• 한국방사선학회논문지
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• 제10권7호
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• pp.483-487
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• 2016

이 연구는 ${\gamma}$선 및 x선 조사 시 AuNPs 입자의 방사선감수성의 향상을 생물물리학적으로 평가하기 위해 두 가지 실험을 시행하였다. 생물학적 방사선 감수성의 평가에 앞서 6시간, 12시간, 18시간, 24시간 incubation한 후 세포생존율(surviving Fraction, SF)값을 비교하여 AuNPs 입자의 독성 여부와 세포질에 입자의 균일 된 분포 여부를 확인 해 보았다. incubation time에 따라 세포생존율(surviving Fraction, SF)이 낮아지지 않음을 확인한 다음 ${\gamma}$선 및 x선 조사 후 Clonogenic assay 실시하고 세포생존율(surviving Fraction, SF)을 구하여 방사선 감수성을 비교 평가하였다. 방사선량 증가 시 세포생존율(surviving Fraction, SF)이 계속해서 낮아졌고 8Gy 조사 시 최대치로 약 30%의 차이가 있음을 확인하였다. 또한 Gate v6.1을 사용하여 몬테카를로 시뮬레이션 후 percent depth dose(PDD)를 구한 뒤 선량 평가하여 약 40% Dose Enhancement가 있음을 확인하였다. 두 가지 실험에 따라 생물물리학적으로 AuNPs 입자는 방사선 감수성이 향상되도록 하며 이는 nanoparticle을 이용한 방사선 병합 치료 시 치료 성적 향상에 큰 도움이 될 것으로 보인다.

• Applied Microscopy
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• 제37권2호
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• pp.135-142
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• 2007

본 연구는 6 MeV LINAC에서 발생한 X-선을 생쥐 생체에 조사한 후 난소에서 난포의 형태적 변화 양상과 난포의 세포자연사가 일어나는 과정을 TUNEL 염색방법을 이용하여 광학현미경으로 관찰하였다. 정상난포와 퇴화난포 및 방사선이 조사된 난포에서 세포예정사가 발생하는 것을 확인하기 위해서 TUNEL 염색을 실시한 결과, 정상난소의 퇴화난포에서 양성반응을 보이는 과립층세포들은 갈색을 띠고 있었고, 핵은 응축되어 나타났다. 그러나, 정상난포에서는 양성반응이 나타나지 않았다. X-선을 조사한 난소의 난포는 TUNEL 염색에 강한 양성반응이 나타났고, 600 cGy의 X-선 조사에서 난모세포는 이미 세포예정사가 진행되어 파괴되었음을 확인할 수 있었다. 그리고 난포막을 형성하고 있는 난막세포의 핵들도 양성반응으로 나타나, 갈색으로 염색이 되었으며, 수질의 결합조직세포들의 핵도 갈색으로 염색되어 관찰되었다. 또한, 대부분의 세포들은 세포예정사가 진행되어 있으며, apoptotic body들이 난포 내에 산재되어 있었다. 이 시기의 난소조직의 전반적인 염색도는 저선량의 X-선 조사에서보다 더 현저히 강한 염색성이 나타났다.

• 한국진공학회지
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• 제20권6호
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• pp.409-415
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• 2011

현재 개발 중인 휴대용 XRF (X-Ray Fluorescence) 장치의 검출감도를 향상시키기 위한 방법을 논의하였다. 대기 기체분자에 의한 강도 손실을 최소화하기 위하여 시료와 검출기 사이에 Vacuum module을 설치하였다. Vacuum module은 대기기체 또는 He 기체를 채울 수 있도록 고안하였다. 그리고 Vacuum module 내부에 He 기체를 채운 상태, 또는 진공상태에서 검출감도의 변화를 조사하였다. 그 결과 다음 3가지 중요한 결과를 얻었다. 첫 번째는, 낮은 에너지 영역(3~4 keV)에서의 XRF 강도가 2~4배 정도 증가하였다. 검출감도의 향상은 검출시간의 단축을 의미하기 때문에, 휴대용 XRF 장치에 있어서 매우 중요한 결과이다. 두 번째는, x-ray emission line의 에너지가 3 keV 이하인 원소의 검출 가능성을 확인하였다. 세 번째는, He 기체를 채운 vacuum module을 사용하면, 휴대용 XRF 장치에 진공밀폐용기를 쓰지 않으면서도 대기기체분자에 의한 흡수를 최소화할 수 있다는 것이다. 세 가지 모두 휴대용 XRF 장치의 개발에 있어서 매우 의미있는 결과로 판단된다.

• Journal of Radiation Protection and Research
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• 제48권4호
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• pp.167-174
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• 2023

Background: A nondestructive test is commonly used to inspect the surface defects and internal structure of an object without any physical damage. X-rays generated from an electron accelerator or a tube are one of the methods used for nondestructive testing. The high penetration of X-rays through materials with low atomic numbers makes it difficult to discriminate between these materials using X-ray imaging. The interaction characteristics of neutrons with materials can supplement the limitations of X-ray imaging in material discrimination. Materials and Methods: The radiation image acquisition process for air-cargo security inspection equipment using X-rays and neutrons was simulated using a GEometry ANd Tracking (Geant4) simulation toolkit. Radiation images of phantoms composed of 13 materials were obtained, and the R-value, representing the attenuation ratio of neutrons and gamma rays in a material, was calculated from these images. Results and Discussion: The R-values were calculated from the simulated X-ray and neutron images for each phantom and compared with those obtained in the experiments. The R-values obtained from the experiments were higher than those obtained from the simulations. The difference can be due to the following two causes. The first reason is that there are various facilities or equipment in the experimental environment that scatter neutrons, unlike the simulation. The other is the difference in the neutron signal processing. In the simulation, the neutron signal is the sum of the number of neutrons entering the detector. However, in the experiment, the neutron signal was obtained by superimposing the intensities of the neutron signals. Neutron detectors also detect gamma rays, and the neutron signal cannot be clearly distinguished in the process of separating the two types of radiation. Despite these differences, the two results showed similar trends and the viability of using simulation-based radiation images, particularly in the field of security screening. With further research, the simulation-based radiation images can replace ones from experiments and be used in the related fields. Conclusion: The Korea Atomic Energy Research Institute has developed air-cargo security inspection equipment using neutrons and X-rays. Using this equipment, radiation images and R-values for various materials were obtained. The equipment was reconstructed, and the R-values were obtained for 13 materials using the Geant4 simulation toolkit. The R-values calculated by experiment and simulation show similar trends. Therefore, we confirmed the feasibility of using the simulation-based radiation image.

• Bulletin of the Korean Chemical Society
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• 제31권2호
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• pp.406-414
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• 2010

A novel polyacrylamide grafted hydrous ferric oxide adsorbent composite has been synthesized by using glow discharge electrolysis plasma. To optimize the synthesis conditions, the following parameters were examined in detail: applied power, discharge time, post polymerization temperature, post polymerization time, amount of crosslinking agent and hydrous ferric oxide gel added and so on. The adsorbent was characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The removal percentage of the adsorbent in Pb(II) solution was examined and the data obtained showed that the adsorbent composite has a high capacity for lead ion. For the use in wastewater treatment, the thermodynamic and kinetic of Pb(II)-capture were also studied. Results indicated that the adsorption reaction was a spontaneous and an endothermic process, and it seems to be obeyed a pseudo-secondorder rate model. Moreover, the adsorption isotherm of Pb(II)-capture is following the Langmuir and Freundlich isotherm models.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.85.2-85.2
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• 2016

With the advent of ultra-short high-intense XFEL (X-ray Free Electron Laser), time-resolved dynamics has become of great importance in exploring femtosecond real-world phenomena of nanoscience and biology. These include studying the response of materials to femtosecond laser excitation and investigating the interaction of XFEL itself with condensed matter. A variety of dynamic phenomena have been investigated such as radiation damage, ultrafast melting process, non-equilibrium phase transitions caused by orbital-lattice-spin couplings. As far as bulk materials are concerned, the sample size has no effect on the following dynamic process. As a result, imaging information is not required by and large. If the sample size is of tens of nanometers, however, sample starts to experience quantum confinement effect which, in turn, affects the following dynamic process. Therefore, to understand the fundamental dynamic phenomena in nano-science, time-resolved imaging information is essential. In this talk, we will briefly introduce scientific highlights achieved in XFEL-based dynamics. In case of bio-imaging, recent scientific topics will be mentioned as well. Finally, we will aim to present feasible topics in ultrafast time-resolved imaging and to discuss the future plan of CXI beamline at PAL-XFEL.

• Clinics in Shoulder and Elbow
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• 제17권3호
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• pp.134-137
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• 2014

To report the fracture of proximal humerus in the lateral anchor site after suture bridge repair. A 57-year-old female patient with shoulder pain on the right-side was admitted through the emergency room following a car accident. Seven weeks before the accident, the patient had undergone surgery at a different hospital for the repair of supraspinatus tendon rupture on the right-side via suture bridge technique. Humerus surgical neck fracture was confirmed by X-ray, and proximal humerus fracture at the anchor site was confirmed by magnetic resonance imaging. Following 7 months of conservative treatment resulted in satisfactory bone union and motion of the shoulder joint. We report the need of close observation during and after the arthroscopic repair of the rotator cuff in patients with osteoporosis.

• Journal of Chest Surgery
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• 제10권2호
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• pp.274-280
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• 1977

As a major cause for postoperative hypoxia, the importance of increased physiological shunting is increasingly emphasized. This study is a review and analysis of postoperative physiological shunting following open heart surgery with the aid of extracorporeal circulation. Sixteen patients were selected from among 21 patients who underwent elective open heart surgery at the Department of Thoracic and Cardiovascular Surgery, Kyungpook National University, School of Medicine, from December, 1975 to September, 1977. The results were as follows: 1. The degree of postoperative physiological shunt was progressively increased from 18.8% mean value one hour after surgery to 22.7% mean value, reaching a peak on the second postoperative days. 2. For up to one week, large physiological shunt[15%] was persisted in one patient. 3. Comparing long[more than 90 minutes] with short[less than 90 minutes] perfusion time group using pump oxygenator, it was found that the physiological shunt increased about 3% in the long as compared with the short perfusion time group. 4. The mean blood pressure was 70-80 mmHg without a remarkable causal relationship between physiological shunt and mean blood pressure. 5. On elevated $PaO_2$[>200 torr], the physiological shunt was decreased less than 20% of cardiac output, but on diminished $PaO_2$[102 torr] after two days, it was 22.7% of cardiac output. From above results, a contrary causal relationship between $PaO_2$ and physiological shunt was obtained. Co Reviewing chest X-rays postperfusion, it was demonstrated that no remarkable causal relationship between roentgen-ray evidence and physiological shunt could be obtained.

• Journal of Chest Surgery
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• 제28권3호
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• pp.228-232
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• 1995

Computed tomography[CT is an effective technique for the evaluation of the thorax following blunt trauma. To evaluate multiply injured 30 patients who were diagnosed as hemothorax in emergency room, computed tomography of thorax was done. The thickness of slice was one centimeter and the entire pleural cavity from the apex to the costophrenic angle was included in the evaluation. Integration and addition of the hemothorax area for each CT slice was made and amount of blood in the pleural cavity was estimated. The slice which showed largest area of hemothorax was selected and the height and width of the hemothorax area were measured. The number of slices which showed radiographic evidence of hemothorax was counted. Regression analysis was done and measured amount of hemothorax, the height and width of the hemothorax area for each slice and number of slices were put as variables. And following equation was derived. V=108.3A-0.8B-7.4C+84.7 [R2=0.74 [ V: amount of hemothorax, A: height, B: width, C: number of slices Total amount of blood from thoracic drainage was compared to the measured amount by computed tomography and the relation between the two values was statistically significant.[p=0.001 In conclusion, quantitative estimation of size of hemothorax was possible by the above equation and the process was very helpful for determination policy of treatment of individual patient.

• Journal of Pharmaceutical Investigation
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• 제18권1호
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• pp.15-21
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• 1988

An inclusion complex of phenytoin (PT) with ${\beta}-cyclodextrin\;({\beta}-CyD)$ in molar ratio of 1 : 1 was prepared, and the interaction between host and guest molecules was confirmed by infrared spectrometry, differential scanning calorimetry and X-ray diffractometry. Suppositories were prepared by the fusion method. PT and $PT-{\beta}-CyD$ complex were added to PEG 1540 and Witepsol H-15 under the vigorous stirring at $40^{\circ}C$. Content uniformity was tested for different formulations of the PT suppositories. The release rates were dependent on the K.P. V dissolution apparatus and the dialyzing tubing method. Then, the release rates were increased in the following order: $PT-{\beta}-CyD$ complex in PEG 1540>PT in PEG 1540>$PT-{\beta}-CyD$ complex in Witepsol H-15>PT in Witepsol H-15. The area under the curve and maximum blood concentration after rectal administration were increased in the following order: $PT-{\beta}-CyD$ complex in PEG 1540>PT in PEG 1540>$PT-{\beta}-CyD$ complex in Witepsol H-15>PT in Witepsol-15.