• Investigative Magnetic Resonance Imaging
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• v.15 no.1
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• pp.48-56
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• 2011

Purpose : The aim of this study is to measure the typical MR variables such as $T_1$- and $T_2$-relaxation times according to morphological characteristics of gold nanopartides as a preliminary study to perform theragnosis using local heating by gold nanopartides. Materials and Methods : Two types of gold nanoparticles were used. Spheres were synthesized by various methods and stirring speed. Rods were synthesized by adding various concentrations of sphere nanopartides. Gold nanopartides were mixed with 2% agarose gel at 1:1 ratio and then signals were acquired using a 1.5T MRI. For the measurements of $T_1$-and $T_2$-relaxation times, TR and TE were varied, respectively. The results were acquired through $T_1$ and $T_2$ curves based on the intensities of MR image using self-developed software. And Statistical analysis was performed. Results : $T_1$ times were measured 1.86 sec and 2.08 sec for sphere and rod, respectively. On the other hands, $T_2$ times were measured 57 ms and 35.45 ms for sphere and rod. Conclusion : The changes of the MR variables according to the morphological characteristics of the gold nanopartides were confirmed. Optimal MR imaging conditions can be obtained by choosing proper TR and TE according to the type of nanoparticles.

• Investigative Magnetic Resonance Imaging
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• v.22 no.2
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• pp.86-93
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• 2018

Purpose: Imaging plays a significant role in diagnosing leptomeningeal metastases. However, the most appropriate sequence for the detection of leptomeningeal metastases has yet to be determined. This study compares the efficacies of contrast-enhanced T2 fluid attenuated inversion recovery (FLAIR) and contrast-enhanced 3D T1 black-blood fast spin echo (FSE) imaging for the detection of leptomeningeal metastases. Materials and Methods: Tube phantoms containing varying concentrations of gadobutrol solution were scanned using T2 FLAIR and 3D T1 black-blood FSE. Additionally, 30 patients with leptomeningeal metastases were retrospectively evaluated to compare conspicuous lesions and the extent of leptomeningeal metastases detected by T2 FLAIR and 3D T1 black-blood FSE. Results: The signal intensities of low-concentration gadobutrol solutions (< 0.5 mmol/L) on T2 FLAIR images were higher than in 3D T1 black-blood FSE. The T2 FLAIR sequences exhibited significantly greater visual conspicuity scores than the 3D T1 black-blood sequence in leptomeningeal metastases of the pial membrane of cistern (P = 0.014). T2 FLAIR images exhibited a greater or equal extent (96.7%) of leptomeningeal metastases than 3D T1 black-blood FSE images. Conclusion: Because of its high sensitivity even at low gadolinium concentrations, contrast-enhanced T2 FLAIR images delineated leptomeningeal metastases in a wider territory than 3D T1 black-blood FSE.

• Communications of the Korean Mathematical Society
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• v.11 no.1
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• pp.71-79
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• 1996

In this paper, we prove for a nonexpansive mapping T that under certain conditions the trajectory $t \to G_t(x), t \in [0,1]$, defined by the equation $G_t(x) = (1 - t)x + tTG_t(x)$ strongly converges to a fixed point of T as $t \to 1^{-1}$.

• Korean Journal of Radiology
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• v.22 no.8
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• pp.1332-1340
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• 2021

Objective: To evaluate the feasibility of a new three-dimensional (3D) MR fingerprinting (MRF) technique for the prostate gland by conducting phantom and clinical studies. Materials and Methods: The new 3D MRF technique used in this study enables quick data acquisition and has a high resolution. For the phantom study, the MRF T1 and T2 values in an in-house phantom were compared with those of goldstandard mapping methods using linear regression analysis. For the clinical study, we evaluated 90 patients who underwent prostate imaging with MRF for suspected prostate cancer between September 2019 and February 2020. The mean T1 and T2 values were compared in the peripheral zone, transition zone, and focal lesions using paired t tests. The differences in the T1 and T2 values according to cancer aggressiveness were evaluated using one-way analysis of variance. Results: In the phantom study, the MRF T1 and T2 values showed a perfect correlation with the gold-standard T1 and T2 values (R > 0.99). In the clinical study, the T1 and T2 values in the peripheral zone were significantly higher than those in the transitional zone (p < 0.001, both). The T1 and T2 values in prostate cancer were significantly lower than those in the peripheral and transitional zones. The higher the grade of cancer, the lower the T2 values. Conclusion: The T1 and T2 values obtained from the 3D MRF showed a perfect correlation with the gold standard values in the phantom study. Differences in the T1 and T2 values among the different zones of the prostate gland were identified using 3D MRF in patients.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.4
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• pp.575-581
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• 2010

Kidney bean was used in the brewing of Takju. The Takju formed varied the percentage of kidney bean used; that is, 0%(only rice) in $T_{-1}$, 100%(only kidney bean) in $T_{-2}$, 90% in $T_{-3}$, 80% in $T_{-4}$, 70% in $T_{-5}$, 60% in $T_{-6}$, and 50% in $T_{-7}$. We determined the total sugar, pH, reducing sugar, alcohol production, acidity, and DPPH free radical scavenging activity of Takju. The acidic value of $T_{-1}$ was above that of $T_{-6}$, and the pH of $T_{-2}$ was above that of $T_{-1}$. Both satisfy the food code parameters (namely, below 0.5 in acidity, 3.8~4.7 in pH). The alcohol production of $T_{-1}$ was above that of $T_{-2}$. For 2 days of fermentation, the reducing sugar of $T_{-1}$ totaled 2, down from 4.96%. After fermentation, there was not much difference from 4 to 12 days. The antioxidative effect of $T_{-1}$ proved to be much better than those of the other. Thus, we can be seen that these results thus indicate that the role of kidney bean added to Takju show good antioxidative activity. From the result of sensory test, we also concluded that the taste of Takju kidney bean is very similar to that of Takju with rice.

• Korean Journal of Organic Agriculture
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• v.17 no.4
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• pp.539-555
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• 2009

The potential of encapsulated inuloprebiotics from domestic Jerusalem artichokes (Helianthustuberosus) as natural antibacterial growth promotor for an antibiotic replacement in broiler chickens was presently assessed through assays of growth performance, serum immunoglobulin production and influence on caecal microflora. Two hundred-forty, 1-day-old, male broilers (Ross 308) were randomly allotted to four treatments (T1-T4), with three replicate pens per treatment and 20 chicks per pen. Broiler chicks were fed a basal diet (T1: control) or basal diet plus antibiotics (T2: Chlorotetracycline, 0.10%), 300 ppm of the inuloprebiotics (T3), or 450 ppm of the inuloprebiotics (T4) for 35 days. Body weight, dressing percentage or weight of breast and thigh muscles relative to carcass weight of T3 and T4 broiler chickens was significantly (P<0.05) higher than T1 and T2 broiler chickens. The weight of abdominal fat from T3 and T4 broiler chickens were significantly (P<0.05) lower than that of T1 and T2 chickens. Serum immunoglobulins in the T3 and T4 groups were significantly (P<0.05) elevated compared to the T1 and T2 groups. The weight of immune organs, thymus and Bursa of Fabricius relative to live body weight in the T3 and T4 groups were significantly (P<0.05) higher than the T1 and T2 groups. Bifidobacteria and Lactobacillus, which are beneficial bacteria, were present in greater numbers in the caecum of T3 and T4 birds than T1 and T2 groups, whereas potentially harmful Escherichiacoli and Salmonella were present in lower numbers, with differences being significant (P<0.05). These results suggest that a diet supplemented with 300 ppm of inuloprebiotics has potential as an antibiotic replacement for organic livestock feed supplement intended to improve production of broiler chicken.

• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.401-407
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• 2011

The purpose of this study is to know the differences of MR spectra, obtained from normal volunteers by variable TE value, through the quantitative analysis of brain metabolites by peak integral and SNR between 1.5T and 3.0T, together with PRESS and STEAM pulse sequence. Single-voxel MR proton spectra of the human brain obtained from normal volunteers at both 3.0T MR system (Magnetom Trio, SIEMENS, Germany) and 1.5T MR system (Signa Twinspeed, GE, USA) using the STEAM and PRESS pulse sequence. 10 healthy volunteers (3.0T:3 males, 2 females; 1.5T : 3 males, 2 females) with the range from 22 to 30 years old (mean 26 years) participated in our study. They had no personal or familial history of neurological diseases and had a normal neurological examination. Data acquisition parameters were closely matched between the two field strengths. Spectra were recorded in the white matter of the occipital lobe. Spectra were compared in terms of resolution and signal-to-noise ratio(SNR), and echo time(TE) were estimated at both field strengths. Imaging parameters was used for acquisition of the proton spectrum were as follow : TR 2000msec, TE 30ms, 40ms, 50ms, 60ms, 90ms, 144ms, 288ms, NA=96, VOI=$20{\times}20{\times}20mm3$. As the echo times were increased, the spectra obtained from 3.0T and 1.5T show decreased peak integral and SNR at both pulse sequence. PRESS pulse sequence shows higher SNR and signal intensity than those of STEAM. Especially, Spectra in normal volunteers at 3.0T demonstrated significantly improved overall SNR and spectral resolution compared to 1.5T(Fig1). The spectra acquired at short echo time, 3T MR system shows a twice improvement in SNR compared to 1.5T MR system(Table. 1). But, there was no significant difference between 3.0Tand 1.5T at long TE It is concluded that PRESS and short TE is useful for quantification of the brain metabolites at 3.0T MRS, our standardized protocol for quantification of the brain metabolites at 3.0T MRS is useful to evaluate the brain diseases by monitoring the systematic changes of biochemical metabolites concentration in vivo.

• Korean Journal of Poultry Science
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• v.26 no.4
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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.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.3
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• pp.95-102
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• 2002

Interactive hashing is a protocol introduced by Naor, Ostrovsk Venkatesan, $Yung^{[1]}$ with t-1 round complexity and $t^2$ - 1 bits communication complexity for given t bits string. In this paper, we propose more efficiently extended interactive hashing protocol with t/m- 1 round complexity and $t^2$/m - m bits communication complexity than NOVY protocol when m is a divisor of t, and prove the security of this.

• Korean journal of food and cookery science
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• v.31 no.4
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• pp.423-430
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• 2015

This study was carried out to investigate the effects of dandelion leaf, root and whole part extracts on the physicochemical characteristics of pork patties stored at $4^{\circ}C$ for 10 days. Four types of pork patties were evaluated: ice-water-added (T0), dandelion leaf extract (T1), dandelion root extract (T2) and dandelion whole part extract (T3). The pH decreased significantly during storage, but increased after 10 days of storage. The pH was highest in T0 during storage. The L value of T0 increased whereas T1, T2 and T3 did not significantly changed during storage. The a value decreased with a longer storage period, and the a values for T1, T2 and T3 were higher than that of T0 during storage. The b value did not change significantly during storage. The TBARS increased with a longer storage period, and the values for T0, T1, T2 and T3 were 0.87, 0.29, 0.47 and 0.31 mg MA/kg, respectively, after 10 days of storage. The VBN content value of T0 increased, but those of T1, T2 and T3 did not significantly change during storage. The water holding capacity of T0 decreased, but those of T1, T2 and T3 did not significantly change during storage. Cooking loss increased during storage and that of T0 was higher than those of T1, T2 and T3. Hardness and chewiness decreased while springiness and cohesiveness increased during storage.