• Progress in Medical Physics
• /
• v.21 no.1
• /
• pp.35-41
• /
• 2010

The purpose of this study is to quantitate regional neurochemical profile of regional normal adult mice brain and assess regional metabolic differences by using ex vivo $^1H$ high-resolution magic angle spinning nuclear magnetic resonance spectroscopy ($^1H$ HR-MAS NMRS). The animals were matched in sex and age. The collected brain tissue included frontal cortex, temporal cortex, thalamus, and hippocampus. Quantitative 1D spectra were acquired on 40 samples with the CPMG pulse sequence (8 kHz spectral window, TR/TE = 5500/2.2 ms, NEX = 128, scan time: 17 min 20 sec). The mass of brain tissue and $D_2O$+TSP solvent were 8~14 mg and 7~13 mg. A total of 16 metabolites were quantified as follow: Acet, NAA, NAAG, tCr, Cr, tCho, Cho, GPC + PC, mIns, Lac, GABA, Glu, Gln, Tau and Ala. As a results, Acet, Cho, NAA, NAAG and mIns were showed significantly different aspects on frontal cortex, hippocampus, temporal cortex and thalamus respectively. The present study demonstrated that absolute metabolite concentrations were significantly different among four brain regions of adult mice. Our finding might be helpful to investigate brain metabolism of neuro-disease in animal model.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.93-93
• /
• 2016

Large scale integrated circuits (LSIs) has been improved by the shrinkage of the circuit dimensions. The smaller chip sizes and increase in circuit density require the miniaturization of the line-width and space between metal interconnections. Therefore, an extreme precise control of the critical dimension and pattern profile is necessary to fabricate next generation nano-electronics devices. The pattern profile control of plasma etching with an accuracy of sub-nanometer must be achieved. To realize the etching process which achieves the problem, understanding of the etching mechanism and precise control of the process based on the real-time monitoring of internal plasma parameters such as etching species density, surface temperature of substrate, etc. are very important. For instance, it is known that the etched profiles of organic low dielectric (low-k) films are sensitive to the substrate temperature and density ratio of H and N atoms in the H2/N2 plasma [1]. In this study, we introduced a feedback control of actual substrate temperature and radical density ratio monitored in real time. And then the dependence of etch rates and profiles of organic films have been evaluated based on the substrate temperatures. In this study, organic low-k films were etched by a dual frequency capacitively coupled plasma employing the mixture of H2/N2 gases. A 100-MHz power was supplied to an upper electrode for plasma generation. The Si substrate was electrostatically chucked to a lower electrode biased by supplying a 2-MHz power. To investigate the effects of H and N radical on the etching profile of organic low-k films, absolute H and N atom densities were measured by vacuum ultraviolet absorption spectroscopy [2]. Moreover, using the optical fiber-type low-coherence interferometer [3], substrate temperature has been measured in real time during etching process. From the measurement results, the temperature raised rapidly just after plasma ignition and was gradually saturated. The temporal change of substrate temperature is a crucial issue to control of surface reactions of reactive species. Therefore, by the intervals of on-off of the plasma discharge, the substrate temperature was maintained within ${\pm}1.5^{\circ}C$ from the set value. As a result, the temperatures were kept within $3^{\circ}C$ during the etching process. Then, we etched organic films with line-and-space pattern using this system. The cross-sections of the organic films etched for 50 s with the substrate temperatures at $20^{\circ}C$ and $100^{\circ}C$ were observed by SEM. From the results, they were different in the sidewall profile. It suggests that the reactions on the sidewalls changed according to the substrate temperature. The precise substrate temperature control method with real-time temperature monitoring and intermittent plasma generation was suggested to contribute on realization of fine pattern etching.

• Korean Journal of Optics and Photonics
• /
• v.12 no.3
• /
• pp.219-224
• /
• 2001

Spectral phase interferometry for direct electric-field reconstruction (SPIDER) was fabricated and used to characterize pulses from a Ti:sapphire oscillator. In the SPIDER apparatus, two replicas of the input pulse were generated with a time delay of 200 fs and were upconverted by use of sum-frequency generation with a strongly chirped pulse using a 8-cm-long SFIO glass block at a 30-11m-thick type II BBO (p-BaBz04) crystal. The resulting interferogram was recorded with a UV-enhanced CCD array in the spectrometer. The spectral phase was retrieved by SPIDER algorithm in combination with independently measured pulse spectrum and the corresponding temporal intensity profile was reconstructed with a duration of 19 fs. As an independent cross-check of the accuracy of the method, we compared the interferometric autocorrelation (lAC) signal calculated from the SPIDER data with a separately measured lAC. The conventional, but unjustified, method of fitting a sechz pulse to the autocorrelation deceivingly yielded a pulse duration of 15 fs. This systematic underestimation of the pulse duration affirms the need for a complete characterization method. From the consideration in this paper, we concluded that the SPIDER could provide an accurate characterization of femtosecond pulses. ulses.

• Journal of Periodontal and Implant Science
• /
• v.41 no.4
• /
• pp.167-175
• /
• 2011

Purpose: Periodontal ligament (PDL) cell differentiation into osteoblasts is important in bone formation. Bone formation is a complex biological process and involves several tightly regulated gene expression patterns of bone-related proteins. The expression patterns of bone related proteins are regulated in a temporal manner both in vivo and in vitro. The aim of this study was to observe the gene expression profile in PDL cell proliferation, differentiation, and mineralization in vitro. Methods: PDL cells were grown until confluence, which were then designated as day 0, and nodule formation was induced by the addition of 50 ${\mu}g$/mL ascorbic acid, 10 mM ${\beta}$-glycerophosphate, and 100 nM dexamethasone to the medium. The dishes were stained with Alizarin Red S on days 1, 7, 14, and 21. Real-time polymerase chain reaction was performed for the detection of various genes on days 0, 1, 7, 14, and 21. Results: On day 0 with a confluent monolayer, in the active proliferative stage, c-myc gene expression was observed at its maximal level. On day 7 with a multilayer, alkaline phosphatase, bone morphogenetic protein (BMP)-2, and BMP-4 gene expression had increased and this was followed by maximal expression of osteocalcin on day 14 with the initiation of nodule mineralization. In relationship to apoptosis, c-fos gene expression peaked on day 21 and was characterized by the post-mineralization stage. Here, various genes were regulated in a temporal manner during PDL fibroblast proliferation, extracellular matrix maturation, and mineralization. The gene expression pattern was similar. Conclusions: We can speculate that the gene expression pattern occurs during PDL cell proliferation, differentiation, and mineralization. On the basis of these results, it might be possible to understand the various factors that influence PDL cell proliferation, extracellular matrix maturation, and mineralization with regard to gene expression patterns.

• Journal of Korean Neurosurgical Society
• /
• v.56 no.3
• /
• pp.188-193
• /
• 2014

Objective : Moyamoya disease (MMD) is a chronic cerebrovascular occlusive disease of unknown etiology. In addition, the neurocognitive impairment of adults with MMD is infrequently reported and, to date, has not been well described. We attempted to determine both the neurocognitive profile of adult moyamoya disease and whether a superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis can improve the neurocognitive impairment in exhibiting hemodynamic disturbance without stroke. Methods : From September 2010 through November 2012, 12 patients with angiographically diagnosed MMD underwent STA-MCA anastomosis for hemodynamic impairment. Patients with hypoperfusion and impaired cerebrovascular reserve (CVR) capacity but without evidence of ischemic stroke underwent a cognitive function test, the Seoul Neuropsychological Screening Battery (SNSB). Five patients agreed to undergo a follow-up SNSB test. Data from preoperative and postoperative neurocognitive function tests were compared and analyzed. Results : Five of 12 patients were enrolled. The median age was 45 years (range, 24-55 years). A comparison of preoperative to postoperative status of SNSB, memory domain, especially delayed recall showed significant improvement. Although most of the domains showed improvement after surgery, the results were not statistically significant. Conclusion : In our preliminary study, large proportions of adult patients with MMD demonstrate disruption of cognitive function. This suggests the possibility of chronic hypoperfusion as a primary cause of the neurocognitive impairment. When preoperative and postoperative status of cognitive function was compared, memory domain showed remarkable improvement. Although further study is needed, neurocognitive impairment may be an indication for earlier intervention with reperfusion procedures that can improve cognitive function.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.33 no.4
• /
• pp.160-167
• /
• 2021

Seabed deformation due to the fault failure have both a spatial variation and temporal history. When the faulting process initiates at a certain point beneath seabed, the failure spreads out to neighboring points, resulting in temporal changes of deformation. In particular, such a process induces tsunami waves from the vertical motion of seabed. The uprising speed of seabed affects the formation of initial surface profile, eventually altering the arrival time and runup of tsunamis at the coast. In this work, we developed a numerical model that can simulate the generation and propagation of tsunami waves by considering the horizontal and vertical changes of seabed in an active and dynamic manner. For the verification of the model, it was applied to the 2011 Tohoku-oki earthquake in Japan and the results confirmed that the accuracy was improved compared to the existing passive and static model.

• Korean Journal of Biological Psychiatry
• /
• v.22 no.3
• /
• pp.140-148
• /
• 2015

Objectives The aim of this study is to investigate the correlation between degenerative changes in brain [i.e., global cortical atrophy (GCA), medial temporal atrophy (MTA), white matter hyperintensities (WMH)] and neurocognitive dysfunction in Korean patients with Alzheimer's disease. Methods A total of 62 elderly subjects diagnosed with Alzheimer's disease were included in this study. The degenerative changes in brain MRI were rated with standardized visual rating scales (GCA or global cortical atrophy, MTA or medial temporal atrophy, and Fazekas scales) and the subjects were divided into two groups according to the degree of degeneration for each scale. Cognitive function was evaluated with Korean version of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD-K) and several clinical features, including apolipoprotein E ${\varepsilon}4$ status, lipid profile and thyroid hormones, were also examined. Chi-square test and Fisher's exact test were performed to analyze the relationship between the degree of cerebral degeneration and neurocognitive functions. Results Demographic and clinical features, except for the age, did not show any significant difference between the two groups divided according to the degree of cerebral degenerative changes. However, higher degree of GCA was shown to be associated with poorer performance in verbal fluency test, word list recall test, and word list recognition test. Higher degree of MTA was shown to be associated with poorer performance in Mini-Mental State Examination in the Korean Version of CERAD Assessment Packet (MMSE-KC), word list recognition test and construction praxis recall test. Higher degree of white matter hyperintensities was shown to be associated with poorer performance in MMSE-KC. Conclusions Our results suggest that severe brain degeneration shown in MRI is associated with significantly poorer performance in neurocognitive tests in patients with Alzheimer's disease. Moreover, the degree of GCA, MTA and white matter hyperintensities, represented by scores from different visual rating scales, seems to affect certain neurocognitive domains each, which would provide useful information in clinical settings.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.12 no.4
• /
• pp.277-288
• /
• 2010

The multi-level $H_2O/CO_2$ profile system has been widely used to quantify the storage and advection effects on energy and mass fluxes measured by eddy covariance systems. In this study, we expanded the utility of the profile system by accommodating air sampling devices for isotope analyses of water vapor and $CO_2$. A pre-evacuated 2L glass flask was connected to the discharge of an Infrared Gas Analyzer (IRGA) of the profile system so that airs with known concentration of $H_2O$ and $CO_2$ can be sampled. To test the performance of this sampling system, we sampled airs from 8 levels (from 0.1 to 40 m) at the KoFlux tower of Gwangneung deciduous forest, Korea. Air samples in the 2L flask were separated into its component gases and pure $H_2O$ and $CO_2$ were extracted by using a vacuum extraction line. This novel technique successfully produced vertical profiles of ${\delta}D$ of $H_2O$ and ${\delta}^{13}C$ of $CO_2$ in a mature forest, and estimated ${\delta}D$ of evapotranspiration (${\delta}D_{ET}$) and ${\delta}^{13}C$ of $CO_2$ from ecosystem respiration (${\delta}^{13}C_{resp}$) by using Keeling plots. While technical improvement is still required in various aspects, our sampling system has two major advantages over other proposed techniques. First, it is cost effective since our system uses the existing structure of the profile system. Second, both $CO_2$ and $H_2O$ can be sampled simultaneously so that net ecosystem exchange of $H_2O$ and $CO_2$ can be partitioned at the same temporal resolution, which will improve our understanding of the coupling between water and carbon cycles in terrestrial ecosystems.

• Journal of Ocean Engineering and Technology
• /
• v.33 no.6
• /
• pp.581-589
• /
• 2019

In order to understand the characteristics of beach deformation, in this study, numerical simulations were conducted using a 3-D hydro-morphodynamic model (HYMO-WASS-3D) to analyze the characteristics of beach deformation due to the coastal groundwater levels. HYMO-WASS-3D directly analyzed the nonlinear interaction between the hydrodynamic and morphodynamic processes in the coastal area. The simulation results of HYMO-WASS-3D showed good agreement with the experimental results on the changes in the profile of the beach in the surf and swash zones. Then, numerical simulations were conducted to examine the characteristics of beach deformation due to the variation of the level of the coastal groundwater. As a result, the beach profiles were examined in relation to the wave breaking in the surf zone and the wave uprush and backwash in the swash zone due to the differences in the water levels. This paper also discussed the temporal and spatial distributions of the velocities, vorticities, and suspended sediments in the surf and swash zones with various levels of the coastal groundwater.

• Applied Science and Convergence Technology
• /
• v.24 no.4
• /
• pp.111-116
• /
• 2015

The graphene oxide (GO) and graphene oxide quantum dots (GOQDs), which have gained research interest as new types of light-emitting materials, were synthesized by the modified Hummers method for oxidation of graphite flake and graphite nanoparticle. The optical properties of GO and GOQDs have been compared by mean of photoluminescence (PL), PL excitation (PLE), UV-vis absorbance, and time-resolved PL. The GO have an absorption peak at 229 nm and shoulder part at 310 nm, whereas the GOQDs show broad absorption with a gradual change up without any absorption peaks. The PL emission of GOQDs and GO showed the green color at 520 nm and the red color at 690 nm, respectively. The red emission of GO showed faster PL decay time than the green emission of GOQDs. In particular, the temporal PL profile of the GO showed redshift from 560 nm to 660 nm after the pump event.