• Archives of Plastic Surgery
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• v.33 no.2
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• pp.213-218
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• 2006

As the large defect of peripheral nerve occurs, the autologous nerve graft is the most ideal method but it has many limitations due to donor site morbidities. Various materials have been developed for the nerve defect as the conduits, but none of these materials is satisfactory. Among them, $Gore-Tex^{(R)}$ tube seems to be one of the most ideal nerve conduit materials at peripheral nerve defect. Many researches have focused on finding the neurotrophic factors. It is recently demonstrated that Valproic acid(VPA) has an effect of axonal regeneration as a neurotrophic factor without enzymatic degradation and toxicity problems. The purpose of this study is to evaluate the effect of VPA on the nerve regeneration at the peripheral nerve defect. A 10 mm gap of rat sciatic nerve was made and $Gore-Tex^{(R)}$ tube filled with biceps femoris muscle was placed at the nerve defect site. We let the rat take VPA as drinking water in experimental group and did not give VPA to the control group. We estimated the results as electrophysiologic and histological aspects for 16 weeks after the surgery. The nerve conduction velocity, total myelinated axon count, myelin sheath thickness and mean nerve fiber diameter significantly increased in VPA-treated experimental group when compared to the control (p < 0.05). From the above results, we conclude that VPA promotes the nerve regeneration at the peripheral nerve defect site. It is suggested that $Gore-Tex^{(R)}$ tube filled with skeletal muscle and VPA administration may be a good substitute for autologous nerve graft.

• Archives of Plastic Surgery
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• v.37 no.2
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• pp.115-121
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• 2010

Purpose: Many topical agents had been used for contaminated wound treatment. Although antimicrobial ointments were widely used as topical agents, their comparative antibacterial and wound healing effects were largely unreported. The purpose of this study was to compare antibacterial effects and wound healing effects of common topical ointments on infected full thickness skin defect in the mouse. Methods: One full thickness skin defects in the mice (n=60) were developed on the back and left open for twenty-four hours. Sixty mice were divided into four groups: group B (dressing with Bactroban$^{(R)}$, n=15), group I (dressing with Iodosorb$^{(R)}$, n=15), group T (dressing with Terramycin$^{(R)}$, n=15), group G (control group, dressing with dry gauze, n=15). The size of wound defects and the grades of wound healing were evaluated at 4, 7, 10 days, and antibacterial effect was evaluated with restricted zone in Mueller Hinton agar by disk diffusion method. After the wound was left open for twenty-four hours, many Staphylococcus aureus was cultured. The wound defect size was decreased in order of Bactroban$^{(R)}$ (B), Iodosorb$^{(R)}$ (I), Terramycin$^{(R)}$ and gauze dressing group in all days, but difference among experimental groups was not statistically significant. The grade score of wound healing was increased in order of Bactroban$^{(R)}$, Iodosorb$^{(R)}$, Terramycin$^{(R)}$ and gauze dressing group, and the difference was statistically significant. Antibacterial effect for was increased in order of Bactroban$^{(R)}$, Iodosorb$^{(R)}$, Terramycin$^{(R)}$ and gauze dressing group, and the difference was statistically significant. Conclusion: Topical antimicrobial ointments application was effective against wound infections by S. aureus. Bactroban$^{(R)}$ may be an optimal topical treatment for infected wounds according to this study. However, further study is necessary to evaluate the clinical efficacy of antimicrobial ointments and to search for the mechanisms that explain their effects.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.2
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• pp.130-138
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• 2006

We have investigated pattern scaling down of silicon stamps through the oxidation technique, During oxidizing the silicon stamps, silicon dioxide that has 300 nm and 500 nm thickness was grown, and critical deformations were not observed in the patterns. There was positive effect to reduce size of patterns because vertical and horizontal patterns have different orientation. We achieved pattern reduction rate of $26\%$. In addition, the formation of polymer patterns had been investigated with varied temperature and pressure conditions to improve the filling characteristics of polymers during nanoimprint lithography when pattern sizes were few micrometers. In these varied conditions, polymers had been affected by free space compensation and elastic stress relaxation for filling the cavities. Based on the results, defect control which is an important issue in the nanoimprint lithography were facilitated.

• Corrosion Science and Technology
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• v.9 no.3
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• pp.109-115
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• 2010

Interstitial-free (IF) steels are widely used for car body material. However, a few types of streaky mark defect are commonly found on hot dip galvannealed (GA) IF steel sheets. In the present study, both the phase structure of a streaky mark defect and the microstructure of the substrate just below it were characterized by optical microscopy (OM) and scanning electron microscopy (SEM). It was found that the bright streaky mark area was composed of ${\delta}$ phase while the dark normal area was full of craters. More than half of the grains at the uppermost surface of the substrate just below the streaky mark defect are unrecrystallized grains which could result from lower finish rolling temperature during hot rolling and be kept stable during the annealing process, while almost all the grains in the normal area are equiaxed grains. In order to confirm the effect of the unrecrystallized grains on the coating morphology, hot dip galvannealing simulation experiments were carried out in IWATANI HDPS. It is proved that the unrecrystallized grains accelerate the Fe-Zn reaction rate during galvannealing and result in a flatter coating surface and an even coating thickness. Finally, a formation mechanism of the streaky mark defect on the hot dip galvannealed IF steel sheet was discussed.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1510-1512
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• 2000

Due to the shrinking of the chip size and increasing of the complexity in the modern electronic devices. the defect of wafer are so important to decide the yield in the device process. The engineers has studied the wafer defects and the characteristics. They published lots of the experimental methods. I did an experiment the gettering effect of the defects due to the high temperature and the long time diffusion. Actually, As the thickness of the wafer backside polysilicon is thicker and the diffusion time is faster. the defects on the wafer are decreased. The polysilicon gram boundaries of the wafer backside played an important part as the defect gettering site.

• Journal of the Korean Institute of Gas
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• v.16 no.2
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• pp.18-24
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• 2012

This research seeks to evaluate damage on type II gas cylinder by an acoustic emission test when executing 20000 cycles fatigue test and thereafter burst test. Used gas cylinders in the experimental are three types as follows; one is sound cylinder, others are cylinders which contain longitudinal and transverse artificial defect. The size of artificial defect is a depth of 3 mm, width of 3 mm and length of 50 mm. In the case of the cylinder which artificial defect, unlike the expectation that it will burst in low pressure, the burst pressure of the cylinder did not differ much according to whether or not there were defects. However, when there was longitudinal defect, the location of burst was near the location of defect. This leads to the effect in which the thickness of the composite material becomes thinner according to the length of the longitudinal defect and this is judged to have an effect on the location of initiation and growth of crack in the liner. Also, for the acoustic emission signal, when there is longitudinal defect, the ratio of an event occurring at defect position among overall hits is more than 50 %, and the source location also accords very precisely with defect position.

• Journal of Korea Foundry Society
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• v.37 no.6
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• pp.181-185
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• 2017

In the present study, the effect of cooling rate on the formation of the porosity in the thick aluminum sand casting was investigated. Nowadays, due to considerations of weight and cost reduction, large scale thick aluminum casting has replaces steel frames for vacuum chambers for semiconductor production. Several thick aluminum castings were manufactured using chill with temperature measurements. The castings were inspected using 3D computed tomography in order to quantify the porosity defect density in the castings. Effects of the thickness of the chill on the porosity defect density were discussed.

• Archives of Plastic Surgery
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• v.37 no.3
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• pp.213-219
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• 2010

Purpose: Iodine has been used for the prevention or management of wound infection as a topical agent. Although iodine was widely used mainly by Betadine$^{(R)}$ and cadexomer iodine, there was no comparative study on the efficacies of dressing methods of iodine. And also it's wound healing effect was not yet clear. The purpose of this study is to compare antibacterial effects and wound healing effects associated with various dressing methods of iodine on infected full thickness skin defect in the mouse. Methods: One full thickness skin defects in the mice (n=60) were developed on the back and left open for twenty-four hours. Sixty mice were divided into four groups : group S (dressing with Betadine$^{(R)}$ soaking, n=15), group T (dressing with Betadine$^{(R)}$ topping, n=15), group I (dressing with Iodosorb$^{(R)}$, n=15), group G (control group, dressing with dry gauze, n=15). The size of the wound defects and the grades of wound healing were evaluated in 4, 7, 10 days, and antibacterial effect was evaluated with restricted zone in Mueller Hinton agar by disk diffusion method. Results: After the wound was left open for twenty-four hours, many Staphylococcus aureus were cultured. The wound defect size was decreased in order of Betadine$^{(R)}$ soaking, Iodosorb$^{(R)}$, Betadine$^{(R)}$ topping and gauze dressing group in all days, but difference among experimental groups was not statistically significant. The grade score of wound healing was increased in order of Betadine$^{(R)}$ soaking, Iodosorb$^{(R)}$, Betadine$^{(R)}$ topping and gauze dressing group, and the difference was statistically significant. Antibacterial effect for S. aureus was increased in order of Iodosorb$^{(R)}$, Betadine$^{(R)}$ soaking, Betadine$^{(R)}$ topping and gauze dressing group, and the difference was statistically significant. Conclusion: Selection of the effective dressing method of iodine for infected wounds remains a controversial decision. According to this study, Iodosorb$^{(R)}$ may be most effective method for antibacterial effect and Betadine$^{(R)}$ soaking may be most effective method for infected wound healing. However, further study is necessary to evaluate the clinical efficacy of dressing methods of iodine and to search for the mechanisms that explain their effects.

• Journal of Korean Society for Quality Management
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• v.50 no.3
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• pp.533-543
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• 2022

Purpose: The purpose of this study is to identify and resolve the causes of defects in the unmanned aerial vehicle launch system(propulsion wire fracture, rear rail deformation) and to prevent recurrence. Methods: The causes of the two defects were derived through fault tree analysis for each of the two defects and fault reproduction tests. In the case of propulsion wire, the installation of a high speed camera to check the behavior of wire was the driving force behind the defect resolution. Results: The results of this study are as follows; It was determined that the thickness of the washer was less than the maximum tolerance of the pulley was the cause of the propulsion wire fracture defect. Failure to comply with the launch procedure and insufficient safety margin were judged as the cause of the rear rail deformation defect. Accordingly, the configuration was changed to remove each defect. Conclusion: The case of this study was conducted to eliminate defects in the launch system for UAV. The causes of defects were estimated through fault tree analysis. After the configuration change, Structural analysis and launch tests were performed to demonstrate the safety and effectiveness of the modified configuration. As a result, the effect of the modified configuration was verified.

• Archives of Plastic Surgery
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• v.37 no.3
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• pp.220-226
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• 2010

Purpose: Many topical agents had been used for burn or wound treatment. An awareness of topical agents on various aspects of wound healing permits the clinician to choose the most appropriate material to advantageously control the wound process and final results. Although polydeoxyribonucleotide (PDRN) was used as a tissue repair stimulating agent in a number of human diseases, such as ulcers and burns, its wound healing effects were largely unreported. We aimed to compare the woundhealing effects of PDRN and common dressing materials on full-thickness skin defect in the mouse. Methods: Full-thickness skin defects were made on the back of mice (N=60). The mice were divided into the following 4 groups according to the dressing used for the wounds: group O (Polydeoxyribonucleotide cream), group I (Polydeoxyribonucleotide solution), group M (Medifoam$^{(R)}$), and group G (dry gauze, control group). We analyzed the gross findings, wound sizes and histological findings for the groups. Results: The rate of wound size was decreased in order of group I, group O, group M and group G. The histological findings revealed that the I group showed more reepithelialization and granulation tissue formation and less inflammatory cell infiltration than the other materials. The grade score of wound healing was increased in order of group I, group O, group M and group G. Conclusion: PDRN applicated wound dressings can be used for treating a full-thickness skin defect wounds. Considering its superior efficacy in comparison to the efficacies of other wound dressings, PDRN soaked gauze dressing should be preferentially used for the treatment of fullthickness skin wounds.