Showing papers by "Chonbuk National University published in 2008"
TL;DR: The present review highlights the necessity for the examination of biosorbents within real situations, as competition between solutes and water quality may affect the biosorption performance.
1,584 citations
TL;DR: The 3.2 Å crystal structure of the bovine Ops*–GαCT peptide complex is presented and signal transfer from the receptor to the G protein nucleotide-binding site is discussed.
Abstract: Opsin, the ligand-free form of the G-protein-coupled receptor rhodopsin, at low pH adopts a conformationally distinct, active G-protein-binding state known as Ops*. A synthetic peptide derived from the main binding site of the heterotrimeric G protein-the carboxy terminus of the alpha-subunit (GalphaCT)-stabilizes Ops*. Here we present the 3.2 A crystal structure of the bovine Ops*-GalphaCT peptide complex. GalphaCT binds to a site in opsin that is opened by an outward tilt of transmembrane helix (TM) 6, a pairing of TM5 and TM6, and a restructured TM7-helix 8 kink. Contacts along the inner surface of TM5 and TM6 induce an alpha-helical conformation in GalphaCT with a C-terminal reverse turn. Main-chain carbonyl groups in the reverse turn constitute the centre of a hydrogen-bonded network, which links the two receptor regions containing the conserved E(D)RY and NPxxY(x)(5,6)F motifs. On the basis of the Ops*-GalphaCT structure and known conformational changes in Galpha, we discuss signal transfer from the receptor to the G protein nucleotide-binding site.
1,069 citations
TL;DR: The crystal structure of ligand-free native opsin from bovine retinal rod cells is presented and shows prominent structural changes in the conserved E(D)RY and NPxxY(x)5,6F regions and in TM5–TM7.
Abstract: In the G-protein-coupled receptor (GPCR) rhodopsin, the inactivating ligand 11-cis-retinal is bound in the seven-transmembrane helix (TM) bundle and is cis/trans isomerized by light to form active metarhodopsin II. With metarhodopsin II decay, all-trans-retinal is released, and opsin is reloaded with new 11-cis-retinal. Here we present the crystal structure of ligand-free native opsin from bovine retinal rod cells at 2.9 angstrom (A) resolution. Compared to rhodopsin, opsin shows prominent structural changes in the conserved E(D)RY and NPxxY(x)(5,6)F regions and in TM5-TM7. At the cytoplasmic side, TM6 is tilted outwards by 6-7 A, whereas the helix structure of TM5 is more elongated and close to TM6. These structural changes, some of which were attributed to an active GPCR state, reorganize the empty retinal-binding pocket to disclose two openings that may serve the entry and exit of retinal. The opsin structure sheds new light on ligand binding to GPCRs and on GPCR activation.
899 citations
TL;DR: The structural health monitoring (SHM) system is of primary importance because it is the structure that provides the integrity of the system, and the related non-destructive test and evaluation methods are discussed in this review.
Abstract: Renewable energy sources have gained much attention due to the recent energy crisis and the urge to get clean energy. Among the main options being studied, wind energy is a strong contender because of its reliability due to the maturity of the technology, good infrastructure and relative cost competitiveness. In order to harvest wind energy more efficiently, the size of wind turbines has become physically larger, making maintenance and repair works difficult. In order to improve safety considerations, to minimize down time, to lower the frequency of sudden breakdowns and associated huge maintenance and logistic costs and to provide reliable power generation, the wind turbines must be monitored from time to time to ensure that they are in good condition. Among all the monitoring systems, the structural health monitoring (SHM) system is of primary importance because it is the structure that provides the integrity of the system. SHM systems and the related non-destructive test and evaluation methods are discussed in this review. As many of the methods function on local damage, the types of damage that occur commonly in relation to wind turbines, as well as the damage hot spots, are also included in this review.
721 citations
TL;DR: Using ZnO nanonails, a hydrazine electrochemical sensor has been fabricated, for the first time, which showed a high and reproducible sensitivity and the limit of detection (LOD) was estimated to be 0.2 microM.
424 citations
TL;DR: This study identified the reference genes that are most suitable for normalizing the gene expression data in Brachypodium and these reference genes will be particularly useful when stress-responsive genes are analyzed in order to produce transgenic plants that exhibit enhanced stress resistance.
Abstract: The wild grass species Brachypodium distachyon (Brachypodium hereafter) is emerging as a new model system for grass crop genomics research and biofuel grass biology. A draft nuclear genome sequence is expected to be publicly available in the near future; an explosion of gene expression studies will undoubtedly follow. Therefore, stable reference genes are necessary to normalize the gene expression data. A systematic exploration of suitable reference genes in Brachypodium is presented here. Nine reference gene candidates were chosen, and their gene sequences were obtained from the Brachypodium expressed sequence tag (EST) databases. Their expression levels were examined by quantitative real-time PCR (qRT-PCR) using 21 different Brachypodium plant samples, including those from different plant tissues and grown under various growth conditions. Effects of plant growth hormones were also visualized in the assays. The expression stability of the candidate genes was evaluated using two analysis software packages, geNorm and NormFinder. In conclusion, the ubiquitin-conjugating enzyme 18 gene (UBC18) was validated as a suitable reference gene across all the plant samples examined. While the expression of the polyubiquitin genes (Ubi4 and Ubi10) was most stable in different plant tissues and growth hormone-treated plant samples, the expression of the S-adenosylmethionine decarboxylase gene (SamDC) ranked was most stable in plants grown under various environmental stresses. This study identified the reference genes that are most suitable for normalizing the gene expression data in Brachypodium. These reference genes will be particularly useful when stress-responsive genes are analyzed in order to produce transgenic plants that exhibit enhanced stress resistance.
378 citations
TL;DR: It is shown that SIRT1 blocks nuclear translocation of cytoplasmic p53 in response to endogenous reactive oxygen species (ROS) and triggers mitochondrial-dependent apoptosis in mouse embryonic stem (mES) cells and suggests that endogenous ROS control is important for mES cell maintenance in culture.
359 citations
TL;DR: DPPH activities was significantly correlated with total content of phenolic compounds in edible mushrooms, while in medicinal mushrooms there was a significant correlation (p < 0.01) between SOD activity and total concentration of Phenolic compounds.
Abstract: A study was conducted to determine the content of phenolic compounds and the antioxidative activity of five edible and five medicinal mushrooms commonly cultivated in Korea. Phenolic compounds were analyzed using high performance liquid chromatography, and antioxidant activity was evaluated by 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and superoxide dismutase activity. A total of 28 phenolic compounds were detected in the mushrooms studied. The average total concentration of phenolic compounds was 326 μg/g, the average being of 174 μg/g in edible mushrooms and 477 μg/g in medicinal mushrooms. The average total flavonoids concentration was 49 μg/g, with averages of 22 and 76 μg/g in edible and medicinal mushrooms, respectively. The DPPH radical scavenging activities ranged between 15 (Pleurotus eryngii) and 70% (Ganoderma lucidum) when reaction time was for 1 min. When reaction time was 30 min, the values ranged between 5 (Pleurotus eryngii) and 78% (Agaricus bisporus). The SOD activity ave...
322 citations
TL;DR: It is shown that the mast cell–expressed orphan serpentine receptor mCCRL2 is not required for expression of IgE-mediated mast cell-dependent passive cutaneous anaphylaxis but can enhance the tissue swelling and leukocyte infiltrates associated with such reactions in mice.
Abstract: Mast cells contribute importantly to both protective and pathological IgE-dependent immune responses. We show that the mast cell–expressed orphan serpentine receptor mCCRL2 is not required for expression of IgE-mediated mast cell–dependent passive cutaneous anaphylaxis but can enhance the tissue swelling and leukocyte infiltrates associated with such reactions in mice. We further identify chemerin as a natural nonsignaling protein ligand for both human and mouse CCRL2. In contrast to other “silent” or professional chemokine interreceptors, chemerin binding does not trigger ligand internalization. Rather, CCRL2 is able to bind the chemoattractant and increase local concentrations of bioactive chemerin, thus providing a link between CCRL2 expression and inflammation via the cell-signaling chemerin receptor CMKLR1.
272 citations
TL;DR: In this article, the results of X-ray diffraction analysis revealed a MPB composition range of x ǫ = 0.06-0.10 for (Na 0.5 Bi 0.10 ) 1− x Ba x TiO 3 system at room temperature, where the relative content of the tetragonal phase is substantially higher than that of the rhombohedral phases.
Abstract: (Na 0.5 Bi 0.5 ) 1− x Ba x TiO 3 ceramics were synthesized by the citrate method and their structure and electrical properties were systematically investigated. The results of X-ray diffraction analysis revealed a MPB composition range of x = 0.06–0.10 for (Na 0.5 Bi 0.5 ) 1− x Ba x TiO 3 system at room temperature. It was found that the piezoelectric and ferroelectric properties of (Na 0.5 Bi 0.5 ) 1− x Ba x TiO 3 compositions near the MPB are rather sensitive to the phase composition and reach preferred values at x = 0.07, where the relative content of the tetragonal phase is substantially higher than that of the rhombohedral phases. (Na 0.5 Bi 0.5 ) 1− x Ba x TiO 3 ceramics present a decrease diffusive factor ( δ ) with increasing BaTiO 3 content, implying a degradation of the relaxor feature and a transition from relaxor ferroelectrics to normal ferroelectrics.
237 citations
TL;DR: The preparation and characterization of gradient polymer surfaces are described, presenting an organized and detailed overview of the state-of-the-art, and the interactions of these surfaces with biological species important in the understanding of the basic science for biomedical application are concentrated.
01 Jan 2008
TL;DR: It was obvious that oxygen containing groups, such as carboxyl and phenolic groups, play a major role in the binding of the Cr(III) resulting from the abiotic reduction of Cr(VI) by the biomass.
Abstract: The reduction of toxic Cr(VI) to the less or nontoxic Cr(III) may be an useful detoxification technique for the treatment of Cr(VI)-contaminated waters. Recently, the protonated biomass of brown seaweed, Ecklonia, was shown to completely reduce Cr(VI) to Cr(III) in the pH range 1-5. The reduction of Cr(VI) to Cr(III) appeared to occur at the surface of the biomass. In this study, abiotic Cr(VI) reduction by the biomass was performed with various contact times, pHs and initial Cr(VI) concentrations, and surface and bulk characteristics of the Cr-laden biomass was then investigated using X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The XPS spectra indicated that the Cr(VI) bound to the biomass was completely reduced to Cr(III) at tested various conditions. XANES and EXAFS spectra of the Cr-laden biomass were very similar to those of Cr(III)-acetate, which means that the Cr bound to the biomass during Cr(VI) reduction had an octahedral geometrical arrangement. The bonding distance of the chromium oxygen atoms was approximately 1.97-1.99 A. In conclusion, it was obvious that oxygen containing groups, such as carboxyl and phenolic groups, play a major role in the binding of the Cr(III) resulting from the abiotic reduction of Cr(VI) by the biomass.
TL;DR: From the present study, it is obvious that there might be some chances of structural modification of components in tea due to enzymes liberated by bacteria and yeast during kombucha fermentation which results in better scavenging performance on nitrogen and superoxide radicals, and poor scavengingperformance on hydroxyl radicals.
TL;DR: It is suggested that leptin reverses the catabolic consequences of total lack of insulin, potentially by suppressing glucagon action on liver and enhancing the insulinomimetic actions of IGF-1 on skeletal muscle, and suggest strategies for making type 1 diabetes insulin-independent.
Abstract: Terminally ill insulin-deficient rodents with uncontrolled diabetes due to autoimmune or chemical destruction of β-cells were made hyperleptinemic by adenoviral transfer of the leptin gene. Within ≈10 days their severe hyperglycemia and ketosis were corrected. Despite the lack of insulin, moribund animals resumed linear growth and appeared normal. Normoglycemia persisted 10–80 days without other treatment; normal physiological conditions lasted for ≈175 days despite reappearance of moderate hyperglycemia. Inhibition of gluconeogenesis by suppression of hyperglucagonemia and reduction of hepatic cAMP response element-binding protein, phoshoenolpyruvate carboxykinase, and peroxisome proliferator-activated receptor-γ-coactivator-1α may explain the anticatabolic effect. Up-regulation of insulin-like growth factor 1 (IGF-1) expression and plasma levels and increasing IGF-1 receptor phosphorylation in muscle may explain the increased insulin receptor substrate 1, PI3K, and ERK phosphorylation in skeletal muscle. These findings suggest that leptin reverses the catabolic consequences of total lack of insulin, potentially by suppressing glucagon action on liver and enhancing the insulinomimetic actions of IGF-1 on skeletal muscle, and suggest strategies for making type 1 diabetes insulin-independent.
TL;DR: In this article, the generalized uncertainty principle due to the absolute minimum length of a black hole was shown to increase the Hawking temperature of the black hole in the anti-de Sitter space.
TL;DR: In this article, the authors investigated the RB5 biosorption of C.I. Reactive Black 5 (RB5) from aqueous solution, using the brown seaweed, Laminaria sp., in both batch and column modes of operation.
TL;DR: Triple antiplatelet therapy after DES implantation decreased angiographic restenosis and extent of late loss, resulting in a reduced risk of 9-month TLR compared with dual antiplatelets therapy in diabetic patients.
TL;DR: The developed Cr( VI)-biosorbent must be a potent candidate to substitute for chemical reductants as well as adsorbents for treating Cr(VI)-bearing wastewaters.
TL;DR: In this article, the copper oxide (CuO) nanoneedles were synthesized by a simple hydrothermal method and X-ray diffraction (XRD) and selected area electron diffraction results showed that they have monoclinic structure with single crystalline phase.
TL;DR: Temperature of 35°C and pH 7 were found to be optimum for maximum degradation and the mixed bacterial consortium showed more growth and degradation than did individual strains.
Abstract: A preliminary study was undertaken to determine the optimal conditions for the biodegradation of a crude oil. Among 57 oil-degrading bacterial cultures isolated from oil-contaminated soil samples, Bacillus sp. IOS1-7, Corynebacterium sp. BPS2-6, Pseudomonas sp. HPS2-5, and Pseudomonas sp. BPS1-8 were selected for the study based on the efficiency of crude oil utilization. Along with the selected individual strains, a mixed bacterial consortium prepared using the above strains was also used for degradation studies. The mixed bacterial consortium showed more growth and degradation than did individual strains. At 1% crude oil concentration, the mixed bacterial consortium degraded a maximum of 77% of the crude oil. This was followed by 69% by Pseudomonas sp. BPS1-8, 64% by Bacillus sp. IOS1-7, 45% by Pseudomonas sp. HPS2-5, and 41% by Corynebacterium sp. BPS2-6. The percentage of degradation by the mixed bacterial consortium decreased from 77 to 45% as the concentration of crude oil was increased from 1 to 12%. Temperature of 35°C and pH 7 were found to be optimum for maximum degradation.
TL;DR: In this article, a simple solution process at 100 °C using copper nitrate, NaOH, and hexamethylenetetramine (HMTA) for 3 h without the use of any complex reagents.
Abstract: Flower-shaped CuO nanostructures have been prepared by the simple solution process at 100 °C using copper nitrate, NaOH, and hexamethylenetetramine (HMTA) for 3 h without the use of any complex reagents. The morphological investigations by field emission scanning electron microscope (FESEM) revealed that the flower-shaped nanostructures are monodispersed in large quantity and exhibit the nanocrystalline nature with monoclinic structure. The flower-shaped morphologies are strongly dependent on the concentration of HMTA, presence or absence of NaOH and HMTA, and reaction time. The possible growth mechanism for the formation of flower-shaped CuO products was also discussed in detail.
TL;DR: Spearman correlation coefficient study showed no significant correlation in the concentration of metals in U. lactuca, water and sediment samples, whereas in water the ratio was found to be Cr>Pb>Cd.
TL;DR: In this article, the electrochemical double-layer capacitive properties of mesoporous carbon (MC) materials with a moderate amount of nitrogen functionality are reported, and two types of N-doped MCs are prepared by ammoxidation performed at different stages of the MC preparation process.
TL;DR: In this paper, a series of nanocomposite polymer electrolytes (NCPEs) comprising nanoparticles of BaTiO3, Al2O3 or SiO2 were prepared by electrospinning technique.
20 Jul 2008
TL;DR: This paper presents a cluster-based resampling method to select better pseudo-relevant documents based on the relevance model, and shows higher relevance density than the baseline relevance model on all collections, resulting in better retrieval accuracy in pseudo-relevance feedback.
Abstract: Typical pseudo-relevance feedback methods assume the top-retrieved documents are relevant and use these pseudo-relevant documents to expand terms. The initial retrieval set can, however, contain a great deal of noise. In this paper, we present a cluster-based resampling method to select better pseudo-relevant documents based on the relevance model. The main idea is to use document clusters to find dominant documents for the initial retrieval set, and to repeatedly feed the documents to emphasize the core topics of a query. Experimental results on large-scale web TREC collections show significant improvements over the relevance model. For justification of the resampling approach, we examine relevance density of feedback documents. A higher relevance density will result in greater retrieval accuracy, ultimately approaching true relevance feedback. The resampling approach shows higher relevance density than the baseline relevance model on all collections, resulting in better retrieval accuracy in pseudo-relevance feedback. This result indicates that the proposed method is effective for pseudo-relevance feedback.
TL;DR: Of the ionic liquids tested, 1-butyl-1-methylpyrrolidinium bromide was found to be the least toxic, which is similar in toxicity level of dimethylformamide.
TL;DR: An affordable composite was prepared from jute fibers and polypropylene (PP) in this article, where the surfaces of the jute fiber were silanized to increase the interfacial adhesion between the Jute fiber and the polymer matrix.
TL;DR: Investigating the clinicopathological features of branch intraductal papillary mucinous neoplasm (IPMN) and to determine safe criteria for its observation found a tumor size of >2 cm was found to be the most valuable predictor of malignancy.
Abstract: Background
The objectives of this study were to investigate the clinicopathological features of branch intraductal papillary mucinous neoplasm (IPMN) and to determine safe criteria for its observation. Most clinicians agree that surgical resection is required to treat main duct-type IPMN because of its high malignancy rate. However, no definite treatment guideline (with respect to surgery or observation) has been issued on the management of branch duct type IPMN.
TL;DR: Genistein significantly decreased reactive oxygen species production, the expression of intercellular adhesion molecule-1 and monocyte chemoattractant protein-1 proteins, and the translocation of the p65 subunit of nuclear factor-kappaB into the nucleus and the infiltration of macrophages in cisplatin-treated normal human kidney HK-2 cells.