Near-Quantum-Noise Axion Dark Matter Search at CAPP around 9.5 μ\mueV

We report the results of an axion dark matter search over an axion mass range of 9.39-9.51 ${\mu}$eV. A flux-driven Josephson parametric amplifier (JPA) was added to the cryogenic receiver chain. A system noise temperature of as low as 200 mK was achieved, which is the lowest recorded noise among published axion cavity experiments with phase-insensitive JPA operation. In addition, we developed a two-stage scanning method which boosted the scan speed by 26%. As a result, a range of two-photon coupling in a plausible model for the QCD axion was excluded with an order of magnitude higher in sensitivity than existing limits.Comment: 6 pages, 4 figure

Smaller pineal gland is associated with rapid eye movement sleep behavior disorder in Alzheimers disease

Background To investigate the association between pineal gland volume and symptoms of rapid eye movement (REM) sleep behavior disorder (RBD) in Alzheimers disease (AD) patients without any feature of dementia with Lewy bodies. Methods We enrolled 296 community-dwelling probable AD patients who did not meet the diagnostic criteria for possible or probable dementia with Lewy bodies. Among them, 93 were amyloid beta (Aβ) positive on 18F-florbetaben amyloid brain positron emission tomography. We measured RBD symptoms using the REM Sleep Behavior Disorder Screening Questionnaire (RBDSQ) and defined probable RBD (pRBD) as the RBDSQ of 5 or higher. We manually segmented pineal gland on 3T structural T1-weighted brain magnetic resonance imaging. Results The participants with pRBD had smaller pineal parenchyma volume (VPP) than those without pRBD (p <  0.001). The smaller the VPP, the more severe the RBD symptoms (p <  0.001). VPP was inversely associated with risk of prevalent pRBD (odds ratio = 0.909, 95% confidence interval [CI] = 0.878–0.942, p <  0.001). Area under the receiver operator characteristic curve for pRBD of VPP was 0.80 (95% CI = 0.750–0.844, p <  0.0001). These results were not changed when we analyzed the 93 participants with Aβ-positive AD separately. Conclusions In AD patients, reduced pineal gland volume may be associated with RBD.This study was supported by the grants from the Korean Health Technology R&D Project, Ministry of Health and Welfare, Republic of Korea (grant no.HI09C1379 [A092077]) and the Institute for Information & Communications Technology Promotion (IITP) grant funded by the Korea government (MSIT) (2018-2-00861, Intelligent SW Technology Development for Medical Data Analysis)

Search for the Sagittarius Tidal Stream of Axion Dark Matter around 4.55 μ\mueV

We report the first search for the Sagittarius tidal stream of axion dark matter around 4.55 $\mu$eV using CAPP-12TB haloscope data acquired in March of 2022. Our result excluded the Sagittarius tidal stream of Dine-Fischler-Srednicki-Zhitnitskii and Kim-Shifman-Vainshtein-Zakharov axion dark matter densities of $\rho_a\gtrsim0.184$ and $\gtrsim0.025$ GeV/cm$^{3}$, respectively, over a mass range from 4.51 to 4.59 $\mu$eV at a 90% confidence level.Comment: 6 pages, 7 Figures, PRD Letter accepte

정상 인지 노인 대상 단일 삼축가속도계 기반 보행분석의 검사-재검사 신뢰도 및 전자식 보행판 시스템과의 비교 연구

학위논문 (석사)-- 서울대학교 대학원 : 의학과 임상의과학과 전공, 2016. 2. 김기웅.Objectives: We investigated the test-retest reliability of spatio-temporal gait parameters measured with a single tri-axial accelerometer (TAA), determined the optimal number of steps required for obtaining acceptable levels of reliability, compared the reliability with the GAITRite® system, studied the level of agreement with parameters derived from GAITRite® system, and compared the reliability and level of agreement of the estimated gait parameters across the three reference axes of the TAA. Methods: A total of 82 cognitively normal elderly participants walked around a 40-m long round walkway twice wearing a TAA at their center of body mass. Gait parameters such as cadence, gait velocity, step time, step length, step time variability, and step time asymmetry were estimated from the low pass-filtered signal of the TAA. Evaluation of the test-retest reliability and comparison with the GAITRite® system were carried out for the estimated gait parameters. Results: Gait parameters using signals from the vertical axis showed excellent reliability for all gait parametersthe intraclass correlation coefficient (ICC) was 0.79-0.90. A minimum of 26 steps and 14 steps were needed to achieve excellent reliability in step time variability and step time asymmetry, respectively. A strong level of agreement was seen for the basic gait parameters between the TAA and GAITRiteⓇ (ICC=0.91-0.96). Conclusion: The measurement of gait parameters of elderly individuals with normal cognition using a TAA placed on the bodys center of mass was reliable and showed superiority over the GAITRiteⓇ with regard to gait variability and asymmetry. Considering its wearability and low price, the TAA system may be a promising alternative to the pressure sensor walkway system for measuring gait parameters.INTRODUCTION 1 METHODS 6 RESULTS 15 DISCUSSION 19 REFERENCES 25 국문 초록 43Maste

Gait analysis data

Test-retest relability of triaxial accelerometer (TAA)<div>Level of agreement between TAA and Gaitrite</div><div>Clinical scores of subjects</div

Triaxial accelerometer based gait analysis

Test-retest relability of triaxial accelerometer (TAA)<div>Level of agreement between TAA and Gaitrite</div><div>Clinical scores of subjects</div

Association between diurnal temperature range and emergency department visits for multiple sclerosis: A time-stratified case-crossover study

Although multiple sclerosis (MS) has been the leading cause of neurologically-induced disability in young adults, risk factors for the relapse and acute aggravation of MS remain unclear. A few studies have suggested a possible role of temperature changes on the relapse and acute aggravation of MS. We investigated the association between short-term exposure to wide diurnal temperature ranges (DTRs) and acute exacerbation of MS requiring an emergency department (ED) visit. A total of 1265 patients visited EDs for acute aggravation of MS as the primary disease in Seoul between 2008 and 2014 from the national emergency database. We conducted a conditional logistic regression analysis of the time-stratified case-crossover design to compare DTRs on the ED visit days for MS and those on control days matched according to the day of the week, month, and year. We examined possible associations with other temperature-related variables (ambient temperature, between-day temperature change, and sunlight hours). Short-term exposure to wide DTRs immediately increased the risk of ED visits for MS. Especially, 2-day average (lag0-1) DTR levels on the day of and one day prior to ED visits exhibited the strongest association (an 8.81% [95% CI: 3.46%-14.44%] change in the odds ratio per 1 degrees C increase in the DTR). Other temperature-related variables were not associated with MS aggravation. Our results suggest that exposure to wider DTR may increase the risk of acute exacerbation of MS. Given the increasing societal burden of MS and the increasing temperature variability due to climate change, further studies are required. (C) 2020 Elsevier B.V. All rights reserved.N

Impact of COVID-19 Pandemic on Children Visiting Emergency Department for Mental Illness: A Multicenter Database Analysis from Korea

We aimed to identify changes in the proportion of pediatric emergency department (PED) visits due to mental illness during the coronavirus disease 2019 (COVID-19) pandemic. This was a retrospective observational study of visits to the PED at six university hospitals from January 2017 to December 2020. We included children aged 5-17 years who were diagnosed with a mental illness. We used segmented regression analysis to identify the change in the proportion of patients with mental illness. A total of 845 patients were included in the analysis. After the first case of COVID-19 was reported in Korea, the number of PED visits significantly decreased by 560.8 patients per week (95% confidence interval (CI): -665.3 to -456.3, p &lt; 0.001). However, the proportion of patients with mental illness increased significantly, by 0.37% per week (95% CI: 0.04% to 0.70%, p = 0.03), at this time point. Subgroup analyses revealed that emotional disorders significantly increased by 0.06% per month (95% CI: 0.02% to 0.09%, p &lt; 0.001) during the pandemic. Our study revealed that an increased proportion of patients with mental illness visited the PED during the COVID-19 pandemic. Specifically, we identified that the proportion of emotional disorders continues to rise during this pandemic.N

Test-Retest Reliability and Concurrent Validity of a Single Tri-Axial Accelerometer-Based Gait Analysis in Older Adults with Normal Cognition.

We investigated the concurrent validity and test-retest reliability of spatio-temporal gait parameters measured with a single tri-axial accelerometer (TAA), determined the optimal number of steps required for obtaining acceptable levels of reliability, and compared the validity and reliability of the estimated gait parameters across the three reference axes of the TAA.A total of 82 cognitively normal elderly participants walked around a 40-m long round walkway twice wearing a TAA at their center of body mass. Gait parameters such as cadence, gait velocity, step time, step length, step time variability, and step time asymmetry were estimated from the low pass-filtered signal of the TAA. The test-retest reliability and concurrent validity with the GAITRite® system were evaluated for the estimated gait parameters.Gait parameters using signals from the vertical axis showed excellent reliability for all gait parameters; the intraclass correlation coefficient (ICC) was 0.79-0.90. A minimum of 26 steps and 14 steps were needed to achieve excellent reliability in step time variability and step time asymmetry, respectively. A strong level of agreement was seen for the basic gait parameters between the TAA and GAITRiteⓇ (ICC = 0.91-0.96).The measurement of gait parameters of elderly individuals with normal cognition using a TAA placed on the body's center of mass was reliable and showed superiority over the GAITRiteⓇ with regard to gait variability and asymmetry. The TAA system was a valid tool for measuring basic gait parameters. Considering its wearability and low price, the TAA system may be a promising alternative to the pressure sensor walkway system for measuring gait parameters

Walking-speed estimation using a single inertial measurement unit for the older adults.

BACKGROUND:Although walking speed is associated with important clinical outcomes and designated as the sixth vital sign of the elderly, few walking-speed estimation algorithms using an inertial measurement unit (IMU) have been derived and tested in the older adults, especially in the elderly with slow speed. We aimed to develop a walking-speed estimation algorithm for older adults based on an IMU. METHODS:We used data from 659 of 785 elderly enrolled from the cohort study. We measured gait using an IMU attached on the lower back while participants walked around a 28 m long round walkway thrice at comfortable paces. Best-fit linear regression models were developed using selected demographic, anthropometric, and IMU features to estimate the walking speed. The accuracy of the algorithm was verified using mean absolute error (MAE) and root mean square error (RMSE) in an independent validation set. Additionally, we verified concurrent validity with GAITRite using intraclass correlation coefficients (ICCs). RESULTS:The proposed algorithm incorporates the age, sex, foot length, vertical displacement, cadence, and step-time variability obtained from an IMU sensor. It exhibited high estimation accuracy for the walking speed of the elderly and remarkable concurrent validity compared to the GAITRite (MAE = 4.70%, RMSE = 6.81 /, concurrent validity (ICC (3,1)) = 0.937). Moreover, it achieved high estimation accuracy even for slow walking by applying a slow-speed-specific regression model sequentially after estimation by a general regression model. The accuracy was higher than those obtained with models based on the human gait model with or without calibration to fit the population. CONCLUSIONS:The developed inertial-sensor-based walking-speed estimation algorithm can accurately estimate the walking speed of older adults