• The Korean Journal of Nuclear Medicine
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• v.33 no.3
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• pp.316-326
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• 1999

Purpose: We evaluated the feasibility of extracting pure left ventricular blood pool and myocardial time-activity curves (TACs) and of generating factor images from human dynamic N-13 ammonia PET using factor analysis. The myocardial blood flow (MBF) estimates obtained with factor analysis were compared with those obtained with the user drawn region-of-interest (ROI) method. Materials and Methods: Stress and rest N-13 ammonia cardiac PET imaging was acquired for 23 min in 5 patients with coronary artery disease using GE Advance tomograph. Factor analysis generated physiological TACs and factor images using the normalized TACs from each dixel. Four steps were involved in this algorithm: (a) data preprocessing; (b) principal component analysis; (c) oblique rotation with positivity constraints; (d) factor image computation. Area under curves and MBF estimated using the two compartment N-13 ammonia model were used to validate the accuracy of the factor analysis generated physiological TACs. The MBF estimated by factor analysis was compared to the values estimated by using the ROI method. Results: MBF values obtained by factor analysis were linearly correlated with MBF obtained by the ROI method (slope = 0.84, r = 0.91), Left ventricular blood pool TACs obtained by the two methods agreed well (Area under curve ratio: 1.02 ($0{\sim}1min$), 0.98 ($0{\sim}2min$), 0.86 ($1{\sim}2min$)). Conclusion: The results of this study demonstrates that MBF can be measured accurately and noninvasively with dynamic N-13 ammonia PET imaging and factor analysis. This method is simple and accurate, and can measure MBF without blood sampling, ROI definition or spillover correction.

• Analytical Science and Technology
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• v.33 no.1
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• pp.33-41
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• 2020

Wet precipitation samples were collected in Jeju City and Mt. Halla-1100 site (a site at an altitude of 1100 m on Mt. Halla) during 2011-2013, and their major ionic species were analyzed to examine the chemical composition and characteristics. A comparison of ion balance, electric conductivity, and acid fraction of precipitation revealed correlation coefficients in the range of r = 0.950~0.991, thereby implying the high quality of analytical data. Volume-weighted mean pH and electric conductivity corresponded to 4.86 and 25.5 µS/cm for Jeju City, and 4.98 and 15.1 µS/cm for Mt. Halla-1100 site, respectively. Ionic strengths of the wet precipitation in Jeju City and Mt. Halla-1100 site corresponded 0.3 ± 0.5 and 0.2 ± 0.2 mM, respectively, thereby indicating that more than 30 % of total precipitation was within a pure precipitation criteria. The precipitation with a pH range of 4.5 - 5.0 corresponded to 40.8 % in Jeju City, while the precipitation with a pH range of 5.0 - 5.5 corresponded to 56.9 % in Mt. Halla-1100 site, thereby indicating slightly more weak acidity than that in Jeju city. The volume-weighted mean concentration (µeq/L) of ionic species was in the order of Na⁺ > Cl^- > nss-SO₄^2- > NO₃^- > Mg²⁺ > NH₄⁺ > H⁺ > nss-Ca²⁺ > PO₄^3- > K⁺ > CH₃COO^- > HCOO^- > NO₂^- > F^- > HCO₃^- > CH₃SO₃^- at Jeju City area, while it corresponded to Na⁺ > Cl^- > nss-SO₄^2- > NO₃^- > NH₄⁺ > H⁺ > Mg²⁺ > nss-Ca²⁺ > PO₄^3- > CH₃COO^- > K⁺ > HCOO^- > NO₂^- > F^- > HCO₃^- > CH₃SO₃^- at Mt. Halla-1100 site. The compositions of sea salts (Na⁺, Cl^-, Mg²⁺) and secondary pollutants (NH₄⁺, nss-SO₄^2-, NO₃^-) corresponded to 66.1 % and 21.8 %, respectively, in Jeju City and, 49.9 % and 31.5 %, respectively, in Mt. Halla-1100 site. The acidity contributions in Jeju City and Mt. Halla-1100 site by inorganic acids, i.e., sulfuric acid and nitric acid, corresponded to 93.9 % and 91.4 %, respectively, and the acidity contributions by organic acids corresponded to 6.1 % and 8.6 %, respectively. The neutralization factors in Jeju City and Mt. Halla1100 site by ammonia corresponded to 29.8 % and 30.1 %, respectively, whereas the neutralization factors by calcium carbonate corresponded to 20.5 % and 25.2 %, respectively. From the clustered back trajectory analysis, the concentrations of most ionic components were higher when the airflow pathways were moved from the continent to Jeju area.

• Archives of design research
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• v.18 no.2 s.60
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• pp.243-254
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• 2005

Great Britain and the United States and Finland are having an interest in long policy subject about child design education through early design education. And they approaches and practices it systematically. The research about the design learning program instance of advanced nation of primary school's design education for various objective is necessary for use with the fundamental reference data for an elementary design education. And so, This research presented the program instance investigation and analysis result of British primary school's design education. U.K is teaching an primary design education from two subjects of Art & Design and Design and Technology which is a legal subject with national curriculum. The analysis result of design relation unit learning program of two subjects is: Design relation unit learning programs of 'Design and Technology' subject's 20 unit which except 4 food relation unit is largely scientific engineering contents that include utility function contents in part. The reason is as behavior styles based on Design process solve problems scientifically & rationally. Design relation 6 units in subject of Art & Design which except the units which relates with the pure fine arts and architecture in 19 units is aesthetic-symbolic and utility-functional contents largely. And so, the result was analyzed about relation of scientific-engineering content of 'Arts & Design' subject is insufficient comparing with 'Design and Technology' subject Specially, I think that the design relation's unit learning program instances of 'Design and Technology' subject of the British primary school which have been presented by this research paper is a possibility becoming one reference model for a program development. And so I expects that this research could be applied in the program development for the primary design education of primary teacher & education agency.

• Clinical and Experimental Pediatrics
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• v.45 no.2
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• pp.247-255
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• 2002

Purpose : This study was undertaken to obtain basic data about the megakaryocyte colony formation of fetal liver cells by using immunocytochemical staining and ex vivo culture with growth factors. Methods : The mononuclear cells were isolated from fetal liver and bone marrow with idiopathic thrombocytopenic purpura(ITP) and pancytopenia. These mononuclear cells were cultured in $MegaCult^{TM}-C$(Stem Cell Tech, Canada) media in the presence of growth factors and CFU-Megakaryocyte( CFU-Mk) colonies were counted on day 12. The expansion of CD34+ and CD41+ cell was analyzed by flow cytometry after 5 days incubation using flask culture. Results : The numbers of CFU-Mk colonies of mononuclear cells obtained from fetal liver in the 11th week gestational age were more than those in the 19th week specimens; growth factors could not enhance the colony expansion in all cases. Total numbers of CFU-Mk colony of fetal liver cells were higher than bone marrow from ITP or pancytopenia groups. The numbers of pure or large CFU-Mk colonies of fetal liver cells were also higher than bone marrow specimens. The rate of CD34+ cell expression of fetal liver was increased after flask culture and the enhancement effect of epression was seen only in cases which added thrombopoietin. The rate of CD41+ cell expression of fetal liver was increased after incubation, but the enhancement effect of growth factors was unclear. Conclusion : This study revealed good results about the megakaryocyte colony assay of fetal liver mononuclear cells using $MegaCult^{TM}-C$ media. This study suggests that the fetal liver could be a good source of megakaryocytic progenitor cells for clinical application in hematopoietic stem cell transplantation.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.33 no.1
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• pp.21-30
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• 2015

Bulguksa Temple, a typical temple of Silla was lost during Japanese Invasion of Korea and there are records of reconstructing in its record, Bulguksa Sajeok. There is no record after that. And reconstructing was stopped due to lack of money and repair works were conducted for two times in Japanese colonial era. First repair work was from 1989 to 1919 and second repair work was conducted from 1922 to 1925. After Liberation, Bulguksa Temple Restoration Committee was established in 1969 and the construction has started since 1970 after excavation investigation to complete in 1973. The shape of south arcade without walls in the main temple of Bulguksa was found in a blue print of Bulguksa in Japanese colonial era in National Archives of Korea now and a picture of Bulguksa in 1902 taken by Sekino Tadashi. It verified the correlation between Gupumyeonji which was discovered in restoration work in 1970s and a legend of Muyoungtap. And a stair from the hall of Paradise to the main temple was introduced as a stair including Pure Land Buddhism doctrine in many literature materials, but a blue print of Bulguksa in Japanese colonial era and reports of excavation investigation in 1970s verified that it was a temporary stair built by Japan and its meaning was given later. This research checked the scenery of Bulguksa Temple before Japanese colonial era and it is intended for basic data to conduct restoration or reconstruction project in the future.

• Journal of the Korean Chemical Society
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• v.38 no.10
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• pp.710-718
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• 1994

We suggest a statistical thermodynamic theory for the conformational transition of a synthetic alanine (Ala), ${\alpha}$-aminoisobutyric acid (Aib) alternative oligopeptide, Buo-(Ala-Aib)$_n$-oMe, where the terminal groups Buo and oMe stand for t-butoxy and methoxy, respectively. Pure Aib homo-oligomers have always been found to adopt $3_{10}$ helical conformations, while polyalanine has always $\alpha$ helical conformation. In an organic solvent (e.g. $CD_3$CN) it shows that the length for the $3_{10}$/${\alpha}$ helix transitions of Buo-(Ala-Aib)$_n$-oMe, is 8 at room temperature. In an aqueous solution oligopeptide has always coil conformation at room temperature. In an organic solution, helical structures of the oligopeptide are more stable than coil structure, so we studied the $$3_{10}/\alpha$ helix transitions, considering coiled-conformations, coiled and $3_{10}$ helical conformations, and coiled and $\alpha$ helical conformations by using the zipper model. We determined the values of parameters ($\sigma_A$, $\sigma_T$, $\xi_A$, $\xi_T$) from the relating published data; $\sigma_A$ = 0.00011, $\sigma_T$ = 0.0060, $\xi_A$ = 10.1, $\xi_T$ = 3.90. The distributions of $\alpha$ helical length can be N-2, N-3, N-4, ${\cdots}$, 3, 2, 1 (N = 2n) while those of $3_{10}$ helical length, N-1, N-2, N-3, N-4, ${\cdots}$, 3, 2, 1.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.1
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• pp.46-52
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• 2009

Statement of problem: Recently, titanium has become popular as superstructure material in implant dentistry because titanium superstructure can be easily milled by means of computer-aided design and manufacture (CAD/CAM) technique. But retention form such as nail head or bead cannot be cut as a result of technical limitation of CAD/CAM milling and bond strength between titanium and porcelain is not as strong as that of conventional gold or metal alloy. Purpose: The objective of this study was to evaluate the shear bond strength of three different materials: heat curing resin, composite resin, porcelain which were bonded to grade II commercially pure Titanium (CP-Ti). Material and methods: Thirty seven CP-Ti discs with 9 mm diameter, 10 mm height were divided into three groups and were bonded with heat curing resin (Lucitone 199), indirect composite resin (Sinfony), and porcelain (Triceram) which were mounted in a former with 7 mm diameter and 1 mm height. Samples were thermocycled for 1000 cycles at between $5-55^{\circ}C$. Shear bond strength (MPa) was measured with Instron Universal Testing Machine with cross head speed of 1 mm/min. The failure pattern was observed at the fractured surface and divided into adhesive, cohesive, and combination failure. The data were analyzed by one-way ANOVA and Scheffe's multiple range test (${\alpha}=0.05$). Results: Lucitone 199 ($17.82{\pm}5.13\;MPa$) showed the highest shear bond strength, followed by Triceram ($12.97{\pm}2.11\;MPa$), and Sinfony ($6.00{\pm}1.31\;MPa$). Most of the failure patterns in Lucitone 199 and Sinfony group were adhesive failure, whereas those in Triceram group were combination failure. Conclusion: Heat curing resin formed the strongest bond to titanium which is used as a CAD/CAM milling block. But the bond strength is still low compared with the bond utilizing mechanical interlocking and there are many adhesive failures which suggest that more studies to enhance bond strength are needed.

• Journal of the Korean Society of Radiology
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• v.7 no.6
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• pp.403-408
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• 2013

This study made a tentative estimation of the shielding rate of barium compound by thickness through monte carlo simulation to apply medical radiation shielding products that can replace existing lead. Barium sulfate($BaSO_4$) was used for the shielding material, and thickness of the shielding material specimen was simulated from 0.1 mm to 5 mm by applying $15{\times}15cm^2$ of specimen area, $4.5g/cm^3$ of density of barium sulfate, and $11.34g/cm^3$ density of lead. Entered source was simulated with 10kVp Step in consecutive X-ray energy spectrum(40 kVp ~ 120 kVp). Absorption probability in 40 kVp ~ 60 kVp showed same shielding rate with lead in 3 mm ~ 5 mm of thickness, but it was identified that under 2 mm, the shielding rate was a bit lower than the existing lead shielding material. Also, the shielding rate in 70 kVp ~ 120 kVp energy band showed similar performance as the existing lead shielding material, but it was tentatively estimated as fairly low shielding rate below 0.5 mm. This study estimated the shielding rate of barium compound as the thickness function of x-ray energy band for medical radiation through monte carlo simulation, and made comparative analysis with existing lead. Also, this study intended to verify application validity of the x-ray shielding material for medical radiation of pure barium sulfate. As a result, it was estimated that the shielding effect was 95% higher than the existing lead 1.5 mm in at least 2 mm thickness of barium compound in medical radiation energy band 70 kVp ~ 120 kVp, and this result is considered valid to be provided as a base data in weight lightening production of radiation shielding product for medical radiation.

• Nuclear Engineering and Technology
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• v.28 no.2
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• pp.118-128
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• 1996

The lattice parameters of stoichiometric $UO_2$ and $U_{1-y}Er_{y}O_2$ in the range of y=0.01 to y =0.33 were determined with use of X-ray diffraction data. Oxygen potentials have been measured by means of a thermogravimetric method in the range of 1200~$1500^{\circ}C$ and $10^{-14}$ $\leq$ $Po_2$ $\leq$ $10^{-3}$ for pure $UO_2$ and $U_{1-y}Er_{y}O_{2{\pm}x}$ solid solutions with y=0.02, y=0.06 and y=0.20, respectively. Their oxygen partial pressures were maintained by controlling $CO_2$/CO mixture atmosphere, and the $Po_2$ values corresponding to x of $U_{1-y}Er_{y}O_{2{\pm}x}$ solid solutions were measured with an electrolyte oxygen sensor. The lattice parameter decreases linearly with an increase in the erbium content. The change of the lattice parameter can be expressed in a linear equation of y as a($\AA$) =5.4695-0.220y for 0 $\leq$y$\leq$0.33. The experimental coefficient of y -0.220 in $U_{1-y}Er_{y}O_2$ was an intermediate value between the calculated values -0.273 and -0.156 in the case of $U^{5+}$ and $U^{6+}$, respectively. The (equation omitted) has been found to undergo abrupt increase in the range of -360 to -270 kJ/mole for y=0.06 and -320 to -220 H/mole for y=0.20, respectively, in the temperature range of 1200-$1500^{\circ}C$. (equation omitted) increases with erbium content, but the effect of the dopant for x =0.01 is less significant than that for stoichiometry. The oxygen potentials for $UO_2$ and $U_{0.98}Er_{0.02}O_{2+x}$ can be approximately represented by the $U^{5+}$/$U^{4+}$ model but those for y$\geq$ 0.06 in $U_{1-y}Er_{y}O_{2{\pm}x}$ solid solutions cannot be interpreted by the mean uranium valence model.

• Journal of the Korean Society of Radiology
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• v.12 no.1
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• pp.1-7
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• 2018

$^{68}Ga$ was eluted from a $^{68}Ge/^{68}Ga$ radionuclide generator. $^{68}Ga$ decays into $^{68}Zn$, with a half life=67.8min. The decay is 88.9 % by ${\beta}$+ and 11.1 % by EC. The main ${\beta}$+ decay (87.7 %) is to the ground level of $^{68}Zn$ and it is a pure positron emission branch. A small fraction decays ${\beta}$+ (1.2 %) into an excited level of $^{68}Zn$, which promptly decays into the ground level with a ${\gamma}$ (1.077 Mev). This can constitute prompt gamma contamination in the PET data, if the 1.077 Mev ${\gamma}$ has a scatter interaction in the patient, and generates a lower energy ${\gamma}$ in coincidence with the positron annihilation pair. The purpose of this study was to evaluate standardized uptake value(SUV) before and after applying prompt gamma rays correction on $^{68}Ga$-DOTATOC PET/CT image. Fifty patient underwent PET/CT 1 hour after injection of the $^{68}Ga$-DOTATOC. The SUVmax and SUVmean of lesions and normal tissues (Pituitary, Lung, Liver, Spleen, Kidney, Intestine) were evaluated before and after applying prompt gamma correction on $^{68}Ga$-DOTATOC PET/CT image. Additionally, the SUVmax of each lesions and SUVmean of the soft tissues were measured on images. and target to background ratios (TBR) were calculated as quantitative indices. Among 15 patients, 25 of lesions (Pancreas, Liver, Thoracic Spine, Brain) with increased uptake on $^{68}Ga$-DOTATOC PET/CT image. SUVmax and SUVmean were increased in lesion site and normal tissue after prompt gamma rays correction. TBR was $51.51{\pm}49.28$ and $55.50{\pm}53.12$ before and after prompt gamma rays correction, respectively. (p<0.0001)