• 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.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.2
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• pp.164-170
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• 2004

Liquid Injection Nozzle(LIN) tube and Calandria tube(CT) in pressurized Heavy Water Reactor (PHWR) are .ross-aligned horizontally. These neighboring tubes can contact each other due to the sag of the calandria tube resulting from the irradiation creep and thermal creep, and fuel load, etc. In order to judge the contact which might be the safety concern, the remote field eddy current (RFEC) technology is applied for the gap measurement in this paper. LIN can be detected by inserting the RFEC probe into pressure tube (PT) at the crossing point directly. To obtain the optimal conditions of the RFEC inspection, the sensitivity, penetration and noise signals are considered simultaneously. The optimal frequency and coil spacing are 1kHz and 200mm respectively. Possible noises during LIN signal acquisition are caused by lift-off, PT thickness variation, and gap variation between PT and CT. The simulated noise signals were investigated by the Volume Integral Method(VIM). Signal analysis on the voltage plane describes the amplitude and shape of LIN and possible defects at several frequencies. All the RFEC measurements in the laboratory were done in variance with the CT/LIN gap and showed the relationship between the LIN gap and the signal parameters by analyzing the voltage plane signals.

• Korean Journal of Digital Imaging in Medicine
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• v.12 no.1
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• pp.27-31
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• 2010

The purpose of this study was to investigated the usefulness of MR perfusion image comparing with SPECT image. A total of pediatric 30 patients(average age : 7.8) with Moyamoya disease were performed MR Perfusion with 32 channel body coil at 3T from March 01, 2010 to June 10, 2010. The MRI sequences and parameters were as followed : gradient Echo-planar imaging(EPI), TR/TE : 2000ms/50ms, FA : $90^{\circ}$, FOV : $240{\times}240$, Matrix : $128{\times}128$, Thickness : 5mm, Gap : 1.5mm. Images were obtained contrast agent administrated at a rate of 1mL/sec after scan start 10s with a total of slice 1000 images(50 phase/1 slice). It was measured with visual color image and digitize data using MRDx software(IDL version 6.2) and also, it was compared of measurement with values of normal and abnormal ratio to analyze hemodynamic change, and a comparison between perfusion MR with technique using Warm Color at SPECT examination. On MR perfusion examination, the color images from abnormal region to the red collar with rCBV(relative cerebral blood volume) and rCBF(relative cerebral blood flow) caused by increase cerebral blood flow with brain vascular occlusion in surrounding collateral circulation advancement, the blood speed relatively was depicted slowly with blue in MTT(Mean Transit Time) and TTP(Time to Peak) images. The region which was visible abnormally from MR perfusion examination visually were detected as comparison with the same SPECT examination region, would be able to confirm the identical results in MMD(Moyamoya disease)judgments. Hymo-dynamic change in MR perfusion examination produced by increase and delay cerebral blood flow. This change with digitize data and being color imaging makes enable to distinguish between normal and abnormal area. Relatively, MR perfusion examination compared with SPECT examination could bring an excellent image with spatial resolution without radiation expose.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.7
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• pp.1098-1105
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• 2004

In order to develop natural food preservatives, the ethanol and water extracts of the Saururus chinensis Baill were prepared. Antimicrobial activity was examined against 10 kinds of harmful microorganisms. The ethanol and water extracts showed the most active antimicrobial activity against B. subtilis and E. coli. The ethanol extract showed stronger antimicrobial activity than that of the water extract. However, the extracts did not show any antimicrobial activity against lactic acid bacteria and yeast. The minimum inhibitory concentrations (MIC) of ethanol extracts against B. subtilis and E. coli were 5 to 10 mg/mL, respectively. Antimicrobial activity of the ethanol extract was not destroyed at 40-12$0^{\circ}C$ and pH 3∼11. The ethanol extract was fractionated in the order of hexane, diethyl ether, ethyl acetate, and water fractions. The highest antimicrobial activity was found in the diethyl ether fraction.

• Journal of Korean Neurosurgical Society
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• v.29 no.11
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• pp.1491-1498
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• 2000

Objectives : Embolization of intracranial aneurysms by using Guglielmi detachable coils(GDC) is proving to be a safe method of protecting aneurysms from rupture. Occasionally, patients with unruptured intracranial aneurysms present with symptoms related to the aneurysm's mass effect on either the brain parenchyma or cranial nerves. In the present study, the authors conducted a retrospective review to evaluate the response to GDC embolization in a series of 6 patients presenting with cranial nerve dysfunction due to mass effect. Patients and Methods : Aneurysms were classified by size, shape, and amount of intraluminal thrombus. Patients were classified by duration of symptoms prior to GDC treatment(range<1 month to>4 years). Clinical assessment was performed within days of the GDC procedure and at later follow-up appointments(range 5-16 months, mean 9 months). Results : In the immediate post-GDC embolization period, one of the five patients had transient worsening of third nerve palsy, which later improved to better than baseline status. Two patients who presented with third nerve deficit from a internal carotid artery-posterior communicating artery junction aneurysm had complete recovery. One patient who presented with hemiparesis and dysarthria from a giant mid-basilar aneurysm showed improvement of these symptoms. One patient who presented with sixth cranial nerve deficit from a cavernous aneurysm showed no change at the 8-months follow-up examination. Conclusion : The endovascular treatment of intracranial aneurysms by using GDC is suggested as an alternative therapeutic method for improving or alleviating neurological deficits produced by mass effect.

• Journal of Korean Neurosurgical Society
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• v.44 no.4
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• pp.228-233
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• 2008

Objective : The standard treatment strategy of intracranial aneurysms includes either endovascular coiling or microsurgical clipping. In certain situations such as in giant or dissecting aneurysms, bypass surgery followed by proximal occlusion or trapping of parent artery is required. Methods : The authors assessed the result of extracranial-intracranial (EC-IC) bypass surgery in the treatment of complex intracranial aneurysms in one institute between 2003 and 2007 retrospectively to propose its role as treatment modality. The outcomes of 15 patients with complex aneurysms treated during the last 5 years were reviewed. Six male and 9 female patients, aged 14 to 76 years, presented with symptoms related to hemorrhage in 6 cases, transient ischemic attack (TIA) in 2 un ruptured cases, and permanent infarction in one, and compressive symptoms in 3 cases. Aneurysms were mainly in the internal carotid artery (ICA) in 11 cases, middle cerebral artery (MCA) in 2, posterior cerebral artery (PCA) in one and posterior inferior cerebellar artery (PICA) in one case. Results : The types of aneurysms were 8 cases of large to giant size aneurysms, 5 cases of ICA blood blister-like aneurysms, one dissecting aneurysm, and one pseudoaneurysm related to trauma. High-flow bypass surgery was done in 6 cases with radial artery graft (RAG) in five and saphenous vein graft (SVG) in one. Low-flow bypass was done in nine cases using superficial temporal artery (STA) in eight and occipital artery (OA) in one case. Parent artery occlusion was performed with clipping in 9 patients, with coiling in 4, and with balloon plus coil in 1. Direct aneurysm clip was done in one case. The follow up period ranged from 2 to 48 months (mean 15.0 months). There was no mortality case. The long-term clinical outcome measured by Glasgow outcome scale (GOS) showed good or excellent outcome in 13/15. The overall surgery related morbidity was 20% (3/15) including 2 emergency bypass surgeries due to unexpected parent artery occlusion during direct clipping procedure. The short-term postoperative bypass graft patency rates were 100% but the long-term bypass patency rates were 86.7% (13/15). Nonetheless, there was no bypass surgery related morbidity due to occlusion of the graft. Conclusion : Revascularization technique is a pivotal armament in managing complex aneurysms and scrupulous prior planning is essential to successful outcomes.

• Journal of Korean Neurosurgical Society
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• v.45 no.4
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• pp.224-230
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• 2009

Objective : We aimed to analyze clinical and radiological outcomes retrospectively in patients with basilar apex aneurysms treated by coiling or clipping. Methods : Outcomes of basilar bifurcation aneurysms were assessed retrospectively in 77 consecutive patients (61 women, 16 men), ranging in age from 25 to 79 years (mean, 53.7 years) from 1999 to 2007. Results : Forty-nine patients out of 77 patients (63.6%) presented with subarachnoid hemorrhages of the 49 patients treated with coiling, 27 (55.1 %) showed complete occlusion of the aneurysm sac. Of these, 13 patients (26.5%) developed coil compaction on angiographic or MRI follow-up, with recoiling required in 9 patients (18.4%). Procedural complications of coiling were acute infarction in nine patients and the bleeding of the aneurysms in six patients. The remaining 28 patients underwent microsurgery : twenty-six of these (92.9%) with microsurgery followed up with conventional angiography. Complete occlusion of the aneurysm sac was achieved in 19 patients (73.1%). Operation-related complications of microsurgery were thalamoperforating artery injuries in three patients, retraction venous injury in two, postoperative epidural hemorrhage (EDH) in one, and transient partial or complete occulomotor palsy in 14 patients. Glasgow Outcome Scores (GOS) were 4 or 5 in 21 of 28 (75%) patients treated with microsurgery at discharge, and at 6 month follow-up, 20 of 28 (70.9%) maintained the same GOS. In comparison, GOS of four or 5 was observed in 36 of 49 (73.5%) patients treated with coiling at discharge and at 6 month follow-up, 33 of 49 patients (67.3%) maintained the GOS from discharge. Conclusion : Basilar top aneurysms were still challenging lesions based on our series. Endovascular or microsurgery endowed with its inborn risks and procedural complications for the treatment of basilar apex aneurysms individually. Microsurgery provided better outcome in some specific basilar apex aneurysms. For reaching the most favorable outcome, endovascular modality as well as microsurgery was inevitably considered for each specific basilar apex aneurysm.

• Journal of Korean Neurosurgical Society
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• v.61 no.4
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• pp.450-457
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• 2018

Objective : Very large (20-25 mm) and giant (${\geq}25mm$) intracranial aneurysms have an extremely poor natural course, and treatment of these aneurysms remains a challenge for endovascular and surgical strategies. This study was undertaken to describe our experiences of endosaccular treatment of very large and giant intracranial aneurysms with parent artery preservation. Methods : From January 2005 to October 2016, twenty-four very large or giant aneurysms in 24 patients were treated by endosaccular coil embolization with parent artery preservation. Nine (37.5%) aneurysms were ruptured and 15 were unruptured, and of these 15, 11 were symptomatic cases and 4 were incidentally discovered. The cohort comprised 17 women and 7 men of mean age 58.5 years (range, 26-82). Mean aneurysm size was 26.0 mm (range, 20-39) and 13 of the 24 aneurysms were giant. Results : Immediate angiographic results were complete occlusion in nine (37.5%) cases, remnant neck in six (25.0%), and remnant sac in nine (37.5%). Overall procedural related morbidity and mortality rates were 12.5% and 4.2%, respectively. Angiographic follow-up was available in 16 patients (66.7%). Mean and median follow-up periods were 27.2 (range, 2-77) and 10.5 months, respectively. In 12 cases (12/16, 75%) stable occlusion was achieved, four cases (4/16, 25%) had recanalized, and two of these were retreated with additional coiling. At clinical follow-up of the nine ruptured cases, three patients (33.3%) achieved a good clinical outcome (Glasgow outcome scale [GOS] score of 4 or 5), two (22.2%) a poor outcome (GOS score of 2 or 3), and four patients (44.4%) expired (GOS 1). On the other hand, of the 15 unruptured cases, 13 patients (86.7%) achieved a good clinical outcome (GOS 4 or 5), one patient a poor outcome (GOS score of 2 or 3), and one patient expired (GOS 1). Conclusion : The present study shows endosaccular treatment of very large or giant intracranial aneurysms with parent artery preservation is both feasible and effective with acceptable morbidity and mortality.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.69-74
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• 2018

Large industrial motors require a large area because of the high risk of shutdown accidents and large industrial accidents due to the lowering of the dielectric strength of the armature windings and overheating problems. Therefore, there is a demand for a large-capacity motor that has small size, light weight, and excellent dielectric strength compared with conventional motors. Superconducting motors have advantages of high efficiency and output power, low size, low weight, and improved stability. This results from greatly increasing the magnetic field generation by using superconductive field coils in rotating machines such as generators and motors. It is very important to design and analyze the cooling system to lower the critical temperature of the wires to achieve superconducting performance. In this study, a field loss analysis and low-temperature heat transfer analysis of the cooling system were performed through the conceptual design of a 100-HP high-temperature superconducting synchronous motor. The field loss analysis shows that a uniform pore magnetic flux density appears when high-temperature superconducting wire is used. The low-temperature heat transfer analysis for gaseous neon and liquid neon showed that a flow rate of 1 kg/min of liquid neon is suitable for maintaining low-temperature stability of the high-temperature superconducting wire.