• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.4
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• pp.315-321
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• 2003

The integrity of the turbine rotors can be assessed by measuring the material properties at service temperature. In order to evaluate the remanent life of turbine rotor steel nondestructively, a measurement system of reversible magnetic permeability using an alternating perturbing magnetic field was constructed. We present a new non-destructive method to evaluate the remanent life of 1Cr-1Mo-0.25V steel using the value of reversible magnetic permeability. This method is based on the existence of reversible magnetic permeability in the differential magnetization around the coercive field strength. We measured the first harmonics voltage induced in a coil using a lock-in amplifier tuned to an exciting frequency. The Results of reversible magnetic Permeability and Wickers hardness on the aged samples show that the peak interval of reversible magnetic permeability (PIRMP) and Vickers hardness decreases as aging time increases. A softening curve is obtained from the correlation between Vickers hardness and the PIRMP. This curve can be used as a non-destructive method to evaluate the remanent life of turbine rotor steel.

• Korean Journal of Medicinal Crop Science
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• v.14 no.3
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• pp.139-142
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• 2006

This study was conducted to develop antibacterial hand towel and dishcloth against food poisoning bacteria, and to examine the dyeability and the antibacterial activity of cotton fabrics against food poisoning bacteria, which was dyed with 1 % extracts of Geranium nepalense at $50\;to\;60^{\circ}C$ minutes. Surface colors of cotton fabrics treated nothing, alum $[AIK(SO_4)_2{\cdot}nH_2O]$, and calcium hydroxide $[Ca(OH)_2]$ with mordants showed grayed-yellow group, that treated copper sulfate $(CUSO_4)$ with mordant was grey-brown group, and that treated sulfate of iron $(FeSO_4{\cdot}7H_2O)$ made grayed-green group. Hue value of cotton fabrics dyed with the extracts of Geranium nepalense and dried until twenty times was an order of descent Y, that dried thirty to forty an order of descent YR. Cotton fabrics dyed with the extracts of Geranium nepalense had the antibacterial activity against food poisoning bacteria such as Staphylococcus aureus, Escherichia coil and Salmonella typhimurium by over 99.99%. And that dried over thirty times showed the antibacterial activities against food poisoning bacteria by 52.91%.

• The korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.775-782
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• 1998

The purpose of this study is to investigate the change of the EGFR mRNA expression in the rat gingival epithelium by the experimental tooth movement. We applied reciprocal force between the upper anterior teeth using NiTi open coil spring and stainless steel wire for 1, 2 3, 7 days. For the detection of EGFR mRNA, in situ hybridization was done in the tissue samples which were taken from the pressure and tension sides of teeth. The results were as follows ; 1. The expression of EGFR mRNA was increased application-time dependently. a. Day 1 mild expression on the basal and spinous cell layers b. Day 2 . moderate expression on the whole layers c. Day 3 : severe expression on the basal and spinous cell layers 4. Day 7 severe expression on the whole layers 2. The expression level of EGFR mRNA in the pressure and tension sides were similar during the whole Period of experiment except seven day application at which the cornified layer of the tension side showed moderate expression. 3. Removal of the appliance after 7-day force application lowered the level of EGRF mRNA expression. It was returned to the mild and control (rare) level at three and seven days after the removal, respectively. In conclusion, EFGR mRNA was increased by the experimental tooth movement on the rat ginigval epithelium. Up-regulation of EGFR mRNA in the gingival epithelium can be regarded as responses to the possible changes caused by the physical stersses to the oral environment to maintain the homeostatic conditions of the periodontium.

• The korean journal of orthodontics
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• v.48 no.4
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• pp.253-261
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• 2018

Objective: Orthodontic root resorption (ORR) due to orthodontic tooth movement is a difficult treatment-related adverse event. Caspases are important effector molecules for apoptosis. At present, little is known about the mechanisms underlying ORR and apoptosis in the cementum. The aim of the present in vivo study was to investigate the expression of tartrate-resistant acid phosphatase (TRAP), caspase 3, caspase 8, and receptor activator of nuclear factor kappa-B ligand (RANKL) in the cementum in response to a heavy or an optimum orthodontic force. Methods: The maxillary molars of male Wistar rats were subjected to an orthodontic force of 10 g or 50 g using a closed coil spring. The rats were sacrificed each experimental period on days 1, 3, 5, and 7 after orthodontic force application. And the rats were subjected to histopathological and immunohistochemical analyses. Results: On day 7 for the 50-g group, hematoxylin and eosin staining revealed numerous root resorption lacunae with odontoclasts on the root, while immunohistochemistry showed increased TRAP- and RANKL-positive cells. Caspase 3- and caspase 8-positive cells were increased on the cementum surfaces in the 50-g group on days 3 and 5. Moreover, the number of caspase 3- and caspase 8-positive cells and RANKL-positive cells was significantly higher in the 50-g group than in the 10-g group. Conclusions: In our rat model, ORR occurred after apoptosis was induced in the cementum by a heavy orthodontic force. These findings suggest that apoptosis of cementoblasts is involved in ORR.

• Physical Therapy Korea
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• v.10 no.3
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• pp.17-27
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• 2003

Repetitive transcranial magnetic stimulation (rTMS) modulates cortical excitability beyond the duration of the rTMS trains themselves. Depending on rTMS parameters, a lasting inhibition or facilitation of cortical excitability can be induced. Therefore, rTMS of high or low frequency over motor cortex may change certain aspects of motor learning performance and cortical activation. This study investigated the effect of high and low frequency subthreshold rTMS applied to the motor cortex on motor learning of sequential finger movements and brain activation using functional MRI (fMRI). Three healthy right-handed subjects (mean age 23.3) were enrolled. All subjects were trained with sequences of seven-digit rapid sequential finger movements, 30 minutes per day for 5 consecutive days using their left hand. 10 Hz (high frequency) and 1 Hz (low frequency) trains of rTMS with 80% of resting motor threshold and sham stimulation were applied for each subject during the period of motor learning. rTMS was delivered on the scalp over the right primary motor cortex using a figure-eight shaped coil and a Rapid(R) stimulator with two Booster Modules (Magstim Co. Ltd, UK). Functional MRI (fMRI) was performed on a 3T ISOL Forte scanner before and after training in all subjects (35 slices per one brain volume TR/TE = 3000/30 ms, Flip angle $60^{\circ}$, FOV 220 mm, $64{\times}64$ matrix, slice thickness 4 mm). Response time (RT) and target scores (TS) of sequential finger movements were monitored during the training period and fMRl scanning. All subjects showed decreased RT and increased TS which reflecting learning effects over the training session. The subject who received high frequency rTMS showed better performance in TS and RT than those of the subjects with low frequency or sham stimulation of rTMS. In fMRI, the subject who received high frequency rTMS showed increased activation of primary motor cortex, premotor, and medial cerebellar areas after the motor sequence learning after the training, but the subject with low frequency rTMS showed decreased activation in above areas. High frequency subthreshold rTMS on the motor cortex may facilitate the excitability of motor cortex and improve the performance of motor sequence learning in normal subject.

• KSBB Journal
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• v.15 no.4
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• pp.331-336
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• 2000

The antimutagenic activity of the extract of Artemisia capillaris THUNB on the mutagenicity induced by benzo(a)pyrene [B(a)P] in the presense of S9 mixture was studied using bacterial mutagenic assay system. Samples harvested in summer and autumn were extracted using ethanol and hot water. Among these extracts the water extract of summer sample had the strongest inhibitory effect against the mutagenenicity of B(a)P, The water extract of Artemisia capillaris THUNB was separated again into ethanol soluble and insoluble parts. The ethanol insoluble part(El) of water extract exhibited higher inhibition effects than the ethanol soluble part against the mutagenic activity of B(a)P. El showed dose-dependent activity on the mutagenicity of B(a)P in SOS Chromotest and Ames test. The 50% inbibition concentraction $(IC_{50}$ of El were $200{\mu}g/assay$ $600{\mu}g/plate$ and $800{\mu}b/plate$ in E. coil PQ37 S. typhimurium TA100 and TA98 respectively. El were showed desmutagenic effect but had no effect on the DNA repair system for B(a)P-induced mutagenesis. HPLC analysis showed that the formation of aflatoxin M1 by cytochrome P-450 1A1 known as playing an impotant role on B(a) P-induced mutagenicity was highly inhibited by El. Therefore we encluded that B(a)P-induced mutagencity can be reduced possible due to the interference of el with cytochrome P-450 1A1-dependent bioactivation.

• Korean Journal of Biological Psychiatry
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• v.24 no.3
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• pp.95-109
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• 2017

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive neuromodulation technique which can change cortical excitability in targeted area by producing magnetic field pulses with an electromagnetic coil. rTMS treatment has been used to treat various neuropsychiatric disorders including depression. In this review, we evaluate the literature on rTMS for depression by assessing its efficacy on different subtypes of depression and different technical parameters. In particular, we focus on the results of randomized clinical trials and meta-analyses for depression after the US Food and Drug Administration approval in 2008, which acknowledged its efficacy and acceptability. We also review the new forms of rTMS therapy including deep TMS, theta-burst stimulation, and magnetic seizure therapy (MST) that have been under recent investigation. High frequency rTMS over left dorsolateral prefrontal cortex (DLPFC), low frequency rTMS over right DLPFC, or bilateral rTMS is shown to be effective and acceptable in treatment for patients with non-psychotic, unipolar depression either as monotherapy or adjuvant. Deep TMS, theta-burst stimulation and MST are promising new TMS techniques which warrant further research.

• Annals of Clinical Neurophysiology
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• v.4 no.2
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• pp.114-118
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• 2002

Backgrounds : Carpal tunnel syndrome (CTS) is a common condition that is usually diagnosed by electrophysiologic studies. However, CTS provide limited information to determine the causes of CTS and to choose the treatment method. We evaluated diagnostic sensitivity of MR imaging and treatment decisions by MR imaging in electrodiagnosed CTS. Methods : 14 patients (26 wrists) with electrodiagnosed CTS were studied using MR imaging. In 26 wrists for which axial T1 & T2 weighted images were obtained at 1.5T with a decided wrist coil. Previously described MR imaging of CTS such as increased median nerve signal, flattening of median nerve, reticular bowing, tenosynovitis and space occupying lesions were retrospectively evaluated. Degree of improvement was evaluated by global symptom score (GSS). The GSS rated symptoms from 0 (no symptoms) to 10 (severe) in each of five categories: pain, numbness, paresthesia, weakness/clumsiness, and nocturnal awakening. Subjects' GSS was recorded at baseline, 2 weeks, 1 month, 6 months after treatment. We decided to medical treatment that showed mainly inflammatory sign such as increased median nerve signal, tenosinovitis and to surgical treatment such as space occupying lesion, high canal pressure sign. Results : MR imaging showed that increased median nerve signal were in 20 wrists (77%), flattening of median nerve were in 6 wrists (23%), reticular bowing were in 3 wrists (12%), tenosynovitis were in 8 wrists (32%), decreased canal size in 2 wrists (7.6%), space occupying lesion were in 1 wrist (4%). A good outcome was revealed in 21 wrists by medical treatment that showed mainly increased median nerve signal, tenosynovitis. The mean GSS were 27.7 at baseline, 11.2 at 2 weeks, 11.0 at 6 months in medical treatment group. Another 5 wrist had surgical treatment shown by ganglion and high canal pressure sign such as median nerve flattening, reticular bowing, decreased canal size: 3 wrists had good prognosis, but 2 wrists (one patient) had no significant improvement due to small carpal tunnel size. Conclusions : Our results are in agreement with most previously described MR imaging signs of CTS. MR imaging plays an important role in several cases and especially in the assessment of failure of surgical treatment. Knowledge of MR findings may permit more rational choice of treatment.

• Investigative Magnetic Resonance Imaging
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• v.21 no.2
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• pp.65-70
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• 2017

Purpose: To optimize the saturation time and maximizing the pH-weighted difference between the normal and ischemic brain regions, on 3-tesla amide proton transfer (APT) imaging using an in vivo rat model. Materials and Methods: Three male Wistar rats underwent middle cerebral artery occlusion, and were examined in a 3-tesla magnetic resonance imaging (MRI) scanner. APT imaging acquisition was performed with 3-dimensional turbo spin-echo imaging, using a 32-channel head coil and 2-channel parallel radiofrequency transmission. An off-resonance radiofrequency pulse was applied with a Sinc-Gauss pulse at a $B_{1,rms}$ amplitude of $1.2{\mu}T$ using a 2-channel parallel transmission. Saturation times of 3, 4, or 5 s were tested. The APT effect was quantified using the magnetization-transfer-ratio asymmetry at 3.5 ppm with respect to the water resonance (APT-weighted signal), and compared with the normal and ischemic regions. The result was then applied to an acute stroke patient to evaluate feasibility. Results: Visual detection of ischemic regions was achieved with the 3-, 4-, and 5-s protocols. Among the different saturation times at $1.2{\mu}T$ power, 4 s showed the maximum difference between the ischemic and normal regions (-0.95%, P = 0.029). The APTw signal difference for 3 and 5 s was -0.9% and -0.7%, respectively. The 4-s saturation time protocol also successfully depicted the pH-weighted differences in an acute stroke patient. Conclusion: For 3-tesla turbo spin-echo APT imaging, the maximal pH-weighted difference achieved when using the $1.2{\mu}T$ power, was with the 4 s saturation time. This protocol will be helpful to depict pH-weighted difference in stroke patients in clinical settings.

• Korean Journal of Food Science and Technology
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• v.49 no.2
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• pp.123-131
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• 2017

Norovirus causes frequent epidemic viral gastroenteritis in Korea. The team for the control of noroviral foodborne outbreaks (NOROTECL) executed a project to trace the cause of norovirus contamination in agricultural products and environmental samples to reduce norovirus outbreaks in Korea. Between January and November in 2015, the contaminations by norovirus and indicator microorganisms such as coliforms, Escherichia coil and male specific coliphage (MSC) were examined in 80 agricultural products, 80 soil samples, 78 human feces samples, 3 animal feces samples, 80 agricultural water samples and 80 river water samples. Semi-nested PCR and DNA sequencing revealed 18 genogroup I and 3 genogroup II noroviruses in a total of 18 samples. These noroviruses were validated by real-time (RT)-PCR analysis. For indicator microorganisms, coliform and E. coli were respectively detected in agricultural products (68, 1%), soils (88, 7%), human feces (44, 12.8%), animal feces (67, 67%), agricultural waters (74, 30%) and river waters (96, 51%). The MSC results revealed 14 positive samples.