• 한국동물학회지
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• 제11권3호
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• pp.85-91
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• 1968

1963年에서 1967年에 걸쳐 서울地區의 人工放射能과 自然放射能을 全放射能의 測定과 放射性核種의 分析을 통하여 硏究하였다. 核分裂生成物의 濃度가 적을때는 \ulcorner은 半減期를 갖는 라듐이나 토리음의 崩壞生成物이 浮游塵의 大部分을 차지하고 있었으며 核分裂生成物에 依한 放射能은 試料 採取후 며칠 지나야 正確히 評價할수 있었다. 7次에 걸친 中共의 核實驗의 結果 두차례의 强放射能이 爆發후 30時間을 前後하여 서울地區에 나타났으며 이들은 1956年에서 1962年 사이에 美國과 蘇聯에서 행한 實驗과 比較할 때 높은 比放射能을 보였으나 持續時間은 아주 짧아서 1週內에 急激히 減少하였다. 이로 보아서 서울地區의 放射能汚染은 中共의 核實驗인 境遇 核實驗의 規模와 實驗高度 및 爆發前後의 氣象條件, 特히 高層對流圈의 제트氣流에 依해서 많은 影響을 받음을 알았다.

• Journal of Radiation Protection and Research
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• 제41권2호
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• pp.155-159
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• 2016

Background: Nuclear reactors produce a great number of antielectron neutrinos mainly from beta-decay chains of fission products. Such neutrinos have energies mostly in MeV range. We are interested in neutrinos in a region of keV, since they may take part in special weak interactions. We calculate reactor antineutrino spectra especially in the low energy region. In this work we present neutrino spectrum from a typical pressurized water reactor (PWR) reactor core. Materials and Methods: To calculate neutrino spectra, we need information about all generated nuclides that emit neutrinos. They are mainly fission fragments, reaction products and trans-uranium nuclides that undergo negative beta decay. Information in relation to trans-uranium nuclide compositions and its evolution in time (burn-up process) were provided by a reactor code MVP-BURN. We used typical PWR parameter input for MVP-BURN code and assumed the reactor to be operated continuously for 1 year (12 months) in a steady thermal power (3.4 GWth). The PWR has three fuel compositions of 2.0, 3.5 and 4.1 wt% $^{235}U$ contents. For preliminary calculation we adopted a standard burn-up chain model provided by MVP-BURN. The chain model treated 21 heavy nuclides and 50 fission products. The MVB-BURN code utilized JENDL 3.3 as nuclear data library. Results and Discussion: We confirm that the antielectron neutrino flux in the low energy region increases with burn-up of nuclear fuel. The antielectron-neutrino spectrum in low energy region is influenced by beta emitter nuclides with low Q value in beta decay (e.g. $^{241}Pu$) which is influenced by burp-up level: Low energy antielectron-neutrino spectra or emission rates increase when beta emitters with low Q value in beta decay accumulate Conclusion: Our result shows the flux of low energy reactor neutrinos increases with burn-up of nuclear fuel.

• 암석학회지
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• 제2권2호
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• pp.104-121
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• 1993

Fission track (FT) thermochronological analyses on Mesozoic granites provide new information about cooling and uplift histories in Southeast Korea. Twenty-nine new FT sphene, zircon and apatite ages and seven track length measurements are presented for eleven granite samples. Measured mineral ages against assumed closure temperatures yield cooling rates for each sample. Relatively rapid (7-$15^{\circ}C$/Ma) and simple cooling patterns from the middle Cretaceouss (ca. 90-100 Ma) granites are caused mainly by a high thermal contrast between the intruding magma and country rocks at shallow crustal levels (ca. 1-2.5 km-depths). On the contrary, a slow overall cooling (1-$4^{\circ}C$/Ma) of the Triassic to Jurassic granites (ca. 250-200 Ma), emplaced at deep depths (>>9 km), may mainly depend upon very slow denudation of the overlying crust. The uplift history of the Triassic Yeongdeog Pluton in the Yeongyang Subbasin, west of the Yangsan Fault, is characterized by a relatively rapid uplift (~0.4 mm/a) before the total unroofing of the pluton in the earliest Cretaceous (~140 Ma) followed by a subsidence (~0.2mm/a) during the Hayang Group sedimentation. Stability of original FT zircon ages (156 Ma) and complete erasure of apatite ages suggest a range of 3 to 5.5 km for the basin subsidence. Since 120 Ma up to present, the Yeongyang Subbasin has been slowly uplifted (~0.04 mm/a). The FT age patterns of Jurassic granites both from the northeastern wing of the Ryeongnam Massif and from the northern edge of the Pohang-Kampo Block indicate that the two geologic units have been slowly uplifted with a same mean rate (~0.04 mm/a) since early Cretaceous. Estimates of Cenozoic total uplifts since 100 Ma are different: Ryeongnam Massif (~6 km)=Pohang-Kampo Block (~6 km)>Yeongyang Subbasin(~4 km).

• Journal of Radiation Protection and Research
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• 제14권2호
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• pp.30-36
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• 1989

고리 1호기의 사용후 핵연료에 함유된 핵종중 핵임계도에 미치는 영향이 큰 22개 핵종에 대한 핵단면적 자료를 XLACS-II에 의해서 ENDF/B-IV로 부터 취해서 FISSLIB(51군 핵단면적 자료)를 만들었다. 그리고 AMPX 조직에 의해서 DLC-43/CSRL 자료로 부터 생산된 51군 핵단면적 자료와 함께 사용할 수 있도록 하였다. 한편 BNL-325와 FISSLIB을 비교하여 후자의 유용성을 확인하였다. 그리고 FISSLIB에 수록된 핵분열 생성물 핵종에 대한 핵군단면적을 기본 입력자료로 하여 무한 배열된 고리 1호기 사용후 핵연료봉에 대한 핵임계도 계산을 수행하였다. 그 결과 냉각기간에 따라 핵분열 생성물 핵종을 고려할 때의 핵임계도는 그것을 무시할 때보다 9-14%의 감소효과를 나타냈다.

• 미생물학회지
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• 제44권2호
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• pp.105-109
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• 2008

발아효모 Saccharomyces cerevisiae의 핵공단백질인 Nic96 단백질과 유사성을 보이는 분열효모 Schizosaccharomyces pombe의 Nup97의 기능과 세포 내 위치를 조사하였다. nup97을 과 발현시켰을 때는 생장과 $poly(A)^{+}$ RNA의 분포에 별다른 이상을 보이지 않았다. 하지만, $kan^{r}$ 유전자를 이용하여 제작한 ${\Delta}nup97$ 결실돌연변이는 nup97의 발현이 억제되면, $poly(A)^{+}$ RNA가 핵 안에 축적되었고 비정상적인 DNA 분포를 보였으며 결국 생장하지 못했다. 한편, Nup97p의 N말단 또는 C말단에 GFP를 붙인 Nup97-GFP 융합단배질의 세포 내 위치를 확인하고자 하였다. 이러한 융합단백질들이 ${\Delta}nup97$ 결실돌연변이의 생장결함을 정상적으로 상보하는 것을 확인하고, nup97-GFP 유전자를 염색체의 nup97 유전자 위치에 삽입한 균주를 제작하였다. 자신의 프로모터에서 발현된 Nup97-GFP 융합단백질은 정상적인 기능을 보였으며, 핵막 주위에 점점 이 위치하였다. 이와 같은 결과들은 Nup97 단백질 역시 핵공단배질로 mRNA의 핵에서 세포질로의 이동에 중요하다는 것을 시사한다.

• 미생물학회지
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• 제52권3호
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• pp.383-387
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• 2016

분열효모 Schizosaccharomyces pombe의 cdc31 유전자는 진화적으로 잘 보존된 $Ca^{2+}$-결합 centrin/CDC31 계열에 속하며 방추극체(spindle pole body)의 한 성분인 단백질을 암호화하고 있다. 이 논문에서는 S. pombe의 Cdc31 단백질이 방추극체뿐만 아니라 TREX-2 복합체의 구성인자로서 mRNA의 핵에서 세포질로의 방출에 영향을 미치는지 알아보았다. cdc31 유전자의 발현을 억제하면 생장 결함을 보였고, $poly(A)^+$ RNA도 핵 안에 축적되는 현상을 보였다. 한편 cdc31 유전자를 과발현시키면, 생장과 mRNA 방출에 결함을 보이진 않았지만 세포의 길이가 길어지는 형태를 보였다. Yeast two-hybrid 분석에서 Cdc31 단백질은 TREX-2 복합체의 또 다른 구성인자인 Sac3 그리고 Pci2와 상호작용을 하였다. 이와 같은 결과들은 S. pombe의 Cdc31 단백질도 역시 TREX-2 복합체의 구성인자로 mRNA 방출에 관여하고 있음을 시사한다.

• Genomics & Informatics
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• 제17권3호
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• pp.28.1-28.9
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• 2019

Bar-code (tag) microarrays of yeast gene-deletion collections facilitate the systematic identification of genes required for growth in any condition of interest. Anti-sense strands of amplified bar-codes hybridize with ~10,000 (5,000 each for up-and down-tags) different kinds of sense-strand probes on an array. In this study, we optimized the hybridization processes of an array for fission yeast. Compared to the first version of the array (11 ㎛, 100K) consisting of three sectors with probe pairs (perfect match and mismatch), the second version (11 ㎛, 48K) could represent ~10,000 up-/ down-tags in quadruplicate along with 1,508 negative controls in quadruplicate and a single set of 1,000 unique negative controls at random dispersed positions without mismatch pairs. For PCR, the optimal annealing temperature (maximizing yield and minimizing extra bands) was 58℃ for both tags. Intriguingly, up-tags required 3× higher amounts of blocking oligonucleotides than down-tags. A 1:1 mix ratio between up- and down-tags was satisfactory. A lower temperature (25℃) was optimal for cultivation instead of a normal temperature (30℃) because of extra temperature-sensitive mutants in a subset of the deletion library. Activation of frozen pooled cells for >1 day showed better resolution of intensity than no activation. A tag intensity analysis showed that tag(s) of 4,316 of the 4,526 strains tested were represented at least once; 3,706 strains were represented by both tags, 4,072 strains by up-tags only, and 3,950 strains by down-tags only. The results indicate that this microarray will be a powerful analytical platform for elucidating currently unknown gene functions.

• Nuclear Engineering and Technology
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• 제46권2호
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• pp.147-158
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• 2014

In order to investigate how the microstructure of fuel/matrix-interaction (FMI) layers change during irradiation, different U-7Mo dispersion fuel plates have been irradiated to high fission density and then characterized using scanning electron microscopy (SEM). Specifially, samples from irradiated U-7Mo dispersion fuel elements with pure Al, Al-2Si and AA4043 (~4.5 wt.%Si) matrices were SEM characterized using polished samples and samples that were prepared with a focused ion beam (FIB). Features not observable for the polished samples could be captured in SEM images taken of the FIB samples. For the Al matrix sample, a relatively large FMI layer develops, with enrichment of Xe at the FMI layer/Al matrix interface and evidence of debonding. Overall, a significant penetration of Si from the FMI layer into the U-7Mo fuel was observed for samples with Si in the Al matrix, which resulted in a change of the size (larger) and shape (round) of the fission gas bubbles. Additionally, solid fission product phases were observed to nucleate and grow within these bubbles. These changes in the localized regions of the microstructure of the U-7Mo may contribute to changes observed in the macroscopic swelling of fuel plates with Al-Si matrices.

• The Korean Journal of Physiology and Pharmacology
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• 제21권6호
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• pp.567-577
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• 2017

Obesity is known to induce inhibition of glucose uptake, reduction of lipid metabolism, and progressive loss of skeletal muscle function, which are all associated with mitochondrial dysfunction in skeletal muscle. Mitochondria are dynamic organelles that regulate cellular metabolism and bioenergetics, including ATP production via oxidative phosphorylation. Due to these critical roles of mitochondria, mitochondrial dysfunction results in various diseases such as obesity and type 2 diabetes. Obesity is associated with impairment of mitochondrial function (e.g., decrease in $O_2$ respiration and increase in oxidative stress) in skeletal muscle. The balance between mitochondrial fusion and fission is critical to maintain mitochondrial homeostasis in skeletal muscle. Obesity impairs mitochondrial dynamics, leading to an unbalance between fusion and fission by favorably shifting fission or reducing fusion proteins. Mitophagy is the catabolic process of damaged or unnecessary mitochondria. Obesity reduces mitochondrial biogenesis in skeletal muscle and increases accumulation of dysfunctional cellular organelles, suggesting that mitophagy does not work properly in obesity. Mitochondrial dysfunction and oxidative stress are reported to trigger apoptosis, and mitochondrial apoptosis is induced by obesity in skeletal muscle. It is well known that exercise is the most effective intervention to protect against obesity. Although the cellular and molecular mechanisms by which exercise protects against obesity-induced mitochondrial dysfunction in skeletal muscle are not clearly elucidated, exercise training attenuates mitochondrial dysfunction, allows mitochondria to maintain the balance between mitochondrial dynamics and mitophagy, and reduces apoptotic signaling in obese skeletal muscle.

• Journal of Radiation Protection and Research
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• 제41권4호
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• pp.354-358
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• 2016

Background: To find out the leak characteristic of research reactor 'HANARO' building in a typhoon condition Materials and Methods: MELCOR code which normally is used to simulate severe accident behavior in a nuclear power plant was used to simulate the leak rate of air and fission products from reactor hall after the shutdown of the ventilation system of HANARO reactor building. For the simulation, HANARO building was designed by MELCOR code and typhoon condition passed through Daejeon in 2012 was applied. Results and Discussion: It was found that the leak rate is $0.1%{\cdot}day^{-1}$ of air, $0.004%{\cdot}day^{-1}$ of noble gas and $3.7{\times}10^{-5}%{\cdot}day^{-1}$ of aerosol during typhoon passing. The air leak rate of $0.1%{\cdot}day^{-1}$ can be converted into $1.36m^3{\cdot}hr^{-1}$, but the design leak rate in HANARO safety analysis report was considered as $600m^3{\cdot}hr^{-1}$ under the condition of $20m{\cdot}sec^{-1}$ wind speed outside of the building by typhoon. Conclusion: Most of fission products during the maximum hypothesis accident at HANARO reactor will be contained in the reactor hall, so the direct radiation by remained fission products in the reactor hall will be the most important factor in designing emergency preparedness for HANARO reactor.