• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.6
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• pp.478-487
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• 2003

In this paper, a type and special feature of Multi-level inverter used in medium-voltage and high-capacity motor driver is introduced. Especially, a power quality and structural advantages of H-Bridge Multi-level inverter is described. It presented the specific structure of power circuit, design method, controller composition and PWM techniques of the cascaded H-Bridge Multi-level inverter which is developed. The feasibility of the developed product based on 3,300V lMVA 7-level H-bridge inverter was studied by experiments and we get conclusion that 1)generate of near-sinusoidal output voltage; 2)is low dv/dt at output voltage; 3)reduce the harmonic injection at input; Experiment demonstrate that it is very economical in productivity because of using the existing production technique and examination equipment, and has the reliability and a good maintenance due to the structure of Power Cell unit combination as well as low cost IGBT.

• Annals of Clinical Neurophysiology
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• v.2 no.1
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• pp.8-12
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• 2000

Purpose : The rapid development and wide popularity of Digital EEG(DEEG) is due to its convenience, accuracy and applicability for quantitative analysis. These advantages of DEEG make one hesitate to use analog EEG(AEEG). To assess the advantage of DEEG system utilizing AEEG(DAEEG) over conventional AEEG and the clinical applicability, a DAEEG system was developed and applied to animal model Methods : Sprague-Dawley rat as status epilepticus model were used for collecting the EEG data. After four epidural electrodes were inserted and connected to 8-channel analog EEG(Nihon-Kohden, Japan), continous. EEG monitoring via computer screen was done from two rats simultaneously. EEG signals through analog amplifier and filters were digitized at digital signal processor and stored in Windows-based pentium personal computer. Digital data were sampled at a rate of 200 Hz and 12 bit of resolution. Acquisition software was able to carry out 'real-time view, sensitivity control and event marking' during continuous EEG monitoring. Digital data were stored on hard disk and hacked-up on CD-ROM for off-line review. Review system consisted of off-line review, saving and printing out interesting segment and annotation function. Results: This DAEEG system could utilize most major functions of DEEG sufficiently while making a use of an AEEG. It was easy to monitor continuously compared to Conventional AEEG and to control sensitivity during ictal period. Marking the event such as a clinical seizure or drug injection was less favorable than AEEG due to slowed processing speed of digital processor and central processing unit. Reviewing EEG data was convenient, but paging speed was slow. Storage and management of data was handy and economical. Conclusion : Relatively simple digital EEG system utilizing AEEG can be set-up at n laboratory level. It may be possible to make an application for clinical purposes.

• Journal of Astronomy and Space Sciences
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• v.32 no.1
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• pp.81-89
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• 2015

In this paper, we describe the development of a bioreactor for a cell-culture experiment on the International Space Station (ISS). The bioreactor is an experimental device for culturing mouse muscle cells in a microgravity environment. The purpose of the experiment was to assess the impact of microgravity on the muscles to address the possibility of long-term human residence in space. After investigation of previously developed bioreactors, and analysis of the requirements for microgravity cell culture experiments, a bioreactor design is herein proposed that is able to automatically culture 32 samples simultaneously. This reactor design is capable of automatic control of temperature, humidity, and culture-medium injection rate; and satisfies the interface requirements of the ISS. Since bioreactors are vulnerable to cell contamination, the medium-circulation modules were designed to be a completely replaceable, in order to reuse the bioreactor after each experiment. The bioreactor control system is designed to circulate culture media to 32 culture chambers at a maximum speed of 1 ml/min, to maintain the temperature of the reactor at $36{\pm}1^{\circ}C$, and to keep the relative humidity of the reactor above 70%. Because bubbles in the culture media negatively affect cell culture, a de-bubbler unit was provided to eliminate such bubbles. A working model of the reactor was built according to the new design, to verify its performance, and was used to perform a cell culture experiment that confirmed the feasibility of this device.

• Journal of the Korean Institute of Gas
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• v.19 no.6
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• pp.34-39
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• 2015

Recently, most of the energy consumed in vehicle is derived from fossil fuels. For this reason, the demand for clean, renewable and affordable alternative energy is forcing the automotive industry to look beyond the conventional fossil fuels. Natural gas represents today a promising alternative to conventional fuels for vehicles propulsion, because it is characterized by a relatively low cost, better geopolitical distribution than oil, lower environmental impact, higher octane number and a higher self ignition temperature. Above all, CNG is an environmentally clean alternative to the existing spark ignition engines with the advantages of minimum change. In this study was installed bi-fuel system that a conventional 2 liters gasoline engine was modified to run on natural gas by a gas injection system. Experiments were mainly carried on the optimization of an ECU control strategy affecting the emission characteristics of CNG/Gasoline bi-fule vehicle. The test results shown that CO2 emission in bi-fuel mode was reduced 16% compared to gasoline fuel in the NEDC mode. Also the amount of CO and HC emissions in bi-fuel and gasoline modes were found to equality. But Compared to gasoline, the bi-fuel mode resulted in higher NOx emissions.

• Korean Journal of Community Nutrition
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• v.4 no.1
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• pp.103-110
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• 1999

The purpose of this study was to determine the effects of taurine supplementation and taurine depletion on blood glucose and blood lipid concentrations in insulin-treated diabetic rats. Four groups of Sprague-Dawley male rats were fed the purified diet for 3 weeks ; nontaurine-supplemented diabetic rats(E0), nontaurine-supplemented diabetic rats with insulin treatment(E0＋I), 1% taurine-supplemented diabetic rats with insulin treatment(E1＋I) and taurine-depleted diabetic rats with insulin treatment(EA＋I). Diabetes was induced by streptozotocin injection(50mg/kg B.W.). Isophane insulin was given subcutaneously into the abdominal wall of the diabetic rats(4 unit/rat/day). E1＋I were supplemented with 1% taurine in drinking water. To induce taurine depletion, EA＋I were treated with 5% $\beta$-alanine in drinking water. E1＋I had significantly higher body weight compared to that of E0. The food intakes of E1＋I and E0＋I were significantly decreased compared to that of E0. There was no sigfniciant difference in food intake between E1＋I and E0＋I. The water intake of rats was significantly different among the groups ; E0>E0＋I>E1＋I>EA＋I. The urine volume of E0 was significantly increased compared to those of insulin-treated goups. The blood glucose concentration of E0 was significantly increased compared to those of insulin-treated groups. In the oral glucose tolerance test(OGTT), E0＋I and E1＋I had significantly lower blood blucose concentrations compared to E0 after 30 min. Also EA＋I had significantly lower bloodglucose concentrtion compared to E0 and E0＋I. The plasma total cholesterol and LDL-cholesterol concentratons of EA＋I were significantly incrased compared to those of other groups. Therefore, it may be suggested that tuarine supplementation is useful for insulin-dependent diabetes in order to prevent diabetic complications suchas cardiac vascular diseases.

• The Korean Nurse
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• v.37 no.2
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• pp.77-86
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• 1998

Yeung Nam University Medical Center, Department Of Central medical Supply Background: The adverse effect of intravenous therapy combined with various complications. Because sterilization technique and appropriate nursing care can prevent various complications, it is important to use appropriate sponge in intravenous therapy. The purpose of study was to identy sterilization effect and detection of bacteria and to provide basic data for use of appropriate disinfectants. Methods: From May 15 1995 to Aug. 3. 1995, disinfectants that were used in Yeung Nam University Medical Center were tested by bacteria culture. To test sterilization effect of disinfectants of intravenous injection sites after disinfection, 10 subjects were used and were tested by bacteria culture for the study. Results: 1) By sterilization effect of disinfectants, bacteria were increased from 103 to 10 from 48 hours in both 2% Zephanon and 2% zephanon that was sterilized by steam, from 10 to 10 from 72 hours and 10 from 48 hours in 70% lsoprophyl alchol. Also, bacterias were detected in 70% lsoprophyl alchol on 48 hours. 2) By stenlization effect of sponge that were used in nursing unit, bacterias were detected in 2% Zephanon on 2 hours, 70% lsoprophyl alchol on 2 hours, 70% lsoprophyl alchol on 8 hours and 70% lsoprophyl alchol on 48 hours. 3) By sterilization effect and detection of bacteria of intravenous site after disinfection, bacterias were detected in 10 of 10 control groups, 8 of 10 sites that were disinfected by steam sterilized 2% zephanon sponge, 6 of 10 sites that were disinfected by 70% lsoprophyl alchol and 4 of 10 sites that were disinfected by 10% Batadine. Conclusions : it is conclued that 70% lsoprophyl alchol is appropriate for intravenous therapy and 10% Betadine is appropriate in ward that were polluted the air and in immunodeficient patients.

• Animal Bioscience
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• v.34 no.6
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• pp.985-992
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• 2021

Objective: Artificial insemination plays an important role in genetic improvement in the goat farming system. The aim of this study was to investigate the effect of cervical application of hyaluronan (HA) on the fertility in goats after cervical artificial insemination using frozen-thawed (F-T) semen. Methods: After oestrous synchronisation with progesterone sponges and pregnant mare serum gonadotropin injection, both nulli- and multi-parous goats, were randomly allocated to 2 groups, and were inseminated with 0.25 mL of F-T semen (150×106 spermatozoa) twice at 52 h and 56 h after sponge removal. Prior to the insemination, goats in Group 1 only were given topical cervical HA application at 48 h after sponge removal. Site of insemination was recorded as os-cervix or intra-cervix or intra-uterus. Pregnancy was tested ultrasonographically 42 days after insemination. The data on pregnancy rates and percentage of animals according to the site of semen deposition were compared by Chi-square analysis. Results: The overall pregnancy rate was significantly (p<0.004) higher in goats with prior application to the cervix with HA (63.3%) than without (36.0%). Same pattern was observed in the pregnancy rates of nulli- and multi-parous goats in both the groups. Percentage of nulliparous goats according to the site of insemination in the HA group did not differ between first and the second insemination. However, in multiparous goats the percentage of animals inseminated intra-cervically was significantly increased (p≤0.05) between the first and the second inseminations. Conclusion: The results suggest that significantly higher fertility rate in the "HA goats" compared to the "without HA" group was because of deeper insemination facilitated by topical cervical application of HA. The deeper insemination into the cervical canal increase the rate of fertilisation when the cervical artificial insemination is performed.

• Clinical and Experimental Reproductive Medicine
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• v.50 no.3
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• pp.185-191
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• 2023

Objective: Although intracytoplasmic sperm injection (ICSI) is a way to deal with in vitro fertilization failure, 3% of couples still experience repeated fertilization failure after attempted ICSI, despite having sperm within normal parameters. These patients are a challenging group whose sperm cannot fertilize the egg during ICSI. Unfortunately, no test can predict the risk of fertilization failure. Phospholipase C zeta (PLCζ) and transition nuclear proteins (TNPs) are essential factors for chromatin packaging during sperm maturation. This study aimed to assess PLCζ1 and TNP1 expression in the sperm of patients with fertilization failure and the correlations among the DNA fragmentation index, PLCζ1 and TNP1 gene and protein expression, and the risk of fertilization failure. Methods: In this study, 12 infertile couples with low fertilization rates (<25%) and complete failure of fertilization in their prior ICSI cycles despite normal sperm parameters were chosen as the case group. Fifteen individuals who underwent ICSI for the first time served as the control group. After sperm analysis and DNA fragmentation assays, quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blot analyses were performed to compare the gene and protein expression of PLCζ and TNP1 in both groups. Results: DNA fragmentation was significantly higher in the fertilization failure group. The qRT-PCR and Western blot results demonstrated significantly lower PLCζ and TNP1 gene and protein expression in these patients than in controls. Conclusion: The present study showed that fertilization failure in normozoospermic men was probably due to deficient DNA packaging and expression of TNP1.

• Anatomy and Cell Biology
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• v.57 no.1
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• pp.13-17
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• 2024

Masseter are commonly botulinum neurotoxin targeted muscle for facial contouring in aesthetic field. However, paradoxical masseteric bulging is common adverse effect that has not been discussed with ultrasonographic observations. Retrospective study has been conducted from October, 2021 to January, 2023, out of 324 patients have done blinded botulinum neurotoxin injection in the masseter at the middle and lower portion of the masseter with each side of 25 units (letibotulinum neurotoxin type A), 3 patients demonstrated paradoxical masseteric bulging has been reported and the image observed by ultrasonography by physician. Based on the observations made, we can infer that the function of the moving muscle involves twisting of the muscle fibers during contraction, along with the twisting of the deep inferior tendon, which causes the muscle to be divided into anterior and posterior compartments rather than into superficial and deep compartments of masseter. In ultrasonographic observe the skin surface of a patient with paradoxical masseteric bulging, it is observable that either the anterior or posterior part contracts significantly. The functional units of anterior and posterior compartment are observable as muscular contraction of inward movement of the muscle from either the anterior or posterior functional unit.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• v.26 no.2
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• pp.130-140
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• 2024

Objective: To assess whether local anesthetic infiltration could minimize the carotid baroreceptor reflex (CBR) which has an incidence after carotid artery stenting (CAS) that varies from 29% to 51%. Methods: This retrospective single-center study included 51 patients (mean age, 70.47 years) who underwent CAS for carotid stenosis. The groups included patients who underwent CAS for asymptomatic ischemic stroke (n=41) or symptomatic disease (n=10). Preprocedural percutaneous lidocaine injections (PPLIs) were administered to 70.6% and 5.9% of patients who underwent elective CAS and emergency CAS, respectively. Results: Among patients who received PPLIs, the mean degree of stenosis was 80.5% (95% confidence interval [CI]: ±10.74, 51-98%). The mean distance from the common carotid artery bifurcation to the most stenotic lesion (CSD) was 8.3 mm (95% CI: ±0.97, 6.3-10.2 mm); the mean angle between the internal carotid artery and common carotid artery (CCA) trunk (IAG) was 65.6° (95% CI: ±2.39, 61-70°). Among patients who did not receive PPLIs, the mean degree of stenosis was 84.0% (95% CI: ±8.96, 70-99%). The mean CSD was 5.9 mm (95% CI: ±1.83, 1.9-9.9 mm); the mean IAG was 60.4° (95% CI: ±4.41, 51-70°). The procedure time was longer in the PPLI group than in the no PPLI group (28.19 [n=39] vs. 18.88 [n=12] days) (P=0.057); the length of intensive care unit stay was shorter in the PPLI group (20.01 [n=36] vs. 28.10 [n=5] days) (P=0.132). Conclusions: Targeted PPLI administration to the carotid bulb decreased aberrant heart rates and blood pressure changes induced by carotid stent deployment and balloon inflation. As CBR sensitivity increases with decreasing distance to the stenotic lesion from the CCA bifurcation, PPLIs may help stabilize patients during procedures for stenotic lesions closer to the CCA.