• Journal of Biomedical Engineering Research
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• v.38 no.1
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• pp.16-24
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• 2017

For the development of feasible retinal prosthesis, one of the important elements is acquiring proper judging tool if electrical stimulus leads to patient's visual perception. If evoked potential to electrical stimulus is recorded in primary visual (V1) cortex, it means that the stimulus effectively evokes visual perception. Therefore, in this study, we established VEP recording system on V1 cortex using BioPAC modules as the judging tool. And the measuring system was evaluated by recording VEP of mice. After anesthesia, normal mice (C57BL/6J strain; n = 6) were secured to stereotaxic apparatus (Harvard Apparatus, USA). For the recording of VEP, the stainless steel needle electrode (impedance: $2-5k{\Omega}$) was positioned on the surface of the cortex through the burr hole at 2.5 mm lateral and 4.6 mm caudal to bregma. DA 100C and EEG 100C BioPAC modules were used for the trigger signal and VEP recording, respectively. When left eye was blocked by black cover and right eye was stimulated by flash light using HMsERG (RetVet Corp, USA), VEP response at left V1 cortex was detected, but there was no response at right V1 cortex. Amplitudes and latencies of P2, N3 peaks of VEP recording varied according to the depths of the electrodes on V1 cortex. From the surface upto $600{\mu}m$ depth, amplitudes of P2 and N3 increased, while deeper than $600{\mu}m$, those amplitudes decreased. The deeper the insertion depth of the electrode, the latency of N1 peaks tends to be delayed. However, there was no statistically significant difference among the latencies of P2 and N3 peaks (P > 0.05, ANOVA). Our VEP recording data such as the insertion depth and the latency and amplitudes of peaks might be used as guidelines for electrically-evoked potential (EEP) recording experiment in near future.

• Asian Journal of Turfgrass Science
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• v.17 no.2_3
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• pp.67-73
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• 2003

A series of studies was conducted during 2 years to investigate the effect of transplanting time and turfgrass species on turf establishment rate of sod for 2002 World Cup Soccer ground construction. The required period of rooting and turf growth for acceptable soccer playing quality on transplanted sod from nursery was tested to collect data for the project authorities of hosting cities and construction companies who were involved in World Cup stadium project. Transplanting time significantly affects on rooting-potential of sod on cool season grass and zoysiagrass, but those effects differently showed by turfgrass species. The enough nursing period for the ground established by Zousiagrass should be secured with proper transplanting time. And the thermal insulation on the turf canopy with other maintenance during Winter should improve the early rooting on zoysiagrass. The sod contained Kentucky bluegrass (85％＋15％ perennial ryegrass, seed wt. basis) showed relatively slow at the early growth and rooting-potential of root, but the potential resulted higher than that of perennial ryegrass turf (85％＋15％ Kentucky) under longer nursing period. Kentucky bluegrass has one of the most strong resistance against environmental stresses, but intensive maintenance practise should be required when the turf transplanted during summer season. Higher mixture rate of perennial ryegrass sod has a rapid root growth compare with other turfgrass species. The rate provided a benefit to an early establishment of turf ground followed by a proper maintenance practise. For the completion of World Cup soccer ground construction for 2002, the most suitable time for sod transplanting in 2001 was March to May or mid Sept. to early Oct. by delayed architect construction schedule.

• Journal of Korean Neurosurgical Society
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• v.29 no.1
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• pp.5-14
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• 2000

Objective : Somatosensory evoked potential(SSEP) has been known to be a good method for evaluating brain stem function, but it is not sufficient to check the fine changes of cortical functions. A fine change of cortical function can be expressed with somatosensory evoked cortical field potential(SSEFP) rather than general SSEP. To confirm the usefulness of SSEFP for evaluating the cortical function, the authors simultaneously measured SSEFP and the intracranial pressure-volume index(PVI) in kaolin-induced hydrocephalic rats. Method : Hydrocephalus was induced with injection of 0.1ml kaolin-suspended solution into the cisterna magna in 60 Sprague-Dawley rats. The authors measured PVI and SSEFP 1 week after injection of kaolin-suspended solution. To evaluate the severity of induced hydrocephalus, we measured the transverse diameter of the lateral ventricle on the coronal slice of the rat brain 0.40mm posterior to the bregma. Result : The typical wave form of SSEFP in control rats showed a negative-positive complex wave at early latency. In SSEFP of normal rats, N0 is 10.0 msec, N1 15.3 msec, P1 31.2 msec and N1-P1 amplitude $15.4{\mu}V$. As hydrocephalus progressed, the peak latency of N1 and P1 were delayed. In mild hydrocephalus, negative peak waves were split. The N1-P1 amplitude was decreased only in severe hydrocephalus. The changes of the characteristics of SSEFP according to the severity of hydrocephalus were well correlated with the changes of PVI. Shunting normalized the characteristics of SSEFP in relation to ventricular sizes and PVI in hydrocephalic rats. Conclusion : SSEFP may be useful for evaluating the impairment of cortical function in hydrocephalus.

• Journal of Korean Neurosurgical Society
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• v.51 no.5
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• pp.286-291
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• 2012

Objective : To investigate the change of latency of cervical dermatomal somatosensory evoked potential (DSEP) according to stimulation intensity (SI) and severity of carpal tunnel syndrome (CTS). Methods : Stimulation sites were the C6, C7, and C8 dermatomal areas. Two stimulation intensities $1.5{\times}$sensory threshold (ST) and $2.5{\times}ST$ were used on both normal and CTS patients. Results : In moderate CTS, the latencies of C6 and C7 DSEP during $1.5{\times}ST$ SI and those of C7 DSEP during $2.5{\times}ST$ SI were significantly delayed compared with the values of normal subjects. Significant correlation between the latency of C7 DSEP of $2.5{\times}ST$ stimulation and the median sensory nerve conduction velocity was observed. Conclusion : We suggest that these data can aid in the diagnosis of cervical sensory radiculopathy using low stimulation intensity and of those who have cervical sensory radiculopathy combined with CTS patients.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.8
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• pp.1080-1087
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• 2008

Lipopolysaccharide binding protein (LBP) and CD14 protein play important roles in the defense against infection of Gram-negative bacteria. In the present study, tissue distribution and polymorphism of porcine LBP and CD14 genes were analyzed. Real-time PCR results showed that the porcine LBP gene was especially highly expressed in liver, while CD14 gene was highly expressed in liver and spleen tissues. A 1,732 bp cDNA fragment of porcine LBP gene and a 1,682 bp genomic DNA fragment of CD14 gene were isolated. Polymorphisms were identified in these two fragments and showed that there were 14 potential SNPs in the porcine LBP gene and 3 potential SNPs in the porcine CD14 gene. Three SNPs, 292G/A (Gly/Ser), 1168G/A (Ala/Thr) of the LBP gene and -61G/A of the CD14 gene, were genotyped using restriction fragment length polymorphism (RFLP) method. Association analyses indicated that polymorphism of the 292G/A locus was significantly associated with porcine immune traits hematocrit (HCT), IgG and delayed-type hypersensitivity (DTH) (p<0.01), and the 1168G/A locus was significantly associated with HCT and mean corpuscular volume (MCV) traits (p<0.05). No significant association was found between the -61G/A locus and immune traits of the pig. Our data indicated that the LBP gene was significantly associated with immune traits of pig. Also, we identified some SNPs which may be useful markers for disease-resistant breeding of pigs.

• Annals of Clinical Neurophysiology
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• v.6 no.2
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• pp.85-91
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• 2004

Background: Needle electromyography (EMG) and motor evoked potential (MEP) of the genioglossus (tongue) are difficult to perform in evaluations of the craniobulbar region in amyotrophic lateral sclerosis (ALS). Therefore, we investigated the yields of needle EMG and MEP recorded from the upper trapezius, since it receives innervation from the lower medulla and upper cervical cord. Methods: Needle EMG and MEP of the upper trapezius were obtained in 17 consecutive ALS patients. The needle EMG parameters recorded included abnormal spontaneous activity and motor unit action potential (MUAP) morphology. An upper motor neuron (UMN) lesion was presumed when either response to cortical stimulation was absent, or the central conduction time was delayed (>mean+2SD). Results: Of the five patients with bulbar-onset ALS, four had abnormalities in the upper trapezius and four in the tongue by needle EMG. In contrast, of the 12 patients with limb-onset ALS, 11 had abnormalities in the upper trapezius, and only five in the tongue. When MEP was performed, it was found that three of the five patients with bulbar symptoms and three of the six patients with isolated limb involvement had abnormal MEP findings. Conclusions: Electrophysiological studies of the upper trapezius are more sensitive those of the tongue in patients without bulbar symptoms. Thus, needle EMG and MEP of the upper trapezius are alternative tools for assessing bulbar and rostral neuraxial involvement in the diagnosis of ALS.

• PNF and Movement
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• v.16 no.2
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• pp.287-294
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• 2018

Purpose: The neurodynamic test used to implicate symptoms arising from the nerve is proposed to selectively increase the strain of the nerve without increasing the strain of adjacent tissue, although this has not yet been established in the time of nerve tension application. This study aimed to investigate the acute effects of nerve stretching time on nerve excitability using compound nerve action potential (CNAP) analysis. Methods: Thirty healthy young adults (mean age=23.10 years) with no medical history of neurological or musculoskeletal disorder voluntarily participated in this study. Nerve excitability was assessed using the median nerve conduction velocity test. The amplitude of the CNAP was measured under three conditions: resting phase (supra-maximal stimulus, without nerve stretching), baseline phase (two-thirds of the supra-maximal stimulus, without nerve stretching), and stretch phase (two-thirds of the supra-maximal stimulus, with 1-5 minutes nerve stretching). One-way repeated measures ANOVA was conducted to compare the latency and amplitude of CNAP. A post-hoc test was analyzed using the contrast test. Results: The latency was significantly delayed after 1 min. of nerve stretching in comparison with the baseline test. However, no significant difference was found during the nerve stretching (1-5 min.). The amplitude was significantly increased by nerve stretching. Conclusion: Nerve stretching can induce nerve excitability without any nerve injury. Based on the results, more than 1 min. of nerve stretching as a neurodynamic test can be a useful method in the clinical setting.

• Journal of the Korea Institute of Building Construction
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• v.19 no.6
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• pp.511-520
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• 2019

The critical chloride content of rebar embedded in concrete was experimentally evaluated according to the admixture replacement ratio and admixture type. Four types of reinforced concrete were mixed OPC 100%, OPC 70% + GGBFS 30%, OPC 40% + GGBFS 60%, and OPC 40% + GGBFS 40% + FA 20%. NaCl solution was supplied to the specimens, and the open circuit potential of the embedded rebar was monitored. The specimens determined to initiate corrosion were cut at intervals of 5mm from the NaCl solution supply surface and conducted to chlorine ion profile. Corrosion initiation time of rebar embedded in concrete was delayed as the admixture replacement ratio increased. Looking at the critical chloride content of the types of reinforced concrete, it was highest in OPC 1.46kg/㎥, followed in order by S30 0.98kg/㎥, TBC 0.74kg/㎥, and S60 0.71kg/㎥.

• Journal of Environmental Health Sciences
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• v.39 no.5
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• pp.426-437
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• 2013

Objective: Gotjawal refers to a special geographical designation found in Jeju Province, Korea, where vegetation forms over a rocky area. Due to the important ecological value of Gotjawal, international concern about such areas is growing. However, only limited information is available regarding environmental contamination of Gotjawal. This study was conducted in order to investigate the levels of contamination and associated ecotoxicological effects of surface water bodies in Gotjawal. Methods: Surface water samples were collected at three sampling sites in two Gotjawal areas and were analyzed for several pharmaceuticals and pesticides in consideration of the potential sources of contamination. The ecotoxicity of the samples was measured using water fleas (Daphnia magna and Moina macrocopa) and zebrafish (Danio rerio). In addition, effects on the gene transcription of zebrafish were investigated following exposure to the samples. Results: Nine pharmaceuticals were detected in the samples, but none of the target pesticides were detected. Following acute exposure to two surface water samples, the survival of waterfleas was significantly reduced, but reproduction was not affected. In zebrafish, time-to-hatch was delayed and fry survival was decreased in some samples. On the other hand, at the transcriptional level, there were no genes significantly influenced by exposure to the samples. Conclusion: This is the first study investigating environmental contamination in Gotjawal areas and associated ecotoxicities. Further studies are warranted to identify the cause of acute Daphnia toxicity and to determine potential consequences of longer-term exposure in Gotjawal areas.

• Journal of Photoscience
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• v.5 no.4
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• pp.169-174
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• 1998

Photosynthetic responses to dehydration were examined by the simulataneous measurement of O2 evolution and chlorophyll (Chl) fluorescence in green pepper leaves. Dehydration was induced by immersing the plant roots directly in the Hoagland solution containing varying concentration (2-30%) of polyethylene glycol(PEG-6000) . Water potential of the leaf was decreased time-and concentation -dependently by PEG-treatment. The decrease in water potential of leaf was correlated with the decrease in both the maximal photosynthesis (Pmax) and quantum yield of O2 evolution, but Pmax dropped more rapidly than quantum yield at all water deficit conditions tested. However, Chl fluorescence parameters were not affected much. Dehydration did not change the initial fluorescence (Fo) and maximum photochemical efficiency(Fv/Fm) of photosystem(PS) II. Both the photochemical quenching (qP) and non-photochemical quenching(NPQ) were not changed by dehydration under low PFR(50 $\mu$mols m-2s-1 ). In contrast, under high PFR(270$\mu$mols m-2s-1)qP was slightly decreased while NPQ was greatly increased. The fast induction kinetics of Chl fluroecence showed no change in Chl fluorescence pattern by dehydration at high PFR (640 $\mu$mols m-2s-1 ), but exhibited a significant drop in peak level(Fp)at low PRFR (70$\mu$mols m-2s-1 ). PS I oxidation and reduction kinetics revealed normal reduction but delayed oxidation to P-700+, suggesting no lesionin electron flow from PSII to PSI , but impaired electron transport to NADP+,These results suggest that water stress caused by PEG-treatment results in the reduction of photosynthesis, promarily due to the reducted electron trasport from PSI to NADP+ or hampered subsequent steps involving Calvin Cycle.