• 한국식품영양과학회지
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• 제21권3호
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• pp.241-246
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• 1992

L-Ascorbic acid (AsA) 생합성이 불가능한 guinea pig을 실험 동물로 하여 collagne 함량이 높은 조직인 폐 및 피부중의 AsA함량과 동일조직중 collagne 함량이 높은 조직인 폐 및 피부중의 AsA 함량과 동일조직중 collagen의 proline잔기의 수산화율을 조사하여 collagne 생합성에 대한 조직중 AsA의 영향에 대해서 알아보았다. Guinea pig(체중 약 250g)를 AsA 무투여군(A), 투여군(B), 300mg/day 투여군(C)으로 나눠 14일간 사육한 후, 마취하에서 개복하여 복부 대동맥으로부터 채혈함과 동시에 간장과 폐를 적출하였으며, 등부위의 피부를 채취하여 분석용 시료로 하였다. 이들 시료로부터 혈청중 alkaline phosphatase (ALP)활성과 각조직중의 AsA 함량, proline 함량 및 그 수산화율, (1-$^{14}$ C) proline 의 incorporation 양을 측정하였다. 그 결과, AsA 토여군인 B, C군의 경우 순조로운 체중증가와 함께 혈청중 ALP활성도 정상값을 나타냈으며 현저한 ALP활성 저하가 관찰되었다. 한편, AsA 함량이 높을수록 (1-14C) proline 의 incorporation 양이 많고 collagne 중의 hydroxyproline 함량도 증가하는 것으로 나타나, 조직중의 collagen합성량과 AsA함량과의 사이에는 높은 상관관계가 존재함이 확인되었다.

• 한국의학물리학회지:의학물리
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• 제25권1호
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• pp.8-14
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• 2014

의료분야에서 방사선 진료기술의 발전에 따라 방사성폐기물의 수량은 급속히 증가하고 있다. 방사성폐기물에는 주로 PET/CT에 사용하는 $^{18}F$을 비롯하여 핵의학검사에 사용하는 $^{99m}Tc$ 등과 같이 반감기가 매우 짧은 방사성동위원소가 함유되어 있다. 이를 처분하기 위하여 국제원자력기구(IAEA)는 개인선량($10{\mu}Sv/y$) 및 집단선량(1 man-Sv/y)과 핵종별 농도에 근거하여 각각 폐기물의 규제해제기준을 제시(IAEA Safety Series No 111-P-1.1, 1992 및 IAEA RS-G-1.7, 2004)하였다. 이 연구에서는 IAEA 기준에 따른 방사능농도를 측정하기 위하여, $^{18}F$, $^{99m}Tc$, $^{123}I$, $^{125}I$ 및 $^{201}TI$ 관련 방사성폐기물을 수집하고 측정용기를 준비하였다. 그리고 MCA를 이용한 감마방사능 측정, 감마계수기를 이용한 감마방사능 측정, 베타입자 방출 핵종의 방사능 측정방법 및 절차를 수립하고, 표준물질을 제작하여 교정하였다. 측정결과를 근거로 방사능 감쇠 유도식을 산출하였으며, 이를 이론식과 대비하여 고찰하였다. 이 연구 결과는 ISO 표준으로 추진할 예정이다.

• Asian-Australasian Journal of Animal Sciences
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• 제9권6호
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• pp.701-703
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• 1996

The influence of phenylalanine (Phe) in the medium on protein synthesis of chicken embryo fibroblasts (CEF) was examined. CEF was derived from 9-d-old embryos by trypsin-EDTA digestion. To examine the deficiency of Phe in the medium, CEF was cultured in Dulbecco's modified Eagle's medium (DMEM) with or without Phe. CEF was also cultured in Dulbecco's phosphate buffered saline (PBS ($Ca^{2+}$, $Mg^{2+}$)) with or without $400{\mu}m$ Phe in order to examine the effect of Phe supplementation. All media were supplemented with 10% (v/v) fetal calf serum. After incubation for 6, 30 and 54 h, protein synthesis was measured by the incorporation of L-[2, $6-^{3}H$] Phe into CEF for further 18 h. Protein synthesis of CEF cultured in DMEM was higher than that in PBS ($Ca^{2+}$, $Mg^{2+}$). High specific radioactivity of Phe due to the low concentration of Phe in the medium resulted in the apparent increase in protein synthesis of CEF. Protein synthesis cultured in PBS ($Ca^{2+}$, $Mg^{2+}$) with Phe did not increase during 72 h of cell culture.

• 대한방사성의약품학회지
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• 제3권1호
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• pp.3-14
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• 2017

Nucleophilic aromatic fluorination has been one of the most explored methods in fluorin-18 based radiochemistry. Unlike electrophilic $[^{18}F]$fluorination methods, no-carrier-added nucleophilic radiofluorination with cyclotron-produced $[^{18}F]$fluoride ion offers better specific radioactivity which is essential aspect to obtain good quality images from positron emission tomography. Contrary to amenable aliphatic radiofluorination, the development of reliable aromatic $[^{18}F]$fluorination methods has been pursued by many research groups; however, no viable method has yet been established. Recently, hypervalent iodine compound draws increasing attention as versatile radiolabeling precursor for various $[^{18}F]$fluoroarenes, since it bears the capacity to introduce fluorine-18 either on electron-deficient or electron-rich aryl ring with enhanced regiospecificity. Other classes of hypervalent iodine congeners often utilized in radiochemistry are iodylarenes, iodonium ylides, and spirocyclic iodonium ylides. Recently developed spirocyclic iodonium ylides have already been avidly employed to provide various $[^{18}F]$aryl fluorides with high labeling efficiency. This metal-free protocol would afford efficient routes, replacing the traditional approaches to $[^{18}F]$fluoroarenes, from prosthetic labeling synthons to complex PET radiotracers.

• Asian-Australasian Journal of Animal Sciences
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• 제18권6호
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• pp.795-801
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• 2005

Eighteen Suffolk wether lambs (BW = 24 kg) were chronically exposed to temperatures of cold (2$^{\circ}C$) or warm (22$^{\circ}C$). The experimental design consisted of a 2${\times}$3 factorial with a single crossover of environment treatment. The sheep were closely shorn and were housed in individual metabolic crates in controlled environment rooms. Sheep consumed pelleted diets ad libitum, which consisted of mainly barley grain and brome grass, and diets contained 7, 11 or 14% crude protein (CP). Animals were catheterized via one jugular vein with a PVC catheter and received a single injection of 60-65 Ci of $^{14}$C]urea. Plasma urea-N (PUN), urinary urea (UU), and carbon specific radioactivity were measured. Urea metabolism was not affected by environment. Percent urea recycling and urea space clearance were highest (p<0.05) on the low nitrogen diet. Urea pool was increased (p<0.10) for the 14% CP diet. Both UU and PUN concentration were positively related (p<0.01) with diet CP content. Therefore, dietary CP content significantly influenced urea metabolism, however, cold exposure did not alter those parameters.

• 대한핵의학회지
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• 제17권2호
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• pp.71-77
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• 1983

Amino acids such as L-tyrosine, L-histidine, and tryptophan, which bear an aromatic ring in the molecule, could successfully be labelled by radioactive iodine through arylthallium ditrifluoroacetate intermediate. Generally, the labelling reaction could proceed in a short labelling time(ca, 20 minutes) and resulted in a high labelling yields and purity of the labelled product. This procedure has, therefore, been proved to be effective as the labelling method of short labelling time and high specific activity. Labelling proteins such as oval albumin and human albumin could also be achieved in $34\sim48%$ net labelling yield by thallating them at the low temperature $(0\sim10^{\circ}C)$, whereas the labelled products were mainly composed of various denatured products by thallating them at the high temperature$(35\sim40^{\circ}C)$, though the radioactivity was highly retained in the labelled products. Uracil and hippuric acid could also be labelled in a short labelling time though their thallation required a prolonged heating procedure. It was proved that this procedure may be effective to label these compounds by short lived radioisotopes. The labelling yields were, however, lower than 30%.

• 한국항행학회논문지
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• 제12권6호
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• pp.611-618
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• 2008

방재통신시스템은 방재행정무선시스템을 주체로 정비되고 최근에는 위성통신을 확대하고, 유선통신과의 상호보완 멀티미디어화 등을 들 수 있다. 유비쿼터스 센서 네트워크를 기반으로 방재정보통신 분야로는 풍수해, 시설안전, 교통안전, 산업안전, 에너지안전, 소방안전, 정보통신 안전, 특수안전 분야에는 방사능 누출사고, 환경오염, 해양오염, 산림재해 등이 있다. 본 논문에서는 USN(Ubiquitous Sensor Network) 기술을 이용한 방재정보통신시스템을 통신 기반시설로서 방재와 관련한 정보를 일원적으로 관리 운용하는 시스템 및 용용에 대하여 연구한다.

• 설비공학논문집
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• 제29권5호
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• pp.220-230
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• 2017

In this study we apply and compare a variety of numerical methods for calculating residence time distribution in decay tanks, a major design component in the for reducing N-16 radioactivity. Our research group has used a streamlined method using user-defined particle numbers. However, this streamlined method has several problems, including low exiting particle ratios, particle diminishing, and unphysical time distribution, among others. We utilize three numerical methods to establish residence time and time distribution (streamlined, discrete phase method [DPM], and user defined scalar [UDS]) and subsequently compare the averaged results of each. The three tests demonstrate the flow features within the decay tanks, which are then numerically simulated to enable comparison. We conclude that although each simulation predicts similar time averages, the UDS methodology provides a smoother time distribution and tracer contour plots at specific times.

• 방사선산업학회지
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• 제11권3호
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• pp.173-179
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• 2017

The small-scale electroplating device was designed and fabricated for Ni-63 sealed source (foil type) with a high specific activity needed for production of betavoltaic battery. The condition of Ni electroplating was optimized by using fabricated electroplating device to establish a Ni-63 electroplating condition on the Ni foil. The results showed that the optimum surface morphology and thickness of Ni deposit was obtained for 1,758 seconds at a current density of $15mA{\cdot}cm^{-2}$ with 0.5% tween 20. Radioisotope Ni-63 electroplating was implemented under established condition. The radioactivity of Ni-63 sealed source was calculated to $28mCi{\cdot}cm^{-2}$, and the thickness of Ni-63 deposit was about $2.4{\mu}m$.

• Nuclear Engineering and Technology
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• 제54권8호
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• pp.3017-3026
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• 2022

The ¹³¹Cs radioisotope with a short half-life time and high average radiation energy can treat the cancer effectively in prostate brachytherapy. The typical ¹³¹Cs production processes have a separation step of the cesium from ¹³¹Ba to obtain a high specific radioactivity. Herein, we suggested a novel ¹³¹Cs separation method based on the Ba²⁺ adsorption of alginate beads. It is necessary to reduce the affinity of alginate beads to cesium ions for a high production yield. The carboxyl group of the alginate beads was replaced by a sulfonate group to reduce the cesium affinity while reinforcing their affinity to barium ions. The modified beads exhibited superior Ba²⁺ adsorption performances to native beads. In the fixed-bed column tests, the saturation time and adsorption capacity could be estimated with the Yoon-Nelson model in various injection flow rates and initial concentrations. In terms of the Cs elution, the modified alginate showed better performance (i.e., an elution over 88%) than the native alginate (i.e., an elution below 10%), indicating that the functional group modification was effective in reducing the affinity to cesium ions. Therefore, the separation of cesium from the barium using the modified alginate is expected to be an additional option to produce ¹³¹Cs.