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Heat Treatment and TG-DTA Analysis of Uranyl Nitrate and Uranium Oxides
Yeojin Kim,Gun Young Yoon,Gyun Seob Song,Yulim Lee,Jae Hak Cheong,Sangjoon Ahn,Jaeyeong Park,Won Pyo Jeong,Seungyeon Choi,Kwang Heon Park 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2
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.
Secure authentication system that generates seed from biometric information
Kim, Yeojin,Ahn, Jung-Ho,Byun, Hyeran The Optical Society 2005 Applied Optics Vol.44 No.5
<P>As biometric recognition techniques are gradually improved, the stability of biometric authentication systems are enhanced. Although bioinformation has properties that make it resistant to fraud, biometric authentication systems are not immune to hacking. We show a secure biometric authentication system (1) to guarantee the integrity of biometric information by mixing data by use of a biometric key and (2) to raise recognition rates by use of bimodal biometrics.</P>
Yeojin Sung,Seungbin Cha,Sang Bum Kim,Hakhyun Kim,Seonghwi Choi,Sejin Oh,Minseo Kim,Yunji Lee,Gino Kwon,Jooyoung Lee,Joo-Youn Lee,한균희,김현석 생화학분자생물학회 2022 BMB Reports Vol.55 No.12
Epithelial-to-mesenchymal transition (EMT)-subtype gastric cancershave the worst prognosis due to their higher recurrence rate,higher probability of developing metastases and higher chemoresistancecompared to those of other molecular subtypes. Pharmacologicallyactionable somatic mutations are rarely found inEMT-subtype gastric cancers, limiting the utility of targeted therapies. Here, we conducted a high-throughput chemical screenusing 37 gastric cancer cell lines and 48,467 synthetic smallmoleculecompounds. We identified YK-135, a small-moleculecompound that showed higher cytotoxicity toward EMT-subtypegastric cancer cell lines than toward non-EMT-subtype gastriccancer cell lines. YK-135 exerts its cytotoxic effects by inhibitingmitochondrial complex I activity and inducing AMP-activatedprotein kinase (AMPK)-mediated apoptosis. We found that thelower glycolytic capacity of the EMT-subtype gastric cancer cellsconfers synthetic lethality to the inhibition of mitochondrialcomplex I, possibly by failing to maintain energy homeostasis. Other well-known mitochondrial complex I inhibitors (e.g., rotenoneand phenformin) mimic the efficacy of YK-135, supportingour results. These findings highlight mitochondrial complex Iinhibitors as promising therapeutic agents for EMT-subtype gastriccancers and YK-135 as a novel chemical scaffold for further drugdevelopment.
Yeojin Lee,Songhyeon Je,Hae‑Rim Kim,Jae Kyung Lee,Euna Choi,Jin Kyung Baek,Heeyon Kim,Bo Hyon Yun,Seok Kyo Seo 대한폐경학회 2023 대한폐경학회지 Vol.29 No.2
Objectives: This study used the Korean National Health and Nutrition Examination Survey (KNHANES) to determine the association between fractures and low muscle mass.Methods: This cross-sectional study used the 2010–2011 KNHANES data. Low muscle mass was defined as (appendicular skeletal muscle mass [kg]/Height2 [m2]) < 5.45 kg/m2, which is < 2 SD below the sex-specific mean of a young reference group. Patients with T-scores between –1.0 and –2.5 indicated osteopenia, whereas those with T-scores lower than –2.5 indicated osteoporosis.Results: Out of 1,306 women enrolled in the study, 330 were diagnosed with low muscle mass according to the abovementioned diagnostic criterion. The prevalence of fractures at various sites was significantly higher in postmenopausal women with low muscle mass than in those without low muscle mass (relative risk [RR], 1.64; odds ratio [OR], 1.62; 95% confidence interval [CI], 1.06–2.48; P = 0.027). Furthermore, the prevalence of fractures was increased by the presence of osteopenia or osteoporosis in addition to low muscle mass (RR, 1.59; OR, 1.60; 95% CI, 1.02–2.49; P = 0.039) and by osteoporosis only (RR, 2.12; OR, 2.29; 95% CI, 1.11–4.70; P = 0.025).Conclusions: Fracture was more prevalent in postmenopausal women with low muscle mass than in those without low muscle mass. This finding is consistent in a subgroup analysis that included women who had osteoporosis or osteopenia. Moreover, the risk of fractures increased as low muscle mass worsened.
( Yeojin Lee ),( Jae Kyung Lee ),( Sanghwa Kim ),( Yeon Ju Lee ),( Kichang Han ),( Man-deuk Kim ),( Heeyon Kim ),( Seok Kyo Seo ) 대한산부인과학회 2022 대한산부인과학회 학술대회 Vol.108 No.-
Objective: Although the surgical treatment remains gold standared in endometrioma, ovarian reserve is injured after the hemostasis and excision of the cyst. Catheter-directed ethanol sclerotherpy is known to affect the ovarian function less, increase efficacy, and reduce complications. This study aims to investigate the changes in ovarian reserve after catheter-directed ethanol sclerotherpy in recurrent endometrioma. Methods: Electronic medical records and pictures in patients with endometrioma who underwent catheter-directed ethanol sclerotherpy were obtainted in single institution from August 2014 to April 2022. Patient with aged >18 years old and AMH level >1.0 and <5.0 were enrolled in the study and age, BMI, cyst diameter, unilaterality, number of loculation and AMH level and CA-125 level before and after 1month, 6month, 1year and 2year of sclerotherapy were obtained. Results: 139 patients were enrolled in the study under IRB. There was significant differnece in AMH level before sclerotherapy in primary and recurrent endometrioma(2.68 vs. 2.04, p-value=0.011). However, there was no statistically significant difference in delta value of AMH after sclerotherapy in primary and recurrent endometrioma in 1month, 6month, 1year and 2year after sclerotherpy(91.78% vs. 96.14%, 74.75% vs. 81.58%, 83.98% vs. 65.79%, 97.08% vs. 52.52%, with p-value=0.593, 0.695, 0.217, 0.069, respectively). Also, this results were consistent regardless of unilaterality and loculation and CA-125 level showed no differerence between primary and recurrent endometrioma on every 1month, 6month, 1year and 2year after sclerotherpy. Conclusion: The effect of Catheter-directed ethanol sclerotherpy on ovarian reserve is not inferior in recurrent endometrioma compared to primary endometrima. Since sclerotherapy is known to less deteriorate the ovarian function than surgical removal of endometrioma, clinician could consider this as the first-line therapy in patient with recurrent endometrioma.
Yeojin Kim,Jiseon Yang,Dohyoung Rim,Uran Oh The Institute of Internet 2023 International journal of advanced smart convergenc Vol.12 No.2
Given the surge in the elderly population, and increasing in dementia cases, there is a growing interest in digital therapies that facilitate steady remote treatment. However, in the cognitive assessment of digital therapies through clinical trials, the absence of log data as an essential evaluation factor is a significant issue. To address this, we propose a solution of utilizing weighted derived variables based on high-importance variables' accuracy in log data utilization as an indirect cognitive assessment factor for digital therapies. We have validated the effectiveness of this approach using machine learning techniques such as XGBoost, LGBM, and CatBoost. Thus, we suggest the use of log data as a rapid and indirect cognitive evaluation factor for digital therapy users.