• Journal of the Korean Institute of Gas
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• v.16 no.3
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• pp.16-21
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• 2012

In this study, the strength safety for 110 liter hydrogen fuel storage tank with 70MPa filling pressure has been analyzed using a FEM technique. The strength safety of a composite fuel tank in which is fabricated by an aluminum liner of 6061-T6 and carbon fiber wound composite layers of T800-24K and T700-12K of Toray, and MR60H-24P of Mitsubishi Ray has been investigated based on the criterion of a strength safety of US DOT-CFFC and Korean Standard. The FEM computed results on the strength safety of 70MPa hydrogen gas tank showed that the hydrogen fuel storage tank in which is fabricated by T800-24K and T700-12K of Toray, and MR60H-24P of Mitsubishi Ray is safe because those two carbon fibers have very similar material properties. But, the composite storage tank with a filling pressure of 70MPa in which is fabricated by T700-12K of Toray may not guaranty the strength safety, and thus this study recommends a composite hydrogen fuel tank under 60MPa.

• Journal of Life Science
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• v.28 no.8
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• pp.985-991
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• 2018

Biological clocks are the basis of temporal control of metabolism and behavior. These clocks are characterized by autonomous free-running oscillation and temperature compensation and are found in animals, plants, and microorganisms. To date, various biological clocks have been reported. These include clocks governing hibernation, sleep/wake, heartbeat, and courtship song. These clocks can be differentiated by the period of rhythms, for example, infradian rhythms (> 24-hr period), circadian rhythms (24-hr period), and ultradian rhythms (< 24-hr period). In yeast (Saccharomyces cerevisiae), at least five different autonomous oscillations have been reported; (1) glycolytic oscillations (T = 1~30 min), (2) cell cycle-dependent oscillations (T = 2~16 hr), (3) ultradian metabolic oscillations (T = 15~50 min), (4) yeast colony oscillations (T = a few hours), and (5) circadian oscillations (T = 24 hr). In this review, we discuss studies on oscillators, pacemakers, and synchronizers, in addition to the application of biological clocks, to demonstrate the nature of autonomous oscillations, especially ultradian metabolic oscillations of S. cerevisiae.

• Food Science of Animal Resources
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• v.36 no.1
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• pp.29-36
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• 2016

This study was performed to investigate the role of pH and temperature postmortem, and to demonstrate the importance of these factors in determining meat quality. Postmortem pH_45min (pH at 45 min postmortem or initial pH) via analysis of Pearson’s correlation showed high positive correlation with pH change pH_c24 (pH change from pH_45min to pH_24h postmortem). However, postmortem pH after 24 h (pH_24h or ultimate pH) had a high negative correlation with pH change, pH_c24, CIE L*, and protein content. Initial temperature postmortem (T_1h ) was positively associated with a change in temperature from 45 min to 24 h postmortem (T_c24) and cooking loss, but negatively correlated with water holding capacity. Temperature at 24 h postmortem (T_24h) was negatively associated with T_c24. Collectively, these results indicate that higher initial pH was associated with higher pH_c24, T_1h, and T_c24. However, higher initial pH was associated with a reduction in carcass weight, backfat thickness, CIE a* and b*, water holding capacity, collagen and fat content, drip loss, and cooking loss as well as decreased shear force. In contrast, CIE a* and b*, drip loss, cooking loss, and shear force in higher ultimate pH was showed by a similar pattern to higher initial pH, whereas pH_c24, carcass weight, backfat thickness, water holding capacity, fat content, moisture content, protein content, T_1h, T_24h, and T_c24 were exhibited by completely differential patterns (p<0.05). Therefore, we suggest that initial pH, ultimate pH, and temperatures postmortem are important factors in determining the meat quality of pork.

• BMB Reports
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• v.40 no.6
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• pp.895-898
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• 2007

The oxygen dependent regulation of DNA replication is an essential property of proliferating mammalian cells. In human T24 bladder cancer cells, several hours of hypoxia leads to reversible DNA replication arrest and re-entry of oxygen induces a burst of replication initiation. This short communication provides strong evidence that PD184352 initiates DNA replication in living hypoxic cells without elevating the oxygen level. PD184352 releases the regular hypoxic replicon arrest, however, at a low intensity compared to the effect of reoxygenation. Moreover, PD184352 shows no effect on normoxically incubated as well as reoxygenated T24 cells.

• 한국초전도학회:학술대회논문집
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• v.16
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• pp.24-24
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• 2006

• Korean Journal of Mathematics
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• v.24 no.4
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• pp.723-736
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• 2016

This paper shows that the solutions to nonlinear perturbed differential system $$y^{\prime}= f(t,y)+{\int_{t_{0}}^{t}g(s,y(s))ds+h(t,y(t),Ty(t))$$ have bounded properties. To show the bounded properties, we impose conditions on the perturbed part ${\int_{t_{0}}^{t}g(s,y(s))ds,\;h(t, y(t),\;Ty(t))$, and on the fundamental matrix of the unperturbed system y' = f(t, y) using the notion of h-stability.

• Progress in Medical Physics
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• v.21 no.4
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• pp.348-353
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• 2010

The purpose of this study was to explore the potentials of a clinical 3T MRI in mouse brains and technical adaptation and optimization. T1-weighted images (T1WI), T2-weighted images (T2WI), FLAIR (Fluid Attenuated Inversion Recovery) images, Gadolinium enhanced T1-weighted images (Gd-T1WI), Diffusion weighted images (DWI) were acquired in brain of 2 mice (weight 20~25 g) with cerebral infarction by occlusion of right middle cerebral artery, 1 hour, 24 hours, 72 hours after infarction and 1 normal mouse brain using clinical 3T MRI scanner. We analyzed differentiation of striatum, ventricle, cerebral cortex, and possibility of detection of acute cerebral infarction. We could differentiate the striatum, ventricle, cerebral cortex on T2WI and on DWI, FLAIR, T1WI, the differentiation of each anatomy of brain was not definite, but acute cerebral infarction was detected on DWI of 1 hour, 24 hours, 72 hours after infarction and on T2WI, FLAIR of 24 hours, 72 hours after infarction. Clinical 3T MRI can be used in differentiation of anatomy of mouse brains and DWI can be helpul in detection of acute cerebral infarction in acute phase. With technical adaptation and optimization clinical 3T MRI can be useful tool for provide preclinical and clinical small animal studies.

• The Korean Journal of Nuclear Medicine
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• v.30 no.4
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• pp.493-501
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• 1996

To assess contribution of T1-201 rest-24 hour delay redistribution in detection of viable myocardium, we studied the predictive value of this redistribution in 17 patients who peformed rest-24 hour delay perfusion SPECT before bypass surgery. Regional wall motion was compared with gated SPECT in 10 patients and echocardiography in 7 patients before and after bypass surgery. Rest and 24 hour delayed uptakes were scored from 0 (normal perfusion) to 3 (defect). In rest SPECT, 56 segments showed perfusion decrease. Thirty four segments(61%) improved after surgery and were defined as viable Nineteen(34%) segments had more uptake of T1-201 at 24 hour delay, and the other 37 segments did not. In 81%(25/31) of segments with mildly decreased perfusion, wall motion after bypass surgery improved, 57% (8/14) of segments with severely decreased perfusion improved, and 9%(1/11) of segments with defects improved. In 14 among 19 segments which had more T1-201 uptakes at 24 hour delay, wall motion was improved(positive predictive value of redistribution: 74%). 20 among 37 segments which had persistent decreases in rest-24 hour redistribution improved and 17 did not(negative predictive value: 46%). Segments having severe perfusion decrease or defects showed improved wall motion after surgery in 64%(7/11), if it had redistribution at delay. Segments with either mildly decreased uptake in resting or rest-delayed redistribution showed improved wall motion in 76%(32/42). Among the 14 segments which showed improvement in wall motion, 10 had partial reversibility in stress-rest images and the other 4 had persistent perfusion defects in stress-rest images. These 4 segments were found viable only with rest-24 hour delayed perfusion SPECT. We concluded that rest T1-201 uptake or redistribution at 24 hour delay should be referred as an evidence to warrant postoperative improvement of abnormal wall motion and we could predict myocardial viability with preoperative rest-24 hour delay perfusion SPECT in the segments with rest perfusion decreases.

• Journal of the Chungcheong Mathematical Society
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• v.24 no.1
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• pp.113-119
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• 2011

Let T be a bounded linear operator on a complex Hilbert space $\mathcal{H}$. An operator T is called class A operator if ${\left|{T^2}\right|}{\geq}{\left|{T^2}\right|}$ and is called class A(k) operator if $({T^*\left|T\right|^{2k}T})^{\frac{1}{k+1}}{\geq}{\left|T\right|}^2$. In this paper, we show that ${\sigma}$ is continuous when restricted to the set of class A operators and consider the tensor products of class A(k) operators.

• Journal of Internet of Things and Convergence
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• v.9 no.2
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• pp.33-40
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• 2023

This study was aimed at examining the effects of aroma blending oil inhalation on academic stress and class concentration in nursing students. The research design was a nonequivalent placebo control group nonsynchronized. The subjects of the study were 24 students in the treatment group and 24 placebo control group. Data collection was from November 4, 2022 to December 3, 2022, and the data were analyzed chi-square test, independent t-test, paired t-test using the SPSS 23.0 Program. The treatment group inhaled aroma blending oil for 10 days showed a significant decrease in academic stress (t=-8.79, p<.001) and a significant increase in class concentration (t=24.44, p<.001).