1,637 research outputs found

    The usefulness of the Korean version of modified Mini-Mental State Examination (K-mMMSE) for dementia screening in community dwelling elderly people

    Get PDF
    BACKGROUND: We assessed whether the Korean version of modified Mini-Mental State Examination (K-mMMSE) has improved performance as a screening test for cognitive impairment or dementia in a general population compared with the Korean Mini-Mental State Examination (K-MMSE). METHODS: Screening interviews were conducted with people aged 65 and over in Noam-dong, Namwon-city, Jeonbuk province. There were 522 community participants, of whom 235 underwent clinical and neuropsychological examination for diagnosis of dementia and Cognitive Impairment No Dementia (CIND). Sensitivity, specificity and areas under the receiver operating characteristic (ROC) curves for the K-mMMSE and the K-MMSE were the main outcome measures. RESULTS: Cronbach's alpha for the K-mMMSE was 0.91, compared with 0.84 for the K-MMSE. The areas under the ROC curves in identifying all levels of CIND or dementia were 0.91 for the K-mMMSE and 0.89 for the K-MMSE (P < 0.05). For the K-mMMSE, the optimal cut-off score for a diagnosis of CIND was 69/70, which had a sensitivity of 0.86 and a specificity of 0.79, while, for a diagnosis of dementia, the optimal cut-off score of 59/60 had a sensitivity of 0.91 and a specificity of 0.78. The K-mMMSE also had a high test-retest reliability (r = 0.89). CONCLUSION: Our findings indicate that the K-mMMSE is more reliable and valid than the K-MMSE as a cognitive screen in a population based study of dementia. Considering the test characteristics, the K-MMSE and modified version are expected to be optimally used in clinical and epidemiologic fields

    Flow-induced vibration of a web floating over a pressure-pad air bar

    Get PDF
    Scope and Method of Study: The aeroelastic (air/web) model is developed by theories of elasticity and fluid dynamics. The flexible web is modeled as a traveling Euler-Bernoulli beam under tension which is exposed to high-speed air flows underneath it, and the aerodynamic pressure is developed from continuity and Navier-Stokes equations. The web is assumed to be a threadline traveling between two rollers over one air bar; there is no variation across the width. To keep a valid threadline model, two-dimensional flow is obtained by two air dams installed along both free edges of the web, to block air escaping in the cross-machine direction. Experiments are limited to a non-traveling web exposed to air-jet flows. The present study is focused on effects of high-speed air flows on the flexible tensioned web; the velocity of the web is neglected because the velocity of the air jet is much higher than the translational velocity in practical applications.Findings and Conclusions: It is observed that divergence-type instability (static deflection) and flutter-type instability (vibration) both occur in the web due to the air-jet flow. The theory used to develop the computations is well supported by the experimental results. Stability criteria are provided and compared with analytical calculations and experiments. Flutter depends strongly on flow speed, and can be controlled by increasing tension, shortening the web span, and (for a single span) centering the air-bar position. The developed theoretical and computational approach could be used for multi-bar analysis

    Analytical and Computational Study of the Asymmetry of Webs Passing Over Pressure-Pad Air Bars

    Get PDF

    Online home appliance control using EEG-Based brain-computer interfaces

    Get PDF
    Brain???computer interfaces (BCIs) allow patients with paralysis to control external devices by mental commands. Recent advances in home automation and the Internet of things may extend the horizon of BCI applications into daily living environments at home. In this study, we developed an online BCI based on scalp electroencephalography (EEG) to control home appliances. The BCI users controlled TV channels, a digital door-lock system, and an electric light system in an unshielded environment. The BCI was designed to harness P300 andN200 components of event-related potentials (ERPs). On average, the BCI users could control TV channels with an accuracy of 83.0% ?? 17.9%, the digital door-lock with 78.7% ?? 16.2% accuracy, and the light with 80.0% ?? 15.6% accuracy, respectively. Our study demonstrates a feasibility to control multiple home appliances using EEG-based BCIs

    Chiroptical signal enhancement in quasi-null-polarization-detection geometry: Intrinsic limitations

    Get PDF
    Despite its unique capability of distinguishing molecular handedness, chiroptical spectroscopy suffers from the weak-signal problem, which has restricted more extensive applications. The quasi-null-polarization-detection (QNPD) method has been shown to be useful for enhancing the chiroptical signal. Here, the underlying enhancement mechanism in the QNPD method combined with a heterodyne detection scheme is elucidated. It is experimentally demonstrated that the optical rotatory dispersion signal can be amplified by a factor of similar to 400, which is the maximum enhancement effect achievable with our femtosecond laser setup. The upper limit of the QNPD enhancement effect of chiroptical measurements could, in practice, be limited by imperfection of the polarizer and finite detection sensitivity. However, we show that there exists an intrinsic limit in the enhancement with the QNPD method due to the weak but finite contribution from the homodyne chiroptical signal. This is experimentally verified by measuring the optical rotation of linearly polarized light with the QNPD scheme. We further provide discussions on the connection between this intrinsic limitation in the QNPD scheme for enhanced detection of weak chiroptical signals and those in optical enantioselectivity and Raman optical activity with a structured chiral field. We anticipate that the present work could be useful in further developing time-resolved nonlinear chiroptical spectroscopy.111Nsciescopu
    corecore