• Investigative Magnetic Resonance Imaging
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• 제12권1호
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• pp.20-26
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• 2008

Purpose : To present the T1 and T2 relaxation times of the major cerebral metabolites at 1.5T and 3.0T and compare those between 1.5T and 3.0T. Materials and Methods : Using the phantom containing N-acetyl aspartate (NAA), Choline (Cho), and Creatine (Cr) at both 1.5T and 3.0T MRI, the T1 relaxation times were calculated from the spectral data obtained with 5000 ms repetition time (TR), 20 ms echo time (TE), and 11 different mixing time (TM)s using STEAM (STimulated Echo-Acquisition Mode) method. The T2 relaxation times were obtained from the spectral data obtained with 3000 ms TR and 5 different TEs using PRESS (Point-RESolved Spectroscopy) method. The T1 and T2 relaxation times obtained at 1.5T were compared with those of 3.0T. Results : The T1 relaxation times of NAA were $2293\;{\pm}\;48\;ms$ at 1.5T and $2559\;{\pm}\;124\;ms$ at 3.0T (11.6% increase at 3.0T). The T1 relaxation times of Cho were $2540\;{\pm}\;57\;ms$ at 1.5T and $2644\;{\pm}\;76\;ms$ at 3.0T (4.1% increase at 3.0T). The T1 relaxation times of Cr were $2543\;{\pm}\;75\;ms$ at 1.5T and $2665\;{\pm}\;94\;ms$ at 3.0T (4.8% increase). The T2 relaxation times of NAA were $526\;{\pm}\;81\;ms$ at 1.5T and $468\;{\pm}\;74\;ms$ at 3.0T (11.0% decrease at 3.0T). The T2 relaxation times of Cho were $220\;{\pm}\;44ms$ at 1.5T and $182\;{\pm}\;35\;ms$ at 3.0T (17.3% decrease at 3.0T). The T2 relaxation times of Cr were $289\;{\pm}\;47\;ms$ at 1.5T and $275\;{\pm}\;57\;ms$ at 3.0T (4.8% decrease at 3.0T). Conclusion : The T1 relaxation times of the major cerebral metabolites (NAA, Cr, Cho), which were measured at the phantom, were 4.1%-11.6% longer at 3.0T than at 1.5T. The T2 relaxation times of them were 4.8%-17.3% shorter at 3.0T than at 1.5T. To optimize MR spectroscopy at 3.0T, TR should be lengthened and TE should be shortened.

• Korean Journal of Poultry Science
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• 제26권4호
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• pp.237-245
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• 1999

This study was conducted to investigate the effect of dietary thyroid hormone (T$_3$and T$_4$) on growth, feed conversion ratio and serum T$_3$or T$_4$concentration of broiler chicks. Zero to six week-old broiler chicks were randomly allocated into seven treatment groups for feeding trials with three replication : control, T$_3$(0.1), T$_3$(1.0), T$_3$(5.0), T$_4$(0.1), T$_4$(1.0), T$_4$(5.0) ppm group. Concentrations of T$_3$and T$_4$in serum were analyzed. The weight gain of T$_3$(1.0), T$_3$(5.0) and T$_4$(5.0) groups were significantly lower than that of control. No statistically significant adverse effect was observed in other groups (p〉0.05). Feed intake was significantly lower in T$_3$(0.1, 1.0 and 5.0) and T$_4$(5.0) than in control group (p〈0.05), and the feed conversion ratio had a similar trend to the feed intake change. The contents of liquid and abdominal fat pad in carcass were significantly decreased in all T$_3$and T$_4$groups (p〈0.05). T$_3$and T$_4$concentration in serum was significantly increased at over 1.0ppm of the hormone supplementation level. As T$_3$addition level increased, T$_4$concentration in serum reduced ; however, T$_3$in serum was directly proportional during fasted were slightly increased when T$_3$or T$_4$was added to broiler diets.

• Investigative Magnetic Resonance Imaging
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• 제15권1호
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• pp.67-71
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• 2011

Purpose : To compare T2 relaxation times (T2) in the cingulate cortex, amygdaloid body, hippocampal body, and insular cortex between 1.5T and 3.0T MR imagers. Materials and Methods : Twelve healthy volunteers underwent FLAIR and CPMG imaging perpendicular to the hippocampal body at both 3.0T and 1.5T. T2 was measured in the cingulate cortex, amygdaloid body, hippocampal body, and insular cortex. The T2 relaxation time ratios of the cingulate cortex, insular cortex, and amygdaloid body to the hippocampal body were compared between 1.5T and 3.0T. Results : The mean T2 of the cingulate cortex, amygdaloid body, hippocampal body, and insular cortex at 1.5T were $109.5{\pm}3.1$, $117.0{\pm}7.1$, $114.7{\pm}2.4$, and $111.3{\pm}2.4$, respectively; $99.7{\pm}3.8$, $100.7{\pm}4.3$, $97.9{\pm}3.4$, and $96.2{\pm}2.0$, respectively, at 3.0T. Percentage changes of T2 in the cingulate cortex, insular cortex, amygdaloid body, and hippocampal body at 3.0T with respect to those at 1.5T were -8.9%, -13.5%, -14.6%, and -13.5%, respectively. The mean T2 ratios of the cingulate gyrus, insular cortex, and amygdaloid body to the hippocampal body at 1.5T and 3.0T were 0.96 and 1.02 (p = 0.003); 1.02 and 1.03 (p>0.05); 0.97 and 0.98 (p>0.05), respectively. Conclusion : T2 decrease in the cingulate cortex was less than the amygdaloid body, insular cortex, and hippocampal body at 3.0T. The mean T2 ratio of the cingulate gyrus to the hippocampal body was significantly different between 1.5T and 3.0T.

• Investigative Magnetic Resonance Imaging
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• 제17권2호
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• pp.83-90
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• 2013

Purpose : To report our clinical experience with cardiac 3.0 T MRI in patients compared with 1.5 T using individually optimized imaging protocols. Materials and Methods: We retrospectively reviewed 30 consecutive patients and 20 consecutive patients who underwent 1.5 T and 3 T cardiac MRI within 10 months. A comparison study was performed by measuring the signal-to-noise ratio (SNR), the contrast-to-noise ratio (CNR) and the image quality (by grading each sequence on a 5-point scale, regarding the presence of artifacts). Results: In morphologic and viability studies, the use of 3.0 T provided increase of the baseline SNRs and CNRs, respectively (T1: SNR 29%, p < 0.001, CNR 37%, p < 0.001; T2-SPAIR: SNR 13%, p = 0.068, CNR 18%, p = 0.059; viability imaging: SNR 45%, p = 0.017, CNR 37%, p = 0.135) without significant impairment of the image quality (T1: $3.8{\pm}0.9$ vs. $3.9{\pm}0.7$, p = 0.438; T2-SPAIR: $3.8{\pm}0.9$ vs. $3.9{\pm}0.5$, p = 0.744; viability imaging: $4.5{\pm}0.8$ vs. $4.7{\pm}0.6$, p = 0.254). Although the image qualities of 3.0 T functional cine images were slightly lower than those of 1.5 T images ($3.6{\pm}0.7$ vs. $4.2{\pm}0.6$, p < 0.001), the mean SNR and CNR at 3.0 T were significantly improved (SNR 143% increase, CNR 108% increase, p < 0.001). With our imaging protocol for 3.0 T perfusion imaging, there was an insignificant decrease in the SNR (11% decrease, p = 0.172) and CNR (7% decrease, p = 0.638). However, the overall image quality was significantly improved ($4.6{\pm}0.5$ vs. $4.0{\pm}0.8$, p = 0.006). Conclusion: With our experience, 3.0 T MRI was shown to be feasible for the routine assessment of cardiac imaging.

• The Transactions of the Korean Institute of Electrical Engineers
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• 제41권5호
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• pp.508-516
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• 1992

In this study, dielectric and piezoelectric properties of 0.05Pb(AlS12/3TWS11/3T)OS13T-0.95Pb(ZrS10.52TTiS10.48T)OS13T system ceramics were investigated with respect to the variations of MnOS12T and FeS12TOS13T additions amounts. The results obtained in this study are summarized as follows: 1. As the amounts of MnOS12T and FeS12TOS13T are increased, tetragonality(c/a) and apparent density were decreased but grain size was increased, also the limits of solubility were revealed because pores were formed at the amounts of 0.3wt% MnOS12T and 0.5wt% FeS12TOS13T. 2. AS the increasing of amounts of MnOS12T and FeS12TOS13T, the temperature of phase transition(TS1cT) was decreased, and pemeability had maximum value at the amount of 0.3wt% MnOS12T but were sharply decreasd for the increasing FeS12TOS13T amounts. 3. As the amounts of MnOS12T and FeS12TOS13T are increased, the electro-mechanical coupling factor(kS1pT) was decreased from 60% to 41%, 19% respectively, but mechanical quality factor(QS1mT) had maximum values 720 for amount of 0.3wt% MnOS12T and 320 the amount of 0.5wt% FeS12TOS13T.

• Journal of the Korean Society of Radiology
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• 제12권2호
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• pp.193-199
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• 2018

In this research, 15 patients were diagnosed with 1.5T and 3.0T MRI instruments (Philips, Medical System, Achieva) to minize Ferromagnetic artifact and find the optimized Tesla. Based on the theory that the 3.0T, when compared to 1.5T, show relatively high signal-to-ratio(SNR), Scan time can be shortened or adjust the image resolution. However, when using the 3.0T MRI instruments, various artifact due to the magnetic field difference can degrade the diagnostic information. For the analysis condition, area of interest is set at the background of the T1, T2 sagittal image followed by evaluation of L3, L4, L5 SNR, length of 3 parts with Ferromagnetic artifact, and Histogram. The validity evaluation was performed by using the independent t test. As a result, for the SNR evaluation, mere difference in value was observed for L3 between 1.5T and 3.0T, while big differences were observed for both L4, and L5(p<0.05). Shorter length was observed for the 1.5T when observing 3 parts with Ferromagnetic artifact, thus we can conclude that 3.0T can provide more information on about peripheral tissue diagnostic information(p<0.05). Finally, 1.5T showed higher counts values for the Histogram evaluation(p<0.05). As a result, when we have compared the 1.5T and 3.0T with SNR, length of Ferromagnetic artifact, Histogram, we believe that using a Low Tesla for Spine MRI test can achieve the optimal image information for patients with disk operation like PLIF, etc. in the past.

• Korean Journal of Fisheries and Aquatic Sciences
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• 제22권5호
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• pp.281-290
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• 1989

Growth of the Korean pomfret, Pampus echinogaster, captured in the East China Sea from January to December 1987, was estimated by annual rings on the vertebral centrum. The time of annual ring formation was approximately during September and October. Von Ber-talanffy growth equations derived from the mean back-calculated fork length(cm) at each age were as follows: for females, $L_{t}=29.17(1-e xp(-0.3213(t+0.7601)))$, for males, $L_t=28.21(1-e xp(-0.3169(t+0.8284)))$, and for sexes combined, $L_t=29.00(1-e xp(-0.3228(t+0.7361)))$, Seasonal growth equations derived from the mean observed fork length (cm) at age by month were as follows: for females, $L_t=29.2(1-e xp(-0.3458(t+0.8182)+(0.3458/2\pi)sin2\pi(t+0.027)))$, and for males, $L_t=28.2(1-e xp(-0.2789(t+1.5913)+(0.2789/2\pi)sin2\pi(t-0.1062)))$.

• Journal of The Korean Society of Grassland and Forage Science
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• 제27권3호
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• pp.209-218
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• 2007

This experiment was conducted to investigate effect of plowing frequency and sowing dates on the agronomic characteristics, feed value, weed yield and palatability of silage corn. Treatments were a basal treatment(C: May 5 seeding, plowing once, weeding control once), T1(May 12 seeding, plowing twice, weeding control 0 time), T2(May 19 seeding, plowing three times, weeding control 0 time, T3(May 26 seeding, plowing four times, weeding control 0 time) and T4(June 2 seeding, plowing five times, weeding control 0 time). The experiment was performed at the College of Life and Natural Sciences of Sangju University in Sangju in 2006. The plant height and ear height showed highly in order to C > T1 > T2 > T3 > T4 treatment, leaf length was the highest at T2 (96.0cm). Leaf width and number of dead leaf were the highest at C and T3 (11.2cm), C, C and T1 (4.6), respectively. Stem diameter was the highest at T3 as 31mm, while T2 was the lowest as 25mm (p<0.05). Ear circle showed highly in order of C > T1 > T4 > T3 > T4 (p<0.05), and tip filling degree was the highest at C treatment as 8.8, while T4 treatment was the lowest as 6.0 (p<0.05). The stem hardness and grain hardness were C < T1 < T2 < T3 < T4 (p<0.05). Stem saccharinity was T1(6.1%) was the highest, while T2(3.0%) was the lowest(P<0.05). Fresh yield of weed was the lowest at C treatment as 500 kg/ha, but T1 treatment was the highest as 44,100 kg/ha (p<0.05). Weed coverage rate showed highly in order of T1 > T2 > T3 > T4 > C treatment (p<0.05). Fresh yield of corn was the highest at C treatment as T3,550 kg/ha, but T4 treatment was the lowest as 65,500 kg/ha (p<0.05). Dry matter yield of corn showed highly in order of C(26,978 kg/ha) > T1(26,130 kg/ha) > T2(20,255 kg/ha) > T3(20,255 kg/ha) > T4(17,508 kg/ha) treatment (p<0.05). Crude protein content was T1(7.69%) > T4(7.42%) > T2(6.34%) > T3(5.99%) > C(5.91%) treatment (p<0.05), and Crude fat content showed highly in order of C (2.13%) > T1(2.04%) > T2(1.96%) > T3(1.95%) > T4(1.84%) treatment. Relative palatability of Holstein, Korean native goat and spotted deer was the highest at C treatment, but Korean native cattle was the highest at T1 treatment.

• Journal of the Korean Applied Science and Technology
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• 제37권3호
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• pp.398-408
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• 2020

The purpose of the present study was to investigate the mechanism of metabolic partitioning between oxidization and esterification of liver fatty acids synthesized and secreted by the liver from egg yolk-fed laboratory rats. Animals were divided into four groups and orally administered egg yolk daily for 30 days: CON (control group, 1.0 g of saline solution), T1 (1.0 g of pork belly oil), T2 (1.0 g of egg yolk), and T3 (1.0 g of pork belly oil and 1.0 g of egg yolk, alternatively each week). The accumulation rate of [¹⁴C]-labelled lipid in liver was lowest in T2 among all treatments (P<0.05). Phospholipid secretion was higher in T2 than other treatments (P<0.05). The triglycerol secretion was highest in T1 and higher in the order of CON, T3, and T2 (P<0.05). Metabolic partitioning rate of phospholipid from total glycerolipid was highest in T2, followed by T3, CON and T1 (P<0.05). The ¹⁴CO₂ production from total glycerolipid was the highest in T2 and showed a high oxidation rate compared to CON, T1, and T3 (P<0.05). Metabolic partitioning of glycerolipid from the liver decreased in triglycerol of T2 compared to CON, T1, and T3, whereas phospholipids of T2 increased (P<0.05).

• Korean Journal of Digital Imaging in Medicine
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• 제17권1호
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• pp.43-48
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• 2015

Intracrnial 3D TOF MR angiography was performed in 30 normal volunteers with both 1.5 and 3.0 T MRI system with high resolutions. Used Voxel sizes were $0.39{\times}0.39{\times}0.2$(1.5 T) and $0.19{\times}0.19{\times}0.35$(3.0 T), respectively. High image quality and depiction of small vessel branches were equality demonstrated with 1.5 T and 3.0 T HR TOF MRA(p<0.05). Intracranial high resolution TOF MRA with 1.5 T and 3.0 T provides high diagnostic information with having merits and demerits in depiction of vascular branches.