Chonbuk National University

About: Chonbuk National University is a education organization based out in Jeonju, South Korea. It is known for research contribution in the topics: Apoptosis & Graphene. The organization has 14820 authors who have published 28884 publications receiving 554131 citations.

Fungicidal Property of Curcuma longa L. Rhizome-Derived Curcumin against Phytopathogenic Fungi in a Greenhouse

Abstract: Fungicidal activity of Curcuma longa rhizome-derived materials against Botrytis cineria, Erysiphe graminis, Phytophthora infestans, Puccinia recondita, Pyricularia oryzae, and Rhizoctonia solani was tested using a whole plant method in vivo. It was compared with synthetic fungicides and four commercially available compounds derived from C. longa. The response varied with the tested plant pathogen. At 1000 mg/L, the hexane extract of C. longa showed fungicidal activities against E.graminis, P. infestans, and R. solani, and the ethyl acetate extract of C. longa showed fungicidal activities against B. cineria, P. infestans, Pu. recondita, and R. solani. Curcumin was isolated from the ethyl acetate fraction using chromatographic techniques and showed fungicidal activities against P. infestans, Pu. recondita, and R. solani with 100, 100, and 63% control values at 500 mg/L and 85, 76, and 45% control values at 250 mg/L, respectively. In the test with components derived from C. longa, turmerone exhibited weak activity against E. graminis, but no activity was observed from treatments with borneol, 1,8-cineole, sabinene, and turmerone. In comparison, potent fungicidal activity with chlorothalonil against P. infestans at 50 mg/L and dichlofluanid against B. cinerea at 50 mg/L was exhibited. These results may be an indication of at least one of the fungicidal actions of curcumin derived from C. longa.

Optical and electrical transport properties in silicon carbide nanowires

Abstract: We report on the optical and electrical transport properties of single-crystalline silicon carbide nanowires (SiC NWs). The NWs were fabricated by a chemical vapor deposition process, and had diameters of <100nm and lengths of several μm. X-ray diffraction and transmission electron microscopy analysis showed the single-crystalline nature of NWs with a growth direction of ⟨111⟩. Photoluminescence characterization showed blue emission at room temperature. The electrical measurements from a field effect transistor structure on individual NWs showed n-type semiconductor characteristics. The resistivity and estimated electron mobility on the NWs are 2.2×10−2Ωcm for 0V of gate voltage and 15cm2∕(Vs), respectively. Our low-resistivity SiC NWs could be applied to a high-temperature operation sensor and actuator due to its own excellent electrical and optical properties.

Making insulin-deficient type 1 diabetic rodents thrive without insulin

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.

A hydrogen storage mechanism in single-walled carbon nanotubes.

Abstract: We have carried out systematic calculations for hydrogen-adsorption and -storage mechanism in carbon nanotubes at zero temperature. Hydrogen atoms first adsorb on the tube wall in an arch-type and zigzag-type up to a coverage of θ = 1.0 and are stored in the capillary as a form of H2 molecule at higher coverages. Hydrogen atoms can be stored dominantly through the tube wall by breaking the C−C midbond, while preserving the wall stability of a nanotube after complete hydrogen insertion, rather than by the capillarity effect through the ends of nanotubes. In the hydrogen-extraction processes, H2 molecule in the capillary of nanotubes first dissociates and adsorbs onto the inner wall and is further extracted to the outer wall by the flip-out mechanism. Our calculations describe suitably an electrochemical storage process of hydrogen, which is applicable for the secondary hydrogen battery.