• Journal of Korean Neurosurgical Society
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• 제37권3호
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• pp.207-212
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• 2005

Objective: Classically, single photon emission tomography is known to be the reference standard for evaluating the hemodynamic status of patients with moyamoya disease. Recently, T2-weighted perfusion magnetic resonance(MR) imaging has been found to be effective in estimating cerebral hemodynamics in moyamoya disease. We aim to assess the utility of perfusion-weighted MR imaging for evaluating hemodynamic status of moyamoya disease. Methods: The subjects were fourteen moyamoya patients(mean age: 7.21 yrs) who were admitted at our hospital between Sep. 2001 to Sep 2003. Four normal children were used for control group. Perfusion MR imaging was performed before any treatment by using a T2-weighted contrast material-enhanced technique. Relative cerebral blood volume(rCBV) and time to peak enhancement(TTP) maps were calculated. Relative ratios of rCBV and TTP in the anterior cerebral artery(ACA), middle cerebral artery(MCA) and basal ganglia were measured and compared with those of the posterior cerebral artery(PCA) in each cerebral hemispheres. Using this data, we analysed the hemodynamic aspect of pediatric moyamoya disease patients in regarding to the age, Suzuki stage, signal change in FLAIR MR imaging, and hemispheres inducing symptoms. Results: The mean rCBV ratio of ACA, MCA did not differ between normal children and moyamoya patients. However the significant TTP delay was observed at ACA, MCA territories (mean = 2.3071 sec, 1.2089 see, respectively, p < 0.0001). As the Suzuki stage of patients is advanced, rCBV ratio is decreased and TTP differences increased. Conclusion: Perfusion MR can be applied for evaluating preoperative cerebral hemodynamic status of moyamoya patients. Furthermore, perfusion MR imaging can be used for determine which hemisphere should be treated, first.

• 대한치과교정학회지
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• 제50권3호
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• pp.188-196
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• 2020

Objective: Preservation of the periodontal ligament (PDL) is vital to the success of tooth autotransplantation (TAT). Increased PDL volumes and facilitated tooth extraction have been observed upon orthodontic preloading. However, it is unclear whether any changes occur in the expressions of bone biomolecules in the increased PDL volumes. This study aimed to determine the expressions of runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), receptor activator of nuclear factor kappa-B ligand (RANKL), and osteoprotegerin (OPG) in PDL upon preloading. Methods: Seventy-two premolars from 18 patients were randomly assigned to experimental groups that received a leveling force for 1, 2, or 4 weeks or to a control unloaded group. Following extraction, PDL volumes from 32 premolars of eight patients (21.0 ± 3.8 years) were evaluated using toluidine blue staining. The expressions of the biomolecules in the PDL from 40 premolars of ten patients (21.4 ± 4.0 years) were analyzed via immunoblotting. Results: The median percentage of stained PDL was significantly higher at 2 and 4 weeks after preloading than in the unloaded condition (p < 0.05). The median RUNX2 and ALP expression levels were significantly higher at 2 and 4 weeks after preloading than in the unloaded condition (p < 0.05), whereas the median RANKL/OPG ratios were significantly higher at 1 and 4 weeks after preloading (p < 0.05). Conclusions: Orthodontic preloading for 4 weeks enhances PDL volumes as well as the expressions of RUNX2, ALP and the RANKL/OPG ratio in the PDL, suggesting this loading period is suitable for successful TAT.

• Mass Spectrometry Letters
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• 제2권4호
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• pp.80-83
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• 2011

Isotope ratio analysis of nuclear materials in individual particles is of great importance for nuclear safeguards. Although secondary ion mass spectrometry (SIMS) and thermal ionization mass spectrometry (TIMS) are utilized for the analysis of individual uranium particles, few studies were conducted for the analysis of individual uranium-plutonium mixed oxide particles. In this study, we applied SIMS and inductively coupled plasma mass spectrometry (ICP-MS) to the isotope ratio analysis of individual U-Pu mixed oxide particles. In the analysis of individual U-Pu particles prepared from mixed solution of uranium and plutonium standard reference materials, accurate $^{235}U/^{238}U$, $^{240}Pu/^{239}Pu$ and $^{242}Pu/^{239}Pu$ isotope ratios were obtained with both methods. However, accurate analysis of $^{241}Pu/^{239}Pu$ isotope ratio was impossible, due to the interference of the $^{241}Am$ peak to the $^{241}Pu$ peak. In addition, it was indicated that the interference of the $^{238}UH$ peak to the $^{239}Pu$ peak has a possibility to prevent accurate analysis of plutonium isotope ratios. These problems would be avoided by a combination of ICP-MS and chemical separation of uranium, plutonium and americium in individual U-Pu particles.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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• pp.23-24
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• 2003

We synthesized a poly[2-(2'-hydroxyphenyl) benzoxazole] under the two step procedures of Suzuki coupling polymerization with corresponding monomers followed by the deprotection of benzyl group. The polymer in DMF solution is applicable to colorimetric sensing fluoride anion, which shows a color change from colorless to yellow. High sensitivity to fluoride anion compared to other anions such as phosphate, chloride, and sulfate is ascribed to the high coordination ability of the 2-(2'-hydroxy phenyl)benzoxazole moiety in the polymer chain. Emission shift by metal cations, which can be applied to fluorescent sensing w as also observed in the polymer solution.

• 한국해양공학회지
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• 제21권3호
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• pp.26-32
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• 2007

A series of large-scale experiments were carried out in order to examine wave-induced liquefaction in a loosely packed sandbed, its afterward high densification and liquefaction by oscillatory pore pressure. The experiments were conducted in a Large Hydro-Geo Flume that can nearly solve the problems of scale effects of the sandbed, and the 50% sieve diameter of sand was 0.2 mm. The generation of residual pore pressure and its afterward high densification which had observed by Takahashi et al. (1999) in a wave flume experiment using fine sand with the size of 0.08 mm. As a result, the relative density of the sandbed after high densification was increased up to 79% and liquefaction by oscillatory pore pressure was not observed.

• Asian-Australasian Journal of Animal Sciences
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• 제13권7호
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• pp.957-961
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• 2000

A series of experiments was conducted to evaluate phytin phosphohydrolysis actlVlty in the rumen and to isolate phytase positive rumen bacteria. Endogenous phytase activity of wheat bran was estimated and compared with that of bacterial phytin phosphohydrolysis. Substantial phytase activity was detected in wheat bran during in vitro rumen incubation. Bacterial phytase activity was suggested not to be high. Only two facultative anaerobes, Klebsiella sp. and Corynebacterium sp. were isolated as phytase producing organisms. These belonged to a minor microbial group in the rumen population. Protozoal fraction showed an initial velocity of phytin phosphohydrolysis 7 times higher than the bacterial fraction.

• 한국전기전자재료학회논문지
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• 제24권5호
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• pp.398-403
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• 2011

Recently, Near-infrared (NIR)colorant is intriguing and attractive but full of challenges. Although some cyanine colorant have been commercialized, near-infrared colorant with intensive NIR absorption, good chemical and photo-stability, and high solubility still remain as target compound. Certain polycyclic aromatic compounds such as quaterrylene represent a key class of NIR colorant and also give rise to outstanding physical and chemical properties after appropriate chemical modification. In this study, We have tried to introduceimide functional group to quaterrylene in order to give chemical and thermal stability. Finally, N,N'-bis (2,6-diisopropylphenyl)-quarterrylene-3,4:13,14-tetracarboximide was synthesized and evaluated its properties using $^1H$ NMR, Maldi-tof, TGA, and UV/VIS/NIR spectroscopy as NIR colorant. The quaterrylene bisimide compound exhibit a excellent thermal stability and chemical stability.

• 한국환경보건학회지
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• 제18권1호
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• pp.105-111
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• 1992

Fifty samples of pregnant women's hair during December 1990~April 1991 in the Seoul area were analyzed for mercury. Mean mercury concentrations for pregnant women were 0.65$\mu$g/g and varied from 0.21$\mu$g/g to 2.44$\mu$g/g. The differences were believed to be due to diet, living area, and personal activity. Mean mercury concentrations were significantly different for the group that at twice a week(0.67$\mu$g/g) and once or less a week(0.55$\mu$g/g). Mean mercury concentrations were compared with the THI (Todai Health Index) Scores. The THI results suggested that the higher scores in MENT(Mental irritability) item had the higher mean mercury concentrations. The factors affecting mercury concentrations of pregnant women's hair must be considered further study. However, hair analysis seemed potentially useful in environmental medicine but its use in clinical investigation for basic diagnosis of mercury poisoning.

• Bulletin of the Korean Chemical Society
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• 제14권6호
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• pp.732-739
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• 1993

Good yields were usually obtained in Pd(O)-catalyzed Suzuki aryl-aryl coupling reaction, even when both coupling partners had an ortho tertiary benzamide functional group. The direct ortho functionalization of oligomeric tertiary benzamides at Snieckus condition is dependent on the chain length. Tertiary benzamide 1 can be o,o-dilithiated only by metal-halogen exchange of the 2,6-dihalo-compound. Bis-tertiary benzamide 9 can be o,o'-dilithiated with excess(4.1 equivalents) s-butyllithium/TMEDA as the lithiating agent. Tris-tertiary benzamide 21 is hard to o,o"-difunctionalize due to steric interactions among the tertiary benzamide functional groups, and due to steric interactions between these functional groups and others (if present) on the termini of the terphenyl unit.

• 한국잠사학회:학술대회논문집
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• 한국잠사학회 2001년도 제44회 추계 학술연구 발표회
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• pp.66-66
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• 2001

no Abstract, See Full Text