Showing papers by "Pusan National University published in 2004"
TL;DR: A striking interplay between ferroelectricity and magnetism in the multiferroic TbMn2O5 is reported, demonstrated by a highly reproducible electric polarization reversal and permanent polarization imprint that are both actuated by an applied magnetic field.
Abstract: Ferroelectric and magnetic materials are a time-honoured subject of study and have led to some of the most important technological advances to date. Magnetism and ferroelectricity are involved with local spins and off-centre structural distortions, respectively. These two seemingly unrelated phenomena can coexist in certain unusual materials, termed multiferroics1,2,3,4,5,6,7,8,9,10,11. Despite the possible coexistence of ferroelectricity and magnetism, a pronounced interplay between these properties has rarely been observed6,12. This has prevented the realization of multiferroic devices offering such functionality13. Here, we report a striking interplay between ferroelectricity and magnetism in the multiferroic TbMn2O5, demonstrated by a highly reproducible electric polarization reversal and permanent polarization imprint that are both actuated by an applied magnetic field. Our results point to new device applications such as magnetically recorded ferroelectric memory.
1,912 citations
TL;DR: Examination of the phenotypes and gene expression profile of the human adipose tissue-derived stromal cells (ATSC) in the undifferentiated states, and compared with that of bone marrow stromAL cells (BMSC) shows that ATSC have a marker expression that is similar to that of BMSC.
Abstract: Human mesenchymal stem cells (MSC), that have been reported to be present in bone marrow, adipose tissues, dermis, muscles and peripheral blood, have the potential to differentiate along different lin
893 citations
TL;DR: Based on first-principles calculations, a model for large-size-mismatched group-V dopants in ZnO agrees with the recent observations that both As and Sb have low acceptor-ionization energies and that to obtain p-type Zn O requires O-rich growth or annealing conditions.
Abstract: Based on first-principles calculations, a model for large-size-mismatched group-V dopants in ZnO is proposed. The dopants do not occupy the O sites as is widely perceived, but rather the Zn sites: each forms a complex with two spontaneously induced Zn vacancies in a process that involves fivefold As coordination. Moreover, an As(Zn)-2V(Zn) complex may have lower formation energy than any of the parent defects. Our model agrees with the recent observations that both As and Sb have low acceptor-ionization energies and that to obtain p-type ZnO requires O-rich growth or annealing conditions.
600 citations
TL;DR: This study proposes a branch and bound (B & B) method to obtain the optimal solution of the QC scheduling problem and a heuristic search algorithm, called greedy randomized adaptive search procedure (GRASP), to overcome the computational difficulty of the B & B method.
485 citations
TL;DR: The lateral pillar classification and age at the time of onset of the disease strongly correlate with outcome in patients with Legg-Calve-Perthes disease.
Abstract: Background: The treatment of Legg-Calve-Perthes disease has been based on uncontrolled retrospective studies with relatively small numbers of patients. This large, controlled, prospective, multicenter study was designed to determine the effect of treatment and other risk factors on the outcome in pa
352 citations
TL;DR: The modified lateral pillar classification and the redefined Stulberg classification are sufficiently reliable and accurate for use in studies of Legg-Calve-Perthes disease and produced kappa values and generalizability coefficients in the excellent range.
Abstract: Background: Accurate and reliable radiographic classifications of the relative severity and outcome of Legg-Calve-Perthes disease are essential in the study of that disease. As part of a prospective multicenter study*, we sought to define more clearly the lateral pillar classification of severity an
278 citations
TL;DR: RLPs stimulated NAD(P)H oxidase–dependent superoxide formation and induction of cytokines in HUVECs via activation of LOX-1, consequently leading to reduction in cell viability with DNA fragmentation, and cilostazol exerts a cell-protective effect by suppressing these variables.
Abstract: Background— Remnant lipoprotein particles (RLPs), products of lipolytic degradation of triglyceride-rich lipoprotein derived from VLDL, exert atherogenesis. In this study, we observed how RLPs induced cytotoxicity in human umbilical vein endothelial cells (HUVECs) and cilostazol prevented cell death. Methods and Results— RLPs were isolated from the plasma of hyperlipidemic patients by use of an immunoaffinity gel mixture of anti–apolipoprotein A-1 and anti–apolipoprotein B-100 monoclonal antibodies. RLPs (50 μg/mL) significantly increased superoxide formation in HUVECs associated with elevated gp91phox mRNA and protein expression and Rac1 translocation, accompanied by increased production of tumor necrosis factor (TNF)-α and interleukin-1β, DNA fragmentation, and cell death. Cilostazol (1 to 100 μmol/L) significantly suppressed not only NAD(P)H oxidase–dependent superoxide production but also TNF-α and interleukin-1β release and restored viability. RLPs activated a lectin-like oxidized low-density lipopro...
231 citations
TL;DR: To discover sources of antioxidative activity in marine algae, extracts from 17 kinds of seaweed were screened for their inhibitory effect on total ROS generation in kidney homogenate using 2′,7′-dichlorofluorescein diacetate (DCFH-DA).
Abstract: Reactive oxygen species (ROS) play an important role in the pathogenesis of many human degenerative diseases such as cancer, aging, arteriosclerosis, and rheumatism Much attention has been focused on the development of safe and effective antioxidants To discover sources of antioxidative activity in marine algae, extracts from 17 kinds of seaweed were screened for their inhibitory effect on total ROS generation in kidney homogenate using 2′,7′-dichlorofluorescein diacetate (DCFH-DA) ROS inhibition was seen in three species:Ulva pertusa, Symphyocladia latiuscula, andEcklonia stolonifera At a final concentration of 25 μg/mL,U pertusa inhibited 8565±2028% of total ROS generation,S latiscula caused 5063±009% inhibitory, and theEcklonia species was 4430±733% inhibitionE stolonifera Okamura (Laminariaceae), which belongs to the brown algae, has been further investigated because it is commonly used as a foodstuff in Korea Five compounds, phloroglucinol (1), eckstolonol (2), eckol (3), phlorofucofuroeckol A (4), and dieckol (5), isolated from the ethyl acetate soluble fraction of the methanolic extract ofE stolonifera inhibited total ROS generation
224 citations
TL;DR: Results suggest that ginsenosides Rg3 and Rh2-induced cell detachment and inhibition of the proliferation of prostate cancer cells may be associated with modulation of three modules of MAP kinases.
Abstract: Ginseng has an anti-cancer effect in several cancer models. This study was to characterize active constituents of ginseng and their effects on proliferation of prostate cancer cell lines, LNCaP and PC3. Cell proliferation was measured by [3H]thymidine incorporation, the intracellular calcium concentration by a dual-wavelength spectrophotometer system, effects on mitogen-activated protein (MAP) kinases by Western blotting, and cell attachment and morphologic changes were observed under a microscope. Among 11 ginsenosides tested, ginsenosides Rg3 and Rh2 inhibited the proliferation of prostate cancer cells. EC50s of Rg3 and Rh2 on PC3 cells were 8.4 microM and 5.5 microM, respectively, and 14.1 microM and 4.4 microM on LNCaP cells, respectively. Both ginsenosides induced cell detachment and modulated three modules of MAP kinases activities differently in LNCaP and PC3 cells. These results suggest that ginsenosides Rg3 and Rh2-induced cell detachment and inhibition of the proliferation of prostate cancer cells may be associated with modulation of three modules of MAP kinases.
213 citations
TL;DR: In this article, the authors investigated new models of dynamical electroweak symmetry breaking resulting from the condensation of fermions in higher representations of the technicolor group, which lie close to the conformal window, and are free from the flavor-changing neutral current problem despite small numbers of flavors and colors.
209 citations
TL;DR: Novel roles for apoLp-III in pattern recognition and multicellular encapsulation reactions in the innate immune response are described, which suggest a wide range of immune functions for a multiple specificity pattern recognition molecule.
Abstract: Lipoproteins and molecules for pattern recognition are centrally important in the innate immune response of both vertebrates and invertebrates. Mammalian apolipoproteins such as apolipoprotein E (apoE) are involved in LPS detoxification, phagocytosis, and possibly pattern recognition. The multifunctional insect protein, apolipophorin III (apoLp-III), is homologous to apoE. In this study we describe novel roles for apoLp-III in pattern recognition and multicellular encapsulation reactions in the innate immune response, which may be of direct relevance to mammalian systems. It is known that apoLp-III stimulates antimicrobial peptide production in insect blood, enhances phagocytosis by insect blood cells (hemocytes), and binds and detoxifies LPS and lipoteichoic acid. In the present study we show that apoLp-III from the greater wax moth, Galleria mellonella, also binds to fungal conidia and beta-1,3-glucan and therefore may act as a pattern recognition molecule for multiple microbial and parasitic invaders. This protein also stimulates increases in cellular encapsulation of nonself particles by the blood cells and exerts shorter term, time-dependent, modulatory effects on cell attachment and spreading. All these responses are dose dependent, occur within physiological levels, and, with the notable exception of beta-glucan binding, are only observed with the lipid-associated form of apoLp-III. Preliminary studies also established a beneficial role for apoLp-III in the in vivo response to an entomopathogenic fungus. These data suggest a wide range of immune functions for a multiple specificity pattern recognition molecule and may provide a useful model for identifying further potential roles for homologous proteins in mammalian immunology, particularly in terms of fungal infections, pneumoconiosis, and granulomatous reactions.
TL;DR: In this article, satellite-tracked drifters were used to detect seasonal currents entering the South China Sea from the Philippine Sea through the Luzon Strait, with ensemble mean speeds of 0.7 ± 0.4 m s−1 and daily mean westward speeds that can exceed 1.65 m s −1.
Abstract: Velocity observations near the surface made with Argos satellite-tracked drifters between 1989 and 2002 provide evidence of seasonal currents entering the South China Sea from the Philippine Sea through the Luzon Strait. The drifters cross the strait and reach the interior of the South China Sea only between October and January, with ensemble mean speeds of 0.7 ± 0.4 m s−1 and daily mean westward speeds that can exceed 1.65 m s−1. The majority of the drifters that continued to reside in the South China Sea made the entry within a westward current system located at ∼20°N that crossed the prevailing northward Kuroshio path. In other seasons, the drifters looped across the strait within the Kuroshio and exited along the south coast of Taiwan. During one intrusion event, satellite altimeters indicated that, directly west of the strait, anticyclonic and cyclonic eddies resided, respectively, north and south of the entering drifter track. The surface currents measured by the crossing drifters were much...
TL;DR: It is demonstrated that Hif-1α is upregulated through SUMO-1 modification at Lys391/Lys477 residues, which may stabilize HIF-1 α and enhance its transcriptional activity.
TL;DR: The combined dark- and light-fermentation of Rhodopseudomonas palustris P4 can increase the H2 production yield on glucose by two-fold and gives a great advantage in process development.
TL;DR: The newly designed and synthesized asymmetric molecular structures of Oxa-PPV, DMOP- PPV, and Oxa -PPV-co-DMOP-PPVs were completely soluble in common organic solvents, and defect-free optical thin film was easily spin-coated onto the indium tin oxide (ITO) substrate.
Abstract: A new series of high brightness and luminance efficient poly(p-phenylenevinylene) (PPV)-based electroluminescent (EL) polymers, poly[2-{4-[5-(4-(3,7-dimethyloctyloxy)phenyl)-1,3,4-oxadiazole-2-yl]phenyloxy}-1,4-phenylenevinylene] (Oxa-PPV), poly[2-{2-((3,7-dimethyloctyl)oxy)phenoxy}-1,4-phenylenevinylene] (DMOP-PPV), and their corresponding random copolymers, poly{[2-{4-[5-(4-(3,7-dimethyloctyloxy)phenyl)-1,3,4-oxadiazole-2-yl]phenyloxy}-1,4-phenylenevinylene]-co-[2-{2-((3,7-dimethyloctyl)oxy) phenoxy}-1,4-phenylenevinylene]} (Oxa-PPV-co-DMOP-PPV), with an electron-deficient 1,3,4-oxadiazole unit on the side groups, were synthesized through the Gilch polymerization method. The newly designed and synthesized asymmetric molecular structures of Oxa-PPV, DMOP-PPV, and Oxa-PPV-co-DMOP-PPV were completely soluble in common organic solvents, and defect-free optical thin film was easily spin-coated onto the indium tin oxide (ITO) substrate. Oxa-PPV shows a high glass transition temperature (Tg), which might be an...
TL;DR: It is suggested that LPA is a critical component of ascites for the motility of pancreatic cancer cells and LPA1 receptors may mediate this activity.
TL;DR: The results suggest that the extract of Rhus verniciflua heartwood containing flavonoid complex could be a potent anticarcinogen.
TL;DR: The data suggest that HBx stabilizes HIF‐1α and leads to angiogenesis during hepatocarcinogenesis, and this work shows that microvessels are more abundant in the dysplastic lesion than in the non‐neoplastic region.
Abstract: Hepatitis B virus X protein (HBx) is closely involved in the development of hepatocellular carcinoma, a highly vascularized solid tumor. Here we show that HBx increases the transcriptional activity and protein level of hypoxia-inducible factor-1alpha (HIF-1alpha) under both normoxic and hypoxic conditions, and it also stimulates angiogenesis. HBx directly interacted with the bHLH/PAS domain of HIF-1alpha but not with the von Hippel-Lindau protein (pVHL). HBx decreased the binding of pVHL to HIF-1alpha and prevented ubiquitin-dependent degradation of HIF-1alpha. In HBx-transgenic mice, HIF-1alpha and vascular endothelial growth factor were strongly detected in the dysplastic lesion, where HBx was also more highly expressed than in the non-neoplastic region of the liver. An immunohistochemical study showed that microvessels are more abundant in the dysplastic lesion than in the non-neoplastic region. Our data suggest that HBx stabilizes HIF-1alpha and leads to angiogenesis during hepatocarcinogenesis.
TL;DR: This study discusses how to dispatch AGVs by utilizing information about locations and times of future delivery tasks by utilizing the heuristic algorithm for overcoming the excessive computational time needed for solving the mathematical model.
Abstract: To reduce delay in ship operations in automated container terminals, it is important to make different types of container handling equipment to operate harmoniously during this operation. Delivery operations by automated guided vehicles (AGVs) play an important role for synchronizing operations of container cranes with yard cranes. This study discusses how to dispatch AGVs by utilizing information about locations and times of future delivery tasks. A mixed-integer programming model is provided for assigning optimal delivery tasks to AGVs. A heuristic algorithm is suggested for overcoming the excessive computational time needed for solving the mathematical model. Objective values and computational times of the heuristic algorithm are compared with those of the optimizing method. To test performances of the heuristic algorithm, a simulation study is performed by considering the uncertainties of various operation times and the number of future delivery tasks for looking ahead. Also, the performance of the heuristic algorithm is compared with those of other dispatching rules.
Journal Article•
TL;DR: Results indicate that human PGN and 1,3-β-d-glucan recognition proteins function as complement-activating lectins.
TL;DR: In this article, the authors investigate the ultimate strength characteristics of steel plate elements with pit corrosion wastage and under in-plane shear loads, and derive closed-form design formulae for the ultimate limit state based risk or reliability assessment of corroded structures.
Abstract: The aim of the present paper is to investigate the ultimate strength characteristics of steel plate elements with pit corrosion wastage and under in-plane shear loads. A series of the ANSYS nonlinear finite element analyses for plate elements under in-plane shear loads are carried out, varying the degree of pit corrosion intensity and the plate geometric properties. Closed-form design formulae for the ultimate strength of pitted plates under edge shear, which are essentially needed for the ultimate limit state based risk or reliability assessment of corroded structures, are derived by the regression analysis of the computed results. The insights developed from the present study will be very useful for damage tolerant design of plated structures with pit corrosion wastage.
TL;DR: Growth assay results showed that microcystin could completely inhibit the growth of carp, but failed to change the fish hepatosomatic index, and it is recommended that a warning system be instituted for announcing the occurrence of micro Cystin-producing water bloom and the possible risk of human intoxication.
TL;DR: During the in vivo analysis of inhibitory activity of the levans against Sarcoma-180 growth, M-, R- and Z-levans showed strong antitumor activity (average 66%) but G-levan (42%) had significantly lower activity.
TL;DR: In this article, a robust adaptive boundary control scheme for axially moving string under a spatio-temporally varying tension and an unknown boundary disturbance is investigated, where the lower bound of the tension variation is assumed to be sufficiently larger than the derivatives of the higher bound.
TL;DR: Thermophilic H2 production from glucose was studied using a continuous trickling biofilter reactor (TBR) packed with a fibrous support matrix and results indicate that the thermophilic TBR is superior to most suspended or immobilized reactor systems reported thus far.
Abstract: Thermophilic H2 production from glucose was studied at 55–64°C for 234 days using a continuous trickling biofilter reactor (TBR) packed with a fibrous support matrix. Important parameters investigated included pH, temperature, hydraulic retention time (HRT), and glucose concentration in the feed. The optimal pH and temperature were 5.5 and 60°C, respectively. With decreasing HRT or increasing inlet glucose concentration, volumetric H2 production rate increased but the H2 production yield to glucose decreased gradually. The biogas composition was almost constant at 53 ± 4% (v/v) of H2 and 47 ± 4% (v/v) of CO2. No appreciable CH4 was detected when the reactor was under a normal operation. The carbon mass balance showed that, in addition to cell mass, lactate, n-butyrate, CO2, and acetate were major products that comprised more than 85% of the carbon consumed. The maximal volumetric H2 production rate and H2 yield to glucose were 1,050 ± 63 mmol H2/l·d and 1.11 ± 0.12 mol H2/mol glucose, respectively. These results indicate that the thermophilic TBR is superior to most suspended or immobilized reactor systems reported thus far. This is the first report on continuous H2 production by a thermophilic TBR system. © 2004 Wiley Periodicals, Inc.
TL;DR: The objective was to investigate the functional and morphological toxicity of benzalkonium chloride on corneal epithelial cells in vitro and to establish anaphylactic tolerance to BAC.
Abstract: Purpose: To investigate the functional and morphological toxicity of benzalkonium chloride (BAC) on corneal epithelial cells in vitro.
Methods: Primary corneal epithelial cells were cultured from rabbit cornea. Corneal epithelial cells containing radioactive 51Cr were exposed for 5 min, 10 min, 30 min and 60 min to concentration of BAC 0.001%, 0.005%, 0.01%, 0.05% and 0.1%. Control cells were treated with phosphate buffer solution alone. 51Cr release from epithelial cells into the supernatant was used as an index of epithelial cell lysis. Cell detachment (index of cell dysfunction) was analysed by measuring 51Cr activity in the supernatant and wash fluid. Morphological cell damage was investigated with transmission electron microscopy.
Results: With the higher concentration and the longer duration of BAC exposure, corneal epithelial cell lysis was increased significantly (P < 0.05). Cells showed severe damage at BAC concentration over 0.05% during 5 min of exposure. Cell dysfunction appeared markedly at BAC concentrations of 0.005% for 30 min of exposure, but decreased with longer exposure times. There was an increase in significant cytoplasmic damage with longer BAC exposure times, although not with a minimal dose of 0.001%. Disrupted cytoplasmic membranes of corneal epithelial cells appeared at the higher BAC concentration of 0.1%, and at the longer exposure time of 30 min with BAC concentration of at least 0.001%.
Conclusions: BAC can induce corneal epithelial dysfunction, which can damage the corneal epithelial barrier. This effect occurs when BAC is used frequently or for periods over 30 min, even when the BAC concentration is low (0.001%).
TL;DR: It is suggested that naringenin may be useful in preventing the development of hepatic fibrosis through in vivo hepatoprotective and anti-fibrogenic effects against DMN-induced liver injury.
Abstract: Naringenin, a phytoalexin found in grapefruits and tomatoes, has been reported to exhibit a wide range of pharmacological properties. In this study, we investigated the protective effect of naringenin on hepatic injury induced by dimethylnitrosamine (DMN) in rats. Oral administration of naringenin (20 and 50 mg/kg daily for 4 weeks) remarkably prevented the DMN-induced loss in body and liver weights and inhibited the elevation of serum alanine transaminase, aspartate transaminase, alkaline phosphatase, and bilirubin levels. Naringenin also restored serum albumin and total protein levels, and reduced the hepatic level of malondialdehyde. Furthermore, DMN-induced collagen accumulation, as estimated by histological analysis of liver tissue stained with Sirius red, was reduced in the naringenin-treated rats. A reduction in hepatic stellate cell activation, as assessed by α-smooth muscle actin staining, was associated with naringenin treatment. In conclusion, these results demonstrate that naringenin exhibited in vivo hepatoprotective and anti-fibrogenic effects against DMN-induced liver injury. It suggests that naringenin may be useful in preventing the development of hepatic fibrosis.
TL;DR: Benthic macroinvertebrate communities in stream ecosystems were assessed hierarchically through two-level classification methods of unsupervised learning and could be useful for assessing ecosystem quality and community variations caused by environmental disturbances.
TL;DR: A variety of matrix/scaffold attachment region (MAR/SAR) elements are screened for their ability to insulate transgene expression from the position effects in CHO cells and it is found that the human beta-globin MAR element is particularly effective.