• Korean Journal of Radiology
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• v.22 no.7
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• pp.1185-1193
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• 2021

Objective: Clear cell sarcoma of the kidney (CCSK) is the second-most common but extremely rare primary renal malignancy in children after Wilms' tumor. The aims of this study were to evaluate the imaging features that could distinguish between CCSK and Wilms' tumor and to assess the features with diagnostic value for identifying CCSK. Materials and Methods: We reviewed the initial contrast-enhanced abdominal-pelvic CT scans of children with CCSK and Wilms' tumor between 2010 to 2019. Fifty-eight children (32 males and 26 females; age, 0.3-10 years), 7 with CCSK, and 51 with Wilms' tumor, were included. The maximum tumor diameter, presence of engorged perinephric vessels, maximum density of the tumor (Tmax) of the enhancing solid portion, paraspinal muscle, contralateral renal vein density, and density ratios (Tmax/muscle and Tmax/vein) were analyzed on the renal parenchymal phase of contrast-enhanced CT. Fisher's exact tests and Mann-Whitney U tests were conducted to analyze the categorical and continuous variables, respectively. Logistic regression and receiver operating characteristic curve analyses were also performed. Results: The age, sex, and tumor diameter did not differ between the two groups. Engorged perinephric vessels were more common in patients in the CCSK group (71% [5/7] vs. 16% [8/51], p = 0.005). Tmax (median, 148.0 vs. 111.0 Hounsfield unit, p = 0.004), Tmax/muscle (median, 2.64 vs. 1.67, p = 0.002), and Tmax/vein (median, 0.94 vs. 0.59, p = 0.002) were higher in the CCSK compared to the Wilms' group. Multiple logistic regression revealed that engorged vessels (odds ratio 13.615; 95% confidence interval [CI], 1.770-104.730) and Tmax/muscle (odds ratio 5.881; 95% CI, 1.337-25.871) were significant predictors of CCSK. The cutoff values of Tmax/muscle (86% sensitivity, 77% specificity) and Tmax/vein (71% sensitivity, 86% specificity) for the diagnosis of CCSK were 1.97 and 0.76, respectively. Conclusion: Perinephric vessel engorgement and greater tumor enhancement (Tmax/muscle > 1.97 or Tmax/vein > 0.76) are helpful for differentiating between CCSK and Wilms' tumor in children aged below 10 years.

• Journal of Microbiology and Biotechnology
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• v.28 no.3
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• pp.482-490
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• 2018

Candida albicans infections are often problematic to treat owing to antifungal resistance, as such infections are mostly associated with biofilms. The ability of C. albicans to switch from a budding yeast to filamentous hyphae and to adhere to host cells or various surfaces supports biofilm formation. Previously, the ethanol extract from Paeonia lactiflora was reported to inhibit cell wall synthesis and cause depolarization and permeabilization of the cell membrane in C. albicans. In this study, the P. lactiflora extract was found to significantly reduce the initial stage of C. albicans biofilms from 12 clinical isolates by 38.4%. Thus, to assess the action mechanism, the effect of the P. lactiflora extract on the adhesion of C. albicans cells to polystyrene and germ tube formation was investigated using a microscopic analysis. The density of the adherent cells was diminished following incubation with the P. lactiflora extract in an acidic medium. Additionally, the P. lactiflora-treated C. albicans cells were mostly composed of less virulent pseudohyphae, and ruptured debris was found in the serum-containing medium. A quantitative real-time PCR analysis indicated that P. lactiflora downregulated the expression of C. albicans hypha-specific genes: ALS3 by 65% (p = 0.004), ECE1 by 34.9% (p = 0.001), HWP1 by 29.2% (p = 0.002), and SAP1 by 37.5% (p = 0.001), matching the microscopic analysis of the P. lactiflora action on biofilm formation. Therefore, the current findings demonstrate that the P. lactiflora ethanol extract is effective in inhibiting C. albicans biofilms in vitro, suggesting its therapeutic potential for the treatment of biofilm-associated infections.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.5
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• pp.403-409
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• 2008

Polymer electrolyte membrane fuel cell (PEMFC) is very interesting power source due to high power density, simple construction and operation at low temperature. But it has problems such as high cost, improvement of performance, effect of temperature and initial start at low temperature. These problems can be approached to be solved by using experiment and mathematical method which are general principles for analysis and optimization of control system for heat and hydrogen detecting management. In this paper, insulation vessel and control system for stable operation of fuel cell at low temperature were developed for experiment. The constant temperature capability and the heating time at sub-zero temperatures with insulation control system were studied by using a heating bar of 60W class. PEMFC stack which was made by 4 cells with $50\;mc^2$ active area in each cell is a thermal source. Times which take to reach constant temperature by the state of insulation vacuum were measured at variable environment temperatures. The test was performed at two conditions: heating mode and cooling mode. Constant temperature capability was better at lower environment temperature and vacuum pressure. The results of this experiment could be used as basis data about stable operation of fuel cell stack in low temperature zone.

• The KIPS Transactions:PartA
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• v.14A no.3 s.107
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• pp.133-140
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• 2007

The SWBF(shrink-wrapped boundary face) algorithm is a recent mesh reconstruction method for constructing a surface model from a set of unorganized 3D points. In this paper, we point out the surface duplication problem of SWBF and propose an improved mesh reconstruction scheme. Our method tries to classify the non-boundary cells as the inner cell or the outer cell, and makes an initial mesh without surface duplication by adopting the improved boundary face definition. To handle the directional unbalance of surface sampling density arise in typical 3D scanners, two dimensional connectivity in the cell image is introduced and utilized. According to experiments, our method is proved to be very useful to overcome the surface duplication problem of the SWBF algorithm.

• Journal of Powder Materials
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• v.23 no.2
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• pp.136-142
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• 2016

As precursors of cathode materials for lithium ion batteries, $Ni_{1/3}Co_{1/3}Mn_{1/3}(OH)_2$ powders are prepared in a continuously stirred tank reactor via a co-precipitation reaction between aqueous metal sulfates and NaOH in the presence of $NH_4OH$ in air or nitrogen ambient. Calcination of the precursors with $Li_2CO_3$ for 8 h at $1,000^{\circ}C$ in air produces dense spherical cathode materials. The precursors and final powders are characterized by X-ray diffraction (XRD), scanning electron microscopy, particle size analysis, tap density measurement, and thermal gravimetric analysis. The precursor powders obtained in air or nitrogen ambient show XRD patterns identified as $Ni_{1/3}Co_{1/3}Mn_{1/3}(OH)_2$. Regardless of the atmosphere, the final powders exhibit the XRD patterns of $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ (NCM). The precursor powders obtained in air have larger particle size and lower tap density than those obtained in nitrogen ambient. NCM powders show similar tendencies in terms of particle size and tap density. Electrochemical characterization is performed after fabricating a coin cell using NCM as the cathode and Li metal as the anode. The NCM powders from the precursors obtained in air and those from the precursors obtained in nitrogen have similar initial charge/discharge capacities and cycle life. In conclusion, the powders co-precipitated in air can be utilized as precursor materials, replacing those synthesized in the presence of nitrogen injection, which is the usual industrial practice.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.6 s.348
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• pp.23-29
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• 2006

In this paper, we propose an effective global placement technique using quadratic programming(QP). In order to resolve cell congestion problem which is a drawback of QP based placement techniques, additional force and grid pre-warping technique are used. We devised a new density function for evaluating proper additional force which depends on density. Grid pre-warping technique relocates cells over entire area according to the relative ordering between coordinates of cells. Using the additional force obtained by the new density function and applying the pre-warping technique iteratively we obtained a well-distributed global placement. Mongrel which is a middle-down methodology based placer takes such a good global placement as an initial placement and produces a final detailed placement. Experimental results show that proposed technique outperforms the FM algorithm based global placement and are comparable with the well-known leading placers, FengShui, Dragon.

• Journal of the Korean institute of surface engineering
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• v.47 no.5
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• pp.227-232
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• 2014

In this study, we propose the application of doping process technology for atmospheric pressure plasma. The plasma treatment means the wafer is warmed via resistance heating from current paths. These paths are induced by the surface charge density in the presence of illuminating Argon atmospheric plasmas. Furthermore, it is investigated on the high-concentration doping to a selective partial region in P type solar cell wafer. It is identified that diffusion of impurities is related to the wafer temperature. For the fixed plasma treatment time, plasma currents were set with 40, 70, 120 mA. For the processing time, IR(Infra-Red) images are analyzed via a camera dependent on the temperature of the P type wafer. Phosphorus concentrations are also analyzed through SIMS profiles from doped wafer. According to the analysis for doping process, as applied plasma currents increase, so the doping depth becomes deeper. As the junction depth is deeper, so the surface resistance is to be lowered. In addition, the surface charge density has a tendency inversely proportional to the initial phosphorus concentration. Overall, when the plasma current increases, then it becomes higher temperatures in wafer. It is shown that the diffusion of the impurity is critically dependent on the temperature of wafers.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.1
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• pp.8-15
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• 2010

An experiment was conducted to evaluate the biologically adverse effect of increased carbon dioxide in seawater on marine bacteria, Vibrio fischeri. We measured the bioluminescence and cell density at every 6 hours for 24 hours of the whole incubation period after exposing test microbes to a range of $CO_2$ concentration such as 380(Control), 1,000, 3,000, 10,000 and 30,000 ppm, respectively. Significant effect on relative luminescence(RLU) of V. fischeri was observed in treatments with $CO_2$ concentration higher than 3,000 ppm at t=12 h. However, the difference of RLU among treatments significantly decreased with the incubation time until t=24 h. Similar trend was observed for the variation of cell density, which was measured as optical density using spectrophotometer. The results showed that a significant relationship between $CO_2$ concentration and bioluminescence of test microbes was observed for the mean time. However, the inhibition of relative bioluminescence and also cell density could be recovered at the concentration levels higher than 3,000 ppm. The dissolved $CO_2$ can be absorbed directly by cell and it can decrease the intracellular pH. Our results implied that microbes might be adversely affected at the initial growing phase by increased $CO_2$. However, they could adapt by increasing ion transport including bicarbonate and then could make their pH back to normal level. Results of this study could be supported to understand the possible influence on marine bacteria by atmospheric increase of $CO_2$ in near future and also by released $CO_2$ during the marine $CO_2$ sequestration activity.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.6
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• pp.24-29
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• 2002

Nitrate removal rate in three cattail wetland cells was investigated. They were a part of a pond-wetland system for stream water treatment demonstration. The system was composed of two ponds and six wetland cells. The acreage of each cell was approximately $150m^2$. The earth works for the system were finished from April 2000 to May 2000 and cattails were planted in the three cells in June 2000. Waters of Sinyang Stream flowing into Kohung Estuarine Lake were pumped into a primary pond, whose effluent was discharged into a secondary pond. The reservoir was formed by a tidal marsh reclamation project and located in southern coastal area of Korean Peninsula. Effluents from the secondary pond were funneled into the three cells. Volumes and water quality of inflow and outflow were analyzed from July 2000 through January 2001. Inflow and outflow averaged $20.2m^3/day$ and $19.8m^3/day$, respectively. Hydraulic retention time was about 1.6 days. Average influent and effluent nitrate concentration was $1.98mg/{\ell}$, $1.38mg/{\ell}$, respectively. Nitrate removal rate averaged $82.6mg\;m^{-2}\;day^{-1}$. Seasonal changes of nitrate retention rates were closely related to those of wetland cell temperatures. The average nitrate removal rate in the cells was a little lower, compared with that of $125.0mg\;m^{-2}\;day^{-1}$ for the wetlands operating in North America. This could be attributed to the initial stage of the cells and inclusion of three cold months into the seven-month study period. Root rhizosphere in wetland soils and litter-soil layers on cell bottoms could not developed. Increase of standing density of cattails within a few years will establish both root zones suitable for the nitrification of ammonia to nitrates and substrates beneficial to the denitrification of nitrates into nitrogen gases, which may lead to increase of the nitrate retention rate.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3715-3721
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• 2013

In this study, the behavior of cells on the modified surface, and the correlation between the modified substrates and the response of cells is described. A close-packed layer of nano-sized silica beads was prepared on a coverslip, and the adhesion, proliferation, and migration of BALB/3T3 fibroblast cells on the silica layer was monitered. The 550 nm silica beads were synthesized by the hydrolysis and condensation reaction of tetraethylorthosilicate in basic solution. The amine groups were introduced onto the surfaces of silica particles by treatment with 3-aminopropyltrimethoxysilane. The close-packed layer of silica beads on the coverslip was obtained by the reaction of the amine-functionalized silica beads and the (3-triethoxysilyl)propylsuccinic anhydride treated coverslip. BALB/3T3 fibroblast cells were loaded on bare glass, APTMS coated glass, and silica bead coated glass with the same initial cell density, and the migration and proliferation of cells on the substrates was investigated. The cells were fixed and stained with antibodies in order to analyze the changes in the actin filaments and nuclei after culture on the different surfaces. The motility of cells on the silica bead coated glass was greater than that of the cells cultured on the control substrate. The growth rate of cells on the silica bead coated glass was slower than that of the control. Because the close-packed layer of silica beads gave an embossed surface, the adhesion of cells was very weak compared to the smooth surfaces. These results indicate that the adhesion of cells on the substrates is very important, and the actin filaments might play key roles in the migration and proliferation of cells. The nuclei of the cells were shrunk on the weakly adhered surfaces, and the S1 stage in which DNA is duplicated in the cell dividing processes might be retarded. As a result, the rate of proliferation of cells was decreased compared to the smooth surface of the control. In conclusion, the results described here are very important in the understanding of the interaction between implanted materials and biosystems.