Kyung-Mook Choi

Exercise training improves basal blood glucose metabolism with no changes of cytosolic inhibitor κB kinase or c-Jun N-terminal kinase activation in skeletal muscle of Otsuka Long–Evans Tokushima fatty rats

Redox‐sensitive stress kinases and heat shock protein 72 (Hsp72) have been considered to be associated with the development of type 2 diabetes in skeletal muscle. However, the effect of exercise training on skeletal muscle of type 2 diabetic models is largely unknown. The purpose of this study was to investigate the effect of 12 weeks of exercise training on gastrocnemius of type 2 diabetic rats, by examining the activation of c‐Jun N‐terminal kinase (JNK), the nuclear factor κB (NF‐κB) pathway and Hsp72. Total hydroperoxide and 4‐hydroxynoneal, as oxidative stress markers, were also examined. Otsuka Long–Evans Tokushima fatty (OLEFT) rats were randomly divided into an exercise training group (Ex‐OLETF, n= 8) and a sedentary group (Sed‐OLETF, n= 8), while Long–Evans Tokushima Otsuka (LETO) rats were used as a control group (Con‐LETO, n= 5). The Ex‐OLETF rats were trained on a treadmill five times a week for 12 weeks. The levels of hydroperoxide and 4‐hydroxynoneal in both Ex‐OLETF and Sed‐OLETF were significantly higher compared with Con‐LETO, but there was no difference between Ex‐OLETF and Sed‐OLETF. Levels of inhibitor κB kinase, JNK activation and p65 nuclear translocation followed a similar pattern to that observed in oxidative stress markers. The level of Hsp72 in Ex‐OLETF was increased by exercise training, but it did not reach the level observed in Con‐LETO. The NF‐κB DNA binding activity in Sed‐OLETF was significantly higher compared with Con‐LETO. Although it was not statistically significant, exercise training in Ex‐OLETF showed a trend to reduce the activation of NF‐κB DNA binding activity compared with Sed‐OLETF (P= 0.104). Our findings indicate that exercise training improves basal glucose metabolism without a change in stress kinases, and that nuclear regulation of NF‐κB activity in diabetic muscle could be regulated independently of the cytosolic pathway. Our study also suggests a possibility that exercise‐induced Hsp72 serves as a protective mechanism in skeletal muscle of OLETF rats.

An operation scheme for make-to-order job-shop production systems

Abstract The purpose of this paper is to solve multi-job order release problem whose objective is to minimize the sum of mean shop floor flow times (SFFTs) of orders subject to due-date constraint. A heuristic algorithm is proposed for the problem by decomposing the load profile of the shop. The load profile is divided into two parts. One is for the planning orders (new orders and unreleased orders) and the other is for the current orders being processed. The advantage of decomposing the load profile is to reduce computational complexity in the estimation step of order completion time. A job dispatching rule is also suggested to synchronize part flows in the shop floor. The experimental results show that work-in-process (WIP) in both bottleneck stations and assembly station, the SFFT of orders, and the percentage of tardy orders are significantly reduced.

Developing a generic FMS for small to medium size industries of Korea

Abstract This article reports on the development of a generic FMS that is suitable for small to medium size industries. It introduces FMS construction tool named “shell”, system building methodology using it. Also, it outlines the overview of the developed FMS(KUFMS) and its computer control system. Furthermore, it elaborates on the intercommunication device that links the machinery to its control computer. The factors considered in the development of KUFMS are low implementation cost, easy implementation, case of expandability, simple modification capability.