• Journal of the Korean institute of surface engineering
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• v.43 no.1
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• pp.25-30
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• 2010

Titanium and titanium alloys are widely used for orthopedic and dental implants for their superior mechanical properties, low modulus, excellent corrosion resistance and good biocompatibility. In this study, corrosion behaviors of nanotube formed on the bone plate of Ti-6Al-4V alloy for dental use have been investigated. $TiO_2$ nanotubes were formed on the dental bone plates by anodization in $H_3PO_4$ containing 0.6 wt % NaF solution at $25^{\circ}C$. Electrochemical experiments were performed using a conventional three-electrode configuration with a platinum counter electrode and a saturated calomel reference electrode. Anodization was carried out using a scanning potentiostat (EG&G Co, Model 263A USA), and all experiments were conducted at room temperature. The surface morphology was observed using field emission scanning electron microscopy (FE-SEM) and energy dispersive x-ray spectroscopy(EDS). The corrosion behavior of the dental bone plates was examined using potentiodynamic test(potential range of -1500~2000 mV) in a 0.9% NaCl solution by potentiostat (EG&G Co, PARSTAT 2273. USA). The inner diameter of nanotube was about 150~180 nm with wall thickness of about 20 nm. The interspace of nanotube to nanotube was 50 nm. The passive region of the nanotube formed bone plates showed the broad range compared to non-nanotube formed bone plates. The corrosion surface of sample was covered with corrosion products.

• Journal of Periodontal and Implant Science
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• v.38 no.3
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• pp.493-502
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• 2008

Purpose: The purpose of this study is to investigate on the regenerative capacity by using different size of graft materials around bony defect around implant. Material and Methods: Dental implant fixtures(Bio-TIS, Korea) were placed into the tibia of 8 rabbits. After placement of implant, artificial defects were created for each group, and the size of bone graft materials were used according to each designated group. 4 weeks after surgery, 8 rabbits were sacrificed. The histologic and histomorphometrical study were done for comparison of the regenerative capacity using $80-90{\mu}m$ and $200{\sim}1000{\mu}m$ size of grafting materials of OCS-$B^{(R)}$. Result: Matured bone formation was significantly increased more in Group E1($80-90{\mu}m$) than in Group E2($200{\sim}1000{\mu}m$). Group E1($80-90{\mu}m$) showed more significant augmentation in marginal length of graft material per unit area than Group E2($200{\sim}1000{\mu}m$). Group E1($80-90{\mu}m$) showed more interspace in graft material than Group E2($200{\sim}1000{\mu}m$). Control group showed no new bone formation around and inside of implanted fixture. Conclusion: Small grafting material size has great influence on bone regeneration.

• Journal of the Korean Institute of Educational Facilities
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• v.27 no.2
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• pp.35-47
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• 2020

The need for communication is emphasized in decision making, design methods and processes for the educational environment that contain new curricula and learning methods. In this study, we tried to find the direction and agenda of learner-centered environment restructuring through the 'user-integrated platform' in which various subjects related to school space environment understand each other's position and overcome the barriers and prejudices of each sector. The project was planned in a 'bottom-up process' method that uncovered the singularities of the previous stage and led the main contents of the next stage. The various subjects who participated in the project shared their own experiences and different positions regarding the school space. At the workshop, the topics of the participating teams were divided into two categories. The teams in the category of the 'school culture and space' insisted innovation of 'the school culture' as a premise for the restructuring of the 'school space', and proposed schools with different interpretations of 'authority and rules of school', 'the meaning of learning and play' and 'the main character of school. The teams in the category of the 'school borders and spaces' focused on 'communication' and proposed schools containing 'emotional care of students', 'borders between schools and villages', 'village community schools', and 'interspace and niche time'. After the workshop, we were able to derive the direction and architectural strategy of the school space restructuring by analyzing the works of the participants. Through this study, we confirmed the possibility of translating user's ideas into the professional domain through careful planning, preparation, facilitation, and analysis in Participatory Design.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup2
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• pp.254-258
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• 2001

Objective : The terminology of degenerative disc disease lacks official standardization. Lacks of such standardization may provoke some clinical and litigation problems. The authors investigated interobserver and intraobserver variability in interpretation of lumbar disc abnormality. Methods : Magnetic resonance imaging studies of the lumbar spine performed prospectively in 50 patients, were read blindly by three doctors dealing spinal disorders, using two nomenclature. Nomenclature I was normal, bulging, protrusion, extrusion. Nomenclature II was normal, bulging, herniation without neural compression, with neural compression. Intraobserver and interobserver variation were measured statistically. Results : Interobserver agreement was 70.4-80.8% for nomenclature I, 76.2-80.2% for nomenclature II. Intraobserver agreement was 84.0-88.0% for nomenclature I, 79.2-86.8% for nomenclature II. Interobserver Kappa statistic was 0.53-0.56 for nomenclature I, 0.54-0.57 for nomenclature II. Intraobserver Kappa statistic was 0.60-0.85 for nomenclature I, 0.53-0.72 for nomenclature II. Conclusion : Experienced doctors showed only moderate interobserver agreement when interpreting disc status on lumbar magnetic resonance imaging. Intraobserver agreement was superior to interbserver. The standardization of nomenclatures for lumbar disc extension beyond interspace are needed.

• Korean Journal of Veterinary Research
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• v.43 no.3
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• pp.349-359
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• 2003

Corpus luteum (CL) is the primary productive organ of progesterone in pregnant cows. Progesterone levels in bovine plasma depend on the volume, weight and shape of the CL. Progesterone productions during the late stages of gestation occur both in the CL and placenta, and placentas producted more progesterone than CL on progesterone prcduction. Because division of progesterone production of these two organs is impoxxible, the CL function can not be determined by plasma progesterone levels following gestation stages. This study was carried out to evaluate histological findings on the CL spurium and CL verum, and also on the CL following the pregnant stages by histological and immunohistochemical and electron microscopical methods and then we expect to assume the functions of CL by histological findings. 1. Proliferations of luteal cells occur by day 120 of gestation, vessel hyperplasia occur by day 90 of gestation, and the walls and lumens of vessels developed by day 120 of pregnancy. 2. Sizes of CL cells increased to maximum around day 200 of gestation and similarly maintained by day 240. So these findings indicated that the function of Cl is most active around day 200 of gestation. 3. On parturation day, the number and size of luteal cells were maintained but stain intensity of the luteal cells and vessels are declined or disappeared, and fibrosis of luteal cells increased, and the vessel lumens are emptied. These findings indicate that CL is inactive. 4. In immunohistochemical findings, proliferative positive cells by PCNA antibody appeared more in number during early stages of gestation but appeared less following course of pregnant stages and not nearly appeared on day 120 of gestation. Apoptotic positive cells by TUNEL methods not nearly appeared on the early pregnant stages and a few appeared at late pregnant stages. So developments of CL proceed until day 120 of gestation and regression of CL was occurred by transform of luteal cells into fibrocytes than by luteal cell apoptosis. 5. In electron microscopical findings, the size of luteal cells increased more in CL verum than in CL spurium. During gestation stages, the size of luteal cells increased, mitochondria in the luteal cell cytoplasms densely and abundantly developed and also swelled mitochondria increased. The interspace of luteal cells are also dilated, transformation of luteal cells into fibrocytes are more number. The lumens and walls of peripheral capillaries of large luteal cells more broadened and thickened, and transformation of large and small luteal cells to fibrocytes are increased. The above findings suggest that function of pregnant CL more developed by day 120 of gestation and are most active around day 200 of gestation and similarly maintained by day 240 and are promptly regressed on paturation day.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.230-236
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• 2020

A trash screen is installed in front of the inflow channel of a drainage pumping station, sewage treatment plant, and a power plant to block floating contaminants. The bottleneck phenomenon, which decreases the water inflow, causes damage to the damper as a result of clogging in between the screen if string type obstacles are not removed. In this paper, the apron was removed, and the screen was expanded, to prevent breakage of the bottleneck phenomenon and string type obstacles. This was designed using an extended rake by adding an inner rake in between the screen interspace to remove the bottleneck phenomenon and string type obstacles. To design the inner rake that satisfies the allowable stresses of the existing damper rake, the experiment points were determined according to the experimental design method using the inner rake vertical length and the thickness of the reinforced section as parameters. The use of the ANSYS static structural module and statistical analysis tool R software gives the optimized shape according to the response surface method. The relative error between the response surface analysis results and the simulation results was 1.63% of the determined optimal design-point rake length of 210.2 mm and the reinforcement section thickness of 2 mm. Through empirical experiments, a test rake was constructed to the actual size, and approximately 97% of the bottleneck phenomenon and string type obstacles could be removed.

• The Journal of Engineering Geology
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• v.20 no.1
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• pp.101-109
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• 2010

There are many slopes generally developed by excavation and cut slope with small steps on massive slopes of roads. Especially these cut slopes which excavating around fault fracture zone need a reinforcement technology in order to ensure safety. In the case of slope excavation, it is difficult to use the existing slope support at fracture zone because of geological characteristics. Especially the factor of safety decreases significantly due to the movement of blocks in bed rocks and the expansion of interspace of discontinuous planes in fractured zones caused by excavation. Thus an efficient reinforcement technique in accordance with geological properties of fracture zones needs to be developed because the existing slope support has a restricted application. Therefore it is necessary to develop the specialized rock bolt technique in order to ensure an efficient factor of safety for anomalous fracture zones in slopes and tunnels. The purpose of this study is to develop newly improved rock bolt to increase a supporting effect of the swellex bolt method used recently as a friction type in fracture zones.

• The Korean Journal of Pain
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• v.1 no.1
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• pp.47-52
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• 1988

Since 1979 forty-three cancer patients have been given intrathecal block at the pain clinic of Yonsei Medical Center. The male patients numbered 23 and female 20 and most of them were in the 4th and 5th decades of age. In 78.6% of the patients, the diagnosis was rectal cancer in 20 cases, cervix cancer in 7 cases, bladder cancer in 4 cases and colon cancer in 3 cases. Thirty six patients with cancer pain were treated by intrathecal 10% phenol-glycerine block and rest of them had only test block. Fourteen patients whose pain sites were lumbar or lumbar and upper sacral dermatomes were put into the lateral recumbent position on the fluoroscopic table. The spinal puncture was performed as close to the spinal roots to be impregnated as possible. In 22 patients the pain sites were covered by the sacral dermatomes and so the L5-S1 interspace was punctured in the sitting position shifted 15 degree to the affected site. Fifty one blocks were performed and their results are classified into three categories: good, fair antral poor. We achieved good results in 38 patients(77.1%), fair in 6 patients(17.1%) and poor in 2 patient(5.7%). Thus a satisfactory pain relief was achieved in 94.2% of patients. After intrathecal block with phenol glycerine, transient voiding difficulty was noted in 7, defecation difficulty in 1, and transient paresthesia and/or muscle weakness was present in 3 patients. The mean duration of pain relief was 2.5 months and longer than the mean survival time of 2.25 months. When patients are selected carefully and tile block is performed with great caution and good technique, the risk is minimal and a long lasting relief of intractable cancer pain achieves a painless life until death.

• Journal of Yeungnam Medical Science
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• v.7 no.2
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• pp.121-130
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• 1990

Plain 0.5% bupivacaine and hyperbaric 0.5% tetracaine were compared for spinal anesthesia in 40 patients undergoing operation of lower extremities. Lumbar puncture was performed with a 22 gauge spinal needle with the patient in the lateral recumbent position. The third lumbar interspace was chosen for the puncture, when a free flow of clear CSF was obtained, the local anesthetic solution (2.5ml of 0.5% bupivacaine or 2.0ml of hyperbaric 0.5% tetracaine) was injected at a rate of 0.1ml/sec without barbotage. After injection of anesthetics, clinical features were observed and compared between the two groups. The results were as follows : 1. The two groups were well matched for age, sex, height and weight. 2. In both groups, sensory block to $T_{12}$ dermatome was obtained within 4 minutes, mean maximal level of analgesia was $T_{6-7}$, and the mean time for maximal level was around 20 minutes. 3. The onset times of motor block were similar in both groups and complete motor block was obtained in all cases within 20 minutes. 4. The duration of analgesia above the $T_{12}$ dermatome was 3 hours, postoperative analgesia was 7 hours. These values were significantly prolonged than those of the tetracaine group(p<0.05). 5. The changes in systolic pressure in the bupivacaine group were significantly less than those of the tetracaine group(p<0.05). 6. The complications after spinal anesthesia were headache, numbness, urinary retention and backpain, and were no significant difference in both groups. From the obtained results, we concluded that plain 0.5% bupivacaine was a relatively satisfactory agent for spinal anesthesia for operation of lower extremities. The time of onset, height of block and the complications of postoperative period were similar in both groups. The advantages of plain 0.5% bupivacaine were less hypotension and long duration of analgesia.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.463-470
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• 2018

Restoration ecology is the practical study of renewing and restoring a spoilt, degraded, or devastated ecosystems in the environment. Because the Korean industry has been drastically developed for the past few decades, the Korean ecosystem requires restoration using regional seed. In this study, we identified the variation of phylogenic relationship of Miscanthus sinensis or Phragmites australis by locations in Korea. Chloroplast DNA atpF-H and psbA-trnH interspace region were used as a molecular marker to resolve the phylogenic relationship in 10 different locations. We performed the molecular phylogenetic analysis with 10 chloroplast DNAs from each location using Kimura 2-parameter. The analysis of Miscanthus showed that all atpF-H genes were exact matches except for Ose san. In contrast to Mischanthus, the atpF-H genes from Phragmites were observed to have more variation. A total of 7 locations revealed the variation in chloroplast gene. According to the phylogenic tree in Phragmites, 2 of 10 samples in 6 locations and 3 of 10 in 1 location showed variation with 0.160-0.181 genetic distance. According to the genetic distance of the Miscanthus sinensis, there were no mutations in all regions except the Hongsung. These results support regional differences and show the necessity for seed collection by region. In the case of Phragmites australis, genetic variation occurred in all regions.