• 한국자기공명학회논문지
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• 제18권1호
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• pp.15-23
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• 2014

The structural properties and relaxation processes of $MCsSO_4$ (M = Na, K, or Rb) crystals were investigated by measuring the NMR spectra and spin-lattice relaxation rates $1/T_1$ of their $^{23}Na$, $^{39}K$, $^{87}Rb$, and $^{133}Cs$ nuclei. According to the NMR spectra, the $MCsSO_4$ crystals contain two crystallographically inequivalent sites each for the M and Cs ions. Further, the relaxation rates of all these nuclei do not change significantly over the investigated temperature range, indicating that no phase transitions occur in these crystals in this range. The variations in the $1/T_1$ values of the $^{23}Na$, $^{39}K$, $^{87}Rb$, and $^{133}Cs$ nuclei in these three crystals with increasing temperature are approximately proportional to $T^2$, indicating that Raman processes may be responsible for the relaxation. Therefore, for nuclear quadrupole relaxation of the $^{23}Na$, $^{39}K$, $^{87}Rb$, and $^{133}Cs$ nuclei, Raman processes with n = 2 are more effective than direct processes.

• 대한원격탐사학회지
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• 제21권5호
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• pp.393-404
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• 2005

As multi-source spatial data fusion mainly deal with various types of spatial data which are specific representations of real world with unequal reliability and incomplete knowledge, proper data representation and uncertainty analysis become more important. In relation to this problem, this paper presents and applies an advanced data representation methodology for different types of spatial data such as categorical and continuous data. To account for the uncertainties of both categorical data and continuous data, fuzzy boundary representation and smoothed kernel density estimation within a fuzzy logic framework are adopted, respectively. To investigate the effects of those data representation on final fusion results, a case study for landslide hazard mapping was carried out on multi-source spatial data sets from Jangheung, Korea. The case study results obtained from the proposed schemes were compared with the results obtained by traditional crisp boundary representation and categorized continuous data representation methods. From the case study results, the proposed scheme showed improved prediction rates than traditional methods and different representation setting resulted in the variation of prediction rates.

• Journal of Welding and Joining
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• 제16권4호
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• pp.83-91
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• 1998

Cracking problems which high temperature plant components suffer during long-term service, occur very often at welded locations. The crack occurs due to accumulated creep damage near fusion line or at heat affected zone (HAZ). However, most of the studies on creep crack growth behavior have been performed with matrix metal not wit welded metal due to the difficulty of interpreting the test results. In this study, creep crack growth rates were measured with C(T) specimens whose cracks were formed along the fusion line or HAZ. The measured crack growth rates were characterized by {TEX}$C_{t}${/TEX}-parameter derived for elastic-primary-secondary creeping material. Since contribution of primary creep was significant for the tested 1Cr-0.5Mo steel, its effect was carefully studied. Effects of crack tip plasticity and material aging were also discussed.

• Journal of Korean Neurosurgical Society
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• 제46권1호
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• pp.45-51
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• 2009

Objective : To evaluate the potential effects of risedronate (RIS) which shows a higher anti-resorptive effect among bisphosphonates, after a posterolateral lumbar intertransverse process spinal fusion using both autograft and allograft in a rat model. Methods : A totoal of 28 Sprague-Dawley rats were randomized into 2 study groups. A posterolateral lumbar intertransverse process spinal fusion was peformed using both autograft and allograft in a rat model. Group I (control) received 0.1 mL of steril saline (placebo) and Group II (treatment) received risedronate, equivalent to human dose (10 ${\mu}g$/kg/week) for 10-weeks period. Results : The fusion rates as determined by manual palpation were 69% in the group I and 46% in the group II (p = 0.251). According to radiographic score, the spinal segment was considered to be fused radiographically in 7 (53%) of the 13 controls and 9 (69%) of the 13 rats treated with RIS (p = 0.851). The mean histological scores were 5.69 ${\pm}$ 0.13 and 3.84 ${\pm}$ 0.43 for the control and treatment groups, respectively. There was a significant difference between the both groups (p = 0.001). The mean bone density of the fusion masses was 86.9 ${\pm}$ 2.34 in the control group and 106.0 ${\pm}$ 3.54 in the RIS treatment group. There was a statistical difference in mean bone densities of the fusion masses comparing the two groups (p=0.001). Conclusion : In this study, risedronate appears to delay bone fusion in a rat model. This occurs as a result of uncoupling the balanced osteoclastic and osteoblastic activity inherent to bone healing. These findings suggest that a discontinuation of risedronate postoperatively during acute fusion period may be warranted.

• Journal of Korean Neurosurgical Society
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• 제37권1호
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• pp.39-43
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• 2005

Objective: For Posterior lumbar interbody fusion(PLIF) various cages or iliac bone dowels are used with or without pedicle screw fixation(PSF). To evaluate and compare the clinical and radiological results of different fusion methods, we intend to verify the effect of added PSF on PLIF, the effect of bone cages and several factors which are thought to be related with the postoperative prognosis. Methods: One hundred and ninety seven patients with lumbar spinal stenosis and instability or spondylolisthesis underwent various fusion operations from May 1993 to May 2003. The patients were divided into five groups, group A (PLIF with autologous bone dowels, N=24), group B (PLIF with bone cages, N=13), group C (PLIF with bone dowels and PSF, N=37), group D (PLIF with bone cages and PSF, N=30) and group E (PSF with intertransverse bone graft, N=93) for comparison and analyzed for the outcome and fusion rate. Results: Outcome was not significantly different among the five groups. In intervertebral height (IVH) changes between pre- and post-operation, Group B ($2.42{\pm}2.20mm$) was better than Group A ($-1.33{\pm}2.05mm$). But in the Group C, D and E, the IVH changes were not different statistically. Fusion rate of group C, D was higher than that of Group A and B. But the intervertebral height(IVH) increased significantly in group B($2.42{\pm}2.20mm$). Fusion rate of group C and D were higher than that of group A and D. Conclusion: Intervertebral cages are superior to autologous iliac bone dowels for maintaining intervertebral height in PLIF. The additional pedicle screw fixation seems to stabilize the graft and improve fusion rates.

• 한국수정란이식학회지
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• 제19권3호
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• pp.191-199
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• 2004

본 연구는 돼지 태아 섬유아세포유래 공여세포를 미세주입에 의해 주입 후 재 조합한 핵 이식 배에 대한 배양액, 세포주기의 동기화, 배양시간 및 난자의 활성화에 따른 융합율과 체외발생율에 대해 조사하였다. 핵 이식 배를 NCSU-23, TL Hepes 및 TZM-3 배양액으로 1시간 및 8시간 배양하였을 때 배반포로의 분할율은 각각 15.6%, 14.0%, 15.0% 및 13.9%, 10.5%, 13.3%로서 배양액 및 시간에 따른 분할율의 유의적인 차이는 없었다. 공여핵원용 세포를 0, 8, 15시간 배양했을 때 G2/M기로의 체외발달율은 12.0%, 18.0%, 48.0%였다(p<0.01). 공여핵원용 세포를 12-24시간 배양했을 때 G2/M기로의 체외발달율은 유의한 증가를 나타내지 않았다. 공여핵원용 세포를 10% FBS + NCSU-23 배양액으로 1-2, 6-8, 12-14일간 배양 후 핵 이식한 배의 융합율은 각각 60.0%, 73.3%, 62.5%였으며, 분할율은 각각 36.0%, 56.7%, 50.0%였다. 0.5% FBS + NCSU-23, 0.5% + TL-Heaps 및 0.5% + TZM-3 배양액으로 5% $O_2$조건 하에서 배양하였을 때 핵 이식배의 $\geq$2 cell 및 배반포로의 발생율은 각각 12.5$\pm$1.6%, 11.1$\pm$1.8%, 11.7$\pm$1.0%였으며, 10% $O_2$조건 하에서 배양하였을 때 핵 이식배의 $\geq$2 cell 및 배반포로의 발생율은 각각 10.5$\pm$1.5%, 9.8$\pm$1.4%, 10.0$\pm$0.8%였다 배양액과 $O_2$ 조건에 따른 유의한 발생율에 차이는 인정되지 않았다.

• Journal of Korean Neurosurgical Society
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• 제57권2호
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• pp.108-113
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• 2015

Objective : Although the L5-S1 has distinct structural features in comparison with other lumbar spine segments, not much is known about adjacent segment degeneration (ASD) at the L5-S1 segment. The aim of study was to compare the incidence and character of ASD of the cephalad and L5-S1 segments after L5 floating lumbar fusion. Methods : From 2005 to 2010, 115 patients who underwent L5 floating lumber fusion were investigated. The mean follow-up period was 46.1 months. The incidence of radiological and clinical ASD of the cephalad and the L5-S1 segments was compared using survival analysis. Risk factors affecting ASD were analyzed using a log rank test and the Cox proportional hazard model. Results : Radiological ASD of the L5-S1 segment had a statistically significant higher survival rate than that of the cephalad segment (p=0.001). However, clinical ASD of the L5-S1 segment was significantly lower survival rates than that of the cephalad segment (p=0.038). Risk factor analysis showed that disc degeneration of the cephalad segment and preoperative spinal stenosis of the L5-S1 segment were risk factors. Conclusion : In L5 floating fusion, radiological ASD was more common in the cephalad segment and clinical ASD was more common in the L5-S1 segment. At the L5-S1 segment, the degree of spinal stenosis appears to be the most influential risk factor in ASD incidences, unlike the cephalad segment.

• Journal of Korean Neurosurgical Society
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• 제60권5호
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• pp.567-576
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• 2017

Objective : Preoperative parameters including the T1 slope (T1S) and C2-C7 sagittal vertical axis (SVA) have been recognized as predictors of kyphosis after laminoplasty, which is accompanied by posterior neck muscle damage. The importance of preoperative parameters has been under-estimated in anterior cervical discectomy and fusion (ACDF) because there is no posterior neck muscle damage. We aimed to determine whether postoperative subsidence and pseudarthrosis could be predicted according to specific parameters on preoperative plain radiographs. Methods : We retrospectively analyzed 41 consecutive patients (male : female, 22 : 19; mean age, $51.15{\pm}9.25years$) who underwent ACDF with a stand-alone polyether-ether-ketone (PEEK) cage (>1 year follow-up). Parameters including SVA, T1S, segmental angle and range of motion (ROM), C2-C7 cervical angle and ROM, and segmental inter-spinous distance were measured on preoperative plain radiographs. Risk factors of subsidence and pseudarthrosis were determined using multivariate logistic regression. Results : Fifty-five segments (27 single-segment and 14 two-segment fusions) were included. The subsidence and pseudarthrosis rates based on the number of segments were 36.4% and 29.1%, respectively. Demographic data and fusion level were unrelated to subsidence. A greater T1S was associated with a lower risk of subsidence (p=0.017, odds ratio=0.206). A cutoff value of T1S<$28^{\circ}$ significantly predicted subsidence (sensitivity : 70%, specificity : 68.6%). There were no preoperative predictors of pseudarthrosis except old age. Conclusion : A lower T1S (T1S<$28^{\circ}$) could be a risk factor of subsidence following ACDF. Surgeons need to be aware of this risk factor and should consider various supportive procedures to reduce the subsidence rates for such cases.

• Asian-Australasian Journal of Animal Sciences
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• 제14권6호
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• pp.759-764
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• 2001

This study was carried out to investigate the effect of activation timing, cell cycle and passage on the development of embryos produced by cumulus cell nuclear transfer in Hanwoo (Korean cattle). Nuclear donor cumulus cells were cultured in Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum at $38.5^{\circ}C$ in a humidified atmosphere of 5% $CO_2$ in air. The 1~6 passages of serum deprived or actively dividing cumulus cells were isolated and used as donor cells. The in vitro matured oocytes were enucleated and then the isolated donor cells were introduced. One pulse of 180 volts for $15{\mu}s$ was applied to induce the fusion between karyoplast and cytoplast. The activation was done before or after the fusion. To activate, oocytes were treated with $10{\mu}M$ calcium ionophore for 5 min immediately followed by 2 mM 6-dimethylaminopurine for 3 h. The nuclear transfer embryos were cultured in $500{\mu}l$ of modified CRlaa supplemented with 3 mg/ml BSA in four well dish covered with mineral oil. After 3 days culture, culture medium was changed into modified CRlaa medium containing 1.5 mg/ml BSA and 5% FBS for 4 days. The incubation environment was 5% $CO_2$, 5% $O_2$, 90% $N_2$ at $38.5^{\circ}C$. There was no blastocyst formation when the nuclear transfer embryos were activated before the fusion, whereas, 29.9% of blastocyst formation was shown when the nuclear transfer embryos were activated after the fusion. When serum deprived and actively dividing cumulus cells were used as nuclear donor cells, the developmental rates to blastocyst were 38.5% and 40.6%, respectively. There was no significant difference between serum deprived and actively dividing cells in the developmental rates. The developmental rates to blastocyst according to 1~6 passages were 37.5~44.4%. However, there were no significant differences among passages. These results indicate that 1~6 passage cumulus cell irrespective of cell cycle could support development of nuclear transfer embryos activated after the fusion.

• 한국대기환경학회지
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• 제28권1호
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• pp.77-85
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• 2012

In this study, emission rates (ER) of biogenic volatile organic compounds (BVOCs) were measured by varying levels of photosynthetically active radiation (PAR). An appropriate plan for ozone reduction according to increasing ecology area ratio in future metropolitan areas was suggested. Several trees were selected as representative tree species in urban areas. Emission rates and composition ratios of monoterpene and isoprene emitted from these trees were estimated and compared. As a result, it was found that emission rates of BVOCs were considerably different depending on tree species. Especially, BVOCs emitted from Platanus orientalis and Quercus mongolica could significantly affect ozone increase in the metropolitan area, because the emission rates were several thousands to ten thousand times higher than those emitted from Zelkova serrata and Prunus serrulata. Furthermore, it was observed that emission rates of BVOCs by species increased maximum up to 10 times when PAR, which has close relations with temperature, rose. It was concluded that tree species such as Zelkova serrata et al., was appropriate for metropolitan areas since the species has low ozone potential and good landscape. Suppose this type of trees are planted on purpose in the urban areas, better ambient air quality will be promised in the future.