• Radiation Oncology Journal
• /
• v.2 no.1
• /
• pp.1-9
• /
• 1984

To evaluate the influence of prior heat treatment on the thermal enhancement of irradiation effect after hyperthermia, an experimental study was carried out using a total of 80 mice. Hyperthermia was carried out at $43^{\circ}C$ for 40 minutes and was repeated with various intervals. A single dose of 3,000 rad was delivered on skin of mouse tail immediately after the second hyperthermia. The skin changes of the irradiated mouse tail were observed from 7th to 35th post-irradiation days, and the skin scores were analyzed. The results are as follows, 1. The radiation damage on mouse skin increased significantly when radiation was combined with hyperthermia. 2. The radiation damage after repeated hyperthermia is significantly less than that after single hyperthermia, when the interval is 1 to 6 days. 3. As a result, thermal tolerance persists from 1 through 6 days after the initial hyperthermia.

• Journal of the Optical Society of Korea
• /
• v.12 no.1
• /
• pp.13-18
• /
• 2008

We numerically investigate by the finite-difference time-domain method the effects of surface termination on directional emission exiting a photonic crystal waveguide. The directed power and far-field beam profile for the original proposal [E. Moreno et al., Phys. Rev. B 69, 121402 (2004)] and its enhancement [S. K. Morrison et al., Appl. Phys. Lett. 86, 081110 (2005)] are computed for different values of some important parameters. We find another surface termination condition with a positive surface displacement in the structure of the original proposal which has a negative surface displacement. Our surface termination is more effective than the original structure, and nearly as effective as the termination for the enhancement, for directional emission. Besides, our termination is simpler than that for the enhancement. We confirm the effectiveness of directional emission from our termination in its far-field beam profile, radiation intensity distribution, and additionally the wave-vector space representation by the Fourier analysis.

• Proceedings of the KIPE Conference
• /
• 2002.11a
• /
• pp.186-189
• /
• 2002

Real-time thermal image is obtained by thermal imaging systems measuring radiant emittence according to law of Plank's blackbody radiation. The histogram of thermal image is not uniform. The signal bands of background and target are separated and grouped in narrow bands. In such a system, contrast enhancement indispensible to distinguish target from background. In this study, plateau histogram equalization using local histogram is proposed for contrast enhancement.

• The Korean Journal of Physiology and Pharmacology
• /
• v.24 no.5
• /
• pp.413-422
• /
• 2020

Delphinidin is a major anthocyanidin compound found in various vegetables and fruits. It has anti-oxidant, anti-inflammatory, and various other biological activities. In this study we demonstrated the anti-cancer activity of delphinidin, which was related to autophagy, in radiation-exposed non-small cell lung cancer (NSCLC). Radiosensitising effects were assessed in vitro by treating cells with a subcytotoxic dose of delphinidin (5 μM) before exposure to γ-ionising radiation (IR). We found that treatment with delphinidin or IR induced NSCLC cell death in vitro; however the combination of delphinidin pre-treatment and IR was more effective than either agent alone, yielding a radiation enhancement ratio of 1.54 at the 50% lethal dose. Moreover, combined treatment with delphinidin and IR, enhanced apoptotic cell death, suppressed the mTOR pathway, and activated the JNK/MAPK pathway. Delphinidin inhibited the phosphorylation of PI3K, AKT, and mTOR, and increased the expression of autophagy-induced cell death associated-protein in radiation-exposed NSCLC cells. In addition, JNK phosphorylation was upregulated by delphinidin pre-treatment in radiation-exposed NSCLC cells. Collectively, these results show that delphinidin acts as a radiation-sensitizing agent through autophagy induction and JNK/MAPK pathway activation, thus enhancing apoptotic cell death in NSCLC cells.

• Proceedings of the Korean Nuclear Society Conference
• /
• 2004.05a
• /
• pp.397-397
• /
• 2004

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.20 no.1
• /
• pp.346-358
• /
• 1996

A finite volume radiation solution method was applied to a non- orthogonal coordinate system for the analysis of radiative-convective heat transfer about a circular cylinder in crossflow. The crossflow Reynolds number based on the cylinder radius was 20, and the fluid Prandtl number was 0.7. The radiative heat transfer coupled with convection was reasonably predicted by the finite volume radiation solution method. The investigation includes the effects of conduction- to-radiation parameter, optical thickness, scattering albedo and cylinder wall-emissivity on heat transfer about the cylinder. As the conduction- to-radiation parameter decreases, the radiative heat transfer rate increases and conduction rate as well due to the increase in temperature gradient on the cylinder wall which is caused by radiation enhancement. With an increase in the optical thickness, the Nusselt number increases significantly and the temperature gradient shows similar behavior. Though the radiative heat transfer increases with the scattering albedo, the total heat transfer decreases. This is because the decrease in the conduction heat transfer exceeds the increase in the radiation heat transfer. As the wall- emissivity increases, the radiation absorbed in the vicinity of the cylinder wall increases and thereby the total heat transfer increases, even though the conduction heat transfer decreases.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.7
• /
• pp.59-67
• /
• 2013

The radiation characteristics of an E-plane linear array antenna composed of inductive loaded patch antennas (ILPAs) are investigated. The radiation characteristics of an ILP array antenna are significantly improved compared to those of a conventional array antenna because the mutual coupling of an ILP array antenna is very small. The patch length of a $5{\times}2$ ILPA for the enhancement of the radiation characteristics of a 5-element E-plane linear array antenna composed of ILPAs is presented.

• Radiation Oncology Journal
• /
• v.30 no.3
• /
• pp.99-107
• /
• 2012

Purpose: The aim of this study was to identify clinical predictive factors for tumor response after preoperative chemoradiotherapy (CRT) in rectal cancer. Materials and Methods: The study involved 51 patients who underwent preoperative CRT followed by surgery between January 2005 and February 2012. Radiotherapy was delivered to the whole pelvis at a dose of 45 Gy in 25 fractions, followed by a boost of 5.4 Gy in 3 fractions to the primary tumor with 5 fractions per week. Three different chemotherapy regimens were used (5-fluorouracil and leucovorin, capecitabine, or tegafur/uracil). Tumor responses to preoperative CRT were assessed in terms of tumor downstaging and pathologic complete response (ypCR). Statistical analyses were performed to identify clinical factors associated with pathologic tumor response. Results: Tumor downstaging was observed in 28 patients (54.9%), whereas ypCR was observed in 6 patients (11.8%). Multivariate analysis found that predictors of downstaging was pretreatment relative lymphocyte count (p = 0.023) and that none of clinical factors was significantly associated with ypCR. Conclusion: Pretreatment relative lymphocyte count (%) has a significant impact on the pathologic tumor response (tumor downstaging) after preoperative CRT for locally advanced rectal cancer. Enhancement of lymphocyte-mediated immune reactions may improve the effect of preoperative CRT for rectal cancer.

• Journal of Korean Neurosurgical Society
• /
• v.57 no.3
• /
• pp.215-218
• /
• 2015

Occasionally, unexpected neurological deficits occur after lumbar spinal surgery. We report a case of monoparesis after lumbar decompressive surgery. A 63-year-old man, who had undergone decompression of L4-5 for spinal stenosis 4 days previously in the other hospital, visted the emergency department with progressive weakness in the left leg and hypoesthesia below sensory level T7 on the right side. He had been cured of lung cancer with chemotherapy and radiation therapy 10 years previously, but detailed information of radiotherapy was not available. Whole spine magnetic resonance (MR) imaging showed fatty marrow change from T1 to T8, most likely due to previous irradiation. The T2-weighted MR image showed a high-signal T4-5 spinal cord lesion surrounded by a low signal rim, and the T1-weighted MR image showed focal high signal intensity with focal enhancement. The radiological diagnosis was vascular disorders with suspicious bleeding. Surgical removal was refused by the patient. With rehabilitation, the patient could walk independently without assistance 2 months later. Considering radiation induced change at thoracic vertebrae, vascular disorders may be induced by irradiation. If the spinal cord was previously irradiated, radiation induced vascular disorders needs to be considered.

• Food Science and Biotechnology
• /
• v.14 no.1
• /
• pp.137-142
• /
• 2005

The genotoxicological safety of fermented vegetables pasteurized by gamma irradiation was examined to consider the possibility of the application of irradiation for extending of fermented vegetables. A fermented vegetable was irradiated at 20 kGy to assure its toxicological safety even at a high dose of radiation. The Ames test with Salmonella typhimurium (TA98, TA100, TA1535, TA1537) and Escherchia coli (WP2), and the chromosomal aberration test in Chinese hamster lung (CHL) cells were performed. In vivo micronucleus test were conducted in mouse bone marrow cells. With or without metabolic activation, negative results were obtained in the Ames test and the chromosomal aberration test. In the micronucleus test, there was no enhancement in the formation of micronucleus, and there were no such significant differences between the irradiated and non-irradiated samples. The observed results indicated that, a level of 20 kGy of gamma irradiation on the fermented vegetable did not bring about any genotoxic effects under the described experimental conditions.