan, Korea and the performance of the system is analyzed.
213 citations
TL;DR: In this paper, a new Fokker-Planck model of the evolution of globular clusters, including gravitational tidal shocks, was presented, and the core collapse time was investigated.
Abstract: We present new Fokker-Planck models of the evolution of globular clusters, including gravitational tidal shocks. We extend our calculations beyond the core collapse by adopting three-body binary heating. EUects of the shocks are included by adding the tidal shock diUusion coefficients to the ordinary Fokker-Planck equation: the —rst-order heating term, S*ET, and the second-order energy dispersion term, S*E2T. As an example, we investigate the evolution of models for the globular cluster NGC 6254. Using the Hipparcos proper motions, we are now able to construct orbits of this cluster in the Galaxy. Tidal shocks accelerate signi—cantly both core collapse and the evaporation of the cluster and shorten the destruction time from 24 to 18 Gyr. We examine various types of adiabatic corrections and —nd that they are critical for accurate calculation of the evolution. Without adiabatic corrections, the destruction time of the cluster is twice as short. We examine cluster evolution for a wide range of the concentration and tidal shock parameters and determine the region of the parameter space where tidal shocks domi- nate the evolution. We present —tting formulae for the core collapse time and the destruction time, covering all reasonable initial conditions. In the limit of strong shocks, the typical value of the core collapse time decreases from to or less, while the destruction time is just twice that number. 10t rh 3t rh The eUects of tidal shocks are rapidly self-limiting: as clusters lose mass and become more compact, the importance of the shocks diminishes. This implies that tidal shocks were more important in the past. Subject headings: celestial mechanics, stellar dynamicsglobular clusters: general ¨ globular clusters: individual (NGC 6254)
212 citations
TL;DR: A competitive nature of GCG with this enzyme for the L-tyrosine binding at the active site of tyrosinase is revealed, which indicates that the consumption of green tea may help prevent cancers in humans and also reduce several free radicals including peroxynitrite.
209 citations
TL;DR: It is concluded that ASC-2 is a bona fidetranscription coactivator molecule of nuclear receptors, and its altered expression may contribute to the development of cancers.
207 citations
TL;DR: Spiral CT has good sensitivity and specificity for the diagnosis of PE and in the majority of patients who do not have PE, it also provides important ancillary information for the final diagnosis.
Abstract: PURPOSE: To prospectively determine the utility of contrast material–enhanced spiral computed tomography (CT) in the examination of patients clinically suspected of having pulmonary embolism (PE). MATERIALS AND METHODS: One hundred ten patients clinically suspected of having PE were examined with contrast-enhanced spiral CT and at least one other imaging modality: ventilation-perfusion scintigraphy, Doppler ultrasonography of deep leg veins, or pulmonary angiography. Chart review or telephone contact with the referring clinician was used to evaluate the contribution of spiral CT to the final clinical diagnosis. RESULTS: Spiral CT helped correctly identify 23 of 25 patients with PE (sensitivity, 92%). In 57 (67%) of the 85 patients without PE, spiral CT provided additional information that suggested or confirmed the alternate clinical diagnosis: pneumonia (n = 14), cardiovascular disease (n = 10), pulmonary fibrosis (n = 7), trauma (n = 6), malignancy (n = 5), pleural disease (n = 4), postoperative changes...
TL;DR: Findings support a role for GRIP in the synaptic anchoring of AMPA receptors but also suggest that GRIP has additional functions unrelated to the binding of AMpa receptors.
Abstract: The NMDA and AMPA classes of ionotropic glutamate receptors are concentrated at postsynaptic sites in excitatory synapses. NMDA receptors interact via their NR2 subunits with PSD-95/SAP90 family proteins, whereas AMPA receptors bind via their GluR2/3 subunits to glutamate receptor-interacting protein (GRIP), AMPA receptor-binding protein (ABP), and protein interacting with C kinase 1 (PICK1). We report here a novel cDNA (termed ABP-L/GRIP2) that is virtually identical to ABP except for additional GRIP-like sequences at the N-terminal and C-terminal ends. Like GRIP (which we now term GRIP1), ABP-L/GRIP2 contains a seventh PDZ domain at its C terminus. Using antibodies that recognize both these proteins, we examined the subcellular localization of GRIP1 and ABP-L/GRIP2 (collectively termed GRIP) and their biochemical association with AMPA receptors. Immunogold electron microscopy revealed the presence of GRIP at excitatory synapses and also at nonsynaptic membranes and within intracellular compartments. The association of native GRIP and AMPA receptors was confirmed biochemically by coimmunoprecipitation from rat brain extracts. A majority of detergent-extractable GluR2/3 was complexed with GRIP in the brain. However, only approximately half of GRIP was associated with AMPA receptors. Unexpectedly, immunocytochemistry of cultured hippocampal neurons and rat brain at the light microscopic level showed enrichment of GRIP in GABAergic neurons and in GABAergic nerve terminals. Thus GRIP is associated with inhibitory as well as excitatory synapses. Collectively, these findings support a role for GRIP in the synaptic anchoring of AMPA receptors but also suggest that GRIP has additional functions unrelated to the binding of AMPA receptors.
TL;DR: In this article, the authors developed a macro-model for measuring brand equity through parsimonious manipulation of the marketing mix, which was then operationalized and tested in three Korean markets in terms of predicted versus actual brand share.
Abstract: Rather than taking the more traditional approach of measuring brand equity for accounting or strategic reasons, the approach taken here is concerned with optimizing brand equity through parsimonious manipulation of the marketing mix. To this end a macro‐model is first developed; this model is then operationalized and tested (in terms of predicted versus actual brand share) in three Korean markets. The contribution of the paper lies in the development of a methodology through which management can efficiently build brand power in their markets. The statistical methods (factor analysis and preference regression) are commonly used in commercial research and the research requirements to build such a model are quite modest – the proposed model makes a theoretical contribution but can also be used as a practical managerial tool.
TL;DR: The antioxidant activity of Eriobotrya japonica was determined by measuring the radical scavenging effect on DPPH radical and lipid peroxidation produced when mouse liver homogenate was exposed to the air at 37°C, using 2-thiobarbituric acid.
Abstract: The antioxidant activity ofEriobotrya japonica was determined by measuring the radical scavenging effect on DPPH (1,1-diphenyl-2-picrylhydrazyl) radical and lipid peroxidation produced when mouse liver homogenate was exposed to the air at 37°C, using 2-thiobarbituric acid (TBA). The methanol extract and its fractions ofEriobotrya japonica leaves showed strong antioxidant activity. The antioxidant activity of EtOAc andn-BuOH soluble fractions were stronger than the others, and were further purified by repeated silica gel, MCI gel CHP-20P, and Sephadex LH-20 column chromatography. Antioxidant chlorogenic acid, quercetin-3-sambubioside fromn-BuOH fraction, and methyl chlorogenate, kaempferol- and quercetin-3-rhamnosides, together with the inactive ursolic acid and 2α-hydroxyursolic acid from EtOAc fraction were isolated. Antioxidant flavonoids and chlorogenic acid also showed prominent inhibitory activity against free radical generation in dichlorofluorescein (DCF) method.
TL;DR: In this article, Melamine resin microcapsules with long self-life containing fragrant Migrin oil were prepared by in situ polymerization from in situ polymeric polymerization.
TL;DR: It is demonstrated that Aloe vera gel and its extracts are angiogenic on the chorioallantoic membrane (CAM) of chick embryo and β-sitosterol is a novel plant-derivedAngiogenic factor which may have potential pharmaceutical applications for the management of chronic wounds.
Abstract: Aloe vera gel has a beneficial effect on wound healing. Because angiogenesis is an essential process in wound healing, we hypothesized that Aloe vera gel might contain potent angiogenic compounds. Here we demonstrate that Aloe vera gel and its extracts are angiogenic on the chorioallantoic membrane (CAM) of chick embryo. Out of the three compounds purified from the final fraction of Aloe vera gel, beta-sitosterol showed a potent angiogenic activity in the CAM assay. In the presence of heparin, beta-sitosterol stimulated neovascularization in the mouse Matrigel plug assay and the motility of human umbilical vein endothelial cells in an in vitro wound migration assay. Thus beta-sitosterol is a novel plant-derived angiogenic factor which may have potential pharmaceutical applications for the management of chronic wounds.
TL;DR: The data suggest that G-Rh2 inhibited the growth of MCF-7 cells, by inducing protein expression of p21 and reducing the protein levels of cyclin D which resulted in the down-regulation ofcyclin/Cdk complex kinase activity, decreasing phosphorylation of pRb, and inhibiting E2F release.
Abstract: Ginsenoside Rh2 (G-Rh2) isolated from the root of Panax ginseng has been shown to have anti-cancer proliferation, differentiation and chemopreventive effects in certain cancer cell types. We investigated the mechanism of G-Rh2-induced growth inhibition in MCF-7 human breast carcinoma cells. G-Rh2 significantly inhibited the cell growth in a concentration-dependent manner, which effect was reversible, and induced a G1 arrest in cell cycle progression. G-Rh2 treatment down-regulated the protein level of cyclin D3 but upregulated the expression of cyclin-dependent kinase (Cdk) inhibitor p21WAF1/CIP1. The increased levels of p21 were associated with increased binding of p21 and Cdk2 concomitant with marked decrease in Cdk2 and cyclin E-dependent kinase activities with no changes in Cdk2 and cyclin E expression. G-Rh2 markedly reduced the phosphorylated retinoblastoma protein (pRb) and enchanced association of unphosphorylated pRb and the transcription factor E2F-1. These data suggest that G-Rh2 inhibited the growth of MCF-7 cells, by inducing protein expression of p21 and reducing the protein levels of cyclin D which resulted in the down-regulation of cyclin/Cdk complex kinase activity, decreasing phosphorylation of pRb, and inhibiting E2F release.
TL;DR: In this article, the authors investigated the catalytic degradation of polyethylene (PE) in a fixed-bed reactor composed of a melter and a catalytic cracking bed.
TL;DR: The DRASTIC/EGIS model was used to evaluate the potential for groundwater contamination in the Cheongju city area, the first of several pilot studies as discussed by the authors, which allows the designation of hydrogeologic settings within the study area, based on a composite description of all the major geologic and hydrogeological factors for each setting.
Abstract: Groundwater contamination is becoming a major environmental problem in South Korea with the marked expansion of the industrial base and the explosive growth of the population. Even in rural areas, the increased use of fertilizers and pesticides, the presence of acid-mine drainage, and increase of volumes of domestic wastewaters are adding to groundwater pollution. The DRASTIC/EGIS model was used to evaluate the potential for groundwater contamination in the Cheongju city area, the first of several pilot studies. The model allows the designation of hydrogeologic settings within the study area, based on a composite description of all the major geologic and hydrogeologic factors for each setting. Then, a scheme for relative ranking of the hydrogeologic factors is applied to evaluate the relative vulnerability to groundwater contamination of each hydrogeologic setting. DRASTIC/EGIS can serve as a tool to evaluate pollution potential and so facilitate programs to protect groundwater resources.
TL;DR: The data suggest that the activity of a putative kinase(s) targeting HSF1 is upregulated in the presence of MG132 or lactacystin, and is likely due to the inhibition of protein degradation of a short-lived, kinase target and/or the cofactor for the kinases, through the ubiquitin-proteasome pathway.
TL;DR: In this article, the authors describe a new method of perform design in muti-stage metal forming processes considering workability limited by ductile fracture, using artificial neural network using the Taguchi method for minimizing objective functions relevant to the forming process.
Abstract: This study describes a new method of perform design in muti-stage metal forming processes considering workability limited by ductile fracture. The finite element simulation combined with ductile fracture criterion has been performed in order to predict ductile fracture. The artificial neural network using the Taguchi method has been implemented for minimizing objective functions relevant to the forming process. The combinations of design parameters used in finite element simulation are selected by orthogonal array in statistical design of experiments. The orthogonal array and the result of simulation are used as train data for artificial neural networks. The cold heading process is taken as an example of designing preforms which do not form any fracture in the finished product. The results of analysis to validate the proposed design method are presented.
TL;DR: In this paper, linear and nonlinear Granger causality tests are used to examine the dynamic relationship between daily Korean stock returns and trading volume, and they find evidence of significant bidirectional linear, nonlinear causality between these two series.
TL;DR: In this paper, a beam search algorithm is developed for the carrier routing problem in order to minimize the total travel distance of straddle carriers in the loading operation of export containers in port container terminals.
TL;DR: T cell responses to CII or CII (255-274) were enhanced in RA, especially in early disease, suggesting that CII-reactive T cells play an important role in the pathogenesis of RA.
Abstract: Objective
To determine the presence of specific immune recognition of type II collagen (CII) and its immunodominant epitope CII (255–274) in patients with rheumatoid arthritis (RA).
Methods
T cell proliferative responses to bovine CII and a synthetic peptide encompassing CII (255–274) in peripheral blood mononuclear cells (PBMC) and synovial fluid mononuclear cells (SFMC) from RA patients, and in PBMC from osteoarthritis (OA) patients and healthy controls were assayed by mixed lymphocyte culture.
Results
The stimulation index (SI) and the number of positive (SI ≥2) T cell responses to CII were higher in RA patients (n = 106) than in OA patients (n = 26) and healthy controls (n = 34). T cell responses to CII (255–274) were also enhanced in RA patients and correlated well with those to CII. In SFMC, positive responses to CII or CII (255–274) were detected in 61.9% of 42 RA patients. T cell responses to CII in SFMC were stronger and more prevalent than peripheral responses. The SI and positive responses to CII were higher in early RA than in late RA. Levels of IgG antibodies to CII in synovial fluid inversely correlated with T cell responses to CII.
Conclusion
T cell responses to CII or CII (255–274) were enhanced in RA, especially in early disease. Synthetic peptide CII (255–274), as well as native CII, could be recognized as immunogenic antigens by T cells, particularly in the synovial fluid. These observations suggest that CII-reactive T cells play an important role in the pathogenesis of RA. Peripheral tolerance induction using CII (255–274) might be useful in the treatment of RA.
Journal Article•
TL;DR: Findings indicate that IL-12p40 may function as an effector molecule as well as an antagonist of IL- 12p70 in vivo, and can initially amplify the immune responses against tumors by directly recruiting macrophages.
Abstract: IL-12p70 plays a pivotal role in regulating the Th1/Th2 balance in the initial stage of immune responses. In contrast, IL-12p40, which is produced excess over IL-12p70, has been known to down-regulate IL-12p70-mediated responses by acting as an antagonist. To investigate in vivo function of IL-12p40, RH7777 rat hepatoma cells were engineered to inducibly express mouse IL-12p40 under the tight control of doxycycline (dox). In the absence of dox, s.c. injection of these cells into syngeneic rat was shown to generate tumors. However, the induction of IL-12p40 by dox was sufficient for inhibiting tumor formation, as well as for tumor regression. Immunohistochemical analysis showed that macrophages, but not CD4+ T, CD8+ T, and NK cells, were predominantly recruited into tumor sites as early as 3 days after IL-12p40 induction. These results were further supported by the observation that IL-12p40, but not C-terminal deletion mutants by more than 5 amino acids, was able to chemoattract peritoneal macrophages in vitro, suggesting that IL-12p40, when produced in a large excess over IL-12p70 in vivo, can initially amplify the immune responses against tumors by directly recruiting macrophages. Our findings indicate that IL-12p40 may function as an effector molecule as well as an antagonist of IL-12p70.
TL;DR: In this article, the Ni-based bulk amorphous alloys with the same thermal and mechanical properties as those for the alloy ribbons were synthesized by using a single exothermic reaction in which crystalline phases of Ni, Ni 3 P, Ni 6 Mo 2 P, Cr 3 P and Cr 0.75 Ni 0.25 P precipitate almost simultaneously.
Abstract: Bulk amorphous Ni-based alloys with high strength were formed in the diameter range up to 1.0 mm for Ni 65 Nb 5 Cr 5 Mo 5 P 14-16 B 4-6 alloys by copper mold casting. The T g and Δ T x (= T x -T g ) of the bulk amorphous alloys are 703 and 50 K, respectively, for the 4%B alloy and 701 and 61 K, respectively, for the 6%B alloy. There is no difference in thermal stability between the bulk and ribbon alloys. The crystallization takes place through a single exothermic reaction in which crystalline phases of Ni, Ni 3 P, Ni 3 B, Ni 6 Mo 2 P 3 , Cr 3 P and Cr 0.75 Ni 0.25 P precipitate almost simultaneously. The necessity of the long-range atomic rearrangement leading to the simultaneous precipitation of the six crystalline phases seems to be the reason for the high glass-forming ability of the Ni-based alloys. The Ni-based bulk amorphous alloys exhibit high tensile fracture strength (σ f ) of 2690 to 2760 MPa, Young's modulus (E) of 95 to 103 GPa, fracture elongation (e f ) of 2.8% and Vickers hardness (H v ) of 840 to 880. The ratios of 9.8H v /3E and σ f /E are nearly the same as those for the corresponding melt-spun amorphous ribbons. The synthesis of the Ni-based bulk amorphous alloys with the same thermal and mechanical properties as those for the alloy ribbons is encouraging for the future development of bulk amorphous nonferrous alloys with high strength.
TL;DR: How to route a straddle carrier during loading operation of export containers in port container terminals is discussed and an efficient optimizing algorithm is developed for the carrier routing problem.
Journal Article•
TL;DR: Data from this study indicate that hypoxia-induced IGF-II expression in HepG2 cells is due to the enhanced activity of Egr-1 on the IGF- II P3 promoter and that the EGr-1 binding site in the IGF/P3 promoter is essential for the transcriptional regulation of IGF/II under hypoxic conditions.
Abstract: We have previously reported that the exposure of human HepG2 cells to hypoxic conditions results in the overexpression of human insulin-like growth factor II (IGF-II) mRNA whose size is 6.0 kb. This particular size of IGF-II mRNA is transcribed under the control of the IGF-II P3 promoter. In the present study, to delineate the molecular mechanism for the activation of the IGF-II gene, we examined the induction of P3 promoter activity in HepG2 cells by hypoxia in the transient expression system. In this system, hypoxia induced a linear increase within 24 h in the expression of luciferase that was driven by the IGF-II P3 promoter. To further delineate which factors mediate this response, the expression pattern of regulators of the P3 promoter, Egr-1, Sp1, and WT1, were analyzed by reverse transcription-PCR and Northern blot analysis. We found that hypoxia increased the expression of Egr-1 but not of Sp1. In contrast, the level of WT1, a repressor of IGF-II expression, was markedly decreased during hypoxia. The mRNA stability assay revealed that the induction of transcription is the mechanism of underlying Egr-1 mRNA elevation. We then investigated the effects of hypoxia on the DNA binding activity of Egr-1. Both electrophoretic mobility shift assay and supershift assay demonstrated that the DNA binding activity of the Egr-1 protein was increased by hypoxia. In addition, the level of Egr-1 protein was also increased under the hypoxia as determined by Western blot analysis. Cotransfection of HepG2 cells with an Egr-1 expression vector and an IGF-II P3 promoter-luciferase reporter plasmid showed that the transcription of IGF-II was activated by Egr-1 in a dose-dependent manner. Moreover, the elevation of IGF-II P3 promoter activity was induced synergistically by the cotreatment of hypoxia with Egr-1 overexpression. Deletion of sequences in the IGF-II P3 promoter containing Egr-1 binding sites did not respond to hypoxic stress. Taken together, these data strongly indicate that hypoxia-induced IGF-II expression in HepG2 cells is due to the enhanced activity of Egr-1 on the IGF-II P3 promoter and that the Egr-1 binding site in the IGF-II P3 promoter is essential for the transcriptional regulation of IGF-II under hypoxic conditions.
TL;DR: A chiral stationary phase (CSP) prepared by bonding (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid to silica gel was successfully employed in resolving various racemic amines and amino alcohols including therapeutically active compounds such as amphetamine, phenylethanolamine, octopamine and norepinephrine as mentioned in this paper.
TL;DR: The vibrational energy relaxation of carbon monoxide in the heme pocket of sperm whale myoglobin was studied by using molecular dynamics simulation and normal mode analysis methods to identify those protein residues that act as the primary "doorway" modes in the vibrational relaxation of the oscillator.
Abstract: The vibrational energy relaxation of carbon monoxide in the heme pocket of sperm whale myoglobin was studied by using molecular dynamics simulation and normal mode analysis methods. Molecular dynamics trajectories of solvated myoglobin were run at 300 K for both the δ- and ɛ-tautomers of the distal His-64. Vibrational population relaxation times of 335 ± 115 ps for the δ-tautomer and 640 ± 185 ps for the ɛ-tautomer were estimated by using the Landau–Teller model. Normal mode analysis was used to identify those protein residues that act as the primary “doorway” modes in the vibrational relaxation of the oscillator. Although the CO relaxation rates in both the ɛ- and δ-tautomers are similar in magnitude, the simulations predict that the vibrational relaxation of the CO is faster in the δ-tautomer with the distal His playing an important role in the energy relaxation mechanism. Time-resolved mid-IR absorbance measurements were performed on photolyzed carbonmonoxy hemoglobin (Hb13CO). From these measurements, a T1 time of 600 ± 150 ps was determined. The simulation and experimental estimates are compared and discussed.