• 대한화장품학회지
• /
• 제39권1호
• /
• pp.39-46
• /
• 2013

칼슘, 마그네슘과 같은 양이온은 피부 장벽을 보호하는 기능이 있다고 알려져 있다. 본 연구의 목적은 칼슘, 마그네슘, 망간, 불소로 이루어진 미네랄워터의 피부 장벽 보호 기능을 확인하기 위한 것이다. 피부가 자외선에 노출되게 되면 밀착연접(tight junction, TJ)이 파괴되며, 밀착연접으로 이루어진 피부 장벽도 손상 받게된다. 미네랄워터가 자외선에 의해 손상된 피부의 장벽기능을 보호할 수 있는지 평가하기 위해 인공피부 모델을 이용한 실험을 진행하였다. 인공피부에 자외선을 조사하고 미네랄워터를 처리하면 피부 장벽 손상을 막아준다. TJ permeability assay를 통하여 자외선 처리 시 손상된 밀착연접 장벽이 미네랄워터 처리에 의해 유지되는 것을 확인하였다. 각질형성세포를 이용한 실험에서 미네랄워터가 밀착연접 구조를 유지시켜 주고, 자외선에 의해 감소된 occludin 단백질의 생성량이 회복되는 것을 확인하였다. 따라서 본 연구를 통해 미네랄워터는 자외선에 의한 피부 장벽 파괴를 막아주는 효과가 있음을 확인할 수 있었다.

• Food Science and Biotechnology
• /
• 제16권1호
• /
• pp.138-141
• /
• 2007

The aim of this study was to investigate the effect of irradiation treatment on the inactivation of pathogens in ready-to-use cooked carrot. The pathogens tested were Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, and Listeria inocua. Following the inoculation of these organisms into cooked carrot (about $10^6-10^8\;CFU/g$), the growth of each was inhibited due to irradiation for 24 hr of storage at $20^{\circ}C$. S. typhimurium and E. coli inoculated into cooked carrot were not detected following irradiation with 3 kGy. S. aureus and L. inocua inoculated into the cooked carrot decreased by 5 logs (CFU/g) following 2 kGy irradiation. The range of $D_{10}$ values was from 0.30-0.50. The Hunter color, $L^*-,\;a^*-$, and $b^*-values$, and the hardness of the cooked carrot were not effected by irradiation treatment. The sensory score of irradiated cooked carrot was not statistically different from that of non-irradiated samples (p>0.05). These results indicate that low dose irradiation can enhance the microbial safety and extend the shelf-life of ready-to-eat foods such as cooked carrot.

• 한국식생활문화학회지
• /
• 제19권2호
• /
• pp.129-138
• /
• 2004

The changes in DNA damage were investigated during storage after irradiation. Beef, pork and chicken were irradiated at 1.0, 3.0 and 5.0 kGy and stored for 6 months at $-20^{\circ}C$. The comet assay was applied to the sample muscles at the beginning of irradiation and at the end of storage. Muscles were isolated, sliced, and the suspended cells were embedded in an agarose layer. After lysis of the cells, they were electrophoresed for 2 min. and then stained. DNA fragmentation in tissues caused by irradiation was quantified as tail length and tail moment (tail length ${\times}$ % DNA in tail) by comet image analyzing system. Right after irradiation, the differences in tail length between unirradiated and irradiated muscles were significant(p<0.05) in beef, pork and chicken. With increasing the increasing doses, statistically significant longer extension of the DNA from the nucleus toward anode was observed. Similarly even 6 months after irradiation, all the irradiated muscles significantly showed longer tail length than the unirradiated controls. The results represented as tail moment showed similar tendency to those of tail length, but the latter parameter was more sensitive than the former. These results indicate that the comet assay could be one of the simple methods of detecting irradiated muscles. Moreover, this method suggest that using comet assay, we were able to detect DNA damage differences even after 6 months after irradiation.

• 한국재료학회지
• /
• 제16권6호
• /
• pp.367-372
• /
• 2006

Polytetrafluoroethylene (PTFE) surface was modified for improving hydrophilicity by ion irradiation in environmental gas of $N_2$ and $NH_3$, respectively. The water contact angle onto the PTFE surface increased from $104{\circ}$ to over $140{\circ}$ by Ar ion irradiation in $N_2$ gas. In the case of $NH_3$ as environmental gas, there were a slight increase of contact angle from ion dose of $1{\times}10^{15}\;to\;5{\times}10^{15}\;ions/cm^2$, and its dramatic decrease to the value of 35o at the conditions of ion dose higher than $1{\times}10^{16}\;ions/cm^2$. It was found from SEM results that the surface morphology of PTFE was changed into one with filament structure after Ar ion irradiation in $N_2$ gas environments. On the contrary, Ar ion irradiation in $NH_3$ gas condition induced the PTFE surface with network structure. Hydrogen ion irradiation resulted in a little change of PTFE surface morphology, comparing with the case of Ar ion irradiation. The water contact angle of hydrogen ion irradiated PTFE surface in reactive gas decreased with increment of ion dose. Hydrogen ion irradiation could improve hydrophilicity with little change of surface morphology. It might be considered from FT-IR results that the improvement in wettability of PTFE surface by ion irradiation in $N_2$ and $NH_3$ gases could be due to the hydrophilic groups of NHx bonds.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2006년도 춘계학술대회
• /
• pp.179-182
• /
• 2006

The effect of electron beam irradiation on dye sensitized solar cell (DSSC) has been studied to examine degradation of DSSC. The high-energy electron beam irradiation affects on the materials and performance of dye sensitized solar cells. We have checked the effects of electron beam irradiation of $TiO_2$ substrate with and without dye adsorption on the photovoltaic performances of resulting DSSCS and also studied the structural and electrical properties of polymers after irradiation. All solar cells materials were irradiated by electron beams with an energy source of 2MeV at different dose rates of 60 kGy, 120 kGy 240 kGy and 900 kGy and then their photoelectrical parameters were measured at 1 sun $(100 mW/cm^2)$. It was shown that the efficiency of DSSC was decreased as increasing the dose of e-beam irradiation due to lowering in $TiO_2$ crystallinity, decomposition of dye and oxidation of FTO glasses. On the other hand, the performance of solid-state DSSC with polyethylene oxide based electrolyte was improved after irradiation of e-beam due to enhancement of its conductivity and breakage of crosslinking.

• Journal of Korean Neurosurgical Society
• /
• 제37권5호
• /
• pp.370-374
• /
• 2005

Objective: We investigated the morphologic changes within 24 hours after a single ${\gamma}$-irradiation in the rat brain. Methods: Forty Sprague-Dawley rats were used. After a burr hole trephination on right parietal area, cerebral hemisphere was irradiated with 2Gy and 5Gy using iridium-192($^{192}Ir$), respectively. The effect was assessed at 4, 8, 12 and 24 hours after irradiation. The histological changes were scored following the detection of edema or disarray severity. TUNEL-positive cells exhibiting apoptotic morphology were counted in irradiated region. Results: Cortical edema and disarray were initially showed at 4 or 8 hour and almost all defined at 24 hour after irradiation. And the injury was wedge shape. TUNEL-positive cells were minimal at 8 hour after irradiation as the number of positive cells were $2.6{\pm}5.27$(n=5) after 2Gy, and $0.8{\pm}0.84$(n=5) after 5Gy. But, the number of apoptotic cells were increased markedly to $60{\pm}6.24$ at 12 hour after 2Gy and to $104{\pm}19.7$ at 24 hour after 5Gy. Conclusion: There were prominent morphologic changes immediately after ${\gamma}$-irradiation. And, apoptosis was increased according to the time period. These findings implicate that brain irradiation induces rapid apoptotic change, which may play an important role in the pathogenesis of radiation-induced pathologic conditions.

• 방사선산업학회지
• /
• 제5권1호
• /
• pp.55-62
• /
• 2011

We investigated the physiological responses by acute and chronic gamma-irradiation in rice. The rice, Oryza sativa L. cv Dongan, plants were irradiated with 100 and 400 Gy of gamma-rays for acute and chronic irradiation, and their morphological, chlorophyll content, MDA, proline and activities of antioxidant enzymes were examined. The plant height of chronic irradiation samples were decrease with increase of a does than the control, but the number of tiller and dry weight of shoot were increased 100 Gy. Carotenoid and chrolorphyll content were decreased of all irradiated plants than non-irradiated plants. But, MDA and proline content were increased in 400 Gy both acute and chronic gamma irradiation. And the activities of antioxidant enzymes were different as gamma-irradiation patterns.

• 방사선산업학회지
• /
• 제6권1호
• /
• pp.55-59
• /
• 2012

Polyacrylonitrile (PAN)-based carbon fibers have been widely used due to their unique chemical, electrical, and mechanical properties. Electron beam irradiation has been extensively employed as means of altering properties of polymeric materials. Electron beam irradiation can induce chemical reactions in materials without any catalyst. Electron beam irradiation may be useful in accelerating the thermal compression stabilization of PAN nanofibers. To investigate the irradiation effect on PAN fibers, PAN nanofibers were irradiated by electron beam at 1,000~5,000 kGy. Irradiated and non-irradiated PAN nanofibers were heated at 180 and $220^{\circ}C$ without applying pressure for 15 min. Then 1 metric ton has been applied for 5 min. SEM images have been found that the fiber kept its morphological behavior after the hot pressing up to electron beam irradiated 1,000 kGy. DSC thermograms showed that the peak temperatures of the exothermic reactions were found to decrease with increasing electron beam irradiation doses and temperature. FT-IR spectra have been found to decrease $C{\equiv}N$ stretch band with increasing the electron beam irradiation dose. These results indicate that the modification of PAN via reactions such as cyclization is significantly enhanced by electron beam irradiation and thermal compression technique.

• 한국식품저장유통학회지
• /
• 제16권4호
• /
• pp.590-593
• /
• 2009

감마선 조사가 미역의 저장성 개선에 미치는 영향을 평가하였다. 미생물 오염도 평가 결과 3 kGy 이하의 선량에서 미생물이 검출되지 않았다. 2주 저장한 후, 조사처리 하지 않은 미역의 미생물이 6 log CFU/g이 증가하였다. 그러나 5 kGy 조사 처리한 미역의 경우 미생물이 검출되지 않았다. 5 kGy의 감마선 조사를 적용하였을 때, 미역의 명도 값이 소폭 증가하였다. 미역의 경도 측정 결과 3 kGy 이하의 감마선 조사에 의해 영향을 미치지 않았으며, 저장기간에 따른 차이는 없는 것으로 나타났다. 이상의 결과를 종합하여 볼 때, 3 kGy 감마선 조사는 미역의 품질에 영향을 받지 않고, 저장성을 연장시킬 수 있는 효과적인 기술이라고 판단된다.

• Nuclear Engineering and Technology
• /
• 제55권8호
• /
• pp.3080-3087
• /
• 2023

Thermoelectric (TE) materials working in radioisotope thermoelectric generators are irradiated by neutrons throughout its service; thus, investigating the neutron irradiation stability of TE devices is necessary. Herein, the influence of neutron irradiation with fluences of 4.56 × 10¹⁰ and 1 × 10¹³ n/cm² by pulsed neutron reactor on the electrical and thermal transport properties of n-type Bi₂Te_2.7Se_0.3 and p-type Bi_0.5Sb_1.5Te₃ thermoelectric alloys prepared by cold-pressing and molding is investigated. After neutron irradiation, the properties of thermoelectric materials fluctuate, which is related to the material type and irradiation fluence. Different from p-type thermoelectric materials, neutron irradiation has a positive effect on n-type Bi₂Te_2.7Se_0.3 materials. This result might be due to the increase of carrier mobility and the optimization of electrical conductivity. Afterward, the effects of p-type and n-type TE devices with different treatments on the output performance of TE devices are further discussed. The positive and negative effects caused by irradiation can cancel each other to a certain extent. For TE devices paired with p-type Bi_0.5Sb_1.5Te₃ and n-type Bi₂Te_2.7Se_0.3 thermoelectric legs, the generated power and conversion efficiency are stable after neutron irradiation.