• Analytical Science and Technology
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• v.23 no.6
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• pp.531-536
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• 2010

A quantitative analytical method has been established for the measurement of inosine 5'-monophosphate dehydrogenase (IMPDH) activity in human peripheral blood mononuclear cells (PBMCs) by ion-pair reversed-phase high performance liquid chromatography equipped with ultraviolet detection (HPLC/UV). IMPDH is a ${\beta}$-nicotinamide adenine dinucleotide hydrate (NAD+)-dependent dehydrogenase in which the enzyme converts inosine 5'-monophosphate (IMP) into xanthosine 5'-monophosphate (XMP). Its activity was measured by quantifying a HPLC chromatogram corresponding to XMP produced during the incubation of lysed PBMCs with IMP as a substrate and $NAD^+$ as a coenzyme. XMP produced was detected at a wavelength of 260 nm. The mobile phase was composed of a mixture of 37 mM potassium dihydrogen phosphate containing 7 mM tetra-n-butylammonium hydrogen sulfate adjusted to pH 5.5 and methanol (85:15, v/v) with a flow rate of 1 mL/min. The calibration curve was linear ($r^2$=0.999999) in the range of $0.2-50.0\;{\mu}M$ and the limit of quantification (LOQ) was $0.2\;{\mu}M$. The intra- and inter-day precisions were between 0.88-1.47% and 0.85-5.24%, respectively. The intra- and inter-day accuracies were between 98.74-99.99% and 99.95-101.65%, respectively. IMPDH activity in 11 Korean healthy volunteers ranged from 18.29 to 36.60 nmol/h/mg protein (mean = $27.70{\pm}6.28\;nmol/h/mg$ protein).

• Nuclear Engineering and Technology
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• v.5 no.1
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• pp.38-43
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• 1973

The spin-rotation constants of the proton and tile fluorine nucleus in C $H_4$, Si $H_4$, Ge $H_4$, C $F_4$, Si $F_4$ and Ge $F_4$ were determined experimentally by the molecular beam magnetic resonance method. From the Hamiltonian and the high field approximation, the quantized energy level is given by the following equation. W $m_{I}$ $m_{J}$=- $g_{I}$ $m_{I}$H- $g_{J}$ $m_{J}$H- $C_{av}$ $m_{I}$ $m_{J}$, where $c_{av}$ is one third of the trace of the C tensor. In the nuclear resonance experiment, the proton and the fluorine nuclear resonance curves consist of many unresolved lines given by v=- $g_{J}$H- $C_{av}$ $m_{I}$, and a Gaussian approximation is made to correlate $c_{av}$ to the experimentally obtained half-width of the resonance curve. In the rotational resonance experiment, the five resonance peaks as predicted by v=- $g_{I}$H- $c_{av}$ $m_{I}$, $m_{I}$=0, $\pm$1 and $\pm$2, were all observed. The magnitude of car was determined by measuring the frequency distance between two adjacent peaks. The sign of $c_{av}$ was determined by the side peak suppression technique. The technique is described, and the sign and magnitude of the spin-rotation constant cav are summarized as following: for C $H_4$ -10.3$\pm$0.4tHz(from the rotational resonance), for SiH +3.71$\pm$0.08kHz(from the nuclear resonance), for Ge $H_4$+3.79$\pm$0.13kHz(from the nuclear resonance), for C $F_4$, -6.81$\pm$0.08kHz(from the rotational resonance), for Si $F_4$, -2.46$\pm$0.06kHz(from the rotational resonance), and finally for Ge $F_4$-1.84$\pm$0.04kHz(from the rotational resonance).onal resonance).esonance).

• The Journal of Korean Obstetrics and Gynecology
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• v.15 no.4
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• pp.45-60
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• 2002

Mouse calvarial osteoblast cells were isolated and cultured. To examine whether the cells produce active gelatinases in culture medium or not,the cells were analyzed using by zymograsphic analysis on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). We show that mouse calvarial osteoblasts in culture constitutively synthesize progelatinase- A. Then, mouse osteoblasts, which were stimulated by PTH, $1,25(OH)_2D_3$, mononuclear cell conditioned medium (MCM) and IL-1 as bone resorption agent's, showed increased collagenolysis by producing the active gelatinase. However, treatment of indomethacin and dexamethasone significantly decreased those effects of collagenolysis in mouse osteoblastic cells. On the other hand, IL-1 in stimulating bone resorption was examined using fetal mouse long bone organ culture. IL-1 stimulated bone resorption and produced marked resorption when present simultaneously. Furthermore, when it was examined the effects of indomethacin and dexamethasone on the dose dependent responses of $IL-1{\alpha}$, indomethacin and dexametasone produced a rightward shift in the IL-1 dose response curve. The results of in vitro cytotoxicities showed that Taeyoungjon-Jahage water extracts(T.Y.J-J.H.G extracts) have no any cytotoxicities in concentrations of $1-200\;{\mu}g/ml$ and furthermore there is no any cytotoxicity even in concentration of $300\;{\mu}g/ml$ on mouse calvarial bone cells. T.Y.J.-J.H.G. extracts had protective activity against PTH (2 units/mI), or MCM (5%, v/v), or $rhIL-1{\alpha}$ (1 ng/mI) or $1,25(OH)_2D3$ (10 ng/ml) , $IL-1{\alpha}$ and $IL-1{\beta}-induced$ collagenolysis in the mouse calvarial cells. Pretreatment of the T.Y.J.-J.H.G.extracts for 1 h, which by itself had little effect on cell survival, did not enhance the collagenolysis, nor significantly reduced the collagenolysis by pretreatment. Furthermore. the medicinal extracts were shown to have the protective effects against collagenolysis induced by $IL-1{\alpha}$ and $IL-1{\beta}$. Pretreatment of the extracts for 1 h significantly reduced the collagenolysis. Interestingly, the T.Y.J.-J.H.G. extracts were shown to have the inhibiting effects against gelatinase enzyme and processing activity induced by the bone resortion agents of PTH, $1,25(OH)_2D_3$, $IL-1{\beta}$ and $IL-1{\alpha}$, with strong protective effect in pretreatment with the extracts. T.Y.J.-J.H.G. extracts were shown to have the inhibiting effects against $IL-1{\alpha}-$ and $IL-1{\beta}-stimulated$ bone resorption and the effect of the pretreatment with a various concentrations of the medicinal extracts were significant. The inhibition extent and phenomena of IL-1 stimulated bone resorption by nonsteroidal anti-inflammatory agents of indomethacin and dexamethasone were similar to those obtained by T.Y.J.-J.H.G. extracts treatment in the mouse calvarial tissue culture system. These results indicated that the T.Y.J.-J.H.G.-water extracts are highly stable and applicable to clinical uses in osteoporosis.

• Korean Journal of Veterinary Research
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• v.41 no.2
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• pp.203-210
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• 2001

Here, we compared the effectiveness of 50 MeV($p{\to}RBe^+$) cyclotron fast neutrons versus $^{60}Co$ ${\gamma}$-rays by the apoptotic fragment frequency in both rat peripheral lymphocytes and crypt cells to check a radiobiological endpoint. The incidence of apoptotic cell death was increased in all irradiated groups, and radiation at all doses trigger rapid changes in both crypt cells and peripheral lymphocytes. These data suggest that apoptosis may play an important role in homeostasis of damaged radiosensitive target organ by removing damaged cells. The curve of dose-effect relationship for these data of apoptotic fragments frequencies was $y=0.3+(6.512{\pm}0.279)D(r^2=0.975)$ after neutrons, while $y=0.3+(4.435{\pm}0.473)D+(-1.300{\pm}0.551)D^2(r^2=0.988)$ after ${\gamma}$-rays. In addition, $y=3.5+(118.410{\pm}10.325)D+(-33.548{\pm}12.023)D^2(r^2=0.992)$ after ${\gamma}$-rays in rat lymphocytes. A significant dose-response relationship was found between the frequency of apoptotic cell and dose. These data show a trend towards increase of the numbers of apoptotic cells with increasing dose. Dose-response curves for high and low linear energy transfer (LET) radiation modalities in these studies were different. The relative biological effectiveness (RBE) value for crypt cells was 1.919. In addition, there were significant peaks on apoptosis induction at 4 and 6h after irradiation, and the morphological findings of the irradiated groups were typical apoptotic fragments in crypt cells that were hardly observed in the control group. Thus, apoptosis induction in both crypt cells and peripheral lymphocytes could be a useful endpoint of rat model for studying screening test and microdosimetic indicator to evaluate the biological effects of radiation-induced cell damage.

• Journal of Korean Society of Forest Science
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• v.34 no.1
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• pp.21-30
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• 1977

Japanese larch (Larix leptolepis) is one of main timber species in Korea that could find much plantation and growing stands on all over the country. It is thought to be in meaningful that a guiding diagram for density control of Japanese larch stands is made to estimate easily the density conditions in the quantitaive, ecological and economic viewpoint. Sample plots for this study are selected from the stands that have not been thinned in recent years, and mean height, mean diameter, dominant height, tree numbers per hectare and stem volume of mean tree are calculated from the each sample plots among total 165 plots In this study, especially, the theory of slenderness of mean tree are applied, that have been identified through the results of the spacing trial. Relative growth characteristics of this species are calculated from the general logistic curve and its formula is $Y=ax^b$. Relatwion between the measured items are found out as follows: 1. Relation between the mean height and tree numbers per hectare by slender class is showing the high correlation as table 1 and fig. 2, and between mean diameter and tree numbers per hectare is also high correlation as table 1 and fig 3. 2. The stem volume can be correctly estimated from height in case that slender class may be known, as showing in table 3 and fig. 4. 3. The stem volume can be more correctly estimated from the relation with $D^2H$ as formula, $Log_e\;V=0.9569\;Log_eD^2H-9.8431$, and relation between stem volume of single tree or volume per hectare and tree numbers per hectare are as following formulas: $Log_e$ stem volume=9.5026-1.6800 $Log_e$ tree numbers per hectare $Log_e$ stem volume per hectare=9.4911-0.6784 $Log_e$ tree numbers per hectare. Stem volume of mean tree, tree numbers per hectare and stem volume per hectare correspond to the mean tree height are calculated to slender class as table 5, 6, 7. Through the above steps, the diagram for density control of Japanese larch are produced as fig. 9. It is thought that this diagram could be applied to control the density of Japanese larch stands.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.3
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• pp.584-609
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• 1995

The purpose of this study was to evaluate the difference of the galvanic corrosion behaviour of the titanium in contact with gold alloy, silva-palladium alloy, and nickel-chromium alloy using the immersion and electrochemical method. And the effects of galvallit couples between titanium and the dental alloys were assessed for their usefulness as materials for superstructure. The immersion method was performed by measuring the amount of metal elementsreleased by Inductivey coupled plasma emission spectroscopy(ICPES) The specimen of fifteen titanium plates, the five gold alloy, five silver-palladium, five nickel-chromium plates, and twenty acrylic resin plates ware fabricated, and also the specimen of sixty titanium plugs, the thirty gold alloy, thirty silver-palladium, and nickelc-hromium plugs were made. Thereafter, each plug of gold alloy, silver-palladium, and nickel-chromium inserted into the the titanium and acrylic resin plate, and also titanium plug inserted into the acrylic resin plate. The combination specimens uf galvanic couples immersed in 70m1 artificial saliva solution, and also specimens of four type alloy(that is, titanium, gold, silver-palladium and nickel-chromium alloy) plugs were immersed solely in 70m1 artificial sativa solution. The amount of metal elements released was observed during 21 weeks in the interval of each seven week. The electrochemical method was performed using computer-controlled potentiosta(Autostat 251. Sycopel Sicentific Ltd., U.K). The wax patterns(diameter 11.0mm, thickness,in 1.5mm) of four dental casting alloys were casted by centrifugal method and embedded in self-curing acrylic resin to be about $1.0cm^2$ of exposed surface area. Embedded specimens were polished with silicone carbide paper to #2,000, and ultrasonically cleaned. The working electrode is the specimen of four dental casting alloys, the reference electrode is a saturated calmel electrode(SCE) and the ounter electrode is made of platinum plate. In the artificial saliva solution, the potential scanning was carried out starting from-700mV(SCE) TO +1,000mV(SCE) and the scan rate was 75mV/min. Each polarization curve of alloy was recorded automatically on a logrithmic graphic paper by XY recorder. From the polarization curves of each galvanic couple, corrosion potential and corrosion rates, that is, corrosion density were compared and order of corrosion tendency was determined. From the experiments, the following results were obtained : 1. In the case of immersing titanium, gold alloy, silver-palladium alloy, and nickel-chromium alloysolely in the artificial saliva solution(group 1, 2, 3, and 4), the total amount of metal elements released was that group 4 was greater about 2, 3 times than group 3, and about 7.8 times than group 2. In the case of group 1, the amount of titanium released was not found after 8 week(p<0.001). 2. In the case of galvanic couples of titanium in contact with alloy(group 5, 6), the total amount of metal elements released of group 5 and 6 was less than that of group 7, 8, 9, and 10(p<0.05). 3. In the case of galvanic couples of titanium in contact with silver-palladium alloy(group 7, 8), the total amount of metal elements released of group 7 was greater about twice than that of group 5, and that of group 8 was about 14 times than that of group 6(p<0.05). 4. In the case of galvanic couples of titanium in contact with nickel-chromium alloy(group 9, 10), the total amount of metal elements released of group 9 and 10 was greater about 1.8-3.2 times than that of group 7 and 8, and was greater about 4.3~25 times than that of group 5 and 6(p<0.05). 5. In the effect of galvanic corrosion according to the difference of the area ratio of cathode and anode, the total amount of metal elements released was that group 5 was greater about 4 times than group 6, group 8 was greater about twice than group 7, and group 10 was greater about 1.5 times than group 9(p<0.05). 6. In the effect of galvanic corrosion according to the elasped time during 21 week in the interval of each 7 week, the amount of metal elements released was decreased markedly in the case of galvanic couples of the titanium in contact with gold alloy and silver-palladium alloy but the total amount of nickel and beryllium released was not decreased markedly in the case of galvanic couples of the titanium in contact with nickel-chromium alloy(p<0.05). 7. In the case of galvanic couples of titanium in contact with gold alloy, galvanic current was lower than any other galvanic couple. 8. In the case of galvanic couples of titanium in contact with nickel-chromium alloy, galvanic current was highest among other galvanic couples.

• Journal of the Korean Electrochemical Society
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• v.4 no.2
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• pp.58-64
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• 2001

YSZ ($8mol\%$ yttria-stabilized zirconia)-modified LSM $(La_{0.85}Sr_{0.15}MnO_3)$ composite cathodes were fabricated by formation of YSZ film on triple phase boundary (TPB) of LSM/YSZ/gas. The YSZ coating film greatly enlarged electrochemical reaction sites from the increase of additional TPB. The composite cathode was formed on thin YSZ electrolyte (about 30 Um thickness) supported on an anode and then I-V characterization and AC impedance analyses were performed at temperature between $700^{\circ}C\;and\;800^{\circ}C$. As results of the impedance analysis on the cell at $800^{\circ}C$ with humidified hydrogen as the fuel and air as the oxidant, R1 around the frequency of 1000 Hz represents the anode Polarization. R2 around the frequency of 100Hz indicates the cathode polarization, and R3 below the frequency of 10 Hz is the resistance of gas phase diffusion through the anode. The cell with the composite cathode produced power density of $0.55\;W/cm^2\;and\;1W/cm^2$ at air and oxygen atmosphere, respectively. The I-V curve could be divided into two parts showing distinctive behavior. At low current density region (part I) the performance decreased steeply and at high current density region (part II) the performance decreased gradually. At the part I the performance decrease was especially resulted from the large cathode polarization, while at the part H the performance decrease related to the electrolyte polarization.

• Progress in Medical Physics
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• v.25 no.1
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• pp.37-45
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• 2014

The accuracy and uniformity of CT numbers are the main causes of radiation dose calculation error. Especially, for the dose calculation based on kV-Cone Beam Computed Tomography (CBCT) image, the scatter affecting the CT number is known to be quite different by the object sizes, densities, exposure conditions, and so on. In this study, the scatter impact on the CBCT based dose calculation was evaluated to provide the optimal condition minimizing the error. The CBCT images was acquired under three scatter conditions ("Under-scatter", "Over-scatter", and "Full-scatter") by adjusting amount of scatter materials around a electron density phantom (CIRS062, Tissue Simulation Technology, Norfolk, VA, USA). The CT number uniformities of CBCT images for water-equivalent materials of the phantom were assessed, and the location dependency, either "inner" or "outer" parts of the phantom, was also evaluated. The electron density correction curves were derived from CBCT images of the electron density phantom in each scatter condition. The electron density correction curves were applied to calculate the CBCT based doses, which were compared with the dose based on Fan Beam Computed Tomography (FBCT). Also, 5 prostate IMRT cases were enrolled to assess the accuracy of dose based on CBCT images using gamma index analysis and relative dose differences. As the CT number histogram of phantom CBCT images for water equivalent materials was fitted with a gaussian function, the FHWM (146 HU) for "Full-scatter" condition was the smallest among the FHWM for the three conditions (685 HU for "under scatter" and 264 HU for "over scatter"). Also, the variance of CT numbers was the smallest for the same ingredients located in the center and periphery of the phantom in the "Full-scatter" condition. The dose distributions calculated with FBCT and CBCT images compared in a gamma index evaluation of 1%/3 mm criteria and in the dose difference. With the electron density correction acquired in the same scatter condition, the CBCT based dose calculations tended to be the most accurate. In 5 prostate cases in which the mean equivalent diameter was 27.2 cm, the averaged gamma pass rate was 98% and the dose difference confirmed to be less than 2% (average 0.2%, ranged from -1.3% to 1.6%) with the electron density correction of the "Full-scatter" condition. The accuracy of CBCT based dose calculation could be confirmed that closely related to the CT number uniformity and to the similarity of the scatter conditions for the electron density correction curve and CBCT image. In pelvic cases, the most accurate dose calculation was achievable in the application of the electron density curves of the "Full-scatter" condition.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.3
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• pp.133-142
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• 2009

In order to understand the present environmental condition and future impingement of Changjiang(Yangtze River) outflow upon the adjacent seas after the scheduled completion of the Sanxia (Three Gorges) Dam in 2009, we tried to estimate the mixing ratios among surface waters of three end-members: Changjiang Water (CW), Kuroshio Water (KW), and East China Sea Water (ECSW) using $^{228}Ra/^{226}Ra$ activity ratio and salinity as tracers. Water samples were collected from 32 stations in November 2005 (R/V Tamgu 3), from 20 stations in July 2006 (R/V Ocean 2000) and from 17 stations in August 2006 (R/V Ieodo) in the northern part of the East China Sea. Radium isotopes in ~300 liters of surface seawater were extracted onboard by filtering through manganese impregnated acrylic fibers and following coprecipitation as $Ba(Ra)SO_4$. Activities of radium isotopes were determined by a high purity germanium detector. Results show that the fraction of CW was in the range of 1-23% in the study area, while KW was in the range of 0-30 % and ECSW 58-100 %. The eastward plume of Changjiang outflow, commonly observed in satellite images during summer and also displayed by the eastward-decreasing CW fraction in this study, could be attributed to Ekman transport caused by the SE monsoon prevailing in this region during summer. Results of this study showed that in the drought season, there was a little or no fraction of CW in the study area. Concentration of dissolved inorganic nitrogen (DIN) showed strong positive relationship with the fraction of CW, suggesting Changjiang as the major source of nitrogen. The mixing curve of DIN indicates the removal of nitrate by biological uptake during the mixing of CW with ambient seawater in the study area.

• Journal of the Korean Society of Radiology
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• v.8 no.4
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• pp.181-187
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• 2014

The purpose of this study were to analyze the characteristic of the glow curves in order to the glow temperature of the thermoluminescent dosimeters (TLDs) for the absorbed dose measurement of the radiation therapy. In this study, we was used the TLDs of the LiF:Mg${\cdot}$Ti, LiF:Mg${\cdot}$Cu${\cdot}$P, $CaF_2$:Dy, $CaF_2$:Mn (Thermo Fisher Scientific Inc., USA). The source-to-solid dry phantom (RW3 slab, IBA Dosmetry, Germany) surface distance was set at 100 cm, and the exposure dose of 100 MU (monitor unit) was used 6- and 15-MV X-rays, and 6- and 12-MeV electron beams in the reference depth, respectively. After the radiations exposure, we were to analyze the glow curves by using the TL reader (Hashaw 3500, Thermo Fisher Scientific Inc., USA) at the fixed heating rate of $15^{\circ}C/sec$ from $50^{\circ}C$ to $260^{\circ}C$. The glow peaks, the trapping level in the captured electrons and holes combined with the emitted light, were discovered the two or three peak. When the definite increasing the temperature of the TLDs, the maximum glow peak representing the glow temperature was follow as; $LiF:Mg{\cdot}Ti$: $185.5{\pm}1.3^{\circ}C$, $LiF:Mg{\cdot}Ti$: $135.0{\pm}5.1^{\circ}C$, $CaF_2$:Dy: $144.0{\pm}1.6^{\circ}C$, $CaF_2$:Mn: $294.3{\pm}3.8^{\circ}C$, respectively. Because the glow emission probability of the captured electrons depend on the heating temperature after the exposure radiation, TLDs by applying the fixed heating rate, the accuracy of measurement will be able to improve within the absorbed dose measurement of the radiation therapy.