• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.82-82
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• 2002

목적： Phase cycling과 fat suppression을 기존 STEAM 펄스시퀀스에 추가 및 최적화함으로써 3.0T 1H MRS 스펙트럼의 quality를 향상시키는 데 그 목적이 있다. 대상 및 방법： 가톨릭의대에 설치된 3.0T MRI를 이용하여 STEAM 펄스시퀀스를 최적화하였다. 우선 CHESS 펄스시퀀스를 이용하여 물 신호를 억제하고, 대사물질의 신호에 영향을 주는 fat 신호를 제거하도록 펄스시퀀스 최적화를 시험하였다. 또한 Phase cycling을 이용하여 Noise 신호를 제거하였다. 스펙트럼을 분석하기 위하여 본 사에서 개발한 MaqSpec 프로그램을 이용하였고, Post-processing을 한 후 펄스시퀀스 변경 전후의 MRS 스펙트럼을 비교하였다.

• Journal of the Korean Magnetic Resonance Society
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• v.13 no.2
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• pp.64-83
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• 2009

The purpose of this study was to evaluate the usefulness of in vivo 3T $^1H$ MRS with short TE for prescreening various brain diseases. Together with ten normal volunteers, 12 brain tumor patients(2 lymphomas, 5 malignant gliomas) and 5(benign meningiomas) and 10 brain ischemic disease patients(6 acute and 4 subacute infarctions) participated. Lymphomas showed increased intensities of Cho and Lac. Likewise, gliomas showed increased Cho and Lac, but with decreased NAA and ${\beta}\;{\gamma}$-Glx; in higher grade of gliomas, Lac, Cho, mI and Lip predominantly increased with decrease of NAA. Benign meningiomas showed increased Cho, Lac and ${\beta}\;{\gamma}$-Glx; with decreased of NAA. The alanine peak at 1.47 ppm is a neuronal marker for meningiomas. Infarctions showed increased Lac and Lip and decreased NAA, ${\alpha}$-Glx and ${\beta}\;{\gamma}$-Glx where Lac increased with decreased of ${\alpha}$-Glx in acute, and Cho, Lac and Lip increased with decrease of NAA in subacute. Elevated Lac and decreased NAA levels were more aggravated in subacute. Clinical application of the $^1H$ MRS with short TE at 3T is able to povide valuable spectral information for prescreening various brain diseases by monitoring the changes of disease-specific cerebral metabolite concentrations in vivo, and consequently, it can be applicable to assessment of differential diagnosis and malignancy as well.

• Journal of Food Hygiene and Safety
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• v.23 no.2
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• pp.113-120
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• 2008

The influence of incubation temperature, pH and media components on bacteriocin production by Lactobacillus plantarum K11 were investigated. The highest activity was observed in MRS broth, but no bacteriocin activity was obtained in TSB. The bacteriocin was produced from the exponential growth phase and its activity also reached a maximum in MRS broth, but then dropped after 16 hr because of degradation by extracellular proteolytic enzymes or exhaustion of medium nutrients. The optimal temperature and pH for production of bacteriocin were $37^{\circ}C$ and pH 7.0 in MRS broth, respectively. The addition of 0.5 or 1.0% glucose and $0.5{\sim}1.5%$ lactose to MRS resulted in the increase of the bacteriocin production. With 0.5% NaCl and $K_2HPO_4$, the activities were significantly higher than that of control, respectively. However, increasing nitrogen sources such as beef extract, casein, and tryptone and salts such as $NH_4PO_4$, $MgSO_47H_2O$, and $MnSO_4H_2O$, had detected a negative influence upon the bacteriocin production. Consequently, because the bacteriocin produced by L. plantarum K11 was affected by various incubation conditions, the bacteriocin activity of L. plantarum K11 applied in food as a novel starter will be dependent on environmental factors such as fermentation conditions and food ingredients.

• Proceedings of the KSMRM Conference
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• 1999.11a
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• pp.36-36
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• 1999

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.86-93
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• 1997

Purpose: To assess the ability of in vivo H-1 MRS to determine the degree of malignancy and to characterize the histopathologic type of intracranial solid tumors. Materials and Methods: In vivo H-1 MR spectra of the pathologically-proven 81 intracranial soild tumors (low-grade glioma 17 cases, high-grade glioma 31 cases, lymphoma 9 cases, meningioma 8 cases, central neurocytoma 4 cases, medulloblastoma 3 cases, PNET 3 cases, metastasis 2 cases, others 4 cases) were analyzed. H-1 MR spectroscopy was performed on a 1.5T MR unit using PRESS sequence with a TR of 2000ms, a TE of 270 or 135ms and a voxel size of $2{\times}2{\times}2cm^3$ for all spectra. N-acetyl aspartate (NAA)/Creatine complex(Cr), Choline complex (Cho)/Cr, and lactate (Lac)/Cr ratios were measured on the peak heights of each resonance and compared among the different tumors. Results: All intracranial solid tumors demonstrated decreased NAA, elevated Cho and lactate, and variable Cr levels. All tumors showed increased Cho/Cr and Lac/Cr, whereas NAA/Cr level was decreased. Mean Cho/Cr and Lac/Cr ratios were significantly higher in high-grade gliomas than in low-grade gliomas. However, NAA/Cr ratio showed no significant difference between low-grade and high-grade gliomas. Very high Cho peaks were seen in lymphomas, meningiomas, medulloblastomas, and neurocytomas in addition to high-grade gliomas. Conclusion: H-1 MRS may be useful in differentiating between low-grade and high-grade gliomas, however cannot characterize the histologic types or subtypes of tumors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05d
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• pp.33-37
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• 2003

Endovaginal and endorectal receiver only surface coil were designed for MR imaging(MRI) and $^1H$ MR spectroscopy(MRS) for the uterine cervix and the prostate. The shape of endovaginal coil wire was rectangular with round comer. The shape of endorectal coil wire was long elliptic shape during insertion and circular shape after insertion. Conventional spin echo and fast spin echo sequences were used as T1 and T2 weighted imaging sequences, respectively. 3D volume localized in vivo $^1H$ MR spectroscopy of the human cervix and prostate was performed using PRESS or STEAM localization method. Using home-built endvaginal and endorectal coils, excellent T1 and T2 images were obtained to visualize early cervical and prostate tumors. 3D volume localized in vivo $^1H$ MRS was useful to differentiate the cancerous tissue from the normal tissue.

• Food Science of Animal Resources
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• v.27 no.3
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• pp.363-370
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• 2007

In order to identify probiotic microorganisms, 25 isolates of Lactobacillus sp. were selected from kimchi based on their growth rates, lactic acid production and salt tolerance. The isolate JK-01 was identified as Lactobacillus plantarum by the API kit and 16S rDNA analysis (99.9% of homology), and named as L. plantarum JK-01. The maximum number of L. plantarum JK-01 was reached at 18 hr fermentation in MRS broth and the pH gradually decreased to 4.5. L. plantarum JK-01 showed high enzyme activities for xylanase, amylase, protease, and phytase on MRS agar plates containing each substrate. L. plantarum JK-01 showed high resistance to acidic pH and bile salts, and grew well even at pH 2.0 and 1.0% bile salt. In particular, L. plantarum JK-01 showed high heat stability as shown by $3.3{\times}10^3$ CFU/mL at $60^{\circ}C$. The isolate showed remarkable antimicrobial activity against E. coli in MRS broth based on its disappearance after 18 hr and clear zone formation using a paper disk assay. These results suggest that L. plantarum JK-01 may be probiotic in nature.

• Applied Biological Chemistry
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• v.49 no.1
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• pp.1-6
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• 2006

This study was carried out to evaluate the growth characteristics of Lactobacillus acidophilus KCCM 32820 and Propionibacterium freudenreichii KCCM 31227 in MRS (De Man-Rogosa-Sharpe), RCM (Reinforced Clostridial Medium) and whey broth. Bacterial growth, increase rate of TTA (Total Titratible Acidity) and decline rate of pH in broth were the greatest in 9-21 hr after culturing Lactobacillus acidophilus KCCM 32820 in MRS. Those were the greatest in 24-60 hr after culturing Propionibacterium freudenreichii KCCM 31227 in RCM. However changes of pH and TTA of broth were the greatest in 18-54 hr after culturing Propionibacterium freudenreichii in RCM after culturing Lactobacillus acidophilus in MRS for 36 hr. Viable cells of Lactobacillus acidophilus KCCM 32820 and Propionibacterium freudenreichii KCCM 31227 revealed larger numbers in 12% whey broth than in 6% whey broth. These also showed larger numbers in pasteurized whey broth than in sterilized whey broth. Lactobacillus acidophilus KCCM 32820 and Propionibacterium freudenreichii KCCM 31227 grew best in pasteurized 12% whey broth.

• Microbiology and Biotechnology Letters
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• v.36 no.2
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• pp.121-127
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• 2008

A strain IDCC 9203 isolated from infant feces was identified as Lactobacillus johnsonii on the basis of 16S rDNA sequence analysis. L. johnsonii IDCC 9203 was highly resistant to acid (MRS broth at pH 2.3) and bile (MRS broth with 0.3% oxgall). The antibacterial activities of L. johnsonii IDCC 9203 was examined against Salmonella typhimurium KCTC 2054. The growth of S. typhimurium KCTC 2054 was inhibited by the cell-free culture supernatant (at pH 4.0) of L. johnsonii IDCC 9203 as well as by the respective control (MRS broth at pH 4.0). Antimicrobial effect against S. typhimurium KCTC 2054 of L. johnsonii IDCC 9203 was probably due to the lactic acid. By an in vitro cell adhesion model, L. johnsonii IDCC 9203 preincubated or coincubated with Caco-2 cells reduced the adhesion of S. typhimurium KCTC 2054 to Caco-2 cells by 74% or 47.1%, respectively. Also in an in vivo model, L. johnsonii IDCC 9203 was colonized in mice intestines which were disrupted by ampicillin treatment. Its proliferation in the mice intestines reduced abnormal salmonella growth from $10^9CFU/g$ feces to $10^5CFU/g$ feces as an indigenous level. The results obtained in this study suggest that L. johnsonii IDCC 9203 may be a potential probiotic strain.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.161-164
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• 1996

An actively-shielded $r^{2}$-gradient coil has been developed for brain localized MRI or MRS. Spatial localization is very useful for spatial volume selection in MRI or MR Spectroscopy(MRS). The radial(or $R^{2}-$) gradient coil is useful in reducing the artifact or in improving the SNR by selecting the volume with less number of RF pulses. It is, however, difficult to implement the coil with a gradient intensity strong enough to use it for practical whole-body MRI system. For example, the smallest volume size for selection is just 6 cm in diameter with a 250 Ampere of current driving for a whole-body system (in case of 70-cm-diameter). In this study, an asymetric $r^{2}$-coil with a small diameter of 35 cm has been designed and implemented for brain localized MRI or MRS. An 8-rod high-pass-type birdcage RF coil has also been implemented. The coil set has been developed for 1.0 Tesla Medison MRI system and its performance has been verified experimentally.