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 & Nanofiber. The organization has 14820 authors who have published 28884 publications receiving 554131 citations.

Catalytic Growth of Single-Wall Carbon Nanotubes: An Ab Initio Study

Abstract: We propose a catalytic growth mechanism of single-wall carbon nanotubes based on density functional total energy calculations Our results indicate nanotubes with an “armchair” edge to be energetically favored over “zigzag” nanotubes We also suggest that highly mobile Ni catalyst atoms adsorb at the growing edge of the nanotube, where they catalyze the continuing assembly of hexagons from carbon feedstock diffusing along the nanotube wall In a concerted exchange mechanism, Ni atoms anneal carbon pentagons that would initiate a dome closure of the nanotube [S0031-9007(97)02791-9]

A piperidine amide extracted from Piper longum L. fruit shows activity against Aedes aegypti mosquito larvae.

Abstract: Mosquito larvicidal activity of Piper longum fruit-derived materials against the fourth-instar larvae of Aedes aegypti was examined. A crude methanol extract of P. longum fruits was found to be active against the larvae, and the hexane fraction of the methanol extract showed a strong larvicidal activity of 100% mortality. The biologically active component of P. longum fruits was characterized as pipernonaline by spectroscopic analyses. The LC(50) value of pipernonaline was 0.25 mg/L. The toxicity of pipernonaline is comparable to that of pirimiphos-methyl as a mosquito larvicide. In tests with available components derived from P. longum, no activity was observed with piperettine, piperine, or piperlongumine.

An improved hydrophilicity via electrospinning for enhanced cell attachment and proliferation.

Abstract: The wettability of electrospun poly(epsilon-caprolactone) (PCL) mats was improved by co-electrospinning with poly(vinyl alcohol) (PVA), by double-spinneret electrospinning method. The improved hydrophilicity of the hybrid PCL/PVA mats was confirmed by water contact angle measurement. The in vitro cell attachment on the hydrophobic PCL and hydrophilically modified PCL/PVA mats was compared by culture studies using human prostate epithelial cells (HPECs). The stability of water-soluble PVA component in the electrospun PCL/PVA mats was checked by thermogravimetric analysis and intensity of fluorescence material after immersion in water for 7 days. The images from scanning electron microscopy, field emission scanning electron microscopy, and optical microscopy showed that the attachment and proliferation rate of HPECs were improved by introducing PVA into the electrospun PCL mats.