• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.43 no.6
• /
• pp.373-387
• /
• 2017

Objectives: The purpose of this study was to introduce our three experiments on bone morphogenetic protein (BMP) and its carriers performed using the critical sized segmental defect (CSD) model in rat fibula and to investigate development of animal models and carriers for more effective bone regeneration. Materials and Methods: For the experiments, 14, 16, and 24 rats with CSDs on both fibulae were used in Experiments 1, 2, and 3, respectively. BMP-2 with absorbable collagen sponge (ACS) (Experiments 1 and 2), autoclaved autogenous bone (AAB) and fibrin glue (FG) (Experiment 3), and xenogenic bone (Experiment 2) were used in the experimental groups. Radiographic and histomorphological evaluations were performed during the follow-up period of each experiment. Results: Significant new bone formation was commonly observed in all experimental groups using BMP-2 compared to control and xenograft (porcine bone) groups. Although there was some difference based on BMP carrier, regenerated bone volume was typically reduced by remodeling after initially forming excessive bone. Conclusion: BMP-2 demonstrates excellent ability for bone regeneration because of its osteoinductivity, but efficacy can be significantly different depending on its delivery system. ACS and FG showed relatively good bone regeneration capacity, satisfying the essential conditions of localization and release-control when used as BMP carriers. AAB could not provide release-control as a BMP carrier, but its space-maintenance role was remarkable. Carriers and scaffolds that can provide sufficient support to the BMP/carrier complex are necessary for large bone defects, and AAB is thought to be able to act as an effective scaffold. The CSD model of rat fibula is simple and useful for initial estimate of bone regeneration by agents including BMPs.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.40 no.3
• /
• pp.83-92
• /
• 1998

Field experiment was performed from August 1996 to January 1998 to examine the applicability of constructed wetland system for wastewater treatment in rural area. The pilot plant was installed in Kon-Kuk University and the school building septic tank effluent was used as an influent to the treatment basin. Hydraulic loading rate was about 0.1 6$0.16^3/m^2$ day and theoretical detention time in the system was 1.38 days. The treatment basin was composed of sand and reed. The influent DO concentration was low and many cases close to zero, but effluent concentration was higher than the influent which implies that oxygen was supplied naturally. The average concentration of influent BOD was 126mg/L, and with average removal rate of 69 % the average effluent concentration was 4Omg/L which satisfied the effluent water quality standard for the system of interest. The average influent concentration of COD was 2Olmg/L and average effluent concentration was 75mg/L with average removal rate of 60%. The performance of BOD and COD tends to deteriorate in the low temperature, and appropriate action needs to be taken during the cold winter time for stable operation. The average influent concentration of SS was 5Omg/L, and effluent was 1 1mg/L with average removal rate of 76% which satisfied the effluent water quality standard for the system of interest. The results for the regulated components, SOD and SS, from the experiment showed that constructed wetland system can meet the effluent water quality standards. The average influent concentration of total phosphorus was 25.6mg/L and average effluent concentration was 7.8mg/L with average removal rate of 63%. Not like the performance of the above components, average nitrogen removal rate was only 11.2% which is not satisfactory. Although, nitrogen is not regulated at this moment, it can cause many environmental problems including eutrophication. Therefore, nitrogen removal efficiency should be improved for actual application. From the result of the field experiment, constructed wetland system was thought to be an appropriate alternative for wastewater treatment in rural area.

• Journal of the Korea Convergence Society
• /
• v.12 no.9
• /
• pp.121-126
• /
• 2021

The purpose of this study is to investigate the effect of balloon blowing exercise on multiple pulmonary function and maximum voluntary ventilation in patients with mild intellectual disabilities in their 20s. 10 people in the experimental group and 10 people in the control group participated in the experiment. The experimental group performed the balloon blowing exercise for 30 minutes a day, and the control group performed the diaphragm breathing exercise for 30 minutes each. The subjects measured voluntary capacity and maximal voluntary ventilation using Fitmate before and after the experiment. Subjects were assessed with Vital capacity(VC) and Maximal voluntary ventilation(MVV) before and after the test and the results were compared with the paired t test. Data analysis was performed with SPSS win 18.0. After the experiment, the experimental group showed higher lung capacity and maximum ventilation than the control group. Through this study, the experimental group increased voluntary capacity and maximum voluntary ventilation more than the control group. It is thought that the quality of life can be improved if we continuously manage the health of intellectuals by developing various breathing exercise programs.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.32 no.4
• /
• pp.431-435
• /
• 1987

Terminal bud removal has been thought as a useful practical management of soybean cultivation in Korea, and such cultivating method has been recommended till recent times. Many experiments about the effect of bud removal have been made, but it is not certain yet. This study was conducted to determine if source potential and seed yield would be affected by bud removal in 4 determinate soybean varieties. Terminal bud was removed by hand at the 5 trifoliolate stage of growth. Data were collected on leaf area and leaf dry matter weight from 58 to 101 DAP by nearly every 10 days and some agronomic characteristics and seed yield after maturity. Removing the apical bud did not increased leaf area and leaf dry matter. Number of modes and pods per a plant was increased by bud removal, but number of seeds per a pod was decreased, and seed yield was unchanged by such offsets. From the data, we concluded the source potential of soybean plants was not increased by terminal bud removal under the planting density, 22,000 pit/l0a, however it would be a useful way to reduce the lodging or over-growth.

• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.8
• /
• pp.1182-1189
• /
• 2007

An intracerebroventricular (ICV) infusion of somatostatin 1-28 (SRIF) was used as a thirst-controlling peptide antagonist to investigate whether or not thirst-controlling peptides are involved in the significant decrease in feed intake during the initial stages of feeding large-type goats on dry forage. A continuous ICV infusion of SRIF was conducted at a small dose of $4{\mu}g$ ml/h for 27 h from day 1 to day 2. Goats (n = 5) were fed roughly crushed alfalfa hay cubes for 2 h twice daily and water was given ad libitum. Feed intake was measured during ICV infusion of artificial cerebrospinal fluid (ACSF) and SRIF. The feed intake during SRIF infusion increased significantly compared to that during ACSF infusion. In comparison to the ACSF treatment, plasma osmolality during the SRIF treatment significantly decreased during the first half of the 2 h feeding period. The factor causing the decrease in plasma osmolality during the ICV infusion of SRIF was a decrease in plasma Na, K, Cl, and Mg concentrations. In comparison to the ACSF infusion treatment, parotid saliva secretion volumes during the 2 h feeding period in the SRIF infusion treatment were significantly larger. While there was no significant difference in cumulative water intake (thirst levels) between the SRIF and the ACSF treatments upon conclusion of the 2 h feeding period, based on the plasma osmolality results it is thought that thirst level increases brought about by alfalfa hay cube feeding in the first half of the feeding period were reduced. It is thought that the somatostatin-induced increases in feed intake during the 2 h feeding period in the present experiment were caused by decreases in plasma osmolality brought about by the somatostatin infusion. As a result, it is suggested that the significant decrease in feed intake during the initial stages of feeding in large-type goats given roughly crushed alfalfa hay cubes, was due to the actions of thirst-controlling peptides.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.6
• /
• pp.713-725
• /
• 2004

The two-dimensional motion of a freely falling circular cylinder in an infinite fluid is investigated numerically using combined formulation. The effect of vortex shedding on the motion of a freely falling cylinder is clearly seen: as the streamwise velocity of the cylinder increases due to gravity, the periodic vortex shedding induces a periodic motion of the cylinder. This motion in turn affects the flow field, which is manifested by the generation of the angular velocity vector of the cylinder parallel to the cross product of the gravitational acceleration vector and the transverse velocity vector of the cylinder. A correlation of St-Re relationship for a freely falling circular cylinder is drawn from the present results. The Strouhal number for a freely falling circular cylinder is found to be smaller than that for a fixed circular cylinder when the two Reynolds numbers based on the streamwise terminal velocity of a freely failing circular cylinder and the free stream velocity of a fixed one are the same. From "thought experiments", it is shown that the transverse motion of the cylinder plays a crucial role in reducing the Strouhal number and has an effect of reducing the Reynolds number from the viewpoint of the pressure coefficient. The mechanism of this reduction in the Strouhal number is revealed by the fact that the freely falling cylinder experiences a smaller lift force than the fixed one due to the transverse motion resulting in the retardation of the vortex shedding.

• Journal of Korean Elementary Science Education
• /
• v.32 no.3
• /
• pp.327-345
• /
• 2013

This study aims to investigate how pre-service elementary school teachers understand 'something scientific', 'being scientific', 'scientific events' and 'scientific questions' through semantic network analysis. To achieve this purpose, this study carried out a central analysis of the frequency and density of words and the degree of connection between key words, a concentric analysis, a click analysis and a common network analysis through text semantic network analysis by using NetMiner 4.0 Program. Based on the results of these analyses, this study came to the following conclusions. Firstly, in perceiving 'something scientific', pre-service elementary school teachers recognized 'verification', 'objective' and 'experiment' as most important words. In other words, they perceived that main grounds for something scientific should be provided through clear facts, possible to be verified and accompanied by an exact and logical theoretical system. In regard to 'being scientific', they perceived 'explanation', 'objective' and 'verification' as most important words, while having a traditional point of view that science is a set that can be explained objectively. Secondly, in regard that the term, 'observation', is contained in 'scientific events', they showed a high rate of understanding it as a scientific event. In regard to scientifical reasons, they showed the highest frequency of 'observation', and for unscientific reasons, they showed the highest frequency of 'behavior'. In perceiving 'scientific questions', they showed the highest frequency of determining bacteria-related questions as scientific. As a reason why they thought as scientific, they mentioned 'observation' most frequently like 'scientific events', while mentioning 'value judgement' as a reason why they thought as unscientific most frequently. From the results of integrated network analysis, this study found out that words pre-service teachers commonly used in stating scientific events or scientific questions were overlapped with words they mentioned for scientific events or scientific questions. As a result, it was found there were many pre-service teachers having interpreted scientific words without clearly distinguishing scientific events or scientific questions.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.16 no.1
• /
• pp.27-35
• /
• 2006

The aim of this study was to identify the sources of benzene detected in airborne of casting workplace where benzene was not used as raw material. We have identified benzene by GC/FID and GC/MSD. In this pilot test, small size iron chamber(diameter 30 cm, height 20 cm) was used. As the raw materials, new sand, recovered sand, and mixed casting sand(new sand + solidifying agent + organic resin + coating material) was tested, respectively. In the new sand benzene was not detected, but in the recovered sand and the mixed casting sand was detected. Xylenesulfonic acid(solidifying agent), one of the mixed casting sand ingredients was thought to product benzene by thermal decomposition above $400^{\circ}$..., but the other raw materials(organic resin and coating material) were thought not to product benzene. In this experiment, the most of benzene by thermal decomposition was produced within 1 hour after pouring the iron solution($1560^{\circ}$...) in small size iron chamber. When the mixed casting sand with coating material was used, the concentration of the produced benzene was average 2.91 ppm(range 1.98~3.72 ppm), and without coating material, benzene concentration was average 0.11 ppm(range 0.08~0.14 ppm).

• Journal of The Korean Association For Science Education
• /
• v.31 no.4
• /
• pp.557-566
• /
• 2011

This study investigated the effect of subject classroom system by examining students' perceptions of science discretion class, which was newly developed as Science Mathematics specialized subject classroom system. Science discretion subject proceeded through inquiry experiments in the subject classroom, applying both block scheduling and divided classes. Surveys were conducted twice in order to find out what the students thought about science discretion subject and subject classroom class. The results have shown that students considered that the teachers have prepared with enhanced enthusiasm and the classes have become more interesting. The satisfaction level for experiment centered subject was very high (84%) and significantly higher in case of science-oriented course students (p<.05) and upper level students (p<.01). In addition, most of the students thought favorably about block scheduling and divided classes.

• Journal of Educational Research in Mathematics
• /
• v.21 no.4
• /
• pp.399-422
• /
• 2011

There has been an agreement on the necessity for each citizen is to be educated, so called, to develop quantitative literacy or statistical literacy, dealing with real world data. For this reason, it is highly demanded to improve traditional statistics education. In particular, critical thought and statistical communication competency cultivation is becoming more crucial in statistics classes. In line with this reform movement in statistics education, we developed tasks facilitating statistical debate among students through inducing cognitive conflict. The tasks employed for this study resulted in playing crucial role to activate statistical debate. Including aforementioned feature about the tasks for this study, we obtained several positive results such as promoting critical thought and conceptual extension by designed teaching experiment focusing on statistical debate.