Wonseok Kim

Effect of electroacupuncture on motor recovery in a rat stroke model during the early recovery stage.

The effect of acupuncture on motor recovery after stroke continues to be debated. This animal study was designed to determine whether acupuncture improves motor function following experimentally induced cerebral ischemia. In addition, we studied whether the outcome of motor function was associated with the expression of BDNF (brain derived neurotrophic factor), trkB (receptor, trkB) and infarct volume. Cerebral ischemia was induced by permanent middle cerebral artery occlusion (MCAO) or MCAO plus bilateral vertebral artery occlusion in Sprague-Dawley rats. The groups studied were a control, treadmill exercise, electroacupuncture and a combined treatment group with both treadmill exercise and electroacupuncture (ExEA). On postoperative day 16, Western blot analysis for BDNF and trkB and estimation of infarct volume were performed. The motor behavior scores were measured 2 and 16-days postoperatively. Comparison of the motor scores among the groups showed that the motor scores in the exercise only group and ExEA group were higher than in the control group on postoperative day 16. No statistical significance was found among the groups in the Western blot analysis and the infarct volume. This study demonstrates no significant additional effect of electroacupuncture on the motor recovery in rats following mild cerebral ischemia during the early recovery stage. Further studies in a rat model with moderate to severe cerebral ischemia, assessment and reassessment for more extended periods after the cerebral ischemia will be required.

Non-Negligible Diffusio-Osmosis Inside an Ion Concentration Polarization Layer.

The first experimental and theoretical evidence was provided for the non-negligible role of a diffusio-osmosis in the ion concentration polarization (ICP) layer, which had been reported to be in a high Peclet number regime. Under the assumption that the hydrated shells of cations were stripped out with the amplified electric field inside the ICP layer, its concentration profile possessed a steep concentration gradient at the stripped location. Since the concentration gradient drove a strong diffusio-osmosis, the combination of electro-osmotic and diffusio-osmotic slip velocity had a form of an anomalous nonmonotonic function with both a single- and multiple-cationic solution. A direct measurement of electrolytic concentrations around the layer quantitatively validated our new investigations. This non-negligible diffusio-osmotic contribution in a micro- and nanofluidic platform or porous medium would be essential for clarifying the fundamental insight of nanoscale electrokinetics as well as guiding the engineering of ICP-based electrochemical systems.

Upper-Limb Function Assessment Using VBBTs for Stroke Patients

Evaluating and quantifying the upper-limb functions are essential to planning effective patient rehabilitation. The box and block test (BBT) is a conventional, simple, and easy-to-apply assessment tool that is used in hospitals, and previous studies have demonstrated its usefulness in stroke rehabilitation. Using a conventional depth-sensing camera, the authors developed a virtual box and block test (VBBT) system for hand, finger, and grasping assessments based on the BBT used for the grasping ability test in hospitals. Such a virtual upper-limb-function assessment tool that can be implemented in a home setting could be a key component in a home-based virtual rehabilitation system. Comparison results between the real and virtual BBTs show the possibilities for virtualizing conventional and unsupervised assessments.

Identifying factors associated with self-rated health according to age at onset of disability

Purpose: Although later-onset disability has been associated with poor self-rated health (SRH), factors mediating differences in SRH related to age at onset of disability remain unclear. The present study was designed to identify the variables explaining poor SRH in later-onset disability. We examined chronic disease and functional status as alternatives to psychosocial adaptation as explanatory variables. Method: Our data were taken from the seventh National Survey for People with Disabilities among Korean individuals ≥18 years of age (n =5311). Results: Those with later-onset disability (onset ages 20–40, 41–64 and ≥65 years) showed higher age-adjusted odds ratios (ORs) for poor SRH compared with those with earlier-onset disability (onset ages 0–19 years). The ORs for poor SRH in individuals with later-onset disability were not substantially changed after adjusting for confounding variables including alternatives to psychosocial adaptation (chronic diseases and functional status) as explanatory variables. Conclusions: Failure to explain poor SRH in later-onset disability with explanatory variables other than psychosocial adaptation indirectly supports the role of psychosocial adaptation in differences in SRH related to age at onset. Because we could not include appropriate measures of psychosocial adaptation, the use of additional instruments should be considered in future studies. Implications for Rehabilitation Poor health-related quality of life (HRQOL) in later-onset disability is not merely due to more prevalent chronic disease and worse functional status. Strategies in helping with psychosocial adaptation after disability may be important to promote HRQOL in people with later-onset disability.

VISUALIZATION OF ION LIGHTNING THROUGH NANOFLUIDIC MEMBRANE

In this work, for the first time, we visibly generated a lightning through nanoporous membrane in micro/nanofluidic platform. Firstly, a micro bubble was formed by Joule heating inside a microchannel with an application of electric field (E) of 100 V/cm. Secondly, vapor phase was changed into plasma phase and bright light was emitted at |E| = 500 V/cm. Finally, it was observed that emitted light propagated through the perm-selective nanoporous membrane along with strong cation flux. These findings would have a scientific significance for the visualization of cation trajectories inside the nanoporous membrane.

Experimental verification of ION concentration distribution near ION concentration polarization layer and its applications

This paper reported a rigorous experimental analysis of ion concentration distributions near a nanoporous membrane in a micro/nanofluidic platform. The distribution was highly polarized due to ion concentration polarization (ICP) phenomenon. While previous studies had reported most of co- and counter-ions were rejected from ICP layer, we showed that, for the first time, most of cations were transported through a cathodic side and anions were consumed by electrode reactions. From this complete picture, we discretionarily collected samples from (1) the brine stream for ink-desalter without the loss of ink molecules, (2) the purified stream for recycling a used dialysate, or (3) the buffer stream for collecting small cationic species.