Pusan National University

About: Pusan National University is a education organization based out in Busan, South Korea. It is known for research contribution in the topics: Population & Catalysis. The organization has 24124 authors who have published 45054 publications receiving 819356 citations. The organization is also known as: Busan National University & Pusan University.

Carbonaceous clusters in irradiated polymers as revealed by UV-Vis spectrometry

Abstract: Carbonaceous clusters-supposed to be the carriers of electric conductivity-are formed along latent tracks of energetic ions in polymers. The different experimental techniques for cluster determination are summarized. Here we present some new results which have been derived from UV-Vis spectrometric examinations. Especially the initial phase of cluster growth is studied in detail. There are hints that a threshold energy density has to be deposited in the polymer before cluster growth sets in. This threshold is similar to the one for producing radicals (as seen by EPR studies), and to the one for the onset of strong polymeric conductivity. The cluster growth is shown to scale rather well with the mean transferred electronic energy density. The increase in cluster growth with energy density is much slower than the one of radical formation and conductivity.

A Look-Ahead Dispatching Method for Automated Guided Vehicles in Automated Port Container Terminals

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.

Increase of NKG2D ligands and sensitivity to NK cell-mediated cytotoxicity of tumor cells by heat shock and ionizing radiation

Abstract: In this study, we have investigated if current cancer therapeutic modalities including hyperthermia and ionizing radiation can increase the expression of NKG2D ligands in human cancer cell lines. The expressions of NKG2D ligands were induced by both heat shock and ionizing radiation in various cell lines including KM12, NCI-H23, HeLa and A375 cells with peaks at 2 h and 9 h after treatment, respectively, although inducibility of each NKG2D ligand was various depending on cell lines. During the induction of NKG2D ligands, heat shock protein 70 was induced by heat shock but not by ionizing radiation. These results were followed by increased susceptibilities to NK cell-mediated cytolysis after treatment with heat shock and ionizing radiation. These results suggest that heat shock and ionizing radiation induce NKG2D ligands and consequently might lead to increased NK cell-mediated cytotoxicity in various cancer cells.