• Journal of the Korean Society of Radiology
• /
• v.85 no.2
• /
• pp.372-380
• /
• 2024

Purpose This study aimed to develop a rabbit iliac stenosis model and evaluate the effects of different mechanical injury techniques on the degree of arterial stenosis. Materials and Methods Eighteen rabbits were divided into three groups: cholesterol-fed with pullover balloon injury (group A; n = 6), cholesterol-fed with localized balloon dilatation (group B; n = 6), and chow-diet with pullover balloon injury (group C; n = 6). After baseline angiography, the left iliac arteries of all rabbits were injured with a 3 × 10 mm noncompliant balloon using either a wide pullover technique (groups A and C) or a localized balloon dilatation technique (group B). A nine-week follow-up angiography was performed, and the angiographic late lumen loss and percentage of stenosis were compared. Results Group A exhibited the most severe late lumen loss (A vs. B, 0.67 ± 0.13 vs. 0.04 ± 0.13 mm, p < 0.0001; A vs. C, 0.67 ± 0.13 vs. 0.26 ± 0.29 mm, p < 0.05; stenosis percentage 32.02% ± 6.54%). In contrast, group B showed a minimal percentage of stenosis (1.75% ± 6.55%). Conclusion Pullover-balloon injury can lead to significant iliac artery stenosis in rabbits with controlled hypercholesterolemia. This model may be useful for elucidating the pathogenesis of atherosclerosis and for evaluating the efficacy of novel therapeutic interventions.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.19 no.3
• /
• pp.203-210
• /
• 1999

Of all the nutrients in liquid manure, N has the greatest potential both for the environment and for increasing forage yields. This experiment was carried out to determine the effect of different types and N rates of liquid manure on mineral content and nitrate-N of oats(Avena sativa L.), soil chemical characteristics in Suweon. Seven treatments consisting of chemical fertilizer $120kg\;N\;ha^{-1}$, liquid cattle manure 120, 240 and $360kg\;N\;ha^{-1}$, liquid swine manure 120, 240 and $360kg\;N\;ha^{-1}$ were arranged in a randomized complete block design with three replications. Compared with the plot of chemical fertilizer, increasing liquid manure N rates increased mineral contents of oats. Nitrate-N contents of oats were ranged from 1,881 to $2,605mg\;kg^{-1}$ in all treatments, which was orderly ranked as chemical fertilizer>liquid cattle manure $360kg\;N\;ha^{-1}$> liquid swine manure $240kg\;N\;ha^{-1}$. Contents of exchangeable cation of the soil were appeared to be higher with increasing liquid manure N rates. Amount of total-N and inorganic-N in soil affected by increasing liquid manure N rates, and there was the highest at liquid swine manure $360kg\;N\;ha^{-1}$ among the treatments. Nitrate-N concentration in infiltration water was not remarkably variable during the experimental period. Based on the results of this experiment, it is suggested that the amount of nitrogen in soil was orderly ranked as liquid swine manure $360kg\;N\;ha^{-1}$, followed by liquid swine manure $240kg\;N\;ha^{-1}$.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.11 no.4
• /
• pp.258-263
• /
• 1991

There are ten NLCF's recommended sorghum-sudangrass hybrids(Sorghum bicolor (L.) Moench), but they have not been evaluated under same environmental conditions. Therefore, a field experiment was conducted to campare forage yield and quality of the NLCF's recommended cultivars of sorghum-sudangrass hybrids at the experimental forage field, College of Agriculture, SNU, Suweon over two years. Among the ten cultivars used, G83F and NC+855 were classified as early maturing cultivars. Pioneer 988 and Sordan 79 were more resistant to leaf blight than the other hybrids. Jumbo, Sordan 79 and SX-17 were susceptible to lodging. No significant differences in dry matter yield were found among the cultivars used, but the dry matter yields of Pioneer 988, TE-Haygrazer and G83F were slightly higher than the other hybrids in 1989 and those of NC+855 and Pioneer 988 were higher in 1990. There were no marked cultivar differences in CP, ADF, NDF and RFV at the first, second and third cuts in 1990, but the ADF, NDF and RFV of sorghum-sudangrass hybrids at the third cut showed more higher than those of the first and second cut forage. In conclusion, there are no forage yield differences among the ten NLCF's recommended sorghum-sudangrass hybrids.

• The korean journal of orthodontics
• /
• v.30 no.2 s.79
• /
• pp.245-260
• /
• 2000

The Objective of this research was to construct the multimedia database system that was necessary for the education of the practitioners and the students. To establish this system, there were technical problems as follows 1) The processing of the images, 2) The rapid processing of the information with the computer network, 3) The development of diagnosis tools, 4) The technique to establish the database system, 5) The link between the database system and the internet, and 6) The method to educate through many cases. The analysis for diagnosis and treatment planning were provided as two parts : model analysis and cephalometric analysis. As a model analysis, arch length discrepancy and Bolton tooth ratio were provided for the part of patient information. Cephalometric analyses were provided in the part of initial diagnosis. The Cephalometric analysis ver 2.0 and the PowerCeph pro 3.3.5 were used to show Tweed, Steiner and Jarabak analysis. In the main part, Kim's analysis and some measurements were added. In the post-treatment or retention part, we show the superimposition of the cephalometrics with which you can find the effectiveness of the various orthodontic treatment The address of this home page is "http://damis.snu.ac.kr/orthodontics"

• Journal of Korean Society of Steel Construction
• /
• v.26 no.3
• /
• pp.177-189
• /
• 2014

When floor vibration problems occur in existing buildings, TMD (tuned mass damper) can be a viable alternative to resolving the problem. Only when TMD has been exactly tuned to the natural frequency of the floor, it can control the vibration as intended in design. However, TMD gets inefficient in the situation where the natural frequency changes as a result of the uncontrollable variation of the floor mass weight. This physical phenomenon is often called as TMD-off-tuning. This study proposes asymmetric TMD for enhancing the robustness of floor vibration control against uncertain natural frequencies. The proposed TMD features two asymmetric linear springs such that the floor vibrational energy can be dissipated through both the translational and rotational motion. An easy-to-use graphical optimization method was developed in this study. The asymmetric TMD proposed outperformed in vibration control by 28% compared to that of conventional TMD. The robustness of asymmetric TMD of this study was two times higher than that of conventional TMD.

• The Journal of Korean Academy of Prosthodontics
• /
• v.28 no.2
• /
• pp.1-28
• /
• 1990

The severe atrophic edentulism with poor neuromuscular control militates against successful conventional denture therapy. To such situation, a prescribing of dental implant treatment has been considered with some probability. Implant materials used as a trial for dental implants includes metals, plastic polymers and ceramics. The purpose of this study was to observe histologic response in osseointegration process at titanium implant-tissue interface based on biocompatibility at specific period of sequential natures which were divided into a half month, one, month, two months, three months and immediate as a base line. In this study, unilateral lower left premolar and molar teeth were extraced in three dogs. After allowing to heal for 6 months, three kinds of osseointegrated implant, $Br{\aa}nemark$, Corevent and kimplant(a prototype of SNU implant study)were inserted in each dog respectively according to the above sequence from front to back. The specimens were taken from those dogs at the same time since implant were inserted quite reverse order of the specified periods, and decalcified and processed for histologic examination for the light microscopy and the electron microscopy. The microscopic histologic findings at the interface between titanium implants and tissue were interpretated as follows : A. Light microscopic findings : a. Immediate : Implant were surrounded by compact bone and spongy bone. Microcrak was observed in the superficial bone tissue. Osteocytes were disappeared and bone lacunae were observed as a vacant space in some parts. In the contacting with the spongy bone, bone trabeculae and bone marrow were in contact with the implant. b. A half Month : Osteoblasts exist as a monolayer in th inner bone trabeculae and do bone additiocn. Osteoblasts&inflammatory cells were observed in some parts. c. One Month : The presence of osteoclasts decreased. Osteoblasts did active bone fromation, and bone marrow was in contact with the implant in the many places. d. Two Months : Bone formation was advanced in comparison with the b and c. The presence of osteoclsts was not observed. e. Three Months : The superficial bone tissue contacted with the implants was entirely composed by the compact bone. B. Electron microscopic findings : a. A half month and one month group : In the parts of the active bone formation, osteoblasts with the well developed endoplasmic reticulum and Golgi apparatus were arranged in the monolayer. In the parts of the bone resorption, ruffled border was well developed and many osteoclasts with the well-developed golgi apparatus, mitochondria, vacuole, vesicle and lysosome were existed. b. Three months group : No osteoblasts were observed in the superficial bone tissue. Bone matrix with collaen fiber was observed. c. No significant dirrerence in the histologic findings was observed in $Br{\aa}nemark$, Core-vent and kimplant.

• Journal of Veterinary Clinics
• /
• v.35 no.4
• /
• pp.126-129
• /
• 2018

This study was performed to describe the outcome of pars plana retinopexy with perfluoro-n-octane (PFO)-silicone oil (SiO) exchange in dogs with rhegmatogenous retinal detachment in Seoul National University Veterinary Medical Teaching Hospital (SNU VMTH) from 2014 to 2017. Nine eyes of 8 dogs were included in this study. Medical records including signalment, history, duration from onset of blindness to surgical intervention, pre-operative findings, duration from surgery to regaining vision, and post-operative complications were evaluated. No eyes were visual before surgery. Duration from onset of blindness to surgical intervention was 2-30 days (median 8 days); duration from surgery to regain vision was 1-14 days (median 6 days); follow-up time was 15-1088 days (median 69 days). Post-operative complications were divided as temporary vs permanent conditions. Temporary complications were corneal ulcer, uveitis, retinal haemorrhage, glaucoma, subconjunctival leakage of SiO, and vitreal haemorrhage. Permanent complications were anterior chamber migration of SiO, retinal degeneration, corneal degeneration, re-detachment, and cataract. Six of 9 eyes regained functional vision, five of which remained visual throughout the follow-up time while the other one lost vision after 3 months because of uveitic glaucoma. In conclusion, pars plana retinopexy with PFO-SiO exchange provided fair outcome in 66.7% cases described in this study.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.16 no.4
• /
• pp.327-337
• /
• 1996

A field experiment was conducted at SNU Experimental Livestock Farm, Suweon in 1995 to determine effect of planting date on forage performance of wm hybrids of four different maturity groups. A split-plot design replicated three times was used, with com hybrids representing four maturity groups (115, 118, 121 and 125 days) being the main plots and planting dates (3124, 415, 415, 425, 515 and 5/15) the sub-plots. 1. Days to emergence and percent emergence from the March 24 planting were, on the average, 36 days and 58%, respectively, but those from the April 5 to May 15 planting averaged 12 days and 92%, respectively. 2. Plant and ear heights increased gradually as the dates of planting were delayed except the May 15 planting, however, percent ear was decreased as the dates of planting were delayed. There was a trend for the mean lodging percentage of the hybrids to be higher as the planting date was delayed. 3. The 115-and 118-day mediumearly maturing hybrids harvested on August 18 produced silages with a dry matter content between 27 and 30% at all planting dates except the May 15 planting, while the 121-and 125-day medium-late maturing hybrids produced silages with a dry matter wntent less than 27% regardless of any planting dates. 4. There were no significant differences in mean dry matter yield among the hybrids, but significant mean TDN yield differences were found. The 115-, 118- and 125-day hybrids had significantly higher mean TDN yield than the 121-day hybrid. There were significant differences in mean dry matter and TDN yields among the planting dates. The mean dry matter and TDN yields from the April 5, 15 and 25 plantings were significantly higher than those of other plantings, however, there were no significant differences in mean TDN yield among the April 5, April 15 and April 25 plantings. No significant planting date $\times$ maturity interactions were found for both the dry matter and TDN yields. 5. Mean stover NDF and ADF contents of the 115- and 118day hybrids were higher than those of the 121- and 125-day hybrids, but the reverse was true for mean stover IVDMD and RFV. Mean stover NDF an ADF contents increased with earlier plantings, but mean stover IVDMD and RFV increased when planting was delayed. Results of this experiment indicate that for corn planting in central and northern areas of Korea, early to mid-April may be the right time with the 115-to 118-day maturity hybrids when silage making before August 20 is taken into consideration.

• Korean Journal of Social Welfare Studies
• /
• v.47 no.4
• /
• pp.151-181
• /
• 2016

The objective of the study is to identify the sub-path of entry into homelessness of young men and enhance understanding them. In specific, homeless risk factors were extracted through their experiences, and based on which the entry paths into homelessness were drawn. The homeless young adults were divided into two groups of those who became homeless in their adolescence and those who entered into homelessness after 19 and their differences were analyzed. As a results, the most prominent differences between the two sub-groups included individual and social factors; most of those who entered homelessness after 19 had physical or psychological problems, while the other group showed delinquency factors in adolescence and adulthood. As for social factors, the former group experienced more financial damage in the process of achieving independence before being homeless, while the latter group had relatively more experience of physical and psychological damage such as bullying, harassment and violence before being homeless and financial frauds. As for investigating the causality relationship of key homeless risk factors by adding a variable of time, and based on which, a constant pattern of entry paths toward homelessness was drawn among each sub-group of homeless young adults. For policy on homelessness, it is required to develop according to the characteristics of homeless young adults. Especially, a specific approach is necessary for the different homeless pathways by sub-group. Furthermore, the study indicated that management and preemptive responses for various homeless risk factors that homeless young adults experienced throughout their lifetime could be important prevention policy against homelessness.

• Journal of the Korea Society for Simulation
• /
• v.28 no.2
• /
• pp.1-14
• /
• 2019

A full scale hydrodynamic simulation that requires an accurate reproduction of shock-induced detonation was conducted for design of an energetic component system. A detailed hydrodynamic analysis SW was developed to validate the reactive flow model for predicting the shock propagation in a train configuration and to quantify the shock sensitivity of the energetic materials. The pyrotechnic device is composed of four main components, namely a donor unit (HNS+HMX), a bulkhead (STS), an acceptor explosive (RDX), and a propellant (BPN) for gas generation. The pressurized gases generated from the burning propellant were purged into a 10 cc release chamber for study of the inherent oscillatory flow induced by the interferences between shock and rarefaction waves. The pressure fluctuations measured from experiment and calculation were investigated to further validate the peculiar peak at specific characteristic frequency (${\omega}_c=8.3kHz$). In this paper, a step-by-step numerical description of detonation of high explosive components, deflagration of propellant component, and deformation of metal component is given in order to facilitate the proper implementation of the outlined formulation into a shock physics code for a full scale hydrodynamic simulation of the energetic component system.