• Journal of Energy Engineering
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• v.21 no.4
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• pp.419-426
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• 2012

A transient, three-dimensional, two-phase flow analysis code, CUPID, has been developed in KAERI. In this work, we performed a preliminary analysis using the CUPID code to investigate the thermal-hydraulic behavior of the moderator in the Calandria vessel of a CANDU reactor. At first, we validated the CUPID code using the three experiments that were performed at Stern Laboratories Inc. To avoid the complexity to generate computational mesh around the Calandria tube bundles, a porous media approach was applied for the region. The pressure drop in the porous media zone was modeled by an empirical correlation. The results of the calculations showed that the CUPID code can predict the mixed flow pattern of forced and natural convection inside the Calandria vessel very well. Thereafter, the analysis was extended to a two-phase flow condition. Also, the local maximum temperature in the Calandria vessel was plotted as a function of the injection flow rate, which may be utilized to predict the local subcooling margin.

• Exercise Science
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• v.21 no.3
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• pp.289-298
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• 2012

In the present study, we investigated the effect of treadmill exercise on apoptotic neuronal cell death in the retinas of streptozotocin-induced diabetic rats. Twenty-eight male Sprague-Dawley rats were used for this study. The animals were divided into four groups(n = 7 in each group):(1) control group, (2) exercise group, (3) diabetes-induced group, (4) diabetes-induced and exercise group. Diabetes mellitus(DM) was induced by intraperitoneal injection of streptozotocin. The rats in the exercise groups were forced to run on the treadmill for 30 minutes once a day, five times per a week, during 12 weeks. In this study, a terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL) assay and western blot for the expressions of caspase-3, cytochrome c, Bax, and Bcl-2 in the retinas were conducted for the detection of apoptotic retinal cell death. The present results showed that the number of TUNEL-positive cells was increased in the retinas of the diabetic rats, whereas treadmill exercise suppressed this number. The expressions of pro-apoptotic factors caspase-3, cytochrome c, and Bax were enhanced and the expressions of anti-apoptotic factor Bcl-2 was decreased in the retinas of the diabetic rats. In contrast, treadmill exercise suppressed the expressions of caspase-3, cytochrome c, and Bax and increased the expression of Bcl-2. The present study demonstrated that treadmill exercise suppressed diabetes-induced apoptotic neuronal cell death in the retinas. Based on the present results, treadmill exercise may be effective therapeutic strategy for the alleviating complications of diabetes patients.

• Korean Journal of Exercise Nutrition
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• v.13 no.3
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• pp.203-209
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• 2009

Periventricular leukomalacia (PVL) is a common white matter lesion affecting the neonatal brains. PVL is closely associated with cerebral palsy (CP). It has been suggested that maternal or placental infection can induce damage to the neonatal brains. In the present study, we investigated the effects of treadmill running and swimming of rat pups on the GFAP and MBP expressions in the brains of rat pups with maternal lipopolysaccharide (LPS)-induced CP. The rats were divided into the six groups for experiment 1: the control group, the control with mild exercise group, the control with moderate exercise group, the LPS-treated group, the LPS-treated with mild exercise group, and the LPS-treated with moderate exercise group (n=6 in each group). The rats in the running groups were forced to run on a motorized treadmill for 30 min 5 times a week for 4 weeks. For experiment 2, the rats were divided into four groups: the control group, the LPS-treated group, the LPS-treated with swimming group, and the LPS-treated with treadmill running group (n = 5 in each group). The rats in the swimming group were made to swim for 30 min once a day for 5 times per week during 2 weeks. The rats in the treadmill running group were made to run for 30 min once a day for 5 times per week during 2 weeks. The present results showed that intracervical maternal LPS injection during pregnancy significantly increased GFAP expression in the striatum and significantly decreased MBP expression in the corpus callosum of rat pups. The present results also showed that treadmill running and swimming significantly suppressed GFAP expression and significantly enhanced MBP expression in the brains of rat pups with maternal LPS-induced CP. This effect of treadmill running was shown as equally both in the mild-intensity exercise and in the moderate-intensity exercise. The present study revealed that exercise, both the treadmill running and swimming, is effective for the treatment of astrogliosis and hypomyelination associated with CP. Here in this study, we showed that treadmill running and swimming are effective for alleviating the detrimental effects of CP.