• 동의생리병리학회지
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• 제20권3호
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• pp.670-674
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• 2006

This experimental study was carried out to investigate the immunostimulating effect of Acanthopanax, as Oriental rhizomata herbs, on jejunal survival, endogenous spleen colony formation, apoptosis in jejunal crypt cells and lipid peroxidation in the liver of mice following Gamma-ray irradiation. The subject of this study includes 72 mice which were divided into each 7 groups. Acanthopanax experiment groups were Acanthopanax. Gamma-ray(lOGy), Acanthopanax. Gamma-ray(3Gy), Acanthopnax. Gamma-ray(1Gy), Gamma-ray control(1OGy), Gamma-ray control(3Gy), Gamma-ray control(1Gy), Normal groups. The results of this study were as follows : Treatment with Acanthopanax showed significantly increased(p<0.05) on the cell death apoptosis in crypt, intestine crypts survival of intestine in mice following low-dose(1Gy) Gamma-ray radiation. And that significantly increased(p<0.05) on jejunal crypt survival and reduced(p<0.05) on lipid peroxidation in mice following high-dose(1OGy) Gamma-ray radiation. The above results suggest that Acathopanax were immunostimulating effectively reduced Gamma-ray irradiation.

• Macromolecular Research
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• 제12권1호
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• pp.112-118
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• 2004

With the goal of enhancing the creep resistance of ultra-high molecular weight polyethylene (UHMWPE), we performed gamma irradiation and post-irradiation annealing at a low temperature, and investigated the crystalline structures and mechanical properties of the samples. Electron spin resonance spectra reveal that most of the residual radicals are stabilized by annealing at 100$^{\circ}C$ for 72 h under vacuum. Both the melting temperature and crystallinity increase after increasing the dose and by post-irradiation annealing. When irradiated with the same dose, the quenched sample having a higher amorphous fraction exhibits a lower swell ratio than does the slow-cooled sample. The measured tensile properties correlate well to the crystalline structure of the irradiated and annealed samples. For enhancing creep resistance, high crystallinity appears to be more critical than a high degree of crosslinking.

• Imaging Science in Dentistry
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• 제30권1호
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• pp.33-48
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• 2000

Purpose : To investigate osseointergration of titanium implants into the tibia of rabbits, which were fed a low calcium diet and irradiated. Materials and Methods : To prepare the experimental model, control group was fed a normal diet and experimental group was fed a low calcium diet for 4 weeks. And then, titanium implants were inserted into the tibia of each rabbit. Experimental group was subdivided into two groups; low calcium diet/non-irradiation group and low calcium diet/irradiation group. The low calcium diet/irradiation group was irradiated with a single absorbed dose of 15 Gy at the 5th postoperative day. At 12, 19, 33, 47, and 61 days after implantation (1, 2, 4, 6, and 8 weeks after irradiation), the bone formation in the bone-implant interface area was examined by light microscopy and fluorescent microscopy. Results and Conclusions: 1. In the control group, there began to form woven bone in the bone-implant interface area at 12 days after implantation. As the experimental time was going on, the amount of bone which was in contact with the implant was increased. 2. In the low calcium diet/non-irradiation group, there began to form woven bone in the bone-implant interface area at 19 days after implantation. Although the amount of bone which was in contact with the implant was increased as the experimental time was going on, the extent of increased bone was weak as compared with control group. 3. In the low calcium diet/irradiation group, there began to form woven bone incompletely in the bone-implant interface area at 19 days after implantation, but there were vascular connective tissues in the bone-implant interface area over the entire experimental period. 4. In the control group and low calcium diet/non-irradiation group, bone labeling bands were observed at 33 days after implantation, which suggests that the bone formation and remodeling was in process, but interstitial bone remodeling was not observed in the low calcium diet/irradiation group.

• KSBB Journal
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• 제26권6호
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• pp.565-568
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• 2011

In this study, it was investigated the antioxidant activity of laminarin degraded by gamma irradiation. Because the activities of antioxidants have been attributed to various mechanisms, different assay methods have been conducted and compared. 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power, and lipid peroxidation inhibitory activity of degraded laminarin were measured and compared with non-degraded. All of these results showed that the antioxidant activity of laminarin degraded by irradiation was increased depending on the absorbed dose. Therefore, gamma irradiation could be an alternative method for the preparation of degraded laminarin with higher antioxidant activity.

• 한국축산식품학회지
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• 제31권3호
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• pp.366-371
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• 2011

Viscosity is critically important for bulgogi sauce. However, exposure to irradiation may decrease the rheological properties of bulgogi sauce. This study was conducted to compare the effects of gamma irradiation (0-9 kGy) on viscosity, molecular weight, pH, reducing end level, and water solubility of xanthan gum, guar gum, and locust bean gum as thickening agents/stabilizers in bulgogi sauce. The physicochemical properties of all samples changed (p<0.05) from 3965 to 0 cP (viscosity), from 6048 to 28 kDa (molecular weight), from 5.79 to 4.62 (pH), from 0.13 mg/mL to 1.72 mg/mL (reducing end level), and from 6% to 87% (water solubility) following gamma irradiation. Viscosity after irradiation was most stable (p<0.05) in xanthan gum (from 1249 to 92 cP) compared with guar gum (from 3965 to 0 cP) and locust bean gum (from 1631 to 0 cP). The sensory properties (texture and taste) of bulgogi sauce prepared with xanthan gum (1%, w/w) were highly maintained (about 7.0-5.0) after high-dose irradiation of up to 40 kGy. These results indicate that xanthan gum can be effectively used as a thickening agent/stabilizer in bulgogi sauce, which had low viscosity after irradiation.

• Journal of Radiation Protection and Research
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• 제37권2호
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• pp.56-62
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• 2012

To determine the biological effects of low-dose-rate radiation ($^{137}Cs$, 2.95 mGy/h) on EL4 lymphoma cells during 24 h, we investigated the expression of genes related to apoptosis, cell cycle arrest, DNA repair, iron transport, and ribonucleotide reductase. EL4 cells were continuously exposed to low-dose-rate radiation (total dose: 70.8 mGy) for 24 h. We analyzed cell proliferation and apoptosis by trypan blue exclusion and flow cytometry, gene expression by real-time PCR, and protein levels with the apoptosis ELISA kit. Apoptosis increased in the Low-dose-rate irradiated cells, but cell number did not differ between non- (Non-IR) and Low-dose-rate irradiated (LDR-IR) cells. In concordance with apoptotic rate, the transcriptional activity of ATM, p53, p21, and Parp was upregulated in the LDR-IR cells. Similarly, Phospho-p53 (Ser15), cleaved caspase 3 (Asp175), and cleaved Parp (Asp214) expression was upregulated in the LDR-IR cells. No difference was observed in the mRNA expression of DNA repair-related genes (Msh2, Msh3, Wrn, Lig4, Neil3, ERCC8, and ERCC6) between Non-IR and LDR-IR cells. Interestingly, the mRNA of Trfc was upregulated in the LDR-IR cells. Therefore, we suggest that short-term Low-dose-rate radiation activates apoptosis in EL4 lymphoma cells.

• 한국작물학회지
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• 제48권4호
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• pp.334-338
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• 2003

The objective of this study was to demonstrate whether or not the deleterious effects of accelerated aging on seed vigour and viability are alleviated by interaction with gamma irradiation. Seeds of soybean (Glycine max L.) were artificially aged and subsequently irradiated with 4 and 8 Gy of gamma irradiation. Germination rate was negatively affected by accelerated aging and positively by gamma irradiation, with a positive interaction of a 3day-seed aging treatment occurring with 4 Gy, possibly suggesting that 4 Gy of gamma irradiation partially offset the adverse effects of seed aging on germination. However, 5-day aged seeds did not gain any benefits from the gamma irradiation. Electrolyte leakage from the seeds increased with the duration in days aged. Irradiation, however, did not impose any effects on the leakage. Respiration rate of the seed with hypocotyl and primary root was significantly low for the aged seeds, but not for the seeds with both irradiation and aging treatments. Accelerated aging decreased the dry weight of the hypocotyl and primary root of the seeds without any measurable effects of irradiation. $\alpha$-Amylase activity decreased with seed aging and positively responded to gamma irradiation. The data is discussed with regard to the possible roles of gamma irradiation for improving the seed vigour and viability of aged seeds.

• 전자공학회논문지
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• 제50권12호
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• pp.247-253
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• 2013

본 연구의 목적은 Direct DR(Digital Radiography), Indirect DR, I.I(Image Intensifier) DR에서 X선 광자 검출 방식에 따른 선량측정 및 획득된 영상을 정량적이고 객관적인 측정을 통해 DR System을 비교 평가 하는 것이다. Rando phantom을 사용하여 입사표면선량을 측정하였으며, 측정된 입사표면선량 값을 통해 PCXMC 프로그램을 사용하여 유효선량과 방사선 조사로 인한 위험을 평가하였다. 21cm 아크릴 phantom을 사용하여 SNR(Signal to Noise Ratio), NPS(Noise Power Spectrum), CNR(Contrast to Noise Ratio)을 측정하였으며, 측정값은 통계학적 분석기법을 사용하여 유의성을 평가하였다. 입사표면선량, 주요장기선량, 유효선량 모두 direct DR이 가장 낮게 측정되었으며, direct DR 선량을 기준으로 I.I type DR은 약 1.3배, indirect DR은 약 2.4배 높은 선량 비율로 측정되었다. 방사선량에 따른 위험도 역시 동일한 비율로 측정되었다. SNR 측정 결과 direct DR측정값을 기준으로 I.I DR은 약 7.25배, indirect DR이 약 1.48배 낮은 비율로 측정되었다. CNR 측정 결과 direct DR 측정값을 기준으로 I.I DR은 약 1.16배 높고, indirect DR이 약 0.87배 낮은 비율로 측정되었다. 따라서 a-selenium 검출소자를 사용하여 X선 광자를 검출하는 방식인 direct DR은 적은 선량으로 우수한 화질의 영상을 구현함으로써 선량에 민감한 소아나 생식선이 포함된 검사 등에 유용할 것으로 사료된다. 또한 많은 진단 정보를 위한 영상 평가가 요구되는 경우에는 indirect DR이 유용할 것으로 판단된다.

• 대한두경부종양학회지
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• 제7권1호
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• pp.3-9
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• 1991

Brachytherapy is a method of radiotherapy in advantage to achieve better local control with minimum radiation toxicity in comparison with external irradiation because radiation dose is distributed according to the inverse square low of gamma-ray emitted from the implanted sources. The main characteristics of brachytherapy are delivering of higher dose to target volume shortening of total treatment period and sparing of normal tissue. Recent development of iridium ribbons for low dose rate implant provides improvement of technology of brachytherapy in terms of safety and efficiency. High dose rate method. on the other hand, is effective to avoid unnecessary expoure of medical personnel.

• Journal of Microbiology and Biotechnology
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• 제11권3호
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• pp.524-528
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• 2001

The measurement of radiation response using simple and informative techniques would be of great value in studying the genetic risk following occupational, therapeutic, or accidental exposure to radiation. When patients receive radiation therapy, many suffer from side effects. Since each patient receives a different dose due to different physical conditions, it is important to measure the exact dose of radiation received by each patient to lessen the side effects. Even though several biological dosimetric systems have already been developed, there is no ideal system that can satisfy all the criteria for an idean dosimetric system, especially for low-dose radiation as used in radiation therapy. In this study, an SOS Chromotest of E. coli PQ37 was evaluated as a novel dosimeter for low-dose gamma-rays. E. coli PQ37 was originally developed to screen chemical mutagens using the SOS Chromotest-a colorimtric assay, based on the induction of ${\beta}$-galactosidase ue to DNA damage. The survival fraction of E. coli PQ37 decreased dose-dependently with an increasing dose of cobalt-60 gamma-rays. Also, a good linear correlation was found between the biological damage revealed by the ${\beta}$-galactosidase expression and the doses of gamma-rays. The expression of ${\beta}$-galactosidase activity that responded to low-dose radiation under 1 Gy was $Y=0.404+(0.089{\pm}0.3)D+(-0.018{\pm}0.16)D^2$ (Y, absorbance at 420 nm; D, Dose of irradiation) as calculated using Graph Pad In Plot and Excel. When a rabbit was fed with capsules containing an agar block embdded with E. coli PQ37 showed a linear response to the radiation doses. Accordingly, the results confirm that E. coli PQ37 can be used as a sensitive biological dosimeter fro cobalt-60 gamma-rays. To the best of our knowledge, this is the first time that a bacterium has been used as a biological dosimeter, especially for low-dose radiation.