본 논문은 회분식 반응기에서 습식 산화법으로 합성한 칼륨 페레이트(VI)에 의한 난분해성 아조 염료Reactive Black 5의 분해 과정을 연구하는 것을 목적으로 한다. 수용액에서 RB5의 분해는 pH, Ferrate (VI) 투입량, 초기 농도, 수용액 온도 등 다양한 변수의 조건에서 연구되었다. RB5 경우에는 최대 분해 효율은 pH 7.0에서 63.2%가 달성되었으며, 이 실험 조건에서 얻은 kapp 값은 190.49 M-1s-1 으로 나타났다. 온도 또한 가장 중요한 매개 변수 중 하나로 연구되었으며, 그 결과로부터 온도(45°C까지)를 증가시키면 페레이트(VI)에 의한 아조 화합물 염료의 분해 효율이 증가하고, 온도가 45°C를 초과하면 분해 효율이 저하되는 것으로 나타났다.

배경/목적: ROS는 악성종양의 성장 및 공격과 관련이 있다. UDCA는 담도암 세포에서 진행과 전이에 밀접한 EGFR-MAPK 신 호 경 로 와 EMT를 억 제 한 다 . 이 연 구 는 UDCA가 담도암세포에서 ROS 생성 및 그에 관련된 바이오마커에 어떠한 영향을 주는지 알아보기 위해 시행되었다. 방 법 : 인간 간외 담관암 세포주인 SNU-245세포를 배양하였다. 세포생존율은 MTT assays로, ROS는 세포 ROS assays kit로 측정하였다. Western blotting으로 다양한 표적 단백질의 발현 수준을 측정하였다. 특정 유전자의 억제를 위해 siRNA를 사용하였고, 특정 유전자의 과발현을 위해 shRNA를 사용하였다. 결과: UDCA는 담도암 세포에서 DCA에 의한 peroxide와 ROS가 생성되는 것을 억제하였으며, DCA로 발현이 증강된 STAT3, PRX2 및 SOD2를 억제하였고, IGF-1에 의해 발현이 증강된 NOX2 및 NOX4를 억제하였다. 또한, 담도암 세포에서 SiRNA를 이용한 STAT3 및 PRX2의 억제는 UDCA 처치와 상관없이 EGF에 의해 약화된 E-cadherin 발현을 복원하고 EGF에 의해 증가된 N-cadherin 발현을 억제하였는데, 이는 UDCA의 EMT 억제에 PRX2/STAT3가 상당한 역할을 하는 것을 의미한다. 덧붙여, UDCA는 담도암 세포에서 DCA에 의해 억제된 catalase의 발현을 복원하였다. 한편, ShRNA를 사용한 NOX4의 과발현의 유도는 UDCA의 항종양 효과를 상쇄하였다. 결론: UDCA는 담도암 세포에서 ROS 생성을 억제하고, ROS 제거를 향상시킴으로써, 결국 EMT와 관련된 STAT3 및 PRX2를 억제한다, 따라서, UDCA는 ROS 활성도 및 EMT의 억제를 통하여 담도암 세포의 성장 및 침습을 억제하는 데 기여한다.

The effect of various physicochemical processes, such as seawater intrusion, on the performance of the engineered barrier should be closely analyzed to precisely assess the safety of high-level radioactive waste repository. In order to evaluate the impact of such processes on the performance of the engineered barrier, a thermal-hydrological-chemical model was developed by using COMSOL Multiphysics and PHREEQC. The coupling of two software was achieved through the application of a sequential non-iterative approach. Model verification was executed through a comparative analysis between the outcomes derived from the developed model and those obtained in prior investigations. Two data were in a good agreement, demonstrating the model is capable of simulating aqueous speciation, adsorption, precipitation, and dissolution. Using the developed model, the geochemical evolution of bentonite buffer under a general condition was simulated as a base case. The model domain consists of 0.5 m of bentonite and 49.5 m of granite. The uraninite (UO2) was assigned at the canister-bentonite interface as the potential source of uranium. Assuming the lifetime of canister as 1,000 years, the porewater mixing without uranium leakage was simulated for 1,000 years. After then, the uranium leakage through the dissolution of uraninite was initiated and simulated for additional 1,000 years. In the base case model, where the porewater mixing between the bentonite and granite was the only considered process, the gypsum tended to dissolve throughout the bentonite, while it precipitated in the vicinity of bentonite-granite boundary. However, the precipitation and dissolution of gypsum only showed a limited effect on the performance of the bentonite. Due to the low solubility of uraninite in the reduced environment, only infinitesimal amounts of uranium dissolved and transported through the bentonite. Additional cases considering various environmental processes, such as seawater or cement porewater intrusion, will be further investigated.

The nuclide management process for reducing the environmental burden being developed by the Korea Atomic Energy Research Institute is performed in molten salts, resulting in contaminated salt wastes containing fission products such as Cs, Sr, Ba, and rare-earth nuclides. In addition, the spent fuel of a molten salt reactor (MSR) contains a variety of fission products, and a purification process may be required for the reuse of the salt and the separation and disposal of the fission products in the spent nuclear fuel. The melt-crystallization method is a technique used for the purification and separation of chemicals or metals based on the different melting points of the different substances. In a recent study, our group developed a reactive-crystallization method using Li2CO3 precipitation agent to precipitate metal corrosion from the reactor through a chlorination reaction by HCl and Cl2, which may occur in chloride molten salt, and successfully precipitated the metal precipitate and purified and recovered LiCl salt. In this study, reactive-crystallization method has been established for removing fission products and corrosive materials. Using the reactive crystallization method, white LiCl-KCl salt that was not discolored by metal corrosion was recovered through the crystallization plates, and fission products and metal elements were shown to be suppressed to several ppm in the purified salt. Consequently, high-purity salts were recovered with high nuclide and corrosive separation efficiencies. The reactive crystallization procedure can also be applied to other salt waste systems, such as MSR nuclear fuel treatment and molten salt chemistry for the elimination of corrosive substances.

Various disposal methods for spent nuclear fuels (SNFs) are being researched, and one of these methods involves separating high heat-generating nuclear isotopes such as Strontium-90 (90Sr) and Cesium-137 (137Cs) for deep disposal. These isotopes has relatively short half-lives and substantial decay energies. Especially, 90Sr undergoes decay through Yttrium-90 to Zirconium-90, emitting intense heat with beta radiation. Therefore, the removal of these high heat-generating isotopes will significantly contribute to reducing disposal site area. To remove 90Sr from SNFs, molten salt was utilized in KAERI. During this process, it was discovered that 90Sr dissolves in the molten salt in the form of SrCl2 and/or Sr4OCl6. Afterwards, it is crucial to recover 90Sr in the form of oxide from the salt to create immobilized forms for disposal. This can be achieved by reactive distillation with K2CO3. However, the amount of 90Sr within the SNFs is only 0.121wt%, and even if all the 90Sr in the SNFs were to leach into the molten salt, the quantity of 90Sr in the molten slat would still be very small. Therefore, adding K2CO3 to the molten salt for reactive distillation could result in significant possibilities of side reactions occurring. In this study, a two-step process was employed to mitigate the side reactions: the 1st step involves evaporating the all molten salts and the 2nd step includes adding K2CO3 to make oxides through solid-solid reaction. Eutectic LiCl-KCl, which is the most commonly used salt, was employed. The eutectic LiCl-KCl with SrCl2 was heated at 850°C for 2 h to evaporate the salts under a vacuum (> 0.02 torr). However, after examining the distillation product before the solid-solid reaction, it was observed that SrCl2 reacted with KCl in the salt, resulting in the formation of KSr2Cl5. It means that salts containing KCl are not suitable candidates for reactive distillation aimed at producing immobilized forms. As an alternative, MgCl2 could be a highly promising candidate because it is inert to SrCl2 and according to a recent study in KAERI, MgCl2 exhibited the most efficient separation of Sr among various salts. Therefore, we plan to proceed with the two-step reactive distillation using MgCl2 for the future work.

본 연구의 목적은 남자 대학 엘리트 조정선수의 2000 m 로잉 에르고미터 수행 후 저온침수 처 치를 통해 혈중 젖산, LDH, MDA 및 SOD의 변화에 긍정적인 영향을 주어 피로 회복에 미치는 영향을 구명하는 데 있다. 이에 남자 대학 엘리트 조정선수 10명을 대상으로 고강도 로잉 에르고미터 2,000 m 수 행 후 비 처치와 저온 침수 처치의 효과를 비교하였다. 측정 변인들에 대한 결과를 검증하기 위해 처치 및 시기 간 상호작용 효과를 분석하기 위해 ANOVA를 실시하였고 각 항목별 유의수준 .05로 설정하여 다음 의 결과를 도출하였다. 젖산은 시기 간 주효과가 나타났고(p<.001) 그룹 내 시기별 차이가 났다(p<.001). 또한, LDH는 그룹 내 시기별 차이가 나타났다(p<.05). MDA는 그룹×시기 간 상호작용 효과가 나타났고 (p<.05), 그룹 간(p<.05), 시기 간(p<.001) 주효과가 나타났다. SOD는 그룹 간, 시기 주효과가 나타났고 (p<.05) 회복 30분 후 그룹 간 차이가 나타났다(p<.05). 이를 종합해 볼 때, 본 연구에서 실시한 저온침수처치가 조정 선수의 혈중 피로 물질, 활성산소 및 항산화 효소에 유의한 효과를 나타냈다. 따라서 운동선수 의 고강도 훈련 후 저온침수를 적극 활용할 것을 권장한다.

LILW disposal repository in Gyeongju, South Korea is considered with a concrete mixture that uses Ordinary Portland Cement (OPC) partially substituted with supplementary cementitious materials (SCMs). The degradation of cementitious materials that result from chemical and physical attacks is a major concern in the safety of radioactive waste disposal. We present a reactive transport model utilized as one of the geochemical simulation approaches for the timescales of concern that range from hundreds to thousands of years. The purpose of this study is to investigate the sensitivity of parameters in concrete disposal systems and to evaluate the influence of various assumptions on the chemical degradation of the systems using a reactive transport model. A reactive transport model in the concrete disposal vault was developed to evaluate the behavior of engineered barriers composed of cementitious materials. The sensitivity analysis was performed using reactive transport models through the coupling between COMSOL and PHREEQC. The databases selected for the analysis are the Thermochimie database presented by ANDRA. Among many variables considered, two variables that can highly affect chemical degradation were selected for detailed sensitivity analysis for dealing with uncertainties. This is important because the chemical degradation mechanism is generally sensitive to precipitation and diffusion coefficient. The first factor is precipitation, which might be the most important factor in chemical degradation because it acts as a calcium leaching of cementitious materials in a disposal system in a highly alkaline environment, increasing the porosity of the system. To predict the change in annual precipitation, the measurement of the precipitation observatory station in the nearest area of Gyeongju for the past 80 years was collected. The second factor is the diffusion coefficient, which plays an essential role in the durability of the concrete disposal system, promoting the decalcification of cementitious minerals, accelerating system degradation, and increasing the porosity of its system, thereby facilitating the migration of radionuclides. The diffusion coefficient values used in studies similar to this work were calculated and evaluated using the box-and-whisker method. The results of the sensitivity analyses for the reactive transport model in the concrete disposal system will be presented. The sensitivity cases show that the results obtained are much more sensitive to changes in transport parameters.

With the increasing demand for a repository to safely dispose of high-level radioactive waste (HLW), it is imperative to conduct a safety assessment for HLW disposal facilities for ensuring the permanent isolation of radionuclides. For this purpose, the Korea Atomic Energy Research Institute (KAERI) is currently developing the Adaptive Process-based total system performance assessment framework for a geological disposal system (APro). A far-field module, which specifically focuses on fluid flow and radionuclide transport in the host rock, is one of several modules comprising APro. In Korea, crystalline rock is considered the host rock for deep geological disposal facilities due to its high thermal conductivity and extremely low permeability. However, the presence of complex fracture system in crystalline rock poses a significant challenge for managing fluid flow and nuclide transport. To address this challenge, KAERI is participating in DECOVALEX-2023 Task F1, which seeks to compare and verify modeling results using various levels of performance assessment models developed by each country for reference disposal systems. Through the benchmark problems suggested by DECOVALEX-2023 Task F1, KAERI adopts the Discrete Fracture-Matrix (DFM) as the primary fracture modeling approach. In this study, the transport processes of reactive tracers in fractured rock, modeled with DFM, are simulated. Specifically, three different tracers (conservative, decaying, adsorbing) are introduced through the fracture under identical injecting conditions. Thereafter, the breakthrough curves of each tracer are compared to observe the impact of reactive tracers on nuclide transport. The results of this study will contribute to a better understanding of nuclide behavior in subsurface fractured rock under various conditions.

APro, a modularized process-based total system performance assessment framework, was developed at the Korea Atomic Energy Research Institute (KAERI) to simulate radionuclide transport considering coupled thermal-hydraulic-mechanicalchemical processes occurring in a geological disposal system. For reactive transport simulation considering geochemical reactions, COMSOL and PHREEQC are coupled with MATLAB in APro using an operator splitting scheme. Conventionally, coupling is performed within a MATLAB interface so that COMSOL stops the calculation to deliver the solution to PHREEQC and restarts to continue the simulation after receiving the solution from PHREEQC at every time step. This is inefficient when the solution is frequently interchanged because restarting the simulation in COMSOL requires an unnecessary setup process. To overcome this issue, a coupling scheme that calls PHREEQC inside COMSOL was developed. In this technique, PHREEQC is called through the “MATLAB function” feature, and PHREEQC results are updated using the COMSOL “Pointwise Constraint” feature. For the one-dimensional advection-reaction-dispersion problem, the proposed coupling technique was verified by comparison with the conventional coupling technique, and it improved the computation time for all test cases. Specifically, the more frequent the link between COMSOL and PHREEQC, the more pronounced was the performance improvement using the proposed technique.

목적 : 반응성 청색광차단 염료를 하이드로겔 콘택트렌즈에 화학적으로 고정시켰고, 제조된 콘택트렌즈의 청색 광차단 기능의 분석 및 첨가된 염료를 정량하고자 한다. 방법 : Vinyl sulfone-기반의 반응성 염료인 Reactive Orange 16 Dye를 다량의 알콜 작용기를 함유하는 하 이드로겔 콘택트렌즈에 화학적으로 결합시켰다. 콘택트렌즈의 청색광차단 특성 및 염료의 정량은 UV-vis spectrophotometer를 이용하여 확인하였다. 결과 : 청색광차단기능의 Reactive Orange 16 Dye가 성공적으로 하이드로겔 콘택트렌즈에 결합되었다. UV-vis spectra 분석을 통해 염료를 함유한 콘택트렌즈들이 우수한 청색광차단 기능을 보임을 확인하였다. Beer-Lambert의 법칙을 이용하여, 콘택트렌즈에 첨가된 Reactive Orange 16 Dye를 정량하였으며, 반응 염료 의 농도 조절을 통해, 콘택트렌즈의 청색광차단율을 조절할 수 있었다. 결론 : 본 연구에서는 청색광차단 기능의 반응성 염료를 하이드로겔 콘택트렌즈에 화학적 결합을 통해 고정시 키고, 청색광차단 기능을 분석하였다. 화학적 반응에서 청색광차단 염료의 농도가 증가할수록, 380~500 nm 사 이의 청색광 파장 영역에서의 차단 세기와 첨가된 염료의 양이 같이 증가함을 확인하였다. 대량생산이 가능한 청 색광차단 콘택트렌즈의 개발은 기능성 안광학의료기기 개발에 큰 역할을 할 것으로 기대된다.

C-reactive protein (CRP) is an acute-phase protein produced by hepatocytes. The plasma concentration of CRP peaks around 48 hours following stimulation. A rapid decrease in CRP levels is observed when the stimuli end. Considering these characteristics of CRP, it is used to evaluate acute inflammatory responses in clinics. In addition, as it reflects the degree of surgical trauma, measuring the CRP concentration is an effective method of evaluating tissue damage depending upon the surgical method. As CRP is also an acute-phase protein in dogs, the purpose of the present study was to compare the factors related to acute inflammatory responses between dogs undergoing elective general surgery (GS) and orthopedic surgery (OS). A total of 44 healthy dogs were included in this study. The sex ratio of dogs that underwent OS was similar. Both groups showed increased CRP levels and white blood cell (WBC) counts on post-operative day (POD) 1-2. The CRP level in the OS group on POD 1-2 was significantly higher than that of the GS group and it was increased about 16-fold compared to the pre-operative value. No significant difference in WBC counts was observed between the two groups. Although a slight increase in the WBC count was observed on POD 1-2 in both groups, it was near the reference range during follow-up. Thus, measuring CRP levels can be more effective in evaluating acute inflammatory responses than WBC counts. Although a high level of post-operative serum CRP concentrations was observed in the OS group, it rapidly decreased to a level similar to the pre-operative value if there were no post-operative complications.

분자 중심에 두 가지 다른 형태의 길고 강직한 core 구조를 함유하고 양 말단에 적당한 길이의 스페이서와 중합이 가능한 아크릴기를 포함하도록 설계된 두 종류의 액정단량체를 설계, 합성하였으며, 분자구조를 1H-NMR을 통해 확인 하였다. 합성된 액정단량체의 액정 특성을 DSC와 편광현미경을 사용하여 조사한 결과 각각 냉각 온도를 기준으로 84.6~74.0 oC와 133.5~91.6 oC 사이에서 스멕틱 상을 나타냄을 확인하였다. 특히 경직된 선형의 아세틸렌기를 포함하는 액정단량체(PRM-2)의 경우에는 보다 스멕틱 액정상의 발현 온도 범위가 넓을 뿐 아니라 좀 더 정렬도(order parameter)가 높은 스멕틱 A상을 나타냄을 확인 할 수 있었다.

본 연구는 반응성애착장애 유아의 언어 및 놀이발달의 변화과정을 그림책 읽어주기와 놀이참여를 통한 상담자의 개입으로 2018년 6월15일부터 2019년 1월 30일까지 주 2회 총 56회기로 약 7개월여 동안 단일대상으로 탐색연구 하였다. 상담자는 유아의 반응에 일관적이며 수용적인 태도로 자극을 촉진하고, 민감한 반응으로 상호작용하였다. 이에 따른 반응성애착장애 유아의 언어 및 놀이발달 변화과정은 다음과 같이 6단계로 나타났다. 첫째, 자극-불안정 접촉의 혼란스러 운 단계. 둘째, 자극-접촉의 안정의 단계. 셋째, 자극-촉진 수용의 단계. 넷째, 자극-습득 내면화 단계. 다섯째, 자극-표현 변화의 단계. 여섯째, 자극-확장 적 응의 단계로 변화하면서 유아는 일상생활에 적응하며 자신의 세계를 구축하였 다. 이러한 변화의 과정은 반응성애착장애 유아의 부모나 다양한 치료 현장의 상담사, 유아교육현장 교사들에게 개입을 위한 길잡이가 되어줄 것이다.

A variety of composite powders having different aluminum and carbon contents are prepared using various organic solvents having different amounts of carbon atoms in unit volume as ball milling agents for titanium and aluminum ball milling. The effects of substrate temperature and post-heat treatment on the texture and hardness of the coating are investigated by spraying with this reduced pressure plasma spray. The aluminum part of the composite powder evaporates during spraying, so that the film aluminum content is 30.9 mass%~37.4 mass% and the carbon content is 0.64 mass%~1.69 mass%. The main constituent phase of the coating formed on the water-cooled substrate is a non-planar α2 phase, obtained by supersaturated carbon regardless of the alloy composition. When these films are heat-treated at 1123 K, the main constituent phase becomes  phase, and fine Ti2AlC precipitates to increase the film hardness. However, when heat treatment is performed at a higher temperature, the hardness is lowered. The main constitutional phase of the coating formed on the preheated substrate is an equilibrium gamma phase, and fine Ti2AlC precipitates. The hardness of this coating is much higher than the hardness of the coating in the sprayed state formed on the water-cooled substrate. When hot pressing is applied to the coating, the porosity decreases but hardness also decreases because Ti2AlC grows. The amount of Ti2AlC in the hot-pressed film is 4.9 vol% to 15.3 vol%, depending on the carbon content of the film.

The aluminum (Al)/copper oxide (CuO) complex is known as the most promising material for thermite reactions, releasing a high heat and pressure through ignition or thermal heating. To improve the reaction rate and wettability for handling safety, nanosized primary particles are applied on Al/CuO composite for energetic materials in explosives or propellants. Herein, graphene oxide (GO) is adopted for the Al/CuO composites as the functional supporting materials, preventing a phase-separation between solvent and composites, leading to a significantly enhanced reactivity. The characterizations of Al/CuO decorated on GO(Al/CuO/GO) are performed through scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy mapping analysis. Moreover, the functional bridging between Al/CuO and GO is suggested by identifying the chemical bonding with GO in X-ray photoelectron spectroscopy analysis. The reactivity of Al/CuO/GO composites is evaluated by comparing the maximum pressure and rate of the pressure increase of Al/CuO and Al/CuO/GO. The composites with a specific concentration of GO (10 wt%) demonstrate a well-dispersed mixture in hexane solution without phase separation.