• 대한통합의학회지
• /
• 제10권2호
• /
• pp.105-113
• /
• 2022

Purpose: The purpose of this study is to investigate the effect of non-invasive transcranial direct current stimulation (tDCS) on muscle activity, including 10 m WT, TUG, and BBS, in hemiplegic stroke patients. Methods: This study was conducted on 42 inpatients diagnosed with hemiplegia due to stroke at hospital B in Daejeon for more than 6 months. Walking training was conducted for six weeks, five times a week for 30 minutes, with a general walking group (14 people), tDCS walking group (14 people), and tDCS (sham) walking group (14 people). Results: As a result of the study, the change in the muscle activity before and after tDCS intervention was significantly increased in the tibialis anterior muscle in the CG group. In the EG group, the erector spine (lumbar), rectus femoris, and tibialis anterior muscles significantly increased. In the SEG group, significant increases were observed in the rectus femoris and tibialis anterior muscles. Significant differences were found in the rectus femoris and tibialis anterior muscles in the comparison between groups after intervention according to tDCS application. Also, 10 m WT, TUG, and BBS were significantly increased in the CG, EG, and SEG groups after intervention, and there were significant differences in 10 m WT, TUG, and BBS in comparison between groups after intervention according to tDCS application. Conclusion: As a result, tDCS is an effective in improving the walking ability of stroke patients, and in particular, it effectively increases the muscle activity of the rectus femoris and tibialis anterior muscles, which act directly on walking, and also improves the speed and stability of walking. It is considered being an effective method to increase the gait of stroke patients by combining it with the existing gait training.

• 대한물리치료과학회지
• /
• 제29권3호
• /
• pp.75-84
• /
• 2022

Background: This study was to investigate the effect of non-invasive transcranial direct current stimulation due to hemiplegic patients due to stroke on temporal and spatial gait ability. Design: Randomized sham controlled trial. Methods: For the study method, 42 patients with hemiplegia due to stroke were randomly assigned to 14 patients each, and the general walking group, tDCS walking group, and tDCS (sham) walking group were subjected to 5 times a week, 30 minutes a day, and 6 weeks. In the temporal gait variables of hemiplegic patients due to stroke, the effect of the gait time, gait cycle, single support, double support, swing phase, stance phase, gait speed, cadence were measured. In spatial variables, one step length and one step length were measured. Results: As a result of the study, the EG group significantly increased in the step time, gait velocity, and cadence of the paralysis side in the comparison of temporal walking variables between groups according to the application of tDCS of walking ability in hemiplegic patients due to stroke patients(p<.05). In the change in spatial walking variables between groups according to the application of tDCS, the step length and stride length of the EG group showed a significant increase. Both the comparison of temporal and spatial symmetry walking variables between groups according to tDCS application was not significant(p>.05) Conclusion: As a result, tDCS has an effective effect on the improvement of the gait ability of stroke patients. In particular, it is an effective method of physical therapy that can improve the cadence and speed of gait, which can be combined with the existing gait training to effectively increase the gait of hemiplegia due to stroke patients.

• 대한약침학회지
• /
• 제25권4호
• /
• pp.326-343
• /
• 2022

Neurological disorders represent a substantial healthcare burden worldwide due to population aging. Acorus gramineus Solander (AG) and Acorus tatarinowii Schott (AT), whose major component is asarone, have been shown to be effective in neurological disorders. This review summarized current information from preclinical and clinical studies regarding the effects of extracts and active components of AG and AT (e.g., α-asarone and β-asarone) on neurological disorders and biomedical targets, as well as the mechanisms involved. Databases, including PubMed, Embase, and RISS, were searched using the following keywords: asarone, AG, AT, and neurological disorders, including Alzheimer's disease, Parkinson's disease, depression and anxiety, epilepsy, and stroke. Meta-analyses and reviews were excluded. A total of 873 studies were collected. A total of 89 studies were selected after eliminating studies that did not meet the inclusion criteria. Research on neurological disorders widely reported that extracts or active components of AG and AT showed therapeutic efficacy in treating neurological disorders. These components also possessed a wide array of neuroprotective effects, including reduction of pathogenic protein aggregates, antiapoptotic activity, modulation of autophagy, anti-inflammatory and antioxidant activities, regulation of neurotransmitters, activation of neurogenesis, and stimulation of neurotrophic factors. Most of the included studies were preclinical studies that used in vitro and in vivo models, and only a few clinical studies have been performed. Therefore, this review summarizes the current knowledge on AG and AT therapeutic effects as a basis for further clinical studies, and clinical trials are required before these findings can be applied to human neurological disorders.

• Journal of Audiology & Otology
• /
• 제23권3호
• /
• pp.145-152
• /
• 2019

Background and Objectives: The present study aims to investigate whether the cochlear implant electrode array design affects the electrophysiological and psychophysical measures. Subjects and Methods: Eighty five ears were used as data in this retrospective study. They were divided into two groups by the electrode array design: lateral wall type (LW) and perimodiolar type (PM). The electrode site was divided into three regions (basal, medial, apical). The evoked compound action potential (ECAP) threshold, T level, C level, dynamic range (DR), and aided air conduction threshold were measured. Results: The ECAP threshold was lower for the PM than for the LW, and decreased as the electrode site was closer to the apical region. The T level was lower for the PM than for the LW, and was lower on the apical region than on the other regions. The C level on the basal region was lower for the PM than for the LW whereas the C level was lower on the apical region than on the other regions. The DRs on the apical region was greater for the PM than for the LW whereas the DR was narrower on the apical region than on the other regions. The aided air conduction threshold was not different for the electrode design and frequency. Conclusions: The current study would support the advantages of the PM over the LW in that the PM had the lower current level and greater DR, which could result in more localized neural stimulation and reduced power consumption.

• 대한청각학회지
• /
• 제23권3호
• /
• pp.145-152
• /
• 2019

Background and Objectives: The present study aims to investigate whether the cochlear implant electrode array design affects the electrophysiological and psychophysical measures. Subjects and Methods: Eighty five ears were used as data in this retrospective study. They were divided into two groups by the electrode array design: lateral wall type (LW) and perimodiolar type (PM). The electrode site was divided into three regions (basal, medial, apical). The evoked compound action potential (ECAP) threshold, T level, C level, dynamic range (DR), and aided air conduction threshold were measured. Results: The ECAP threshold was lower for the PM than for the LW, and decreased as the electrode site was closer to the apical region. The T level was lower for the PM than for the LW, and was lower on the apical region than on the other regions. The C level on the basal region was lower for the PM than for the LW whereas the C level was lower on the apical region than on the other regions. The DRs on the apical region was greater for the PM than for the LW whereas the DR was narrower on the apical region than on the other regions. The aided air conduction threshold was not different for the electrode design and frequency. Conclusions: The current study would support the advantages of the PM over the LW in that the PM had the lower current level and greater DR, which could result in more localized neural stimulation and reduced power consumption.

• Journal of Power Electronics
• /
• 제17권2호
• /
• pp.501-513
• /
• 2017

The fundamental small-signal modeling of lithium-ion (Li-ion) batteries and a parameter evaluation approach are investigated in this study to describe the dynamic behaviors of small signals accurately. The main contributions of the study are as follows. 1) The operational principle of the small signals of Li-ion batteries is revealed to prove that the sinusoidal voltage response of a Li-ion battery is a result of a sinusoidal current stimulation of an AC small signals. 2) Three small-signal measurement conditions, namely stability, causality, and linearity, are proved mathematically proven to ensure the validity of the frequency response of the experimental data. 3) Based on the internal structure and electrochemical operational mechanism of the battery, an AC small-signal model is established to depict its dynamic behaviors. 4) A classical least-squares curve fitting for experimental data, referred as Levy's method, are introduced and developed to identify small-signal model parameters. Experimental and simulation results show that the measured frequency response data fit well within reading accuracy of the simulated results; moreover, the small-signal parameters identified by Levy's method are remarkably close to the measured parameters. Although the fundamental and parameter evaluation approaches are discussed for Li-ion batteries, they are expected to be applicable for other batteries.

• 대한통합의학회지
• /
• 제2권3호
• /
• pp.31-37
• /
• 2014

Purpose : Delayed onset muscle soreness(DOMS) is a common problem that can interfere with rehabilitation as well as activities of daily living. The purpose of this study was to compare the effect of both trascutaneous electrical nerve stimulation(TENS) Micro current(MC) and only normal Therapy on Delyed Onset Muscle Soreness(DOMS). Method : The Methods ten untrained and male volunteer subjects were randomly assigned to one of two treatment groups: 1) a group that received TENS (60Hz) MC($60{\mu}A$, 3pps) a control group that received no MC treatment. Subjects performed repeated eccentric exercise of the non-dominant forearm flexor muscle with submaximal intensity by the simply designed eccentric exercise devices. Treatments were applied after 24hours and 48hours. Subjects attended on two consecutive days for treatment and measurement of paining(visual analogue scale: VAS) and CK(Creatine kinase) on a daily basis. Measurements were taken after treatment. Results : 1) There were no significant differences between TENS and MENS by two-way repeated ANOVA. The Results that t-test for VAS revealed significant differences within TENS group. 3) The t-test for VAS, and Creatine Kinase of time revealed significant differences within MC group. Conclusion : These findings suggest that both TENS and MENS had effect on DOMS.

• 대한의용생체공학회:의공학회지
• /
• 제31권2호
• /
• pp.87-93
• /
• 2010

Researches for stem cells have been focused on scientists in biomedical sciences as well as clinical application for its great therapeutic potentials. Stem cells have two distinct characteristics: self-renewal and differentiation. In this short review, the links between stem cell research and biomedical engineering is discussed based on the basic characteristics of stem cells. This concept can be extended to the fundamental questions of biological sciences for cells such as proliferation, apoptosis, differentiation, and migration. For understanding proliferation and apoptosis of stem cells, techniques from biomedical engineering such as surface patterning, MEMS, nanotechnologies have been used. The advanced technologies such as microfluidic technologies, three dimensional scaffold fabrication, and mechanical/electrical stimulation have also been used in cell differentiation and migration. Basic and unsolved questions in the stem cell research field have limitations by studying conventional technologies. Therefore, the strategic fusion between stem cell biology and novel biomedical engineering field will break the barriers for understanding fundamental questions of stem cells, which can open the window for the clinical applications of stem cell based therapeutics as well as regeneration of damaged tissues.

• 한국응용약물학회:학술대회논문집
• /
• 한국응용약물학회 1998년도 춘계학술대회
• /
• pp.1-4
• /
• 1998

Impaired insulin action in Type 2 diabetes is thought to lead to hyperglycemia, with both environmental and complex genetic factors playing key roles. Although the primary lesion in Type 2 diabetes is unknown, a number of studies suggest that metabolic defects in the liver, skeletal muscle and fat, and pancreatic ${\beta}$-cells contribute to the disease. These metabolic abnormalities are characterized by the overproduction of hepatic glucose, impaired insulin secretion, and peripheral insulin resistance. In current pharmacological treatment of Type 2 diabetes, sulfonylurea (SU) drugs have mainly been used as oral hypoglycemic drugs to stimulate endogenous insulin secretion from ${\beta}$ cells. SU drugs, however, sometimes aggravate the disease by causing fatigue of the pancreatic ${\beta}$ cells, which leads to reduced drug efficacy after long-term treatment. This class of drugs also leads to enhanced obesity arising from the stimulation of endogenous insulin secretion in obese Type 2 diabetic patients, plus an increased incidence of SU-induced hypoglycemia. Since 1980, a major challenge has been made by us to develop a potential pharmacological therapy for the treatment of insulin resistance in peripheral tissues and/or suppression of abnormal hepatic glucose production in Type 2 diabetic patients. Such a drug would be expected to have fewer side effects and retain long-term efficacy.

• KIEE International Transactions on Electrophysics and Applications
• /
• 제5C권1호
• /
• pp.28-32
• /
• 2005

In the Langmuir-Blodgett (LB) technique, a monolayer on the water surface is transferred onto a substrate, which is raised and dipped through the surface. From this, multilayers can be obtained in which constituent molecules are periodically arranged. The LB technique has attracted considerable interest in the fabrication of electrical and electronic devices. Many researchers have investigated the electrical properties of monolayer and multiplayer films. Dendrimers represent a new class of synthetic macromolecules characterized by a regularly branched treelike structure. Multiple branching yields a large number of chain ends that distinguish dendrimers from conventional star-like polymers and microgels. The azobenzene dendrimer is one of the dendritic macromolecules that include the azo-group exhibiting a photochromic character. Due to the presence of the charge transfer element of the azo-group and its rod-shaped structure, these compounds are expected to have potential interest in electronics and ptoelectronics, especially in nonlinear optics. In the present paper, we give pressure stimulation to organic thin films and detect the induced displacement current.