Browsing by Author "Shin, Jae C."

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    Coexistence of filamentary and homogeneous resistive switching with memristive and meminductive memory effects in Al/MnO2/SS thin film metal–insulator–metal device
    Kamble, Girish U.; Shetake, Nitin P.; Yadav, Suhas D.; Teli, Aviraj M.; Patil, Dipali S.; Pawar, Sachin A.; Karanjkar, Milind M.; Patil, Pramod S.; Shin, Jae C.; Orlowski, Marius K.; Kamat, Rajanish K.; Dongale, Tukaram D. (2018-09-19)
    In the present investigation, we have experimentally demonstrated the coexistence of filamentary and homogeneous resistive switching mechanisms in single Al/MnO2/SS thin film metal–insulator–metal device. The voltage-induced resistive switching leads to clockwise and counter-clockwise resistive switching effects. The present investigations confirm that the coexistence of both RS mechanisms is dependent on input voltage, charge-flux and time. Furthermore, the non-zero I–V crossing locations and crossovers hysteresis loops suggested that the developed device has memristive and meminductive properties. The memristive and meminductive memory effects are further confirmed by electrochemical impedance spectroscopy. The results suggested that the mem-device dynamics and electrochemical kinetics during different voltage sweeps and sweep rates are responsible for the coexistence of filamentary and homogeneous resistive switching mechanisms as well as memristive and meminductive memory effect in single Al/MnO2/SS metal–insulator–metal device. The coexistence of both RS effects is useful for the development of high-performance resistive memory and electronic synapse devices. Furthermore, the coexistence of memristive and meminductive memory effects is important for the development of adaptive and self-resonating devices and circuits.
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    Functional brain network changes associated with maintenance of cognitive function in multiple sclerosis
    Helekar, Santosh A.; Shin, Jae C.; Mattson, Brandi J.; Bartley, Krystle; Stosic, Milena; Saldana-King, Toni; Montague, P. Read; Hutton, George J. (Frontiers, 2010-11-22)
    In multiple sclerosis (MS) functional changes in connectivity due to cortical reorganization could lead to cognitive impairment (CI), or reflect a re-adjustment to reduce the clinical effects of widespread tissue damage. Such alterations in connectivity could result in changes in neural activation as assayed by executive function tasks. We examined cognitive function in MS patients with mild to moderate CI and age-matched controls. We evaluated brain activity using functional magnetic resonance imaging (fMRI) during the successful performance of the Wisconsin card sorting (WCS) task by MS patients, showing compensatory maintenance of normal function, as measured by response latency and error rate. To assess changes in functional connectivity throughout the brain, we performed a global functional brain network analysis by computing voxel-by-voxel correlations on the fMRI time series data and carrying out a hierarchical cluster analysis. We found that during the WCS task there is a significant reduction in the number of smaller size brain functional networks, and a change in the brain areas representing the nodes of these networks in MS patients compared to age-matched controls. There is also a concomitant increase in the strength of functional connections between brain loci separated at intermediate-scale distances in these patients. These functional alterations might reflect compensatory neuroplastic reorganization underlying maintenance of relatively normal cognitive function in the face of white matter lesions and cortical atrophy produced by MS.