• Imaging Science in Dentistry
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• 제37권1호
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• pp.35-43
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• 2007

Purpose : To observe direct effect of irradiation on cariogenic Streptooccus mutans. Materials and Methods : S. mutans GS5 was exposed to irradiation with a single absorbed dose of 10, 20, 30, and 40Gy. Viability and changes in antibiotic sensitivity, morphology, transcription of virulence factors, and protein profile of bacterium after irradiation were examined by pour plate, disc diffusion method, transmission electron microscopy, RT-PCR, and SDS-PAGE, respectively. Results : After irradiation with 10 and 20Gy, viability of S. mutans was reduced. Further increase in irradiation dose, however, did not affect the viability of the remaining cells of S. mutans. Irradiated 5. mutans was found to have become sensitive to antibiotics. In particular, the bacterium irradiated with 40Gy increased its susceptibility to cefotaxime, penicillin, and tetracycline. Under the transmission electron microscope, number of morphologically abnormal cells was increased as the irradiation dose was increased. S. mutans irradiated with 10 Gy revealed a change in the cell wall and cell membrane. As irradiation dose was increased, a higher number of cells showed thickened cell wall and cell membrane and Iysis, and appearance of ghost cells was noticeable. In RT-PCR, no difference was detected in expression of gtfB and spap between cells with and without irradiation of 40Gy. In SDS-PAGE, proteins with higher molecular masses were gradually diminished as irradiation dose was increased. Conclusion : These results suggest that irradiation affects the cell Integrity of S. mutans, as observed by SDS-PAGE, and as manifested by the change in cell morphology, antibiotic sensitivity, and eventually viability of the bacterium.

• 한국컴퓨터정보학회논문지
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• 제26권2호
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• pp.119-124
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• 2021

본 연구에서는 자외선 조사 방향에 따른 화장품 살균 효율성을 확인하고자 하였다. 실험에는 그람양성균인 S.aureus에 대하여 자외선 살균의 실효 조사 각을 측정하였고 자외선 조사 방향에 따른 거리별 살균 영역의 변화를 연구하였다. 그리고 자외선 수평 조사 시 살균 효율을 높일 수 있는 방법으로서 누출 자외선을 반사시키는 방법을 제시해보았다. 그 결과 자외선 조사 각은 제품 설명에 비해 더 작게 측정되었고 자외선 조사 방향에 따른 살균 영역의 경우 수직 조사 시 시료와의 거리가 멀어질수록, 수평 조사 시 시료와의 거리가 가까울수록 살균 영역이 증가하였다. 또한 자외선 수평 조사 시 누출 자외선을 반사시키는 것으로 살균 효율을 높일 수 있는 것을 확인 하였다.

• 한국축산식품학회지
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• 제44권4호
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• pp.779-789
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• 2024

The effects of irradiation on meat constituents including water, proteins, and lipids are multifaceted. Irradiation leads to the decomposition of water molecules, resulting in the formation of free radicals that can have both positive and negative effects on meat quality and storage. Although irradiation reduces the number of microorganisms and extends the shelf life of meat by damaging microbial DNA and cell membranes, it can also accelerate the oxidation of lipids and proteins, particularly sulfur-containing amino acids and unsaturated fatty acids. With regard to proteins, irradiation affects both myofibrillar and sarcoplasmic proteins. Myofibrillar proteins, such as actin and myosin, can undergo depolymerization and fragmentation, thereby altering protein solubility and structure. Sarcoplasmic proteins, including myoglobin, undergo structural changes that can alter meat color. Collagen, which is crucial for meat toughness, can undergo an increase in solubility owing to irradiation-induced degradation. The lipid content and composition are also influenced by irradiation, with unsaturated fatty acids being particularly vulnerable to oxidation. This process can lead to changes in the lipid quality and the production of off-odors. However, the effects of irradiation on lipid oxidation may vary depending on factors such as irradiation dose and packaging method. In summary, while irradiation can have beneficial effects, such as microbial reduction and shelf-life extension, it can also lead to changes in meat properties that need to be carefully managed to maintain quality and consumer acceptability.

• 한국의학물리학회지:의학물리
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• 제6권2호
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• pp.21-28
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• 1995

전신방사선조사를 시행할 때 우선적으로 해결되어야 할 과제는 총선량의 결정과 머리, 목, 폐, 복부, 골반과 다리등 모든 부위에 동일한 선량을 조사하는 것이다. 본 연구에서는 머리, 목, 폐등 밀도와 두께에 따른 선량보정을 A1으로 만든 조직보상체를 이용하는 미네소타대학 방법(방법 1) 과 소아들이 장시간 동안 편안한 자세로 움직이지 않고 치료받을수 있도록 본원에서 개발한 고정치료틀에 조직등가물질로 머리, 목, 폐등을 보정한 방법(방법 2)의 선량분포를 비교검토하였다. 방법 1에서는 95.6％에서 100％의 선량분포를 보였으며, 방법 2 에서는 95.4％에서 100％의 선량분포를 보였다. 또한 방법 2 에서 중심 부위와 표면 부위의 선량분포는 머리 부위에서 103.4％, 목 부위에서 101.5％, 배꼽 부위에서 102.3％를 나타내었다.

• The Korean Journal of Physiology
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• 제4권2호
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• pp.61-67
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• 1970

In view of the importance of sulfhydryl groups in producing a chemical protection against ionizing radiation, an attempt was made to evaluate the changes of intrinsic non-protein sulfhydryl (NP-SH) and non-Protein disulfide(NP-SS) of the lung and liver tissues of rabbits following the whole body X-irradiation with 900 r either in single or fractionated $(300\;r{\times}3)$ dose. NP-SH was measured by Ellman's method, and NP-SS was measured by the electrolytic reduction method described by Dohan. Experiment was performed at 1,3,5,24 and 48 hours post·irradiation, and the results were compared with the control. The results thus obtained are summarized as follows; 1) Intrinsic levels of NP-SH and NP-SS of normal rabbits were $0.77{\pm}0.10$ and $0.61{\pm}0.07\;{\mu}mol/gm$ wet weight in liver, and $0.28{\pm}0.03$ and $0.54{\pm}0.03$ in lung tissues respectively. 2) NP-SH of liver after single X-irradiation showed no significant change in general, but at 48 hours post·irradiation, it was elevated comparing with the normal value. 3) Levels of NP-SS in liver was decreased than the normal value in the irradiated groups, and the lowest level was observed at 3 hours after single X-irradiation and at 5 hours after fractionated irradiation. 4) In lung tissues, levels of NP-SS showed no significant change from the control at earlier experimental hours, but a great decrease was observed at later Part of the experiment.

• Imaging Science in Dentistry
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• 제38권1호
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• pp.39-47
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• 2008

Purpose: The aim of this study was to observe a direct effect of irradiation on the periodontopathic Porphyromonas gingivalis (P. gingivalis). Materials and Methods: P. gingivalis 2561 was exposed to irradiation with a single absorbed dose of 10, 20, 30, and 40Gy. Changes in viability and antibiotic sensitivity, morphology, transcription, and protein profile of the bacterium after irradiation were examined by pour plating method, disc diffusion method, transmission electron microscopy, RT-PCR, and immunoblot, respectively. Results: Viability of irradiated P. gingivalis drastically reduced as irradiation dose was increased. Irradiated P. gingivalis was found to have become more sensitive to antibiotics as radiation dose was increased. With observation under the transmission electron microscope, the number of morphologically abnormal cells was increased with increasing of irradiation dose. In RT-PCR, decrease in the expression of fimA and sod was observed in irradiated P. gingivalis. In immunoblot, change of profile in irradiated P. gingivalis was found in a number of proteins including 43-kDa fimbrillin. Conclusion: These results suggest that irradiation may affect the cell integrity of P. gingivalis, which is manifested by the change in cell morphology and antibiotic sensitivity, affecting viability of the bacterium.

• 폴리머
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• 제29권1호
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• pp.91-95
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• 2005

화학적 가교와 방사선 가교에 의해 내열특성을 가진 PVA 수화젤을 제조하였다. 제조된 수화젤의 젤화율, 팽윤도와 젤강도 같은 기계적 특성을 측정하였다. 젤화율은 화학적 가교 반응시간과 방사선 조사선량이 증가할수록 증가하였고, 화학적 가교 후에 방사선 가교를 했을 경우에 화학적 가교만 했을 때보다 높은 값을 보였다. 젤강도는 화학적 가교 반응시간이 증가할수록 증가하였고, 방사선 조사선량이 감소할수록 증가하였다. 5시간 화학적 가교만 한수화젤과 화학적 가교 후에 방사선 가교를 한 수화젤이 고온에서의 내열특성이 우수하였다.

• 생약학회지
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• 제36권3호통권142호
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• pp.220-223
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• 2005

The purposes of this study was to develop the best one among the methods using dry heat, gamma irradiation and alcohol gas, to sterilize Scutellariae Radix selected based on high frequency of circulation between merchants and high susceptibility to microbial contamination, through comparing these methods in terms of the followings; ⅰ) the efficacy of sterilization in comparison with cost, and ⅱ)the alteration of chemical components of these herbal medicines. The results of this study will be taken advantage of establishment of the maximum limit of microorganism contaminated in herbal medicines. From the results of this study we conclude the followings: ⅰ) The sterilizing method using dry heat may be inappropriate, because it seriously changed their color and morphology which is an essential criterion to estimate a measure of quality between merchants and consumers, although it effectively got rid of contaminated microorganism and did not alter major components, baicalin; ⅱ) The sterilizing method using gamma irradiation may be appropriate, because it showed a strong sterilizing effect, and no alteration of chemical components, color and morphology; ⅲ)The sterilizing method using alcohol gas may also be appropriate, because it had a similar effects as in the case of gamma irradiation. Collectively, we suggest that appropriate sterilizing methods to guarantee the microbial quality of this herbal medicine may be those using gamma irradiation and alcohol gas.

• Asian-Australasian Journal of Animal Sciences
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• 제23권8호
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• pp.1112-1117
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• 2010

This study was conducted to evaluate and compare the quality changes of commercial sliced and pizza cheeses processed by gamma and electron beam irradiation. The $L^*$-value of sliced and pizza cheeses decreased and the $a^*$-value decreased only in pizza cheese by both irradiation sources. There was no change in pH. There was no difference in 2-thiobarbituric acid reactive substances (TBARS) value between non-irradiated and irradiated samples at a dose of 3 kGy or less (p<0.05). However, both irradiation sources resulted in increased TBARS value in sliced and pizza cheeses at 5 kGy. Sensory evaluation revealed that irradiation influenced odor, taste and overall acceptability of both cheeses and may cause the limitation of consumers' acceptance for irradiated cheese products. Results indicate that both gamma and electron beam irradiations with less than 3 kGy may not influence significantly the physicochemical quality of sliced and pizza cheeses. However, to meet a market requirement, a method to overcome the sensory deterioration of cheeses should be developed and applied.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.397-398
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• 2008

This paper performed the basic study for fabricating the low level laser therapy apparatus, and one of the goals of this paper was to make this apparatus used handily. The apparatus has been fabricated using the 655nm laser diode and microprocessor unit. The apparatus used a 655 nm laser diode for laser medical therapy and was designed for a pulse width modulation type to increase stimulation effects. And then, each experiment was performed to irradiation group and non-irradiation group for cells. MTT assay method was chosen to verify the cell increase of two groups and the effect of irradiation on cell proliferation was examined by measuring 590nm transmittance of ELISA reader. As a result, the cell increase of cells was verified in irradiation group as compared to non-irradiation group.