• Bulletin of the Korean Chemical Society
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• 제33권2호
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• pp.403-408
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• 2012

In this study, the homogenous Pd nanoparticles (Pd NPs) were first prepared with bayberry tannin (BT) as the stabilizers. Subsequently, the obtained bayberry tannin-stabilized Pd nanoparticles (BT-Pd) were immobilized onto ${\gamma}-Al_2O_3$ to prepare heterogeneous ${\gamma}-Al_2O_3$-BT-Pd catalysts. Fourier Transformation Infrared Spectrum (FTIR) and X-ray Photoelectron Spectroscopy (XPS) analyses confirmed that the Pd NPs were well stabilized by the phenolic hydroxyl groups of BT. Transmission Electron Microscopy (TEM) observation indicated that the diameter of the Pd NPs can be effectively controlled in the range of 4.2-16.0 nm by varying the amount of BT. It is found that the ${\gamma}-Al_2O_3$-BT-Pd catalysts exhibit highly activity for various olefin hydrogenations. For example, the initial TOF (turnover frequency) of the ${\gamma}-Al_2O_3$-BT-Pd in the allyl alcohol hydrogenation is as high as $12804 mol{\cdot}mol^{-1}{\cdot}h^{-1}$. Furthermore, the ${\gamma}-Al_2O_3$-BT-Pd can be reused 5 times without significant loss of activity, exhibiting a superior reusability as compared with conventionally prepared ${\gamma}-Al_2O_3$-Pd catalysts.

• Journal of Plant Biotechnology
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• 제46권2호
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• pp.88-96
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• 2019

Terpenes constitute a large class of secondary metabolites in plants. The Oryza sativa terpene synthase is a vital gene in plant defense response. In this study, the molecular and physiological functions of Oryza sativa terpene synthase 30 (OsTPS30, LOC_Os08g07080) were investigated after exposure of the seeds and plants to gamma-rays. The OsTPS30 expression was slightly induced at 200 Gray (Gy), but was significantly induced at 400 Gy. The total terpenoid was synthesized more in OsTPS30-overexpressing (OX-OsTPS30) Arabidopsisthaliana plants than in wild-type (WT) plants. The OX-OsTPS30 plants exhibited resistance to gamma-rays, as compared to WT. The OX-OsTPS30 plants had significantly increased height and weight after gamma irradiation. Additionally, the activity of antioxidant enzymes was increased more in OX OsTPS30 plants than in WT plants after gamma irradiation. Furthermore, the OsTPS30-GFP fusion protein was mostly localized in the chloroplast, suggesting that OsTPS30 is putative MEP pathway-related terpene synthase.

• Nuclear Engineering and Technology
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• 제34권6호
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• pp.545-552
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• 2002

We developed an ultra low background gamma ray spectrometer particularly suitable for experiment which require lower detection limit. The background of a germanium spectrometer is suppressed by applying active and passive shielding technique at the same time. The active shielding devices consist of plastic scintillating plates of 50 mm thick and anti-coincidence electronic system. The shielding is made of 150 mm thick walls of very low activity lead,20 mm with activity of <10 Bq/kg and 130 mm with activity of <50 Bq/kg. The observed background count rates are 1.2 $s^{-1}$ and 0.36 $s^{-1}$ without and with the active shielding, respectively, overall the energy regions from 30 keV to 3 MeV The cosmic ray induced background is suppressed by a rate of 0.8 $s^{-1}$ at the present work. The detection efficiency curve necessary to obtain the radioactivity of environmental samples has been precisely determined on the energy regions from 80 to 2000 keV with a 10$^3$ ml marinelli beaker sample, consisting of the calibrated radionuclides $^{109}$ Cd, $^{57}$ CO, $^{139}$ Ce, $^{203}$ Hg, $^{113}$ Sn, $^{85}$Sr, $^{137}$ Cs, $^{60}$ Co and $^{88}$ Y. Virtues Of the method are demonstrated by measuring the activity of $^{137}$ Cs contained in the powdered milk.

• Journal of Radiation Protection and Research
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• 제47권1호
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• pp.16-21
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• 2022

Background: Epidemiological observations such as mental retardation, physical deformities, etc., in children besides different types of cancer in the adult population of the Malwa region have been reported. The present study is designed to get insight into the role of naturally occurring radioactive material (NORM) in causing detrimental health effects observed in the general population of this region. Materials and Methods: Deep soil samples were collected from different locations in the Malwa region. Their activity concentrations were determined using low-level background gammaray spectrometry. High efficiency and high purity germanium detector capped in a lead-shielded chamber having a resolution of 1.8 keV at 1,173 keV and 2.0 keV at the 1,332 keV line of ⁶⁰Co was used in the present work. Data were evaluated with Genie-2000 software. Results and Discussion: Mean activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K in deep soil were found to be 101.3 Bq/kg, 65.8 Bq/kg, and 688.6 Bq/kg, respectively. The mean activity concentration of ²³⁸U was found to be three and half times higher than the global average prescribed by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). It was further observed that the activity concentration of ²³²Th and ⁴⁰K has a magnitude that is nearly one and half times higher than the global average prescribed by UNSCEAR. In addition, the radioisotope ¹³⁷Cs which is likely to have its origin in radiation fallout was also observed. It is postulated that the NORM present in high quantity in deep soil somehow get mobilized into the water aquifers used by the general population and thereby causing harmful health problems. Conclusion: It can be stated that the present work has been able to demonstrate the use of low background gamma-ray spectrometry to understand the role of NORM in causing health-related effects in a general population of the Malwa region of Punjab, India.

• 미생물학회지
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• 제2권1호
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• pp.1-11
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• 1964

Yung Nok Lee (Dept. of Biology, Korea University) : Studies on the phosphate metabolism in Chlorella, with special reference to polyphosphate. Kor. J. Microbiol., Vol.2, No.1, p1-11 (1964). 1. Uniformly $^{32}P$-labeled Chlorella cells which were irradiated with Cobalt-60 gamma-rays of about 70, 000 $\gamma$ dose, were further grown in a standard "cold" medium ("hot".rarw."cold"), and some portions of the algae were taken out at the begining of, and at intervals during the culture, and subjected to analyze the contents of $^{32}P$- and total P in various fractions of the cell materials. Results obtained were compared with those of nonirradiated normal cells. 2. Amounts of phosphate in various fractions of the nonirradiated normal Chlorella cells were measured using uniformly $^{32}P$--labeled cells. Analysis of the $^{32}P$--labeled algal cells showed that the highest value in P-content was the fraction of RNA followed by those of lipid, polyphosphate "C" polyphosphate "B", DNA, nucleotidic labile phosphate compounds, polyphosphate "A" and protein. It was observed that content of total polyphosphates in a single Chlorella cell was almost equal to RNA-P content in the cell, and the amount of RNA-P was almost equal to ten times of DNA-P content. 3. When the $^{32}P$--labeled algae which were irradiated with gamma-rays were grown in a normal "cold" medium, phosphate contents in the fraction of DNA, nucleotidic labile phosphate compounds and protein decreased markedly, while the contents of phosphate in the fractions of polyphosphate "C" and potyphosphate "B" increased in comparison with those of unirradiated normal cells. So, it was considered that the pretreatment of above mentioned dose of gamma-ray inhibited DNA and protein synthesis from polyphosphate in Chlorella cells. 4. Proceeding the culture of $^{32}P$--labeled Chlorella in a "cold" standard medium, whose synthetic activity of DNA and protein from polyphosphate was disturded by gamma-ray irradiation, the amounts of $^{32}P$-in the fraction of polyphosphate "C" increased, in contrast with those of polyphosphate "B" fraction. According to these experimental results, it was inferred that polyphosphate "B" could transform into polyphosphate "C" in normal growing Chlorella cells.sults, it was inferred that polyphosphate "B" could transform into polyphosphate "C" in normal growing Chlorella cells.ing Chlorella cells.

• 약학회지
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• 제43권2호
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• pp.278-284
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• 1999

This study deals with the biological changes in mice after ${\gamma}-irradiated$. Four weeks old BALA/c mice were irradiated with 6.5Gy of ${\gamma}-ray$ on the fifth day after oral administration of radioprotectants such as ascorbic acid, tocopherol and cysteine. Control group was irradiated with 6.5Gy without pre-administration of radioprotectors. Blood cells and sperm cells were counted and body, testis and spleen were weighed 3 days after irradiation. And also liver antioxidant activity and range of spleen immune cells were measured. Differences in most biological parameters were not clearly distinguished between experimental groups. However, the relative spleen weight, the relative testis weight and the population size of spleen immune cells such as T helper cells, B cells and macrophages measured by means of FACS showed significant difference between irradiated and radioprotectant administered group. It is concluded that the relative spleen weight, the relative testis weight and the population size of spleen immune cells are easy and useful parameters for assessing the effect of radioprotective substances and for quantifying biological damage of radiation, as well.

• 공업화학
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• 제10권4호
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• pp.557-562
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• 1999

압축천연가스 자동차에서 배출되는 메탄의 산화를 위한 Pd 촉매의 특성을 조사하였다. 알루미나에 담지된 Pd 촉매와 La과 Ce의 조촉매가 첨가된 촉매들을 함침법으로 제조하였다. 메탄산화 반응은 U-튜브 흐름 반응기에서 공간속도(GHSV)가 $72000h^{-1}$이고 반응온도가 $200{\sim}800^{\circ}C$ 범위에서 실험을 수행하였다. 촉매는 XRD, XPS, BET 표면적 및 수소화학흡착 실험에 의하여 특성화되었다. $Pd/{\gamma}-Al_2O_3$ 촉매 제조시 전구체로 $Pd(NO_3)_2$를 사용하고 $600^{\circ}C$로 소성하였을 때 $CH_4$ 산화의 활성이 가장 높았다. 소성된 $Pd/{\gamma}-Al_2O_3$ 촉매에서 palladium은 대부분 PdO로 존재하였으며, 이것의 메탄 산화 반응 활성이 환원된 촉매에 대부분 존재하는 Pd 금속 보다 높았다. 넓은 범위의 redox ratio에서 실험을 반복하면 $Pd/{\gamma}-Al_2O_3$ 촉매의 활성이 감소하고 높은 활성을 보이는 window 영역이 좁아지는 특성을 보였다. 조촉매로 Ce가 첨가된 촉매는 오히려 메탄 산화 활성이 감소하였으며, 조촉매로 La 이 첨가된 $Pd/La/{\gamma}-Al_2O_3$ 촉매는 담체와 Palladium의 열적 안정성이 향상되어 $1000^{\circ}C$에서 aging된 후에도 우수한 활성을 보였다. 또한 $Pd/La/{\gamma}-Al_2O_3$ 촉매의 NO에 의한 $CH_4$ 제거 반응 특성에서 산소가 존재하지 않는 경우 redox ratio가 1.2 근처에서 메탄이 모두 제거되었으나 산소가 존재하면 메탄 제거율이 크게 감소하였다.

• 핵의학기술
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• 제22권1호
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• pp.46-50
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• 2018

검출기 외부에 강한 선원은 collimator와 상호 작용으로 산란선이 만들어지게 되는데, 그 산란선이 영상에 얼마나 영향을 주는지 평가하고자 한다. SKY LITE를 사용하여, phantom study의 경우, $^{99m}Tc$ 1.11 GBq를 점선원으로 만들어 검출기 주변을 $10^{\circ}$ 간격으로 돌아가면서 측정하여 각 각도에서의 산란선의 정도를 계수율과 스펙트럼으로 분석을 하였다. Patient study의 경우, 3-phase bone scan을 하는 환자를 대상으로, blood flow와 blood pool 영상을 획득하면서 산란선의 양과 스펙트럼을 분석하였다. 추가로 blood pool 검사 시, 환자의 손위에 납가운을 올려놓고 영상을 획득하였고, 환자의 몸에 납가운을 입히고 영상을 획득하여 각 영상에서의 산란선과 스펙트럼을 비교, 평가하였다. 그 결과, phantom study의 경우, 후방에서는 산란선의 없었지만, 측면부터 전방 $50^{\circ}$ 까지는 산란선이 많이 검출 되었다. patient study의 경우 blood flow 영상과 blood pool 영상에서 환자 몸에서 나온 감마선으로 인해 생긴 산란선이 입사됨을 알 수 있었다. 그리고 납가운은 손 위를 차폐하는것 보다, 환자 몸을 차폐 하는 것이 산란선이 많이 줄었다. 그러므로 외부에 강한 선원이 존재하고, hand blood flow, blood pool 검사처럼 계수 자체가 낮을 검사를 할 경우, 몸에서 나오는 선원 자체를 차폐하는 것이 산란선을 줄이는데 보다 효과가 있으며, 영상에서도 배후 방사선을 줄이는데 효과가 있음을 알 수 있었다.

• 대한화학회지
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• 제36권1호
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• pp.147-156
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• 1992

${\alpha}-{\beta}-,{\gamma}$-알루미나 및 MgO를 담체로 사용하여 담지된 납산화물 촉매를 제조하였다. 담지된 납산화물 촉매상에서 메탄의 $C^{2+}$ 탄화수소로의 전환반응은 MgO 담지촉매에서 $C^{2+}$ 선택도가 최대로 얻어졌으며, ${\gamma}$-알루미나 담지 PbO 촉매에서는 $CO_2$ 선택도가 높았다. 그리고 ${\alpha}$-알루미나 담지촉매에서는 중간정도의 활성이 얻어졌으며, ${\beta}$-알루미나 담지촉매에서는 활성이 거의 나타나지 않았다. 이러한 반응특성은 촉매의 격자산소의 활성에 크게 의존하였으며, 또한 격자 산소의 활성은 담체와 산화물간의 상호작용과 담체의 성질에 영향받았다. 특히 MgO 담지 촉매에서는 X-선 회절분석에서 여타의 담체에서보다 PbO 산화물의 (002)면의 피크 세기가 (111)면의 세기에 비해 훨씬 크게 나타난 것으로 볼 때 메탄의 Oxidative Coupling 반응에서의 표면산화물-담체 상호작용(SOSI)의 한 예로 여겨졌다.

• Natural Product Sciences
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• 제12권1호
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• pp.1-7
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• 2006

We have screened the cytoprotective effect on ${\gamma}-ray$ radiation induced oxidative stress from forty one Korean plant extracts. Carpinus laxiflora (caulis), Quercus salicina (caulis), and Castanopsis cuspidata (caulis) were found to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and intracellular reactive oxygen species (ROS). As a result, extracts of three plants reduced cell death of Chinese hamster lung fibroblast (V79-4) cells induced by $H_2O_2$ treatment. In addition, these extracts protected cell death of V79-4 cells damaged by ${\gamma}-ray$ radiation. In addition, these extracts scavenged ROS generated by radiation. Taken together, the results suggest that Carpinus laxiflora, Quercus salicina, and Castanopsis cuspidata protect V79-4 cells against oxidative damage by radiation through scavenging ROS.