• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.12
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• pp.1056-1061
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• 2007

A sublimation epitaxial method, referred to as the Closed Space Technique (CST) was adopted to produce thick SiC epitaxial layers for power device applications. In this study, we aimed to systematically investigate surface morphologies and electrical properties of SiC epitaxial layers grown with varying a SiC/Al ratio in a SiC source powder during the sublimation growth using the CST method. The surface morphology was dramatically changed with varying the SiC/Al ratio. When the SiC/Al ratio of 90/1 was used, the step bunching was not observed in this magnification and the ratio of SiC/Al is an optimized range to grow of p-type SiC epitaxial layer. It was confirmed that the acceptor concentration of epitaxial layer was continuously decreased with increasing the SiC/Al ratio. 4H-SiC MESFETs haying a micron-gate length were fabricated using a lithography process and their current-voltage performances were characterized. It was confirmed that the increase of the negative voltage applied on the gate reduced the drain current, showing normal operation of FET device.

• Pediatric Infection and Vaccine
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• v.31 no.1
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• pp.37-45
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• 2024

Purpose: This study aimed to examine the clinical features and determinants of macrolide-unresponsive Mycoplasma pneumoniae pneumonia (MUMP) and to assess the differences in the time to fever resolution between doxycycline (DXC), tosufloxacin (TFX) and corticosteroid (CST) as second-line treatment. Methods: We retrospectively analyzed the medical records of patients under the age of 18 who were admitted to Nowon Eulji University Hospital between July 2018 and February 2020, diagnosed with mycoplasma pneumonia. Macrolide resistance was confirmed by detecting point mutations in the 23S rRNA gene. MUMP was clinically defined by persistent fever (≥38.0℃) lasting for 72 hours or more after the initiation of macrolide treatment. In cases of MUMP, patients were treated with an addition of CST, or the initial macrolide was replaced either DXC or TFX. Results: Out of 157 cases of mycoplasma pneumonia, 83 cases (52.9%) did not respond to macrolides. Patients with MUMP exhibited significantly higher C-reactive protein (CRP) levels (3.2±3.0 vs. 2.4±2.2 mg/dL, P=0.047), more frequent lobar/segmental infiltrations or pleural effusions (56.6% vs. 27.0%, P<0.001; 6.0% vs. 0.0%, P=0.032), and a higher prevalence of 23S rRNA gene mutations (96.4% vs. 64.6%, P<0.001) when compared to those with macrolide-susceptible M. pneumoniae pneumonia. In terms of second-line treatment, 15 patients (18.1%) responded to CST, 30 (36.1%) to DXC, and 38 (45.8%) to TFX. The time to defervescence (TTD) after initiation second-line treatment was significantly shorter in the CST group compared to the DXC (10.3±12.7 vs. 19.4±17.2 hours, P=0.003) and TFX groups (10.3±12.7 vs. 25.0±20.1 hours, P=0.043), with no significant difference observed between the DXC and TFX groups (19.4±17.2 vs. 25.0±20.1 hours, P=0.262). Conclusions: High CRP levels, the presence of positive 23S rRNA gene mutation, lobar or segmental lung infiltration, and pleural effusion observed in chest X-ray findings were significant factors associated with macrolide unresponsiveness. In this study, CST demonstrated a shorter TTD compared to DXC or TFX. Further, larger-scale prospective studies are needed to determine the optimal second-line treatment for MUMP.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.4019-4023
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• 2014

This study examined the effectiveness of ultrasound on enhancing the dewaterability and volume reduction of bio solids from a waste treatment plant. The test specimen was obtained from a storage tank immediately before the dewatering process at a local treatment plant. The test conditions included the energy levels of ultrasonic waves and treatment time. The tests were undertaken using three types of different treatment processors (7 liter, 1 ton, 7 ton container). The capillary suction time (CST) and the viscosity of sludge, which is one of the influencing factors for dewaterbility, were obtained under various test conditions. The results showed that ultrasound increases the CST of the raw specimens, whereas a significant reduction (20 % of the maximum value) of CST occurred in the sample with ultrasound and flocculent. The decrease in viscosity reached 40 % of the maximum value. A centrifugal test was performed to examine the characteristics of the sludge settlement. The settling rate and time required to reach the final values were both enhanced by the ultrasonic energy. An ultrasonic treatment is potentially useful tool for reducing the amount of released sludge. To examine the possible use of field application, the real scale sonic processor was designed and operated. The results were similar (50 % of the maximum value) to those of laboratory experiments.

• Journal of Korean Medical Science
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• v.33 no.43
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• pp.268.1-268.11
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• 2018

Background: We aimed to compare the therapeutic efficacy of prolonged macrolide (PMC), corticosteroids (CST), doxycycline (DXC), and levofloxacin (LFX) against macrolide-unresponsive Mycoplasma pneumoniae (MP) pneumonia in children and to evaluate the safety of the secondary treatment agents. Methods: We retrospectively analyzed the data of patients with MP pneumonia hospitalized between January 2015 and April 2017. Macrolide-unresponsiveness was clinically defined with a persistent fever of ${\geq}38.0^{\circ}C$ at ${\geq}72$ hours after macrolide treatment. The cases were divided into four groups: PMC, CST, DXC, and LFX. We compared the time to defervescence (TTD) after secondary treatment and the TTD after initial macrolide treatment in each group with adjustment using propensity score-matching analysis. Results: Among 1,165 cases of MP pneumonia, 190 (16.3%) were unresponsive to macrolides. The proportion of patients who achieved defervescence within 48 hours in CST, DXC, and LFX groups were 96.9% (31/33), 85.7% (12/14), and 83.3% (5/6), respectively. The TTD after initial macrolide treatment did not differ between PMC and CST groups (5.1 vs. 4.2 days, P = 0.085), PMC and DXC groups (4.9 vs. 5.7 days, P = 0.453), and PMC and LFX groups (4.4 vs. 5.0 days, P = 0.283). No side effects were observed in the CST, DXC, and LFX groups. Conclusion: The change to secondary treatment did not show better efficacy compared to PMC in children with macrolide-unresponsive MP pneumonia. Further studies are needed to guide appropriate treatment in children with MP pneumonia.

• The Journal of Korean Physical Therapy
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• v.27 no.1
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• pp.78-80
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• 2015

Purpose: Many studies have attempted to elucidate the motor recovery mechanisms of stroke. In the current study, we report on a patient with infarction who showed recovery of an injured corticospinal tract (CST), using diffusion tensor imaging (DTI). Methods: A 20-year-old male presented with severe paralysis of the left extremities following an infarction in the right corona radiate and basal ganglia. The patient showed good motor recovery as much as being able to manipulate object using his left hand and could walk independently on stairs at 9 months after onset. Results: At 1 month after onset, the right CST showed decreased fiber volume due to the partial injury at the level of the corona radiate, and no (motor evoked potential) MEP was evoked from the right hemisphere. By contrast, the results at 9 months showed increased fiber volume of the right CST and the amplitude of MEP had improved to normal range on TMS. Conclusion: These results suggest that the severely injured right CST and MEP amplitude had been recovered during 9 months. Therefore, this result has important implications for brain plasticity and brain rehabilitation in patients with infarction.

• The Korea Journal of Herbology
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• v.30 no.1
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• pp.33-42
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• 2015

Objectives : The aim of this study was to evaluate the antitumor effects of Cheongpyesagan-tang(CST) and YKK012 on colon cancer. Methods : MTT assay was used to evaluate the cytotoxicity of Single herbs and combinations of CST and YKK012 on murine colon cancer cells, Colon 38. To explain effects of apoptosis in colon cancer, we performed the western blot. Effects of CST and YKK012 on antitumor activity of CPT-11 using the murine colon38 allograft tumor in BDF1 mice. Results : Single herbs and combinations of CST and YKK012 was tested in vitro, Rhei Radix (RH) and Scutellariae Radix (SC) and YKK012 showed dose-response cytotoxicity on Colon 38. This might be due to the apoptosis, as we see Bax and Caspase-3, which are apoptotic factors, was expressed in RH and SC treated cells. YKK012 also showed increased expression of Caspase-3. In mouse colorectal cancer xenograft model of colon38 cells, herbal combinations showed tendencies of tumor regression, but was not significant. Furthermore, because toxicity was observed in CST group, we reduced the dose of CST for the next experiment. The anti-tumor effects of herbal combinations were insufficient to be used as single anti-tumor agent. With simultaneous usage of CPT-11, contrary to that CST showed no synergistic effects, YKK012 which was composed by the combination of four $ER{\beta}$ selective herbs, significantly reduced the size of tumor and Bax expression was increased. Conclusions : We suggest YKK012 can be a effective cancer adjuvant therapy with CPT-11 on colon cancer.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.6
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• pp.1275-1279
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• 2012

In this paper, we design of dual-band microstrip antenna for wireless communication. We used IEEE 802.11a and Hyper LAN (5.725~5.825 GHz). The proposed antenna substrate is FR-4, size is $22mm{\times}23mm$, thickness is 1.6mm and used to CST Microwave Studio 2010 program. As a result the simulation has good result and good return loss below -10 dB at 5 GHz and 5.8 bandwidth.

• Resources Recycling
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• v.13 no.3
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• pp.12-18
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• 2004

A study on the enhancement of the dewaterability of sewage sludge was carried out by using the sea waste materials as a dewatering aid. It was made from a starfish and a shell by heating at $105∼700 ^{\circ}C$ and centrifuge and belt press were used as a mechanical dewatering process. The moisture content of sludge cake was reduced by 15∼22% (w/w) after addition of the dewatering aid at the dose of 1∼8 g/100mL of digested sludge. CST (capillary suction time) was measured to evaluate the effect of dewatering aid on sludge dewatering properties. CST was reduced after addition of a shell while increased after addition of a starfish. Enhancement of dewaterability after addition of a shell was better than that of a starfish. The heating temperature effect of the dewatering aid on dewaterability was not clear.

• The Korean Journal of Pain
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• v.19 no.2
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• pp.159-163
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• 2006

Background: Despite the enormous amount of basic research on neuropathic pain, there is the lack of an objective diagnostic test for complex regional pain syndrome (CRPS). The aim of this study was to evaluate the usefulness of cold stress thermography in the diagnosis of CRPS. Methods: The study involved 12 patients with CRPS type 1, according to the IASP criteria, who were compared with 15 normal healthy volunteers. All subjects underwent thermographic examination under baseline conditions at $21^{\circ}C$. A cold stress test (CST; $10^{\circ}C$ water for 1 minute) was then applied to both hands below the wrists, immediate, and after 10 and 20 minutes. Results: The temperature asymmetry between the patients with CRPS and the volunteers showed significant discrimination at the baseline and after a 20 minute recovery period from the CST. Among the study subjects having temperature asymmetry of both hands of less than $1^{\circ}C$ (8 out of 12 CRPS patients and 14 out of 15 volunteer), 7 (87.5%) of the 8 CRPS patients and 3 (21%) of the 14 volunteers showed a temperature difference of more than $1^{\circ}C$ after the 20 minute recovery period. The actual temperature values during the four periods did not discriminate between the patients with CRPS and the volunteers. Conclusions: Thermography, under the CST, could be a more objective test for the diagnosis of CRPS. A temperature asymmetry greater than $1^{\circ}C$ during the 20 minute recovery period following CST provides strong diagnostic information about CRPS, with both high sensitivity and specificity.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.3
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• pp.49-58
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• 2017

PURPOSE: To summarize the evaluation tools of balance [Berg Balance Scale (BBS), timed up and Go (TUG), forward reaching test (FRT)], gait [6 m walking Test (6MWT)], and strength [Chair Stand Test (CST)] for patients with dementia. METHODS: The following databases were searched: Pub MED, Cochrane, Sciences Direct, and Web of Sciences. The inclusion criteria were as follows: 1) repeated measurement design, 2) subjects with dementia, 3) use of testing tools such as the BBS, TUG, FRT, 6MWT, and CST, 4) report the reliability. One reviewer performed the quality assessment of diagnostic accuracy study and two evaluators performed data extraction independently. RESULTS: Six articles and one letter were included. The interrater reliability of 6MWT, TUG, and CST, were acceptable (ICC>.90). However, FRT had unacceptable reliability. In test-retest reliability, only BBS has acceptable reliability (ICC>.90). Others had various reliabilities. The risk of interrater reliability bias was low in all studies. However, the risk of bias of intrarater reliability was low in five studies and moderate in two studies. CONCLUSION: The interrater reliability of the 6MWT, TUG, and CST were acceptable. However, in test-retest reliability, only BBS has acceptable reliability. Therefore, we suggest the use of BBS to test the balance of dementia patients. In addition, the study of tool reliability according to the subtype of dementia is needed in the future.