• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2006년도 제33회 추계학술대회 발표논문집
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• pp.137-137
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• 2006

• Applied Biological Chemistry
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• 제29권1호
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• pp.44-50
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• 1986

Fusarium moniliforme 액체배양으로부터 얻어진 조효소를 황산암모늄 분획침전, Sephadex G-25, Sephadex G-75, Sephadex G-150 및 DEAE-Sephadex A-50 컬럼크로마토그래피를 통하여 2개의 여지분해 효소와 2개의 ${\beta}-glucanase$를 분리하고 팥전분 제조에 이용하였다. 팥을 $50^{\circ}C$에서 2시간동안 섬유소 분해효소와 작용시킨 결과 효소처리구는 세포벽, 세포간극 그리고 전분입자간극이 일부 분해되었음을 알 수 있었다. 0.004 units/ml의 여지분해효소와 0.3 units/ml의 ${\beta}-glucanase$를 혼합 처리했을 때 팥전분 입자의 침강 속도가 최대가 되였고 0.004 units/ml의 여지분해효소와 0.2 units/ml의 ${\beta}-glucanase$를 혼합하여 처리했을 때 수율증가는 약 7%이었다. 증자후와 마쇄후의 폐수에서 혼탁물질은 효소처리구가 대조구보다 약 40% 정도 감소되었다.

• 대한방사선기술학회지:방사선기술과학
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• 제31권1호
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• pp.41-47
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• 2008

한국 성인 남성 표준인(Korean Reference Adult Male)의 기초 자료를 이용하여 수학적 모의 피폭체(Mathematical Phantom)를 제작하였다. 또한 이를 이용하여 방사성옥소($^{131}I$)의 각 장기별 S-value를 산출 하였다. 산출된 S-value는 기존 ICRP-23표준인에 근거하여 산출한 MIRD 5, 및 ORNL-TM 8381자료와 비교해 보았다. 그 결과 S-value는 한국 성인 남성 표준인에 기초한 모의 피폭체가 높은 값을 나타냈다. 이는 몸통이라는 특수한 공간에 위치하게 되는 선원장기(source organ) 및 표적장기(target organ)가 함유하고 있는 구성물질도 중요하지만 그에 못지않게 이들이 차지하고 있는 위치 및 방사성핵종의 특성 또한 중요하게 작용한다는 것을 알 수 있었다.

• Nuclear Engineering and Technology
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• 제54권12호
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• pp.4698-4707
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• 2022

As part of the ICRP Task Group 103 project, we developed ten thyroid models for the pediatric mesh-type reference computational phantoms (MRCPs). The thyroid is not only a radiosensitive target organ needed for effective dose calculation but an important source region particularly for radioactive iodines. The thyroid models for the pediatric MRCPs were constructed by converting those of the pediatric voxel-type reference computational phantoms (VRCPs) in ICRP Publication 143 to a high-quality mesh format, faithfully maintaining their original topology. At the same time, we improved several anatomical parameters of the thyroid models for the pediatric MRCPs, including the mass, overlying tissue thickness, location, and isthmus dimensions. Absorbed doses to the thyroid for the pediatric MRCPs for photon external exposures were calculated and compared with those of the pediatric VRCPs, finding that the differences between the MRCPs and VRCPs were not significant except for very low energies (<0.03 MeV). Specific absorbed fractions (target ⟵ thyroid) for photon internal exposures were also compared, where significant differences were frequently observed especially for the target organs/tissues close to the thyroid (e.g., a factor of ~1.2-~327 for the thymus as a target) due mainly to anatomical improvement of the MRCP thyroid models.

• 한국작물학회지
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• 제46권4호
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• pp.303-308
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• 2001

To investigate the partitioning of newly absorbed N derived from NO$_3$- and NH$_4$$^{+}$, 6 mM $K^{15}$ NO$_3$ or 3 mM ($^{15}$ NH$_4$)$_2$ was fed continuously in Italian ryegrass (Lolium multiflrum L.) for 7 days. Nitrogen metabolites (nitrate, amino acid, soluble- and insoluble protein) were analyzed at the end of $^{15}$ N feeding. Dry weight in shoot, stubble and root was not significantly different between NO$_3$$^{[-10]}$ and NH$_4$$^{+}$ feeding. Total nitrogen content in all three organs was significantly higher in NH$_4$$^{+}$ than NO$_3$$^{[-10]}$ feeding. Sum on N content in reduced N fractions (amino acids + proteins) in shoot, stubble and roots in NH$_4$$^{+}$ feeding increased by 13.3, 12.5 and 35.4 %, respectively, compared to NO$_3$$^{[-10]}$ feeding. The Relative Specific Activity (RSA, percentage of newly absorbed $^{15}$ N relative to total N in a sample) values of amino acids and insoluble proteins were significantly higher in NH$_4$$^{+}$ feeding. Total amount of newly absorbed $^{15}$ N in NO$_3$$^{[-10]}$ and NO$_3$$^{[-10]}$ feeding was 52.3 and 69.5 mg/plant on dry matter basis, respectively. In both NH$_4$$^{+}$ and NO$_3$$^{[-10]}$ grown plants, most of the N was allocated to the shoot, 67.5% in NH$_4$$^{+}$ feeding and 58.8% NO$_3$$^{[-10]}$ feeding, respectively. The $^{15}$ N amount incorporated in the reduced N compounds (amino acids and proteins) in NH$_4$$^{+}$ grown plants significantly increased by 74.8% compared to NO$_3$$^{[-10]}$ grown plants. The increase of the $^{15}$ N amount assimilated to amino acids in NH$_4$$^{+}$ grown plants was remarkably higher in roots as more than 7.25 times compared to NO$_3$$^{[-10]}$ feeding. These results indicated that Italian ryegrass was much efficiently utilized NH$_4$$^{+}$-N for the synthesis of reduced N compounds.reduced N compounds.