• Korean Journal of Food Science and Technology
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• v.14 no.4
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• pp.355-363
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• 1982

In order to develop the commercial storage method of potatoes by irradiation combined with natural low temperature, storage room($450{\times}650{\times}250cm$; year round temperature change, $2-17^{\circ}C;\;70-85%\;R.H.$) on a batch scale followed by irradiation with optimum dose level. Irish cobbler and Shimabara were 100% sprouted after 3 months storage in control, whereas in 15 Krad irradiated group, sprouting was completely inhibited at Irish cobbler for 9 months storage, and at Shimabara for 12 months. The extent of loss due to rot attack after 9 months storage was 6% in control, 6-8% in 10-15 Krad irradiated group at Irish cobbler and weight loss was 16.5% in control, 5.1-5.6% in irradiated group, whereas rotting rate of Shimabara after 12 months storage was 100% in control, 15% in irradiated group and the weight loss of its was 12.6% in control, $7.3{\sim}7.4%$ in irradiated group. The moisture content in whole storage period of two varieties were $72{\sim}82%$ without remarkable changes. The total sugar and ascorbic acid contents were slightly decreased according to the dose increase and elapse of storage period, whereas reducing sugar content was increased. Irish cobbler was 90% marketable after 9 months storage and 85% in Shimabara after 12 months storage.

• The Journal of the Korean Society for Microbiology
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• v.21 no.3
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• pp.311-329
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• 1986

The experimental exposure of animals to sources of ultraviolet radiation (UVR) which emit their energy primarily in the UVB region (280-320nm) is known to result in a number of well-described changes in the recipient's immune competence. Two such changes include a depressed capacity to effectively respond immunologically to transplants of syngeneic UVR tumors and a markedly reduced responsiveness to known inducers of delayedtype (DTH) and contact hypersensitivity (CH) reactions. The results of experiments that were designed to elucidate the mechanisms responsible for UVR-induced immunomodulation have implicated: 1) an altered pattern of lymphocyte recirculation, 2) suppressor T cells(Ts), 3) deviations in systemic antigen presenting cell (APC) potential. 4) changes in the production of interleukin-1-like molecules, and 5) the functional inactivation of epidermal Langerhans cells in this process. The exposure of skin to UVR, therefore, causes a number of both local and systemic alterations to the normal host immune system. In spite of this seeming complexity and diversity of responses, our recent studies have established that each of the UVR-mediated changes is probably of equal importance to creating the UVR-induced immunocompromised state. Normal animals were exposed to low dose UVR radiation on their dorsal surfaces under conditions where a $3.0\;cm^2$ area of skin was physically protected from the light energy. Contact sensitization of these animals with DNFB, to either the irradiated or protected back skin, resulted in markedly reduced CH responses. This was observed in spite of a normal responsiveness following the skin sensitization to ventral surfaces of the UVR-exposed animals. Systemic treatment of the low dose UVR recipients with the drug indomethacin (1-3 micrograms/day) during the UVR exposures resulted in a complete reversal of the depressions observed following DNFB sensitization to "protected" dorsal skin while the altered responsiveness found in the group exposed to the skin reactive chemical through directly UVR-exposed sites was maintained. These studies implicate the importance of EC as effective APC in the skin and also suggest that some of the systemic influences caused by UVR exposure involve the production of prostaglandins. This concept was further supported by finding that indomethacin treatment was also capable of totally reversing the systemic depressions in CH responsiveness caused by high dose UVR exposure (30K joules/$m^2$) of mice. Attempts to analyze the cellular mechanisms responsible established that the spleens of all animals which demonstrated altered CH responses, regardless of whether sensitization was through a normal or an irradiated skin site, contained suppressor cells. Interestingly, we also found normal levels of T effector cells in the peripheral lymph nodes of the UVR-exposed mice that were contact sensitized through normal skin. No effector cells were found when skin sensitization took place through irradiated skin sites. In spite of such an apparent paradox, insight into the probable mechanisms responsible for these observations was provided by establishing that UVR exposure of skin results in a striking and dose-dependent blockade of the efferent lymphatic vessels in all peripheral lymph nodes. Therefore, the afferent phases of immune responses can apparently take place normally in UVR exposed animals when antigen is applied to normal skin. The final effector responses, however, appear to be inhibited in the UVR-exposed animals by an apparent block of effector cell mobility. This contrasts with findings in the normal animals. Following contact sensitization, normal animals were also found to simultaneously contain both antigen specific suppressor T cells and lymph node effector cells. However, these normal animals were fully capable of mobilizing their effector cells into the systemic circulation, thereby allowing a localization of these cells to peripheral sites of antigen challenge. Our results suggest that UVR is probably not a significant inducer of suppressor T-cell activity to topically applied antigens. Rather, UVR exposure appears to modify the normal relationship which exists between effector and regulatory immune responses in vivo. It does so by either causing a direct reduction in the skin's APC function, a situation which results in an absence of effector cell generation to antigens applied to UVR-exposed skin sites, inhibiting the capacity of effector cells to gain access to skin sites of antigen challenge or by sequestering the lymphocytes with effector cell potential into the draining peripheral lymph nodes. Each of these situations result in a similar effect on the UVR-exposed host, that being a reduced capacity to elicit a CH response. We hypothesize that altered DTH responses, altered alloresponses, and altered graft-versus-host responses, all of which have been observed in UVR exposed animals, may result from similar mechanisms.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.3
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• pp.427-432
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• 2017

This study describes the design and implementation of SHF band Downconverter Digital Satellite Communication. The SHF band Downconverter unit consists of PLDRO and Frequency converter. In Frequency converter, microstrip BPF and LPF designed through the pre EM simulation are implemented to minimize the unwanted spurious in Frequency converter. Through the pre-simulation analysis of space environment, the possibility of and minimized about the malfunction of equipment and we designed a reliable SHF band Downconverter through simulation for a TID according to the vibration generated during the launch and space radiation environment, and compared pre-simulation of main performance results to test results about main performances of SHF band Downconverter after production.

• The Journal of the Korean bone and joint tumor society
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• v.5 no.1
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• pp.76-81
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• 1999

Aneurysmal bone cysts are uncommon bony lesions of the spine. Approximately 3-20% of the aneurysmal bone cysts occur in the spine, predominantly in the lumbar region, but they may occur at the any level of the spine. These lesions commonly arise from the neural arch and occasionally invade the pedicle and the vertebral body. The clinical diagnosis of a spinal lesion can be very difficult in the early stages of the disease because specific symptoms and signs are usually absent or only amount to back pain. However, depending on the level of involvement and the extent of neurological compression, a wide variety of neurological symptoms and signs may appear, ranging from mild radicular symptoms to complete paraplegia or tetraplegia. Available treatment options include complete excision or curettage of the lesion with bone graft, but where excision cannot be achieved, low dose radiation or arterial embolization may be used. We report a case of aneurysmal bone cyst in the pedicle of the T10 spine with nonstructural scoliosis of $40^{\circ}$ Cobb's angle which was treated successfully with only curettage of the lesion.

• Journal of radiological science and technology
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• v.15 no.2
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• pp.31-36
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• 1992

Grids can improve the diagnostic quality of chest radiography by trapping the greater part of scattered radiation thus providing more detailed. chest radiographic images. It is most effective mathod of reduce the scatter ratio but must increase the expour factor. The benefit of use of grid is improve the contrast and the loss is increase of patient dose. In chest radiography especially hard quality high voltage radiography it will have to be considered to select the optimum grid with view point of benefit and loss. In this experiment, author got some result of characteristics about 4 different grids with film method. 1. There was no difference the scatter ratio in case of no grid and the scatter ratio was about 60%. 2. 16 : 1 grid was excellent of scatter reduction factor in high voltage chest radiography, next was 10 : 1, CROSS, MICRO FINE grid have low scatter reduction rate compare to 16:1, 10:1 grid. 3. The bucky factor of CROSS grid in accordance of kVp was find out the highest in 4 grids, on the contraly 10 : 1 grid was profitable to the exposure does. 4. With careful consideration in the point of scatter reducion rate and bucky factor, author suggest the 10 : 1 linear grid on the use of chest radiography in $80{\sim}120\;kVp$, 16 : 1 grid in $120{\sim}140\;kVp$.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1788_1789
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• 2009

본 논문에서는 핵폭발과 같은 고준위방사선환경에서의 전자부품소자의 피해평가분석을 통하여 군용전자장비의 내방사선화를 하기 위한 기반기술의 확립을 위한 연구의 일환으로 74AC04(Inverter) IC에 대한 고준위감마선조사시험을 통하여 Co-60 Gamma-ray 선원을 사용하여 총 400Krad[si] 누적 선량에 대한 74AC04 소자의 동작특성 및 전기적 파라메터의 변화분석을 진행하였다. 시험평가 방법 및 절차는 MIL-STD-883G 1019.7[1] 및 ESA/SCC Basic Specification No.22900[2] 절차를 기준으로 하여 동일 lot에 대한 5개의 샘플을 이용하여 동작특성에 영향을 미치는 주요한 전기 적파라메터인 정지소비전류, 입력누설전류, VIL(Maximum Low Level Input Voltage)에 대한 변화추이를 분석하였다. 이번 조사시험을 통하여 입력게이트에서의 누적선량에 따른 TID(Total Ionizing Dose) 효과로 인한 VIL의 감소 추이를 확인 할 수 있었으며 총 누적선량 160Krad 이상에서의 VIL은 허용기준치이하로 감소하였고 정지소비전류의 경우 누적선량에 따른 점진적 증가 현상과 200Krad부근에서의 설계스펙허용치를 초과하는 결과를 확인하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.274-277
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• 2013

CT(Computed Tomography)영상에서 선량과 화질은 중요한 요소이다. 선량은 환자에게 직접적으로 악영향을 끼치는 요소이며, 화질은 환자의 병변을 판단하는데 매우 중요하게 작용한다. 반복적 재구성 알고리즘을 이용하면 저선량 영상에서도 고화질의 영상을 얻을 수 있는지 FBP와 정량적, 정성적으로 비교하였다. 촬영 프로토콜은 관전압 80, 100, 120kVp에서 관전류를 동일하게 200mA로 촬영하여 획득하였으며, 정량적 평가를 위해 SD(Standard Deviation), SNR(Signal to Noise Ratio), MTF(Modulation Transfer Function)를 측정하여 분석하였다. 선량은 80kVp일 때 가장 낮았으며, 120kVp일 때 가장 높았다. 80kVp의 영상을 Toshiba 사(社)의 AIDR 3D(Adaptive Iterative Reduction integrated into $^{SURE}Exposure$)로 재구성하고, 120kVp의 영상에 FBP로 재구성한 다음 정량적 비교를 한 결과 AIDR 3D를 적용한 영상의 SD가 낮게 나왔으며, SNR이 높게 나타났고, MTF 곡선은 유사하게 나타났다. 그리고 FWHM(Full Width at Half Maximum) 값의 오차가 거의 없었다. 결론적으로 AIDR 3D는 저선량에서도 높은 화질을 나타냄을 확인하였다.

• YAKHAK HOEJI
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• v.46 no.1
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• pp.75-80
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• 2002

Quercetin is one of the bioflavonoid compounds and has multiple biological effects such as antioxidant and effective anti-inflammatory agent. Melanin has an important role in protecting human skin from the damaging effects of ultra-violet W) radiation. We studied the effect of quercetin on proliferation of B16/F10 melanoma cells. After 48h treatment of cells with quercetin, the cells exhibited a dose-dependent inhibition in their proliferation without apoptosis. Therefore, the decrease in cell numbers may be due to cell growth arrest, not due to cell death by cytotoxicity. We also investigated the effect of quercetin on melanogenesis of this cells. B16/F10 melanoma cells were grown for 48h in the presence of 0.01~50$\mu\textrm{g}$/ml quercetin and the total melanin contents were measured. Quercetin stimulated melanization of the cells in low concentrations (0.01~20$\mu\textrm{g}$/ml), whereas it inhibited melanization in high concentrations (30~50$\mu\textrm{g}$/ml). It was observed that quercetin differently regulates melanogenesis of B16/F10 melanoma cells dependent on its concentrations.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1282-1288
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• 2020

In the first study, the Radon emanation and radiological hazards associated with radionuclides in soil samples, collected from 9 various date palm farms located in 3 different districts in Saudi Arabia were determined through a high purity Germanium (HPGe) gamma-ray spectrometer. The estimated average values of Radon emanation coefficient and Radon mass exhalation rate for soil samples were 0.535 ± 0.016 and 50.063 ± 7.901 mBqkg^-1h^-1, respectively. The annual effective dose of radionuclides in all sampling locations was found to be lower than UNSCEAR's recommended level of 0.07 mSvy^-1 for soil in an outdoor environment. In the secondary study, gross α and gross β activities in soil and date palm pits samples were measured by a low background α/β counting system. Average values of gross α and gross β activities in soil and date palm pits samples were 5.761 ± 0.360 Bqkg^-1, 38.219 ± 8.619 Bqkg^-1 and 0.556 ± 0.142 Bqkg^-1, 24.266 ± 1.711 Bqkg^-1, respectively.

• Nuclear Engineering and Technology
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• v.52 no.8
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• pp.1749-1755
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• 2020

In present study, TEM foils of Ni-Mo-Cr alloy were directly irradiated with 30 keV Ar ions to allow direct characterization. The defects evolution and element segregation after irradiation were investigated by TEM and HAADF-EDS linear scanning. At low irradiation doses (1.38 and 2.76 dpa), black dots were formed and grew with increasing dose. Complicated defects including peas-shaped dislocation loops, polygon dislocation networks and large loops were visible in samples irradiated to high doses (13.8 and 27.6 dpa). Meanwhile, dislocation channels appeared, in which defects were swept out. Significant Mo depletions at dislocation lines and grain boundaries were induced by irradiation due to large misfits between Mo-Ni atoms and high content of Mo.