118 results on '"Hyunjeong Kim"'
Search Results
2. Reconsidering repurposing: long-term metformin treatment impairs cognition in Alzheimer’s model mice
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So Yeon Cho, Eun Woo Kim, Soo Jin Park, Benjamin U. Phillips, Jihyeon Jeong, Hyunjeong Kim, Christopher J. Heath, Daehwan Kim, Yurim Jang, Laura López-Cruz, Lisa M. Saksida, Timothy J. Bussey, Do Yup Lee, and Eosu Kim
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Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Abstract Metformin, a primary anti-diabetic medication, has been anticipated to provide benefits for Alzheimer’s disease (AD), also known as “type 3 diabetes”. Nevertheless, some studies have demonstrated that metformin may trigger AD pathology and even elevate AD risk in humans. Despite this, limited research has elucidated the behavioral outcomes of metformin treatment, which would hold significant translational value. Thus, we aimed to perform thorough behavioral research on the prolonged administration of metformin to mice: We administered metformin (300 mg/kg/day) to transgenic 3xTg-AD and non-transgenic (NT) C57BL/6 mice over 1 and 2 years, respectively, and evaluated their behaviors across multiple domains via touchscreen operant chambers, including motivation, attention, memory, visual discrimination, and cognitive flexibility. We found metformin enhanced attention, inhibitory control, and associative learning in younger NT mice (≤16 months). However, chronic treatment led to impairments in memory retention and discrimination learning at older age. Furthermore, metformin caused learning and memory impairment and increased levels of AMPKα1-subunit, β-amyloid oligomers, plaques, phosphorylated tau, and GSK3β expression in AD mice. No changes in potential confounding factors on cognition, including levels of motivation, locomotion, appetite, body weight, blood glucose, and serum vitamin B12, were observed in metformin-treated AD mice. We also identified an enhanced amyloidogenic pathway in db/db mice, as well as in Neuro2a-APP695 cells and a decrease in synaptic markers, such as PSD-95 and synaptophysin in primary neurons, upon metformin treatment. Our findings collectively suggest that the repurposing of metformin should be carefully reconsidered when this drug is used for individuals with AD.
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- 2024
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3. RECONSIDERING REPURPOSING: LONG-TERM METFORMIN TREATMENT IMPAIRS COGNITION IN ALZHEIMER’S MODEL MICE
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So Yeon Cho, Hyunjeong Kim, and Eosu Kim
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Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Published
- 2023
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4. Plasma adiponectin levels predict cognitive decline and cortical thinning in mild cognitive impairment with beta-amyloid pathology
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Keun You Kim, Junghee Ha, Minae Kim, So Yeon Cho, Hyunjeong Kim, Eosu Kim, and for the Alzheimer’s Disease Neuroimaging Initiative
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Adiponectin ,Alzheimer’s disease ,Beta-amyloid ,Cortical thickness ,Leptin ,Mild cognitive impairment ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Abstract Background Blood adiponectin and leptin are adipokines that emerged as potential biomarkers for predicting Alzheimer’s disease (AD) owing to their strong connection with obesity. Although obesity affects the relation between beta-amyloid (Aβ) aggregation and cognitive decline, the longitudinal interactive effect of adipokines and Aβ on cognition and brain structures in humans remains unexplored. Hence, we investigated whether plasma levels of adiponectin and leptin are associated with future cognitive decline and cortical thinning across Aβ conditions (Aβ [+] and Aβ [−]) in individuals with mild cognitive impairment (MCI). Methods Of 156 participants with MCI from the longitudinal cohort study of Alzheimer’s Disease Neuroimaging Initiative (ADNI), 31 were Aβ (−) and 125 were Aβ (+) as determined by CSF analysis. The Alzheimer’s Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) scores and the thickness of the parahippocampal and entorhinal cortices were used to evaluate cognition and brain structure, respectively. After stratifying groups by Aβ conditions, the association of cognitive and brain structural changes with baseline plasma levels of adiponectin and leptin was examined. Results Of the total 156 participants, 51 were women (32.7%). The mean age of participants was 74.5 (standard deviation 7.57), and the mean follow-up period was 54.3 months, without a difference between the Aβ (+) and (−) groups. After adjustment for confounders, higher plasma adiponectin levels were associated with a faster increase in ADAS-Cog scores, indicating faster cognitive decline under the Aβ (+) condition (beta = 0.224, p = 0.018). Likewise, participants with higher plasma adiponectin presented faster cortical thinning in the bilateral parahippocampal cortices under the Aβ (+) condition (beta = − 0.004, p = 0.012 for the right side; beta = − 0.004, p = 0.025 for the left side). Interestingly, plasma adiponectin levels were not associated with longitudinal ADAS-Cog scores or cortical thickness in the Aβ (−) condition. Plasma leptin levels were not predictive of cognition or cortical thickness regardless of Aβ status. Conclusion Plasma adiponectin can be a potential biomarker for predicting the speed of AD progression in individuals with Aβ (+) MCI.
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- 2022
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5. Association of metformin use with Alzheimer’s disease in patients with newly diagnosed type 2 diabetes: a population-based nested case–control study
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Junghee Ha, Dong-Woo Choi, Kwang Joon Kim, So Yeon Cho, Hyunjeong Kim, Keun You Kim, Youngseung Koh, Chung Mo Nam, and Eosu Kim
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Medicine ,Science - Abstract
Abstract Metformin reduces insulin resistance, which constitutes a pathophysiological connection of diabetes with Alzheimer’s disease (AD), but the evidence of metformin on AD development was still insufficient and conflicting. We investigated AD risk in patients with newly diagnosed type 2 DM treated with metformin. This retrospective, observational, nested case–control study included patients with newly diagnosed type 2 DM obtained from the Korean National Health Insurance Service DM cohort (2002–2017). Among 70,499 dementia-free DM patients, 1675 AD cases were matched to 8375 controls for age, sex, and DM onset and duration. The association between AD and metformin was analyzed by multivariable regression analyses, adjusted for comorbidities and cardiometabolic risk profile. Metformin use was associated with an increased odds of AD (adjusted odds ratio [AOR] 1.50; 95% CI 1.23–1.83). The risk of AD was higher in patients with a longer DM duration. Furthermore, AD risk was significantly high in DM patients with depression (AOR 2.05; 95% CI 1.02–4.12). Given the large number of patients with DM who are taking metformin worldwide, a double-blinded, prospective study is required to determine the long-term cognitive safety of metformin.
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- 2021
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6. Triazine-Based Small Molecules: A Potential New Class of Compounds in the Antifungal Toolbox
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Karen A. Conrad, Hyunjeong Kim, Mohammad Qasim, Amel Djehal, Aaron D. Hernday, Laurent Désaubry, and Jason M. Rauceo
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antifungal ,Candida ,triazine ,prohibitin ,yeast-to-hyphae transition ,Medicine - Abstract
Invasive fungal infections caused by Candida species remain a significant public health problem worldwide. The increasing prevalence of drug-resistant infections and a limited arsenal of antifungal drugs underscore the need for novel interventions. Here, we screened several classes of pharmacologically active compounds against mammalian diseases for antifungal activity. We found that the synthetic triazine-based compound melanogenin (Mel) 56 is fungicidal in Candida albicans laboratory and clinical strains with minimal inhibitory concentrations of 8–16 µg/mL. Furthermore, Mel56 has general antifungal activity in several non-albicans Candida species and the non-pathogenic yeast Saccharomyces cerevisiae. Surprisingly, Mel56 inhibited the yeast-to-hyphae transition at sublethal concentrations, revealing a new role for triazine-based compounds in fungi. In human cancer cell lines, Mel56 targets the inner mitochondrial integral membrane prohibitin proteins, PHB1 and PHB2. However, Mel56 treatment did not impact C. albicans mitochondrial activity, and antifungal activity was similar in prohibitin single, double, and triple homozygous mutant strains compared to the wild-type parental strain. These results suggests that Mel56 has a novel mechanism-of-action in C. albicans. Therefore, Mel56 is a promising antifungal candidate warranting further analyses.
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- 2023
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7. Treatment of Isolated Sternal Fracture with Ultrasound-Guided Paravertebral Nerve Block: a Case Report and Literature Review
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Jun-Mo Park and Hyunjeong Kim
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fracture ,nerve block ,pain management ,sternum ,ultrasonography ,Medicine (General) ,R5-920 - Abstract
In the case of isolated sternal fractures, conservative treatment with analgesics is common, but pain can persist for more than 10 weeks, which can significantly interfere with daily life. Ultrasound-guided paravertebral nerve block is reported to be a successful means of pain control in patients with chest wall injury or rib fracture. A 70-year-old female patient presented with anterior chest pain that had persisted for 2 weeks despite conservative treatment. Sagittal reconstruction chest computed tomography and sternum lateral oblique x-ray revealed an isolated sternal fracture. An ultrasound-guided bilateral paravertebral nerve block was performed for pain control. After performing the procedure twice at a 1-week interval, the patient reported complete pain alleviation, and no other problems were observed over the 3-month follow-up period. Ultrasound-guided bilateral paravertebral nerve block can help patients with isolated sternal fractures to manage pain and return to normal activities sooner than with oral analgesics.
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- 2019
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8. Generating Mechanism of Catalytic Effect for Hydrogen Absorption/Desorption Reactions in NaAlH4–TiCl3
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Kazutaka Ikeda, Fumika Fujisaki, Toshiya Otomo, Hidetoshi Ohshita, Takashi Honda, Toru Kawamata, Hiroshi Arima, Kazumasa Sugiyama, Hitoshi Abe, Hyunjeong Kim, Kouji Sakaki, Yumiko Nakamura, Akihiko Machida, Toyoto Sato, Shigeyuki Takagi, and Shin-ichi Orimo
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neutron diffraction ,X-ray diffraction ,anomalous X-ray scattering ,X-ray absorption fine structure ,hydrogen storage ,hydride complex ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
The hydrogen desorption and absorption reactions of the complex metal hydride NaAlH4 are disproportionation processes, and the kinetics can be improved by adding a few mol% of Ti compounds, although the catalytic mechanism, including the location and state of Ti, remains unknown. In this study, we aimed to reveal the generating mechanism of catalytic Al–Ti alloy in NaAlH4 with TiCl3 using quantum multiprobe techniques such as neutron diffraction (ND), synchrotron X-ray diffraction (XRD), anomalous X-ray scattering (AXS), and X-ray absorption fine structure (XAFS). Rietveld refinements of the ND and XRD, profiles before the first desorption of NaAlD(H)4–0.02TiCl3 showed that Al in NaAlD(H)4 was partially substituted by Ti. On the other hand, Ti was not present in NaAlH4, and Al–Ti nanoparticles were detected in the XRD profile after the first re-absorption. This was consistent with the AXS and XAFS results. It is suggested that the substitution promotes the formation of a highly dispersed nanosized Al–Ti alloy during the first desorption process and that the effectiveness of TiCl3 as an additive can be attributed to the dispersion of Ti.
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- 2021
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9. Glycolysis on F-18 FDG PET/CT Is Superior to Amino Acid Metabolism on C-11 Methionine PET/CT in Identifying Advanced Renal Cell Carcinoma at Staging
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Suk-Hyun Lee, Jee-Soo Park, Hyunjeong Kim, Dongwoo Kim, Seung-Hwan Lee, Won-Sik Ham, Woong-Kyu Han, Young-Deuk Choi, and Mijin Yun
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F-18 fluorodeoxyglucose ,C-11 methionine ,positron emission tomography ,renal cell carcinoma ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
We evaluated the value of F-18 fluorodeoxyglucose (FDG) and C-11 methionine positron emission tomography/computed tomography (PET/CT) to predict high-Fuhrman grade and advanced-stage tumours in patients with renal cell carcinoma (RCC). Forty patients with RCC underwent F-18 FDG and C-11 methionine PET/CT between September 2016 and September 2018. They were classified into limited (stages I and II, n = 15) or advanced stages (stages III and IV, n = 25) according to pathological staging. Logistic regressions were used to predict the advanced stage using various parameters, including maximum standardised uptake value (SUVmax) and metabolic tumour volume (MTV). Receiver operating characteristic analyses were performed to predict high-grade tumours (Fuhrman 3 and 4). On univariate analysis, tumour size, SUVmax and MTV of F-18 FDG and C-11 methionine, and Fuhrman grades were significant predictors for the advanced stage. On multivariate analysis, F-18 FDG MTV > 21.3 cm3 was the most significant predictor (p < 0.001). The area under the curve for predicting high-grade tumours was 0.830 for F-18 FDG (p < 0.001) and 0.726 for C-11 methionine PET/CT (p = 0.014). In conclusion, glycolysis on F-18 FDG PET/CT and amino acid metabolism on C-11 methionine PET/CT were variable but increased in high-grade RCCs. Increased MTV on F-18 FDG PET/CT is a powerful predictor of advanced-stage tumours.
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- 2021
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10. Optimizing reproducibility of operant testing through reinforcer standardization: identification of key nutritional constituents determining reward strength in touchscreens
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Eun Woo Kim, Benjamin U. Phillips, Christopher J. Heath, So Yeon Cho, Hyunjeong Kim, Jemeen Sreedharan, Ho-Taek Song, Jong Eun Lee, Timothy J. Bussey, Chul Hoon Kim, Eosu Kim, and Lisa M. Saksida
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Reinforcer ,Operant behavior ,Calories ,Touchscreen chamber ,Standardization ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Abstract Reliable and reproducible assessment of animal learning and behavior is a central aim of basic and translational neuroscience research. Recent developments in automated operant chamber technology have led to the possibility of universal standard protocols, in addition to increased translational potential, reliability and accuracy. However, the impact of regional and national differences in the supplies of available reinforcers in this system on behavioural performance and inter-laboratory variability is an unknown and at present uncontrolled variable. Therefore, we aimed to identify which constituent(s) of the reward determines reinforcer strength to enable improved standardization of this parameter across laboratories. Male C57BL/6 mice were examined in the touchscreen-based fixed ratio (FR) and progressive ratio (PR) schedules, reinforced with different kinds of milk-based reinforcers to directly compare the incentive values of plain milk (PM, high-calorie: high-fat/low-sugar), strawberry-flavored milk (SM, high-calorie: low-fat/high-sugar), and semi-skimmed low-fat milk (LM, low-calorie: low-fat/low-sugar) on the basis of differences in caloric content, sugar/fat content, and flavor. Use of a higher caloric content reward was effective in increasing operant training acquisition rate. Total trial number completed in FR and breakpoint in PR were higher using the two isocaloric milk products (PM and SM) than the lower caloric LM, with comparable outcomes between PM and SM conditions, suggesting that total caloric content determines reward strength. Analysis of within-session changes in response rate revealed that overall outputs in FR and PR primarily depend on the response rate at the initial phase of a session, which itself was dependent on reinforcer caloric content. Interestingly, the rate of satiation, indicated by decay in response rate within a FR session, was highest when reinforced with SM, suggesting a rapid satiating effect of sugar. The key contribution of reward caloric content to operant performance was confirmed in a multi-laboratory study using the touchscreen 5-choice serial reaction time task (5-CSRTT) reinforced by two isocaloric milk-based liquid rewards with different countries of origin, which yielded consistent performance parameters across sites. Our results indicate that milk-based liquid reinforcer standardization can be facilitated by matching caloric content across laboratories despite regional or national differences in other non-caloric aspects of the reinforcers.
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- 2017
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11. True Tracheal Bronchus: Classification and Anatomical Relationship on Multi-Detector Computed Tomography
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Hyunjeong Kim, Young Tong Kim, Sung Shick Jou, and Woong Hee Lee
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multidetector computed tomography ,bronchus ,congenital abnormalities ,classification ,Medical physics. Medical radiology. Nuclear medicine ,R895-920 - Abstract
Purpose To propose the imaging classification of true tracheal bronchus (TTB) on multi-detector computed tomography (MDCT), and to evaluate its anatomical relationship with surrounding structures. Materials and Methods This study included 44 patients who were diagnosed with TTB on MDCT for 6 years. We classified TTB into five types, based on the existence of the right upper lobe bronchus originating from the right main bronchus and the number of segmental bronchi of TTB. We analyzed the site of origin and the running direction of TTB based on its anatomical relationship with surrounding structures and some ancillary findings. Results The imaging classification of TTB included Type I (47.7%), Type II (13.6%), Type III (11.4%), Type IV (25.0%), and Type V (2.0%). According to the site of origin of TTB, below the aortic arch (52.3%) and at the level of the aortic arch (43.1%) were the two main sites of origin, whereas the frequency of the site of origin above the azygos arch, at the level of the azygos arch, and below the azygos arch was 27.3%, 38.6%, and 34.1%, respectively. Considering both aortic and azygos arches, below the aortic arch and below the azygos arch were the most common sites of origin (27.3%). With respect to the running direction of TTB, in all cases, TTB passed below the azygos arch to the right upper lobe. There was no statistically significant (p > 0.05) difference in age or sex between types of TTB. Ancillary findings included tracheal stenosis (n = 2), narrowing of the right main bronchus (n = 2), luminal narrowing of TTB and bronchiectasis at the distal portion (n = 1), and a highly located azygos arch above the aortic arch (n = 2). Conclusion The proposed imaging classification of TTB and its anatomical relationship with surrounding structures will improve our understanding of various imaging features and embryological development of TTB. Radiologists should pay careful attention to evaluation of the airway including the trachea on thoracic imaging.
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- 2017
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12. Trend of Daily Sports Participation in Korean Aged Population and Sports Policy: A Review of Research on Public Daily Sports Participation
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Misuk KIM, Sejeong PARK, Hyunjeong KIM, Eunsurk YI, and Sangwan JEON
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Korean aged population ,Sports policy ,Public daily sports participation ,Public aspects of medicine ,RA1-1270 - Abstract
Background: This study aimed to investigate the trend of physical activity and daily sports participation in the Korean aged population through the review of ‘Research on Public Daily Sports Participation’ published by the Ministry of Culture, Sports and Tourism. The main purpose was to suggest the best health and sports policy for the future. Methods: The result of the research conducted by the government was published 13 times in total from 1989 to 2015. The aged were defined as people in their 60s and 70s since 2006. Based on the research published 7 times from 2006 to 2015, this study analyzed the changes and the trend recognition of health status, physical activities, sports activity effects and environment in the aged population in South Korea. Results: Majority of the aged population was found to hardly recognize their health status, but positively aware of physical and sports activity effect, particularly that the sports facility environment has been improving. Therefore, it is encouraged to set up elderly-friendly routine sports environment to motivate their participation and consequently establish healthy exercise culture. Conclusion: This study has great significance as it suggests the direction of future health and sports policy by analyzing the trend of previous physical activities and daily sports participation among the aged population based on the government-published research.
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- 2018
13. Locomotion Techniques for Dynamic Environments: Effects on Spatial Knowledge and User Experiences.
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Hyunjeong Kim, Sang-Bin Jeon, and In-Kwon Lee
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- 2024
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14. Optimized single-layer MoS2 field-effect transistors by non-covalent functionalisation
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Kim, HyunJeong Kim WungYeon, O'Brien, Maria, McEvoy, Niall, Yim, Chanyoung, Marcia, Mario, Hauke, Frank, Hirsch, Andreas, Kim, Gyu-Tae, and Duesberg, Georg S.
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Physics - Applied Physics - Abstract
Field-effect transistors (FETs) with non-covalently functionalised molybdenum disulfide (MoS2) channels grown by chemical vapour deposition (CVD) on SiO2 are reported. The dangling-bond-free surface of MoS2 was functionalised with a perylene bisimide derivative to allow for the deposition of Al2O3 dielectric. This allowed the fabrication of top-gated, fully-encapsulated MoS2 FETs. Furthermore, by the definition of vertical contacts on MoS2, devices, in which the channel area was never exposed to polymers, were fabricated. The MoS2 FETs showed high mobilities for transistors fabricated on SiO2 with Al2O3 as top-gate dielectric. Thus, gate-stack engineering using innovative chemistry is a promising approach for the fabrication of reliable electronic devices based on 2D materials.
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- 2018
15. Effects of Simulator Sickness and Emotional Responses When Inter-pupillary Distance Misalignment Occurs.
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Hyunjeong Kim and Ji-Hyung Park
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- 2019
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16. Biomedical image analysis competitions: The state of current participation practice.
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Matthias Eisenmann, Annika Reinke, Vivienn Weru, Minu Dietlinde Tizabi, Fabian Isensee, Tim J. Adler, Patrick Godau, Veronika Cheplygina, Michal Kozubek 0001, Sharib Ali, Anubha Gupta, Jan Kybic, J. Alison Noble, Carlos Ortiz-de-Solórzano, Samiksha Pachade, Caroline Petitjean, Daniel Sage, Donglai Wei 0001, Elizabeth Wilden, Deepak Alapatt, Vincent Andrearczyk, Ujjwal Baid, Spyridon Bakas, Niranjan Balu, Sophia Bano, Vivek Singh Bawa, Jorge Bernal, Sebastian Bodenstedt, Alessandro Casella, Jinwook Choi, Olivier Commowick, Marie Daum, Adrien Depeursinge, Reuben Dorent, Jan Egger, Hannah Eichhorn, Sandy Engelhardt, Melanie Ganz, Gabriel Girard, Lasse Hansen, Mattias P. Heinrich, Nicholas Heller, Alessa Hering, Arnaud Huaulmé, Hyunjeong Kim, Bennett A. Landman, Hongwei Bran Li, Jianning Li, Jun Ma 0016, Anne L. Martel, and et al.
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- 2022
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17. PAIP 2020: Microsatellite instability prediction in colorectal cancer.
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Kyungmo Kim, Kyoungbun Lee, Sungduk Cho, Dong Un Kang, Seongkeun Park, Yunsook Kang, Hyunjeong Kim, Gheeyoung Choe, Kyung Chul Moon, Kyu Sang Lee, Jeong Hwan Park, Choyeon Hong, Ramin Nateghi, Fattaneh Pourakpour, Xiyue Wang, Sen Yang 0006, Seyed Alireza Fatemi Jahromi, Aliasghar Khani, Hwa-Rang Kim, Doo-Hyun Choi, Chang Hee Han, Jin Tae Kwak, Fan Zhang, Bing Han, David Joon Ho, Gyeong Hoon Kang, Se Young Chun, Won-Ki Jeong, Peom Park, and Jinwook Choi
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- 2023
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18. The Effect of School Field Practice on Pre-service Early Childhood Teachers’ Teaching Competence and Teaching Efficacy
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Kyungnam Choi and Hyunjeong Kim
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- 2023
19. A Study on the Status and Necessity of Public Relations (PR) Activities of Domestic Early Childhood Education Institutions
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Hyunjeong Kim and Jongae Kown
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- 2023
20. Validation of LC-MS/MS and GC-MS/MS based analysis for 7 pesticides using QuEChERS
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Miok Song, Hyunjeong Kim, Eunsun Yun, Chunyeong Lee, Namhoon Kim, Bokyung Jung, Youngju Lee, Misun Kim, Heesoon Kim, Heejin Choi, and Jinkyung Yu
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Applied Microbiology and Biotechnology ,Food Science ,Biotechnology - Published
- 2023
21. Pressure cells for in situ neutron total scattering: time and real-space resolution during deuterium absorption
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Kazutaka Ikeda, Hidetoshi Ohshita, Toshiya Otomo, Kouji Sakaki, Hyunjeong Kim, Yumiko Nakamura, Akihiko Machida, and Robert B. Von Dreele
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General Biochemistry, Genetics and Molecular Biology - Abstract
In situ gas-loading sample holders for two-dimensionally arranged detectors in time-of-flight neutron total scattering experiments have been developed to investigate atomic arrangements during deuterium absorption using time and real-space resolution. A single-crystal sapphire container was developed that allows conditions of 473 K and 10 MPa hydrogen gas pressure. High-resolution transient measurements detected deuterium absorption by palladium that proceeded within a few seconds. A double-layered container with thick- and thin-walled vanadium allowed conditions of 423 K and 10 MPa hydrogen gas pressure. The deuterium occupation sites of a lanthanum–nickel–aluminium alloy are discussed in detail on the basis of real-space high-resolution data obtained from in situ neutron scattering measurements and reverse Monte Carlo structural modeling.
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- 2022
22. 'A Study on Infectious Disease Cases and Prevention Countermeasures in Early Childhood Education Institutions: Focused on the Analysis of Media Reports and the Perception of Early Childhood Teachers'
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Jongae Kwon and Hyunjeong Kim
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- 2022
23. Relationship Between Adipokines, Cognition, and Brain Structures in Old Age Depending on Obesity
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Junghee Ha, Seyul Kwak, Keun You Kim, Hyunjeong Kim, So Yeon Cho, Minae Kim, Jun-Young Lee, and Eosu Kim
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Aging ,Geriatrics and Gerontology - Abstract
Background Adipokines such as leptin and adiponectin are associated with cognitive function. Although adiposity crucially affects adipokine levels, it remains unclear whether the relationship between adipokines and cognition is influenced by obesity. Methods We enrolled 171 participants and divided them into participants with obesity and without obesity to explore the effect of obesity on the relationship between adipokines and cognition. In addition to plasma levels of leptin and adiponectin, multidomain cognitive functions and brain structures were assessed using neuropsychological testing and magnetic resonance imaging. Association between levels of these adipokines and Alzheimer’s disease (AD) was then assessed by logistic regression. Results We found that cognitive function was negatively associated with leptin levels and leptin-to-adiponectin ratio (LAR). Such correlations between leptin and cognitive domains were prominent in participants with obesity but were not observed in those without obesity. Leptin levels were associated with lower hippocampal volumes in participants with obesity. A significant interaction of leptin and obesity was found mostly in the medial temporal lobe. Both leptin and LAR were positively associated with insulin resistance and inflammation markers in all participants. Of note, LAR was associated with a higher risk of AD after adjusting for demographic variables, Apolipoprotein E genotype, and body mass index. Conclusions Obesity might be a factor that determines how adipokines affect brain structure and cognition. Leptin resistance might influence the relationship between adipokines and cognition. In addition, LAR rather than each adipokine levels alone may be a better indicator of AD risk in older adults with metabolic stress.
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- 2022
24. Local Structural Change of V–Ti–Cr Alloy Hydrides Depending on Hydrogen Absorption/Desorption Cycles
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Kazutaka IKEDA, Sho Sashida, Toshiya Otomo, Hidetoshi Ohshita, Takashi Honda, Takafumi Hawai, Hiraku Saito, Shinichi Itoh, Tetsuya Yokoo, Kouji SAKAKI, Hyunjeong Kim, Yumiko Nakamura, Akihiko Machida, Daiju Matsumura, and Wojciech A. Slawinski
- Published
- 2023
25. Tuning the hydrogenation properties of Ti1+Cr2-Mn laves phase compounds for high pressure metal-hydride compressors
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Kouji Sakaki, Véronique Charbonnier, Hyunjeong Kim, Hirotoshi Enoki, and Kohta Asano
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Materials science ,Hydrogen ,Renewable Energy, Sustainability and the Environment ,Hydride ,Analytical chemistry ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Laves phase ,Condensed Matter Physics ,Metal ,Hysteresis ,Fuel Technology ,chemistry ,visual_art ,Desorption ,visual_art.visual_art_medium ,Fugacity ,Absorption (chemistry) - Abstract
Ti1+yCr2-xMnx compounds with a hexagonal MgZn2-type structure were investigated for their potential use in metal-hydride (MH) compressor applications. Here, the targeted MH compressor should absorb hydrogen below 30 MPa at 30 °C and desorb hydrogen at 80 MPa when heated at 80 °C. The pressure (P)-composition (C) isotherms were measured at pressures up to 40 MPa. Because of the very high pressures, the fugacity was taken into account. Details are given on how to determine the absorption and desorption enthalpies and entropies from the fugacity. The Van't Hoff plots were used to estimate the critical temperatures (TC). The P–C isotherms of all the compounds exhibit relatively small hysteresis and flat plateaus but the absorption and desorption pressures need to be increased. Superstoichiometry of y = 0.05 tends to decrease the plateau pressure and increase its slope, which is not desired for our target. On the other hand, the increase of Mn content led to higher TC as well as higher and flatter plateaus. Cr is a key element to get small hysteresis.
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- 2021
26. Pressure cells for
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Kazutaka, Ikeda, Hidetoshi, Ohshita, Toshiya, Otomo, Kouji, Sakaki, Hyunjeong, Kim, Yumiko, Nakamura, Akihiko, Machida, and Robert B, Von Dreele
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- 2022
27. Crystal and local structures of La2Co7H obtained by synchrotron X-ray total scattering
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Kenji Iwase, Takashi Ueno, Seiya Mashii, Hyunjeong Kim, Kouji Sakaki, and Kazuhiro Mori
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Mechanics of Materials ,Mechanical Engineering ,Materials Chemistry ,Metals and Alloys - Published
- 2023
28. A Meta-analysis on the Effects of the Personality Education Program Using Picture-books on Children’s Pro-social Behavior and Self-regulation Ability
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Sunghyoun Cho and Hyunjeong Kim
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Prosocial behavior ,Picture books ,media_common.quotation_subject ,Meta-analysis ,Personality ,General Medicine ,Psychology ,media_common ,Developmental psychology - Published
- 2021
29. Magnesium- and intermetallic alloys-based hydrides for energy storage: modelling, synthesis and properties
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Luca Pasquini, Kouji Sakaki, Etsuo Akiba, Mark D Allendorf, Ebert Alvares, Josè R Ares, Dotan Babai, Marcello Baricco, Josè Bellosta von Colbe, Matvey Bereznitsky, Craig E Buckley, Young Whan Cho, Fermin Cuevas, Patricia de Rango, Erika Michela Dematteis, Roman V Denys, Martin Dornheim, J F Fernández, Arif Hariyadi, Bjørn C Hauback, Tae Wook Heo, Michael Hirscher, Terry D Humphries, Jacques Huot, Isaac Jacob, Torben R Jensen, Paul Jerabek, Shin Young Kang, Nathan Keilbart, Hyunjeong Kim, Michel Latroche, F Leardini, Haiwen Li, Sanliang Ling, Mykhaylo V Lototskyy, Ryan Mullen, Shin-ichi Orimo, Mark Paskevicius, Claudio Pistidda, Marek Polanski, Julián Puszkiel, Eugen Rabkin, Martin Sahlberg, Sabrina Sartori, Archa Santhosh, Toyoto Sato, Roni Z Shneck, Magnus H Sørby, Yuanyuan Shang, Vitalie Stavila, Jin-Yoo Suh, Suwarno Suwarno, Le Thi Thu, Liwen F Wan, Colin J Webb, Matthew Witman, ChuBin Wan, Brandon C Wood, Volodymyr A Yartys, UAM. Departamento de Física de Materiales, Pasquini L., Sakaki K., Akiba E., Allendorf M.D., Alvares E., Ares J.R., Babai D., Baricco M., Bellosta Von Colbe J., Bereznitsky M., Buckley C.E., Cho Y.W., Cuevas F., De Rango P., Dematteis E.M., Denys R.V., Dornheim M., Fernandez J.F., Hariyadi A., Hauback B.C., Heo T.W., Hirscher M., Humphries T.D., Huot J., Jacob I., Jensen T.R., Jerabek P., Kang S.Y., Keilbart N., Kim H., Latroche M., Leardini F., Li H., Ling S., Lototskyy M.V., Mullen R., Orimo S.-I., Paskevicius M., Pistidda C., Polanski M., Puszkiel J., Rabkin E., Sahlberg M., Sartori S., Santhosh A., Sato T., Shneck R.Z., Sorby M.H., Shang Y., Stavila V., Suh J.-Y., Suwarno S., Thi Thu L., Wan L.F., Webb C.J., Witman M., Wan C., Wood B.C., Yartys V.A., Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), National Institute of Advanced Industrial Science and Technology [Tokyo] (AIST), Kyushu University [Fukuoka], Sandia National Laboratories [Livermore], Sandia National Laboratories - Corporation, Helmholtz-Zentrum Geesthacht (GKSS), Departamento de Física Aplicada [UAM Madrid], Universidad Autónoma de Madrid (UAM), Ben-Gurion University of the Negev (BGU), Università degli studi di Torino = University of Turin (UNITO), Curtin University [Perth], Planning and Transport Research Centre (PATREC), Korea Advanced Institute of Science and Technology (KIST), Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Matériaux, Rayonnements, Structure (MRS), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Institute for Energy Technology (IFE), Institut Teknologi Sepuluh Nopember [Surabaya] (ITS), Lawrence Livermore National Laboratory (LLNL), Max Planck Institute for Intelligent Systems [Tübingen], Max-Planck-Gesellschaft, Université du Québec à Trois-Rivières (UQTR), Aarhus University [Aarhus], Hefei University of Technology (HFUT), University of Nottingham, UK (UON), University of the Western Cape, Tohoku University [Sendai], Military University of Technology, Technion - Israel Institute of Technology [Haifa], Uppsala Universitet [Uppsala], University of Oslo (UiO), Shibaura Institute of Technology, Griffith University [Brisbane], and University of Science and Technology Beijing [Beijing] (USTB)
- Subjects
hydrogen storage material ,nanostructure ,hydrogen storage materials ,energy storage ,intermetallic alloys ,Intermetallics Compounds ,Magnesium Compounds ,Física ,[CHIM.MATE]Chemical Sciences/Material chemistry ,General Medicine ,intermetallic alloy ,magnesium ,catalysts ,multiscale modelling ,Hydrogen Sorption ,Titanium Alloys ,catalyst - Abstract
Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAM, Hydrides based on magnesium and intermetallic compounds provide a viable solution to the challenge of energy storage from renewable sources, thanks to their ability to absorb and desorb hydrogen in a reversible way with a proper tuning of pressure and temperature conditions. Therefore, they are expected to play an important role in the clean energy transition and in the deployment of hydrogen as an efficient energy vector. This review, by experts of Task 40 'Energy Storage and Conversion based on Hydrogen' of the Hydrogen Technology Collaboration Programme of the International Energy Agency, reports on the latest activities of the working group 'Magnesium- and Intermetallic alloys-based Hydrides for Energy Storage'. The following topics are covered by the review: multiscale modelling of hydrides and hydrogen sorption mechanisms; synthesis and processing techniques; catalysts for hydrogen sorption in Mg; Mg-based nanostructures and new compounds; hydrides based on intermetallic TiFe alloys, high entropy alloys, Laves phases, and Pd-containing alloys. Finally, an outlook is presented on current worldwide investments and future research directions for hydrogen-based energy storage
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- 2022
30. A Research on UX(User eXperience) of the Middle-aged on Kinect-Based Games that induce physical activity
- Author
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Hyunjeong Kim
- Subjects
User experience design ,business.industry ,Human–computer interaction ,Physical activity ,Serious game ,Psychology ,business - Published
- 2020
31. Hydrogenation Properties of Mg83.3Cu7.2Y9.5 with Long Period Stacking Ordered Structure and Formation of Polymorphic γ-MgH2
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Véronique Charbonnier, Kohta Asano, Kouji Sakaki, and Hyunjeong Kim
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Inorganic Chemistry ,Crystallography ,chemistry ,Magnesium ,Long period ,Stacking ,chemistry.chemical_element ,Physical and Theoretical Chemistry - Abstract
Nanosizing is known to affect the hydrogenation properties of magnesium. For this reason, the long period stacking ordered (LPSO) structures, made of the stacking of nanolayers of magnesium and nan...
- Published
- 2020
32. Reaction paths via a new transient phase in non-equilibrium hydrogen absorption of LaNi2Co3
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Tetsu Watanuki, Yumiko Nakamura, Hyunjeong Kim, Akihiko Machida, Kohta Asano, and Kouji Sakaki
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Diffraction ,Materials science ,Hydrogen ,Renewable Energy, Sustainability and the Environment ,Alloy ,Analytical chemistry ,Energy Engineering and Power Technology ,chemistry.chemical_element ,engineering.material ,Condensed Matter Physics ,Synchrotron ,law.invention ,Fuel Technology ,chemistry ,law ,Phase (matter) ,engineering ,Transient (oscillation) ,Hydrogen absorption ,Dissolution - Abstract
This study investigated the non-equilibrium hydrogen absorption reaction paths of the AB5-type LaNi2Co3 alloy using time-resolved in situ synchrotron X-ray diffraction. Diffraction data were collected every second for reactions under two hydrogen loading pressures. Hydrogen absorption with a hydrogen loading of 1 MPa rapidly transformed α phase to a transient phase (estimated to be LaNi2Co3H3.1–3.6, named γ∗); this has not previously been observed under equilibrium processes. The γ∗ phase continuously transformed into the γ phase (LaNi2Co3H4.5–5.0), and the β phase (LaNi2Co3H~3.6) was not formed. When 0.18 MPa of hydrogen was loaded, initially, the γ∗ phase appeared, followed by the formation of the β phase, finally transforming into the γ phase. These results indicate that a higher loading pressure promotes the formation of the γ∗ phase and assists its continuous transformation into the γ phase by enhancing the dissolution of hydrogen into the α and γ∗ phases.
- Published
- 2020
33. A Study on Political Relations of Japan’s Keidanren with South Korea
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Song Junghyun and HyunJeong Kim
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Politics ,Political science ,Economic history - Published
- 2020
34. Unveiling Nanoscale Compositional and Structural Heterogeneities of Highly Textured Mg0.7Ti0.3Hy Thin Films
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Herman Schreuders, Kouji Sakaki, Akihiko Machida, Bernard Dam, Yumiko Nakamura, Naoyuki Maejima, Kohta Asano, Hyunjeong Kim, and Tetsu Watanuki
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Inorganic Chemistry ,010405 organic chemistry ,Chemistry ,Nanotechnology ,Physical and Theoretical Chemistry ,Thin film ,010402 general chemistry ,01 natural sciences ,Nanoscopic scale ,Mechanism (sociology) ,0104 chemical sciences - Abstract
Thin films often exhibit fascinating properties, but the understanding of the underlying mechanism behind such properties is not simple. This is partially because of the limited structural informat...
- Published
- 2020
35. The Anti-inflammatory and Immune-Boosting Potential of Quercetin-3-O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranoside in LPS–Stimulated RAW264.7 Macrophages
- Author
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Jae-Yoon Jang, Jae Myo Yu, Yong-Hun Cho, Sun Chul Kang, Bong-Jeun An, Jae Yong Park, Han-Hyuk Kim, Debasish Kumar Dey, Hyunjeong Kim, and Hyun-Gug Jung
- Subjects
Lipopolysaccharide ,010405 organic chemistry ,Chemistry ,medicine.drug_class ,Pharmacology ,medicine.disease_cause ,01 natural sciences ,Anti-inflammatory ,0104 chemical sciences ,Nitric oxide ,010404 medicinal & biomolecular chemistry ,chemistry.chemical_compound ,Immune system ,Downregulation and upregulation ,medicine ,General Pharmacology, Toxicology and Pharmaceutics ,Protein kinase A ,Quercetin ,Escherichia coli - Abstract
Diospyros kaki L.f., Ebenaceae, have been used since centuries in traditional medicines in many Asian countries as it contains numerous flavonoids. Out of those plenty flavonoids, quercetin-3-O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranoside (1) was found to be one of those active components of the plant. In the present study, we confirmed the non-toxicity behavior of 1 on RAW 264.7 macrophage cells and demonstrated its anti-inflammatory property. Our result indicates that 1 treatment significantly controlled the upregulation of the mitogen-activated protein kinase pathway in a dose-dependent manner in the Escherichia coli produced lipopolysaccharide induced infection background. In addition, its treatment significantly reduced the nitric oxide level, and down-regulated the protein expression of TNF-α, PGE2, IL-1β, IL-6, COX-2, and iNOS in lipopolysaccharide stimulated RAW 264.7 macrophage cells. Taken together, our results suggested that 1 efficiently modulates the MAPK signaling pathway and controlled the inflammatory event. Collectively, the result of the study confirmed the potential of 1 as a potent drug candidate and suggested its usage against the inflammatory diseases.
- Published
- 2020
36. Metallurgical Synthesis of Mg2FexSi1–x Hydride: Destabilization of Mg2FeH6 Nanostructured in Templated Mg2Si
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Herman Schreuders, Asaya Fujita, Kouji Sakaki, R.J. Westerwaal, Yongming Wang, Tetsu Watanuki, Bernard Dam, Masaaki Doi, Akihiko Machida, Yumiko Nakamura, Shigehito Isobe, Hyunjeong Kim, Naoyuki Maejima, and Kohta Asano
- Subjects
010405 organic chemistry ,Chemistry ,Hydride ,Magnesium ,chemistry.chemical_element ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Inorganic Chemistry ,Hydrogen storage ,Chemical engineering ,Hydrogen fuel ,Gravimetric analysis ,Physical and Theoretical Chemistry - Abstract
Magnesium-based transition-metal hydrides are attractive hydrogen energy materials because of their relatively high gravimetric and volumetric hydrogen storage capacities combined with low material...
- Published
- 2020
37. Structural evolution of carbon dots during low temperature pyrolysis
- Author
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Hui Luo, Leonardo Lari, Hyunjeong Kim, Servann Hérou, Liviu Cristian Tanase, Vlado K. Lazarov, and Maria-Magdalena Titirici
- Subjects
General Materials Science - Abstract
Carbon dots (CDs) are an emerging class of photoluminescent material. Their unique optical properties arise from the discrete energy levels in their electronic states, which directly relate to their crystalline and chemical structure. It is expected that when CDs go through structural changes via chemical reduction or thermal annealing, their energy levels will be altered, inducing unique optoelectronic properties such as solid-state photoluminescence (PL). However, the detailed structural evolution and how the optoelectronic characteristics of CDs are affected remain unclear. Therefore, it is of fundamental interest to understand how the structure of CDs prepared by hydrothermal carbonisation (HTC) rearranges from a highly functionalised disordered structure into a more ordered graphitic structure. In this paper, detailed structural characterisation and in situ TEM were conducted to reveal the structural evolution of CDs during the carbonisation process, which have demonstrated a growth in aromatic domains and reduction in oxidation sites. These structural features are correlated with their near-infrared (NIR) solid-state PL properties, which may find a lot of practical applications such as temperature sensing, solid-state display lighting and anti-counterfeit security inks.
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- 2022
38. Assessment of organochlorine pesticides in the atmosphere of South Korea: spatial distribution, seasonal variation, and sources
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Myungsup Lee, Sumin Lee, Seam Noh, Kwang-Su Park, Seok Min Yu, Seunghwa Lee, Young-Sun Do, Young Hee Kim, Myunghee Kwon, Hyunjeong Kim, and Min-Kyu Park
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Air Pollutants ,Atmosphere ,Hexachlorobenzene ,Hydrocarbons, Chlorinated ,General Medicine ,Seasons ,Management, Monitoring, Policy and Law ,Pesticides ,Pollution ,General Environmental Science ,Environmental Monitoring - Abstract
Organochlorine pesticides (OCPs) are widely used in certain countries. We determined atmospheric concentrations, distribution patterns, and seasonal variations of OCPs at four sites in South Korea for 1 year. Samples of 22 OCPs were collected using a high-volume air sampler, and measured via the isotope dilution method with HRGC/HRMS. In South Korea, pentachlorobenzene (PeCB), hexachlorocyclohexane (HCB), and endosulfan (EnSF) were dominant, accounting for 87% of total OCPs. Spatial distributions showed significant differences and the highest levels were observed in Seosan (295.2 pg·m
- Published
- 2021
39. Nanostructural Perspective for Destabilization of Mg Hydride Using the Immiscible Transition Metal Mn
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Kohta Asano, Kouji Sakaki, Hyunjeong Kim, Bernard Dam, Akihiko Machida, Yanshan Lu, Tetsu Watanuki, and Herman Schreuders
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Hydrogen ,Hydride ,chemistry.chemical_element ,Inorganic Chemistry ,Metal ,Hydrogen storage ,chemistry ,Chemical engineering ,Transition metal ,visual_art ,Phase (matter) ,Desorption ,visual_art.visual_art_medium ,Dehydrogenation ,Physical and Theoretical Chemistry - Abstract
Phase segregation in hydride-forming alloys may persist under the action of multiple hydrogenation/dehydrogenation cycles. We use this effect to destabilize metal hydrides in the immiscible Mg-Mn system. Here, in the MgxMn1-x thin films, the Mg and Mn domains are chemically segregated at the nanoscale. In Mn-rich compositions, the desorption pressure of hydrogen from MgH2 is elevated at a given temperature, indicating a thermodynamic destabilization. The increase in the desorption pressure of hydrogen reaches ∼2.5 orders in magnitude for x = 0.30 at moderate temperatures. Such large thermodynamic destabilization allows the MgH2 to reversibly absorb and desorb hydrogen even at room temperature. Our strategy to use immiscible elements for destabilization of MgH2 is effective and opens up the possibility for the development of advanced and low-cost hydrogen storage and supply systems.
- Published
- 2021
40. Generating Mechanism of Catalytic Effect for Hydrogen Absorption/Desorption Reactions in NaAlH4–TiCl3
- Author
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Takashi Honda, Toru Kawamata, Fumika Fujisaki, Akihiko Machida, Kazutaka Ikeda, Kazumasa Sugiyama, Yumiko Nakamura, Hyunjeong Kim, Shin Ichi Orimo, Hiroshi Arima, Toyoto Sato, Hidetoshi Ohshita, Hitoshi Abe, Kouji Sakaki, Shigeyuki Takagi, and Toshiya Otomo
- Subjects
X-ray absorption fine structure ,Technology ,Materials science ,QH301-705.5 ,QC1-999 ,Neutron diffraction ,anomalous X-ray scattering ,Catalysis ,hydrogen storage ,Hydrogen storage ,neutron diffraction ,Desorption ,General Materials Science ,Biology (General) ,Instrumentation ,QD1-999 ,Fluid Flow and Transfer Processes ,Process Chemistry and Technology ,Physics ,General Engineering ,Engineering (General). Civil engineering (General) ,hydride complex ,Computer Science Applications ,X-ray diffraction ,Chemistry ,X-ray crystallography ,Physical chemistry ,Complex metal hydride ,Anomalous X-ray scattering ,TA1-2040 - Abstract
The hydrogen desorption and absorption reactions of the complex metal hydride NaAlH4 are disproportionation processes, and the kinetics can be improved by adding a few mol% of Ti compounds, although the catalytic mechanism, including the location and state of Ti, remains unknown. In this study, we aimed to reveal the generating mechanism of catalytic Al–Ti alloy in NaAlH4 with TiCl3 using quantum multiprobe techniques such as neutron diffraction (ND), synchrotron X-ray diffraction (XRD), anomalous X-ray scattering (AXS), and X-ray absorption fine structure (XAFS). Rietveld refinements of the ND and XRD, profiles before the first desorption of NaAlD(H)4–0.02TiCl3 showed that Al in NaAlD(H)4 was partially substituted by Ti. On the other hand, Ti was not present in NaAlH4, and Al–Ti nanoparticles were detected in the XRD profile after the first re-absorption. This was consistent with the AXS and XAFS results. It is suggested that the substitution promotes the formation of a highly dispersed nanosized Al–Ti alloy during the first desorption process and that the effectiveness of TiCl3 as an additive can be attributed to the dispersion of Ti.
- Published
- 2021
41. Displacement of hydrogen position in di-hydride of V-Ti-Cr solid solution alloys
- Author
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Kouji Sakaki, Hyunjeong Kim, Eric H. Majzoub, Akihiko Machida, Tetsu Watanuki, Kazutaka Ikeda, Toshiya Otomo, Masataka Mizuno, Daiju Matsumura, and Yumiko Nakamura
- Subjects
Polymers and Plastics ,Metals and Alloys ,Ceramics and Composites ,Electronic, Optical and Magnetic Materials - Published
- 2022
42. Effect of Human Umbilical Cord Matrix-Derived Mesenchymal Stem Cells on Bisphosphonate-Related Osteonecrosis of the Jaw
- Author
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Young-Nam Kim, Bu-Kyu Lee, Gwanghyun Yang, and Hyunjeong Kim
- Subjects
business.industry ,medicine.medical_treatment ,Osteoporosis ,Mesenchymal stem cell ,Biomedical Engineering ,Medicine (miscellaneous) ,Parathyroid hormone ,Cell Differentiation ,Mesenchymal Stem Cells ,Bisphosphonate ,medicine.disease ,Mesenchymal Stem Cell Transplantation ,Rats ,Umbilical Cord ,In vivo ,medicine ,Cancer research ,Animals ,Humans ,Bisphosphonate-Associated Osteonecrosis of the Jaw ,Original Article ,Stem cell ,Bone regeneration ,business ,Osteonecrosis of the jaw - Abstract
BACKGROUND: Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a severe sequela caused by bisphosphonates (BPs), which are widely used to treat osteoporosis or other malignancies. However, the mechanism underlying BRONJ remains unclear. Recently, human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) have been studied for treatment of diverse diseases and injuries. This study aimed to investigate the therapeutic effects of hUC-MSCs in BRONJ. METHODS: The therapeutic effects of hUC-MSCs were examined in rat bone marrow (rBM)-derived cells using cell viability, colony-forming, and real-time PCR assays and FACS for analyzing essential proinflammatory and bone regeneration markers in vitro. To demonstrate the in vivo therapeutic and adverse effects of transfused hUC-MSCs, micro-CT, H&E staining, IHC (Angiogenesis marker gene expression) staining, and parathyroid hormone (PTH)/calcium assay were conducted in a BRONJ-induced animal model. RESULTS: BP-induced cytotoxicity and inflammation in rBM-derived cells decreased, after co-culture with hUC-MSCs. The expression levels of bone regeneration markers (RUNX2, OSX, and BMP-2) significantly increased in BP-treated rBM-derived cells, after co-culture with hUC-MSCs. The BP-induced abnormal shift in RANKL/OPG expression ratio in rBM-derived cells was normalized by hUC-MSCs. Consistent with these in vitro results, transfused hUC-MSCs markedly decreased BRONJ and significantly healed injured mucosa in the BRONJ-induced animal model. The animals exhibited serious destruction of the kidney structure and increases in serum PTH and calcium levels, which were significantly normalized by hUC-MSC transfusion. CONCLUSION: hUC-MSCs exerted therapeutic effects on BRONJ in vitro and in vivo through their anti-cytotoxicity, anti-inflammatory activity and ability to recover bone regeneration. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13770-021-00372-x.
- Published
- 2021
43. A study on multi-hole machining of high-power density electron beam using a vaporized amplification sheet
- Author
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Seung-Yub Baek, HyunJeong Kim, Joohyung Lee, and Sung-Taek Jung
- Subjects
0209 industrial biotechnology ,Electron beam machining ,Materials science ,Mechanical Engineering ,02 engineering and technology ,Welding ,Acceleration voltage ,Industrial and Manufacturing Engineering ,Computer Science Applications ,law.invention ,Brass ,020901 industrial engineering & automation ,Machining ,Control and Systems Engineering ,law ,visual_art ,Vaporization ,visual_art.visual_art_medium ,Cathode ray ,Composite material ,Software ,Leakage (electronics) - Abstract
Recently, electron beam machining technology has been used in various ways depending on the industrial field. It is used in technologies in the fields of shipbuilding, aerospace, and transportation. In the case of the existing electron beam machining technology, a technology for welding or joining two materials was proposed. In this paper, in order to perform electron beam drilling, a multi-hole is created by increasing the instantaneous vaporization pressure during electron beam machining through a vaporized amplification sheet. A vaporized amplification sheet was prepared for electron beam drilling. The vaporized amplification sheet was made of a 1:3.25 combination of silicone and brass powder. Also, in order to bond the produced vaporized amplification sheet to the SUS 304 stainless steel, a primer was applied on the surface of the metal material to firmly bond the two materials with different properties. If the bonding is weak, the effectiveness decreases due to pressure leakage during electron beam machining. Multi-holes were processed using the fabricated material to fix an acceleration voltage of 120 kV and a current of 12 mA. Also, to compare the multi-hole shape and the processing result, the comparison was performed according to the exposure time of the electron beam. The lower the exposure time, the more fine holes were secured, and as the exposure time increased, the molten pool phenomenon occurred, and processing was not performed in the experimental results.
- Published
- 2021
44. Therapeutic effect of mesenchymal stem cells derived from human umbilical cord in rabbit temporomandibular joint model of osteoarthritis
- Author
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Eunju Kang, Jumi Park, Jene Choi, Gwanghyun Yang, Bu-Kyu Lee, and Hyunjeong Kim
- Subjects
Male ,0301 basic medicine ,lcsh:Medicine ,Inflammation ,Osteoarthritis ,Pharmacology ,Mesenchymal Stem Cell Transplantation ,Umbilical cord ,Article ,03 medical and health sciences ,0302 clinical medicine ,Human Umbilical Vein Endothelial Cells ,Animals ,Humans ,Medicine ,lcsh:Science ,Multidisciplinary ,business.industry ,Regeneration (biology) ,Cartilage ,Mesenchymal stem cell ,lcsh:R ,Temporomandibular Joint Disorders ,Chondrogenesis ,medicine.disease ,Disease Models, Animal ,030104 developmental biology ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,Mesenchymal stem cells ,lcsh:Q ,Rabbits ,Stem cell ,medicine.symptom ,business - Abstract
Osteoarthritis (OA) is a degenerative condition of the temporomandibular joint (TMJ) characterised by chronic inflammation and damage to joint structures. Because of the complexity of TMJ-OA, only symptomatic treatments are currently available. Recent reports have shown that many of stem cells can exert anti-inflammatory and tissue-regenerating effects. In this study, we investigated the potential cartilage-regenerating and anti-inflammatory effects of human umbilical cord matrix-mesenchymal stem cells (hUCM-MSCs) for the treatment of TMJ-OA. hUCM-MSC lines, isolated from different donors, which showed different activities in vitro. Using a selected cell line, we used different concentrations of hUCM-MSCs to assess therapeutic effects in a rabbit model of monosodium iodoacetate-induced TMJ-OA. Compared with the untreated control group, the potential regenerative result and anti-inflammatory effects of hUCM-MSCs were evident at all the tested concentrations in rabbits with induced TMJ-OA. The median dose of hUCM-MSCs showed the prominent cartilage protective effect and further cartilage regeneration potential. This effect occurred via upregulated expression of growth factors, extracellular matrix markers, and anti-inflammatory cytokines, and reduced expression of pro-inflammatory cytokines. The anti-inflammatory effect of hUCM-MSCs was comparable to that of dexamethasone (DEX). However, only hUCM-MSCs showed potential chondrogenesis effects in this study. In conclusion, our results indicate that hUCM-MSCs may be an effective treatment option for the treatment of TMJ-OA.
- Published
- 2019
45. Verification of the structural relationship among athlete Julsil, self-regulation, and flow in adolescent athletes
- Author
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Sungho Kwon, Hyunjeong Kim, and Sangwook Kang
- Subjects
Adolescent athletes ,media_common.quotation_subject ,05 social sciences ,030229 sport sciences ,050105 experimental psychology ,Structural equation modeling ,Research model ,Developmental psychology ,03 medical and health sciences ,0302 clinical medicine ,Flow (mathematics) ,Action (philosophy) ,Perception ,0501 psychology and cognitive sciences ,Measurement invariance ,Psychology ,media_common ,High school athletes - Abstract
The purpose of this study was to explore the structural relationship among the perception of athlete Julsil, self-regulation, and flow of adolescent athletes. A total of 425 middle school and high school athletes completed a survey. Structural equation modeling analysis was conducted to verify the research model. The result of verifying the structural relationship among athlete Julsil, self-regulation and flow indicates that self-regulation was found to mediate the relationship between athlete Julsil and flow. In addition, measurement invariance was verified across gender and school that can be applied equally to various groups. Through these results, it was verified that athlete Julsil is an important psychological factor for adolescent athletes. In addition, they need to have a firm mental attitude by themselves and to move them to action for peak performance.
- Published
- 2019
46. Interrogation of the Effect of Polymorphism of a Metal‐Organic Framework Host on the Structure of Embedded Pd Guest Nanoparticles
- Author
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Krishnan Murugappan, Craig E. Buckley, Joshua D. Butson, Petra Ágota Szilágyi, Debbie S. Silvester, Martin Saunders, and Hyunjeong Kim
- Subjects
Phase transition ,Nanocomposite ,Materials science ,Pair distribution function ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Polymorphism (materials science) ,Metal-organic framework ,Particle size ,Physical and Theoretical Chemistry ,0210 nano-technology ,Nanoscopic scale - Abstract
Metal-organic frameworks (MOFs) are very promising host materials for nanoscale guest materials. However, some MOFs such as MIL-53 are known to undergo phase transitions which can complicate the guest particle size control. In this study, Pd nanoparticles embedded in Al-MIL-53 were synthesised via (a) electrodeposition and (b) gas-phase reduction. A thorough structural investigation revealed that each synthesis method most likely favoured a different phase of Al-MIL-53, presenting the possibility of MOF phase selection as a technique for size control of embedded nanoparticles. For the first time, we hereby report the use of pair distribution function analysis to successfully investigate the structure and morphology of guest particles embedded in a MOF host.
- Published
- 2019
47. Abstract 3527: Novel bacteria strains, CJRS-10671 and CJRS-10672, enhance anti-tumor efficacy in LLC1 syngeneic model and humanized PDX mice model
- Author
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Arim Min, Bo-eun Kwon, Hyunjeong Kim, Hyunkyung Park, Jiyoung Lee, Kyoung-Ho Pyo, and Byoung Chul Cho
- Subjects
Cancer Research ,Oncology - Abstract
Background: Immune checkpoint inhibitor has emerged as remarkable therapeutic that improves the anti-cancer effect of patients. However, response rate is low in a large proportion of patients. The overall efficacy of immune checkpoint inhibitor therapy remains unsatisfactory. Recently, live biotherapeutic products (LBPs) have emerged as potential therapeutics to overcome the limitation of immune checkpoint inhibitor. Here, we demonstrated the efficacy of CJRS-10671 and CJRS-10672 in tumor bearing mice models. Methods: To evaluate anti-tumor effects, 109 CFU/mouse CJRS-10671 was administered via oral gavage twice daily (BID) alone or in combination with anti-PD-1 (10 mg/kg, QOD, i.p.) for 10 days in a Lewis Lung Carcinoma (LLC1) syngeneic tumor model. Tumor growth was measured by calipers 3 times per week. We analyzed immune cell profiles by flow cytometry. In lung squamous cell carcinoma patient derived xenograft (PDX) model,109 CFU/mouse CJRS-10671 and CJRS-10672 were orally administered twice daily (BID) alone or in combination with pembrolizumab (10 mg/kg, Q5D, i.p.) for 35 days. Tumor growth was measured by calipers 3 times per week. We analyzed immune cell profiles and single cell RNA sequencing. Results: In LLC1 syngeneic tumor model, CJRS-10671 alone suppressed tumor growth comparable to that of immune checkpoint inhibitor (anti-PD-1 antibody) only treatment group. Combined administration of CJRS-10671 and immune checkpoint inhibitor significantly suppressed tumor growth (pTGI-75%).We confirmed that administration of CJRS-10671 increased population of CD8+ central memory T cells in tumor. Also, TGI (%) directly related features were mostly antigen presentation and monocyte origin cells, especially macrophage in immune-profiling analysis. Furthermore, we observed that CJRS-10671 and CJRS-10672 were associated with signaling of damage-associated molecular pattern (DAMP) and especially CJRS-10671 was related to nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling by single cell RNA sequencing analysis. Conclusion: CJRS-10671 and CJRS-10672, single administration or combination with anti-PD-1 antibody, have potential anti-tumor effect. Citation Format: Arim Min, Bo-eun Kwon, Hyunjeong Kim, Hyunkyung Park, Jiyoung Lee, Kyoung-Ho Pyo, Byoung Chul Cho. Novel bacteria strains, CJRS-10671 and CJRS-10672, enhance anti-tumor efficacy in LLC1 syngeneic model and humanized PDX mice model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3527.
- Published
- 2022
48. Metformin Use and Subsequent Alzheimer’s Disease Incidence in Patients With Newly Diagnosed Type 2 Diabetes: a Population-based Nested Case-control Study
- Author
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Junghee Ha, Dong Woo Choi, Kwang Joon Kim, So Yeon Cho, Hyunjeong Kim, Keun You Kim, Yongseung Koh, Chung Mo Nam, and Eosu Kim
- Abstract
Background: Metformin reduces insulin resistance, which may be shared pathophysiology between diabetes mellitus (DM) and Alzheimer’s disease (AD). Thus, it has been hypothesized that metformin may be effective against AD; however, evidence of metformin effects on AD development remains insufficient and conflicting. We investigated Alzheimer’s disease risk in patients with newly diagnosed type 2 diabetes mellitus treated with metformin.Methods: This retrospective, observational, nested case-control study included enrolled patients with newly diagnosed type 2 diabetes mellitus in the Korean National Health Insurance Service diabetes mellitus cohort (2002–2017). Among 70,499 DM patients who were dementia-free at the time of DM diagnosis, 1,675 AD cases identified were matched to 8,375 controls by age, sex, and DM onset and duration. Association of AD with metformin use were analyzed using multivariable conditional logistic regression analyses adjusted for comorbidities and cardiometabolic risk profile. Results: Metformin use was associated with an increased adjusted odds ratio (AOR) of AD (1.50; 95% CI, 1.23–1.83). The strength of the association increased with the cumulative daily defined dose per day in metformin users. The risk was more pronounced among patients with a longer duration of DM (1.48; 95% CI, 1.14 to 1.91, for a DM duration of 5–9 years; 2.18; 95% CI, 1.41 to 3.39 for a duration greater than 10 years), while no statistical significance was found in the patients with DM duration less than 5 years (AOR 0.88; 95%CI 0.54–1.43). Furthermore, the risk of AD was significantly higher in DM patients with depression (AOR 2.05; 1.02–4.12). Conclusions: Given the huge number of patients with DM who are taking metformin worldwide, a double-blinded, prospective study is required to determine the long-term cognitive safety of metformin.
- Published
- 2021
49. mTORC2 Assembly Is Regulated by USP9X-Mediated Deubiquitination of RICTOR
- Author
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Sandra Malmgren Hill, Sung Min Son, David C. Rubinsztein, Farah H. Siddiqi, Hyunjeong Kim, Lidia Wrobel, Cansu Karabiyik, Siddiqi, Farah [0000-0001-9185-0163], Son, Sungmin [0000-0002-3536-1952], Karabiyik, Cansu [0000-0001-7993-1825], Rubinsztein, David [0000-0001-5002-5263], and Apollo - University of Cambridge Repository
- Subjects
0301 basic medicine ,Male ,Cellular homeostasis ,USP9X ,Mechanistic Target of Rapamycin Complex 2 ,mTORC2 ,General Biochemistry, Genetics and Molecular Biology ,Deubiquitinating enzyme ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Cell Line, Tumor ,ubiquitin-specific protease 9X ,Animals ,Humans ,Mechanistic target of rapamycin ,PI3K/AKT/mTOR pathway ,posttranslational modification ,biology ,Ubiquitination ,growth factor signaling ,Cell biology ,Mice, Inbred C57BL ,030104 developmental biology ,Cell metabolism ,HEK293 Cells ,Rapamycin-Insensitive Companion of mTOR Protein ,Gene Expression Regulation ,Gene Knockdown Techniques ,biology.protein ,Intercellular Signaling Peptides and Proteins ,Female ,RICTOR ,Protein Processing, Post-Translational ,Ubiquitin Thiolesterase ,030217 neurology & neurosurgery ,Deubiquitination ,HeLa Cells ,Protein Binding ,Signal Transduction - Abstract
The mechanistic target of rapamycin complex 2 (mTORC2) controls cell metabolism and survival in response to environmental inputs. Dysregulation of mTORC2 signaling has been linked to diverse human diseases, including cancer and metabolic disorders, highlighting the importance of a tightly controlled mTORC2. While mTORC2 assembly is a critical determinant of its activity, the factors regulating this event are not well understood, and it is unclear whether this process is regulated by growth factors. Here, we present data, from human cell lines and mice, describing a mechanism by which growth factors regulate ubiquitin-specific protease 9X (USP9X) deubiquitinase to stimulate mTORC2 assembly and activity. USP9X removes Lys63-linked ubiquitin from RICTOR to promote its interaction with mTOR, thereby facilitating mTORC2 signaling. As mTORC2 is central for cellular homeostasis, understanding the mechanisms regulating mTORC2 activation toward its downstream targets is vital for our understanding of physiological processes and for developing new therapeutic strategies in pathology.
- Published
- 2021
- Full Text
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50. Suppression of the Phase Coexistence of the fcc-fct Transition in Hafnium-Hydride Thin Films
- Author
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Kouji Sakaki, Kohta Asano, Kazutaka Ikeda, Bernard Dam, Herman Schreuders, Shigenobu Hayashi, Toshiya Otomo, Hyunjeong Kim, and L. J. Bannenberg
- Subjects
Diffraction ,Materials science ,Letter ,Hydrogen ,business.industry ,Hydride ,chemistry.chemical_element ,Hafnium ,Metal ,chemistry ,Chemical physics ,Hydrogen economy ,Phase (matter) ,visual_art ,visual_art.visual_art_medium ,General Materials Science ,Physical and Theoretical Chemistry ,Thin film ,business - Abstract
Metal hydrides may play a paramount role in a future hydrogen economy. While most applications are based on nanostructured and confined materials, studies considering the structural response of these materials to hydrogen concentrate on bulk material. Here, using in situ in- and out-of-plane X-ray diffraction and reflectometry, we study the fcc ↔ fct transition in Hf thin films, an optical hydrogen-sensing material. We show that the confinement of Hf affects this transition: compared to bulk Hf, the transition is pushed to a higher hydrogen-to-metal ratio, the tetragonality of the fct phase is reduced, and phase coexistence is suppressed. These nanoconfinement effects ensure the hysteresis-free response of hafnium to hydrogen, enabling its remarkable performance as a hydrogen-sensing material. In a wider perspective, the results highlight the profound influences of the nanostructuring and nanoconfinement of metal hydrides on their structural response to hydrogen with a significant impact on their applicability in future devices.
- Published
- 2021
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