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.

Electrospun nonwovens of shape‐memory polyurethane block copolymers

Abstract: Synthesized shape-memory polyurethane (PU) block copolymers were used to prepare electrospun nonwovens via electrospinning. PU solutions were prepared with a mixed solvent of N,N-dimethylformamide and tetrahydrofuran. The electrospun PU nonwovens were prepared with hard-segment concentrations of 40 and 50 wt %. The morphology of the electrospun fibers was investigated with scanning electron microscopy. The average diameter of low-viscosity (ca. 130–180 cPs) electrospun fibers was about 800 nm, and the morphology of the electrospun nonwovens was beaded-on fibers. In contrast, the average diameter of high-viscosity (ca. 530–570 cPs) electrospun fibers was about 1300 nm. In an investigation of the mechanical properties of the electrospun PU nonwovens, it was found that the tensile strength increased as the hard-segment concentration increased within a similar range of viscosities. Also, the tensile strength of the electrospun PU nonwovens in the machine direction was higher than that in the transverse direction because of a difference in the velocities of the drum collectors. The electrospun PU nonwovens with hard-segment concentrations of 40 and 50 wt % were found to have a shape recovery of more than 80%. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 460–465, 2005

A comprehensive in vitro and in vivo study of ZnO nanoparticles toxicity

Abstract: Nowadays, the exploration of zinc oxide nanoparticles (ZnO NPs) based products is booming in the various directions of bio-nanomedicine and other consumer products, but the comprehensive toxicological impact posed by ZnO NPs still remains unclear. The present study systematically investigates and correlates the toxicity evaluation of ZnO NPs in RAW 264.7 murine macrophages (in vitro) and male ICR mice (in vivo) by two different administration routes, i.e. g.i. and i.p. at different doses. The in vitro studies showed a slight rise in intracellular reactive oxygen species level (ROS), NF-κB transcription factor expression (TF) and NPs uptake at higher dose, indicating the non-toxic nature of ZnO NPs below 100 μg mL−1 doses. The in vivo results demonstrate a slight gain in body weight (BW), reduction in the organ weight, mild to severe pathological alteration in the organs depending upon NP dosage and mode of administration routes. The histopathological investigation suggests that the liver, kidney, lung, spleen, and pancreas may be the target organs for ZnO NPs according to the administration routes. Serum biochemistry assay shows an elevation in the GPT and ALP level, suggesting liver dysfunction. To our knowledge, this is the first study to report the toxic effects of ZnO NPs through i.p. administration. Further, the present work will offer a deeper understanding regarding the toxicology and in vivo behaviours of ZnO NPs in mice depending upon the various administration routes.