• Journal of Korean Neurosurgical Society
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• v.64 no.1
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• pp.78-87
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• 2021

Objective : Intraoperative neurophysiological monitoring (IONM) has been widely used during spine surgery to reduce or prevent neurologic deficits, however, its application to the surgical management for cervical myelopathy remains controversial. This study aimed to assess the success rate of IONM in patients with cervical myelopathy and to investigate the factors associated with successful baseline monitoring and the effect of increasing the stimulation intensity by focusing on motor evoked potentials (MEPs). Methods : The data of 88 patients who underwent surgery for cervical myelopathy with IONM between January 2016 and June 2018 were retrospectively reviewed. The success rate of baseline MEP monitoring at the initial stimulation of 400 V was investigated. In unmonitorable cases, the stimulation intensity was increased to 999 V, and the success rate final MEP monitoring was reinvestigated. In addition, factors related to the success rate of baseline MEP monitoring were investigated using independent t-test, Wilcoxon rank-sum test, chi-squared test, and Fisher's exact probability test for statistical analysis. The factors included age, sex, body mass index, diabetes mellitus, smoking history, symptom duration, Torg-Pavlov ratio, space available for the cord (SAC), cord compression ratio (CCR), intramedullary increased signal intensity (SI) on magnetic resonance imaging, SI length, SI ratio, the Medical Research Council (MRC) grade, the preoperative modified Nurick grade and Japanese Orthopedic Association (JOA) score. Results : The overall success rate for reliable MEP response was 52.3% after increasing the stimulation intensity. No complications were observed to be associated with increased intensity. The factors related to the success rate of final MEP monitoring were found to be SAC (p<0.001), CCR (p<0.001), MRC grade (p<0.001), preoperative modified Nurick grade (p<0.001), and JOA score (p<0.001). The cut-off score for successful MEP monitoring was 5.67 mm for SAC, 47.33% for the CCR, 3 points for MRC grade, 2 points for the modified Nurick grade, and 12 points for the JOA score. Conclusion : Increasing the stimulation intensity could significantly improve the success rate of baseline MEP monitoring for unmonitorable cases at the initial stimulation in cervical myelopathy. In particular, the SAC, CCR, MRC grade, preoperative Nurick grade and JOA score may be considered as the more important related factors associated with the success rate of MEP monitoring. Therefore, the degree of preoperative neurological functional deficits and the presence of spinal cord compression on imaging could be used as new detailed criteria for the application of IONM in patients with cervical myelopathy.

• Journal of Periodontal and Implant Science
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• v.54 no.1
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• pp.13-24
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• 2024

Purpose: This study investigated the adjunctive effect of light-emitting diodes (LEDs) in the treatment of experimental periodontitis. Methods: Experimental periodontitis was induced by placing ligatures around the mandibular second, third, and fourth premolars of 6 beagles for 3 months. After ligature removal, periodontitis progressed spontaneously for 2 months. The animals' hemimandibles were allocated among the following 3 groups: 1) no treatment (control), 2) scaling and root planing (SRP), and 3) SRP with LED irradiation at 470-nm and 630-nm wavelengths (SRP/LED). The probing pocket depth (PPD) and gingival recession (GR) were measured at baseline, 6 weeks, and 12 weeks. The clinical attachment level (CAL) was calculated. After 12 weeks, histological and histomorphometric assessments were performed. The distances from the gingival margin to the apical extent of the junctional epithelium (E) and to the connective tissue (CT) attachment were measured, as was the total length of soft tissue (ST). Results: PPD and CAL increased at 12 weeks compared with baseline in the control group (6.31±0.43 mm to 6.93±0.50 mm, and 6.46±0.60 mm to 7.61±0.78 mm, respectively). PPD and CAL decreased at 12 weeks compared with baseline in the SRP group (6.01±0.59 to 4.81±0.65 mm, and 6.51±0.98 to 5.39±0.93 mm, respectively). PPD and CAL decreased at 12 weeks compared with baseline in the SRP/LED group (6.03±0.39 to 4.46±0.47 mm, and 6.11±0.47 to 4.78±0.57 mm, respectively). The E/ST and CT/ST ratios significantly differed among the 3 groups (P<0.05). The clinical parameters and histologic findings demonstrated that 470-nm and 630-nm wavelength LED irradiation accompanying SRP could improve treatment results. Conclusions: Within the study limitations, 470 nm and 630 nm wavelength LED irradiation might provide additional benefits for periodontitis treatment.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.5 no.1
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• pp.39-51
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• 1999

Background and Purpose. Objective measurements of hamstring muscle length are needed to quantify baseline limitations and to document the effectiveness of therapeutic interventions. Several indirect clinical tests for measuring hamstring muscle length are available, but influence of their test procedure is not well documented. The purpose of this study were 1) to describe hamstring muscle length as reflected by use of six tests(active straight leg raising(ASLR), passive straight leg raising(PSLR), passive straight leg raising with the lower back flat(PSLRB), active knee extension(AKE), passive knee extension(PKE), hip joint angle(HJA). 2) to examine the correlation among the tests. Subjects, Sixty subjects(30 men. 30 women) ranging in age from 18 to 25 years(mean 20.2 years) and with no limitation hamstring flexibility and no neurological and orthopedical problems. Methods. All subjects performed six tests. A inclinometer was used to determine the end point of range of motion. HJA was measured using an inclinometer placed over the sacrum. PSLRB were tested PSLR with the low back flat and the opposite thigh slightly flexed and support on pillows. Results, A mean ASLR value of 85.9 degrees, PSLR value of 99.9 degrees, PSLRB value of 109.8 degrees, AKE value of 77.2 degrees PKE value of 83.1 degrees and HJA value of 73.0 degrees were obtained for all subjects. A dependent t-test showed significant difference between the angles of ASLR and PSLR(p<0.001). There was a significant difference between the angles of PSLR and PSLRB(p<0.001). There was a significant difference between the angles of AKE and PKE(p<0.001). The highest correlation was between PSLR and PSLRB(r=0.915, p<0.001). All SLR tests were significants related(p<0.001), as well as AKE and PKE(p<0.001). The lowest correlation was between PKE and HJA(r=0.171. p>0.05). Conclusion and Discussion. The results indicated that the hip flexion angles for ASLR, PSLR and PSLRB were a difference, and the knee extension angles for AKE and PKE were a difference.

• Journal of radiological science and technology
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• v.41 no.1
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• pp.1-6
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• 2018

The purpose of this study is to provide baseline data on lung field size measured radiological method by chest PA image in normal Korean. The subject of this study is 496 normal persons who performed chest PA examination using x-ray digital radiography system. The measurement method is from the apex of right and left lung to the costophrenic angle of both lung, from the top of the image to the lowest costophrenic angle of both lung and transverse line of the largest lung area. As a result of this study, the following conclusions were obtained. A lung field size of male is larger than the female(p<0.05). The younger the age, the longer both lung length and total lung height statistically significant. As a increase height and length, A lung field size was increased(p<0.05). But, BMI is not associated with a lung field size. This study will be data of reference data when radiological technologists perform chest PA examination.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.2
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• pp.19-29
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• 2019

Purpose : To determine whether an advanced rehabilitation therapy combined with conventional rehabilitation therapy consisting of sensorimotor exercises that would be superior to a usual treadmill training in gait ability and fall risk in subacute stroke patients. Methods : Thirty subjects randomly assigned to either multi-sensorimotor training group (n=19) or treadmill training group (n=18). Both groups first performed conventional physical therapy for 30 min, after which the multi-sensorimotor training group performed multi-sensorimotor training for 30 min, and the treadmill training group performed treadmill gait training for 30 min. Both groups performed the therapeutic interventions 5 days per week for 8 weeks. Gait ability was evaluated using the GAITRite system and Fall risk was measured using the Biodex Balance system before intervention and after 8 weeks. Results : There were no intergroup differences between demographic and clinical characteristics at baseline (p>.05). Both groups showed a significant improvement in gait ability (p<.05) and Fall risk (p<.05). In particular, the multi-sensorimotor training group showed more significant differences in gait velocity (p=.05), step length (p=.01) and stride length (p=.014) than the treadmill training group. Conclusion : The multi-sensorimotor training program performed on multiple types of sensory input had beneficial effect on gait ability. A large-scale randomized controlled study is needed to prove the effect of this training.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2124-2129
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• 2007

A VCHP was fabricated and tested for its thermal performance. The container was made of copper, and the working fluid was water. STS-316 screen of mesh number 100 was inserted as a capillary structure. As a baseline performance, a normal heat pipe of the same dimensions was tested in advance to compare with VCHP, where an inert gas container was attached. The outer diameter of the heat pipe was 12.8 mm and the total length was 600 mm. The evaporator and the condenser lengths were both 200 mm. The thermal load ranged from 20 to 300W. Typical result revealed that the operating temperature of the VCHP stayed almost constant, while that of the normal heat pipe varied as much as 40$^{\circ}C$. Therefore, it was demonstrated that the VCHP is very effective for temperature control of heat-dissipating devices.

• The KSFM Journal of Fluid Machinery
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• v.1 no.1 s.1
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• pp.32-40
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• 1998

Aerodynamic performance of a cooling fan of driving motor was enhanced modifying the vane-shroud configuration. Performance of a target model was evaluated to obtain baseline data. The aerodynamic performance and sound pressure level were tested and measured with different numbers of vane of increased length. The tested models show high and stable performance and low values of specific noise level. The long vane-shroud structure induces more stable through flow and decreases the tip leakage flow, which contributes to the increases of performance and efficiency. The sound pressure level increases for the modified model, however, specific noise level decreases.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.274-277
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• 2008

Pohang Wind Energy Research Center (PoWER-C) is developing a 3 MW Radial Flux Permanent Magnet (RFPM) Synchronous Generator for offshore Wind Energy Converter (WEC). The blade rotor rpm is 15.7 and the gear ratio is set to be 92.93. The nominal generator rpm at the rated load is about 1459. Baseline design with surface mounted PM magnets are completed. However, there is some concern about the excessive eddy current heating in the magnets. To alleviate this problem, another design with embedded magnet is going on. With embedded magnets, the generator length should be increased to compensate the increased flux leakage. But the field fluctuation in the magnets due to the slots are greatly reduced. This means less eddy currents and lower magnet operating temperature. In this report, engineering efforts for embedded rotor is presented.

• 유체기계공업학회:학술대회논문집
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• 1998.12a
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• pp.183-190
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• 1998

This paper introduces the part of efforts to develop a derivative type turbo-shaft engine from an existing baseline engine for multi-purpose helicopters targeting at 4000kg of take-off weight for 10-12 passengers. As a first step in meeting the development goal of increasing the output power to 840hp from 720hp with minimum modification, two stage axial compressor was redesigned to obtain the higher pressure ratio by removing the inlet guide vane and increasing the chord length. As a result, two stage axial compressors were designed to have the flow rate of 3.04 kg/s, the pressure ratio of 2.01 and the adiabatic efficiency of $85\%$. Its performance tests were carried out and verification of test results and redesign are under progress. Aerodynamic and structural analyses of the preliminary design are mainly described in this paper.

• New & Renewable Energy
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• v.6 no.3
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• pp.47-54
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• 2010

Foundation plays an important role in the offshore wind turbine system. Different from conventional foundations, the suction caisson is proven to be economical and reliable. In this work, three-dimensional finite element method is used to check the suitability of suction caisson foundation. NREL 5MW wind turbine is chosen as a baseline model in our simulation. The maximum overturning moment and vertical load at the mudline are calculated using FAST and Bladed. Meanwhile the soil-structure interaction response from our simulation is also compared with the experiment data from Oxford university. The design parameter such as caisson length, diameter of skirt and spacing of multipod are investigated. Accordingly based on these parameters suggestions are given to use suction caisson foundations more efficiently.