The solid-state chemistry of uranium is essential to the nuclear fuel cycle. Uranyl nitrate is a key compound that is produced at various stages of the nuclear fuel cycle, both in front-end and backend cycles. It is typically formed by dissolving spent nuclear fuel in nitric acid or through a wet conversion process for the preparation of UF6. Additionally, uranium oxides are a primary consideration in the nuclear fuel cycle because they are the most commonly used nuclear fuel in commercial nuclear reactors. Therefore, it is crucial to understand the oxidation and thermal behavior of uranium oxides and uranyl nitrates. Under the ‘2023 Nuclear Global Researcher Training Program for the Back-end Nuclear Fuel Cycle,’ supported by KONICOF, several experiments were conducted at IMRAM (Institute of Multidisciplinary Research for Advanced Materials) at Tohoku University. First, the recovery ratio of uranium was analyzed during the synthesis of uranyl nitrate by dissolving the actual radioisotope, U3O8, in a nitric acid solution. Second, thermogravimetric-differential thermal analysis (TG-DTA) of uranyl nitrate (UO2(NO3)2) and hyper-stoichiometric uranium dioxide (UO2+X) was performed. The enthalpy change was discussed to confirm the mechanism of thermal decomposition of uranyl nitrate under heating conditions and to determine the chemical hydrate form of uranyl nitrate. In the case of UO2+X, the value of ‘x’ was determined through the calculation of weight change data, and the initial form was verified using the phase diagram for the U-O system. Finally, the formation of a few UO2+X compounds was observed with heat treatment of uranyl nitrate and uranium dioxide at different temperature intervals (450°C-600°C). As a result of these studies, a deeper understanding of the thermal and chemical behavior of uranium compounds was achieved. This knowledge is vital for improving the efficiency and safety of nuclear fuel cycle processes and contributes to advancements in nuclear science and technology.

To find an alternative for synthetic pesticides, methanol extract from plant samples were tested for their insecticidal activity against insect. The extract of Asiasarum sieboldii had strongly insecticidal activity against Plutella xylostella. Roots of A. sieboldii were extracted with methanol, and the concentrated extract was partitioned with n-hexane, ethylacetate, n-buthanol and H2O. The highest activity was shown in the hexane fraction. Activity-guided fractionation led to the isolation of two amides from hexane fration through the repeated silica gel column chromatographic separations. From the interpretation of spectropic data including NMR, MS, IR, the chemical structures of compounds were determined as dodeca-2E,4E,8Z,10Z-tetraenoic acid isobutylamide and dodeca-2E,4E,8Z, 10E-tetraenoic acid isobutylamide. These compounds showed insecticidal activity on P. xylostella by 96.7% at 100ppm. The liquid formulation controlled on cabbage effectively. The extract and compounds from A. sieboldii showed insecticidal activity against Nilaparvata lugens. As a naturally occurring pesticide, A. sieboldii could be useful as a new botanic insecticide.

Background : Methicillin-Resistant Staphylococcus aureus (MRSA) is a multidrug-resistant (MDR) strain. Especially, MRSA is developing resistance to available antibacterial agents and causing complications in the treatment of infections related to skin, soft tissue, respiratory, bone, joint, and endovascular disorders. Therefore, antibacterial agent combination therapy appears to be a useful option, particularly in developing countries where antibiotic availability is limited. (+)-Usnic acid (UA) is uniquely found in lichens, and is especially abundant in genera such as Usnea and Cladonia. UA has antimicrobial activity against human and plant pathogens. Therefore, UA may be a good antibacterial drug candidate for clinical development. Methods and Results : In search of a natural products capable of inhibiting this multidrug-resistant bacteria, we have investigated the antimicrobial activity of UA against MRSA. In this study, the effects of a combination of UA and permeable agents against MRSA were investigated. For the measurement of cell wall permeability, UA with concentration of Ethylenediaminetetraacetic acid (EDTA) was used. In the other hand, Sodium azide (NaN3) was used as inhibitors of ATPase. These results suggest that the antibacterial effect of UA was potentiated by membrane-binding agents and ABC transporter-inhibiting agents, implying that antibacterial activity is associated with damage of the cell wall and inhibition of ATPase function by UA. Conclusion : UA and in combination with EDTA and NaN3 could lead to the development of new combination antibiotics against MRSA infection. The results of this study appear to be promising, and they are expected to enhance the use of natural products as drugs.

Background : Cynanchum wilfordii and Cynanchum auriculatum belong to the Asclepiadaceae family and appear morphologically similar. In order to discriminate them, it is needed to find the presence of sap and the leaf shapes: C. auriculatum has a blade ovate leaf comparing to C. wilfordii. However, in the herbal medicine market, they have been handled as cut and dried roots. Due to their similar morphology, it is limited to distinguish the roots of C. wilfordii and C. auriculatum. Recently in Korea, it has been a critical issue to misuse these two roots in the herbal market and food industry. Thus, it is required to establish a robust tool for the discrimination and quality control of them. Methods and Results : To separation and characterization of flavor compounds, C. wilfordii and C. auriculatum samples were analyzed by head space solid phase micro extraction (HSS) fiber coupled with gas chromatography-mass spectrometry using Rtx-5MS (30 m x 0.25 mm x 0.25 μm) column. As a result, We have identified compounds of a few hundred in aliphatic aldehydes and aliphatic alcohols, alkenes and acids, aromatic compounds, aromatic compounds containing nitrogen & sulfur, etc,. In particular, The aliphatic and aromatic compounds had been clearly separated on the second dimensional direction by using two-dimensional GC. Conclusion : The volatile flavor compounds of C. wilfordii and C. auriculatum could easily analyzed without pre-treatment with improved resolution and sensitivity using HSS-GCxGC-TOFMS. We have identified compounds of a few hundred in C. wilfordii and C. auriculatum sample. And It was more accurately qualitative confirmed with separation of GCxGC and TSD. We have confirmed the PCA and PLS-DA Plot that was classified depending on C. wilfordii and C. auriculatum through multivariate statistical analysis of the identified flavor compounds.