• Archives of Pharmacal Research
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• 제29권12호
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• pp.1125-1131
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• 2006

This study was undertaken to elucidate the effect of diallyl disulfide (DADS), an oil-soluble organosulfur compound found in garlic, in suppressing human nasopharyngeal carcinoma cells. A potent increase (of at least 9-fold) in apoptotic cells has accompanied 1) a decrease in cell viability, 2) a increase of the fraction of S-phase cells by up to 63.8%, and 3) a transient increase of the phospho-p38 and phospho-p42/44 (phosphorylated p38 MAPK and phosphorylated p42/44 MAPK) in a time-and concentration-dependent manner. These results indicate that DADS can induce apoptosis in human nasopharyngeal carcinoma cells via, at least partly, S-phase block of the cell cycle, related to a rise in MAPK phosphorylation.

• Journal of Astronomy and Space Sciences
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• 제14권1호
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• pp.80-86
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• 1997

지구 주변의 방사선대에 존재하는 고에너지 입자들은 위성계의 전자 재료, 부품, 및 집적 회로 등에 일시적 또는 장기적인 영향을 준다. 따라서 이러한 고에너지 입자들에 의한 우주 방사선 환경에 대한 정보를 아는 것은 매우 중요하다. 총 방사선의 양을 측정하는 장치로서 MOSFET을 개량한 RADFET을 많이 사용하는데, 본 연구에서는 $Co^{60}{\gamma}-ray$를 이용하여 TOT500 RADFET을 보정하였다. 그 결과, 방사선에 대한 RADFET의 특성 곡선 변화가 온도의 변화에 매우 민감한 것을 확인하였다. 또한, 우리별 1호에서의 TDERUF과를 위성의 온도와 비교하였으며, 그 결과 TDE 실험에 나타난 특이한 형상은 지구에 의한 위성의 식 현상에서 비롯된 온도 변화가 주된 원인이었음을 확인하였다.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.402-409
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• 2024

High energy neutron irradiations impact on structural and electrical properties of alumina are studied with particular emphasis on real time in-situ radiation induced conductivity measurement in low flux region. Polycrystalline Al₂O₃ samples are subjected to high energy neutrons produced from D-T neutron generator and Am-Be neutron source. 14 MeV neutrons from D-T generator are chosen to study the role of fast neutron irradiation in the structural modification of samples. Real time in-situ electrical measurement is performed to investigate the change in insulation resistance of Al₂O₃ due to radiation induced conductivity at low flux regime. During neutron irradiation, a significant transient decrease in insulation resistance is observed which recovers relative higher value just after neutron exposure is switched off. XRD results of 14 MeV neutron irradiated samples suggest annealing effect. Impact of relatively low energy neutrons on the structural properties is also studied using Am-Be neutrons. In this case, clustering is observed on the sample surface after prolonged neutron exposure. The structural characterizations of pristine and irradiated Al₂O₃ samples are performed using XRD, SEM, and EDX. The results from these characterizations are analysed and interpreted in the manuscript.

• 한국정보통신학회논문지
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• 제16권10호
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• pp.2329-2334
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• 2012

본 논문에서는 초기 핵 펄스방사선에 대한 군 무기체계내의 반도체 소자에 대한 피해를 분석하기 위해 피해평가 모델개발 연구를 수행하였다. 우선 핵 펄스방사선을 입력신호로 모델링하고 물성과 구조특성에 따라 정밀하게 모델로 구현한 다이오드 소자에 인가하여 소자내부에서 생성되는 전하들의 거동을 모사하고 출력특성을 분석하였다. 구축한 펄스방사선 피해 평가모델의 신뢰성 검증을 위해서 모델링한 소자와 동일한 공정변수로 제작한 다이오드 소자에 대해 유사한 특성의 펄스 방사선을 조사하고 출력전압의 순간 변화량을 실측하는 실험을 진행하였다. 실험결과 얻은 실측값은 동일소자의 모델에 대한 입력 펄스방사선의 출력 시뮬레이션 결과와 22.9%의 오차를 보여 개발한 피해평가 모델을 통해 핵 펄스방사선의 전자소자 피해현상을 비교적 정확히 모사하고 있음을 확인할 수 있었다.

• Journal of Oral Medicine and Pain
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• 제43권3호
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• pp.84-86
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• 2018

Salivary and lacrimal gland dysfunction is relatively frequent after radioiodine therapy. In most cases this is a transient side effect, but in some patients it may persist for a long period or appear late. Radioiodine ($^{131}I$) therapy is often administered to patients following total thyroidectomy to treat well-differentiated follicular cell-derived thyroid cancer. In addition to the thyroid, $^{131}I$ accumulates in the salivary glands, giving rise to transient or permanent salivary gland damage. Salivary gland dysfunction following radioiodine therapy can be caused by radiation damage. But, it also may be associated with $Sj{\ddot{o}}gren$ syndrome (SS) developed after radioiodine therapy. It would be recommended that the evaluation for SS including anti-SSA/Ro and anti-SSB/La should be considered before and after radioiodine therapy.

• Nuclear Engineering and Technology
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• 제55권1호
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• pp.209-214
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• 2023

The effect of thermal annealing on defect recovery of in-core neutron-irradiated 4H-SiC was investigated. Au/SiC Schottky diodes were manufactured using a 4H-SiC epitaxial wafer that was neutron-irradiated at the HANARO research reactor. The electrical characteristics of their epitaxial layers were analyzed under various conditions, including different neutron fluences (1.3 × 10¹⁷ and 2.7 × 10¹⁷ neutrons/cm²) and annealing times (up to 2 h at 1700 ℃). Capacity-voltage measurements showed high carrier compensation in the neutron-irradiated samples and a recovery tendency that increased with annealing time. The carrier density could be recovered up to 77% of the bare sample. Deep-level-transient spectroscopy revealed intrinsic defects of 4H-SiC with energy levels 0.47 and 0.68 eV below the conduction-band edge, which were significantly increased by in-core neutron irradiation. A previously unknown defect with a high electron-capture cross-section was discovered at 0.36 eV below the conduction-band edge. All defect concentrations decreased with 1700 ℃ annealing; the decrease was faster when the defect level was shallow.

• 대한두경부종양학회지
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• 제13권2호
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• pp.221-227
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• 1997

The authors reviewed 106 cases of parotid gland tumor at Presbyterian Medical Center seen during the past 10 years between January, 1986 and December, 1995. The results were obtained as follows; 1) 86 cases(81.1%) were benign tumors and 20 cases(18.9%) were malignant tumors. 2) Overall male and female sex ratio was 1 : 1.4. 3) For benign tumors, the mean age was 47.9 and for malignant tumors, the mean age was 43.4. 4) Clinical manifestations in benign tumors were palpable mass in 86 cases(100%), pain in 6 cases(6.9%), facial nerve palsy in 2 cases(2.3%), lymphadenopathy in 1 case(1.2%); and in malignant tumors, palpable mass in 20 cases(100%), pain in 7 cases(35%), facial nerve palsy in 2 cases(10%) and lymphadenopathy in 3 cases(15%). Thus, the presence of pain, facial nerve palsy and lymphadenopathy suggest malignant tumors. 5) Operative procedures in benign tumors included superficial parotidectomy in 53 cases(61.6%), total parotidectomy in 10 cases(11.6%), local excision in 23 cases(26.7%); and in malignant tumors, superficial parotidectomy in 3 cases, total parotidectomy in 1 case, local excision in 1 case, superficial parotidectomy with supraomohyoid neck dissection in 6 cases, total parotidectomy with supraomohyoid neck dissection in 8 cases, total parotidectomy with radical neck dissection in 1 case. 6) Postoperative complications in benign tumors were transient facial nerve palsy in 14 cases, Frey's syndrome in 2 cases. In malignant tumors complications included transient facial nerve palsy in 3 cases and permanent facial nerve palsy in 1 case. 7) Pleomorphic adenoma was the most common benign parotid tumor and mucoepidermoid carcinoma was the most common malignant tumor. 8) In our review of 20 patients with malignant parotid tumors, all patients who received supraomohyoid neck dissection and postoperative radiation therapy remain alive from 1986 to 1995 years. Two deaths in this series were adenoid cystic carcinoma patients who failed to receive postoperative radiation therapy. These series of cases have been studied in order to determine whether supraomohyoid neck dissection and postoperative radiation therapy may have further therapeutic effect.

• Journal of Radiation Protection and Research
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• 제48권3호
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• pp.124-130
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• 2023

Background: When bipolar junction transistors (BJTs) are used as switches, their switching characteristics can be deteriorated because the recombination time of the minority carriers is long during turn-off transient. When BJTs operate as low frequency switches, the power dissipation in the on-state is large. However, when BJTs operate as high frequency switches, the power dissipation during switching transients increases rapidly. Materials and Methods: When silicon (Si) BJTs are irradiated by fast neutrons, defects occur in the Si bulk, shortening the lifetime of the minority carriers. Fast neutron irradiation mainly creates displacement damage in the Si bulk rather than a total ionization dose effect. Defects caused by fast neutron irradiation shorten the lifetime of minority carriers of BJTs. Furthermore, these defects change the switching characteristics of BJTs. Results and Discussion: In this study, experimental results on the switching characteristics of a pnp Si BJT before and after fast neutron irradiation are presented. The results show that the switching characteristics are improved by fast neutron irradiation, but power dissipation in the on-state is large when the fast neutrons are irradiated excessively. Conclusion: The switching characteristics of a pnp Si BJT were improved by fast neutron irradiation.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1996년도 추계학술발표회 논문집
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• pp.171-175
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• 1996

thermal diode is a device which allows heat to be transferred in one direction by convection due to difference of density of fluid. Vertical plate for heat collection and radiation are of utility for design of thermal diode. It was considered the transient process of air filled thermal diode with guide vane which combined rectangular and parallelogrammic shape enclosures. Gr was kept constantly on 1.60$\times$1010 and error range was $\pm$2% during the experiment. Nu was examined when inclined angle are 15$^{\circ}$and 45$^{\circ}$and, also the experiments was carried out with and without guide vane as well. Specially, The effect of guide vane was sensitive. Developed region inclined angle, which is characteristic of system.

• 대한기계학회논문집B
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• 제29권1호
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• pp.27-34
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• 2005

We analyze in detail axially symmetric theoretical study for the photothermal pulsed radiometry of a cylindrical model. The theoretical solutions describe the transient infrared radiation from the sample heated by short-duration pulsed heating. In the conventional transmission radiometry technique, the excitation source and the detector are on opposite sides of the sample, otherwise in the new single ended radiometry technique, the excitation source and the detector are on same sides of the sample. The analytical solution described for photothermal radiometry in this study would not need to cut or polish samples to measure the thermal diffusivity. Therefore the radial area and axial thickness of samples are not limited. The effects of excitation pulse duration and the area of heat source are discussed.