• Analytical Science and Technology
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• v.19 no.2
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• pp.149-154
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• 2006

A gas chromatography-mass spectrometric method was developed for the determination of formaldehyde in urine and saliva. In a 20 mL glass tube, 0.2 mL of urine or saliva was taken. Further, 1.8 mL of 0.1 M HCl, 0.1 mL of 2,000 mg/L 2,4-dinitrophenyl hydrazine and $20{\mu}l$ of 500 mg/L acetone-$d_6$ as internal standard were added in the tube and sealed tightly with cap. The solution was shaken for 20 min at room temperature and extracted using 4 mL of toluene. The extract was concentrated and redissolved with $100{\mu}l$ of acetonitrile, and then measured by gas chromatography-mass spectrometer (selected ion monitoring). The detection limit was 2.0 ng/mL and 0.5 ng/mL in saliva and urine, respectively. The calibration curves showed good linearity with r = 0.997 and 0.998 for saliva and urine, respectively. The method was used to analyze formaldehyde in rat urine after oral exposure. The developed method may be use ful to the monitoring for formaldehyde exposure in human.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.1
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• pp.23-30
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• 2003

This pot experiment was conducted to find out the effects of slaked lime($L_{0}$ ; 0.00, $L_1$; 3.75, $L_2$; 7.50, $L_3$; 11.25ｇ/pot) and silicate fertilizers($S_1$; 3.75, $S_2$; 7.50, $S_3$; 11.25ｇ/pot) on the seedling growth and yield of grass/clover mired swards on newly reclaimed hilly soil, and it's differences between both the soil improvers. The results obtained are summarized as fellows: Comparing with the $L_{0}$ treatment without soil improver, the seedling vigour and yields of both forages were markedly enhanced by the application of soil improver. The positive offsets of soil improvers tended to be relative higher on ladino clover than orchardgrass in mixed swards. The seeding vigour, botanical composition, and yield of ladino clover were more markedly influenced by the application of silicate fertilizer than slaked line. The yields of ladino clover were increased 75.8% by the 51 over $L_1$, and 32.0% by the $S_2$ over $L_2$, respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.3
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• pp.206-213
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• 2004

As far as an opening device of fishing gears is concerned, applications of a kite are under development around the world. The typical examples are found in the opening device of the stow net on anchor and the buoyancy material of the trawl. While the stow net on anchor has proved its capability for the past 20 years, the trawl has not been wildly used since it has been first introduced for the commercial use only without sufficient studies and thus has revealed many drawbacks. Therefore, the fundamental hydrodynamics of the kite itself need to ne studied further. Models of plate and canvas kite were deployed in the circulating water tank for the mechanical test. For this situation lift and drag tests were performed considering a change in the shape of objects, which resulted in a different aspect ratio of rectangle and trapezoid. The results obtained from the above approaches are summarized as follows, where aspect ratio, attack angle, lift coefficient and maximum lift coefficient are denoted as A, B, $C_L$ and $C_{Lmax}$ respectively : 1. Given the triangular plate, $C_{Lmax}$ was produced as 1.26${\sim}$1.32 with A${\leq}$1 and 38$^{\circ}$B${\leq}$42$^{\circ}$. And when A${\geq}$1.5 and 20$^{\circ}$${\leq}$B${\leq}$50$^{\circ}$, $C_L$ was around 0.85. Given the inverted triangular plate, $C_{Lmax}$ was 1.46${\sim}$1.56 with A${\leq}$1 and 36$^{\circ}$B${\leq}$38$^{\circ}$. And When A${\geq}$1.5 and 22$^{\circ}$B${\leq}$26$^{\circ}$, $C_{Lmax}$ was 1.05${\sim}$1.21. Given the triangular kite, $C_{Lmax}$ was produced as 1.67${\sim}$1.77 with A${\leq}$1 and 46$^{\circ}$B${\leq}$48$^{\circ}$. And when A${\geq}$1.5 and 20$^{\circ}$B${\leq}$50$^{\circ}$, $C_L$ was around 1.10. Given the inverted triangular kite, $C_{Lmax}$ was 1.44${\sim}$1.68 with A${\leq}$1 and 28$^{\circ}$B${\leq}$32$^{\circ}$. And when A${\geq}$1.5 and 18$^{\circ}$B${\leq}$24$^{\circ}$, $C_{Lmax}$ was 1.03${\sim}$1.18. 2. For a model with A=1/2, an increase in B caused an increase in $C_L$ until $C_L$ has reached the maximum. Then there was a tendency of a very gradual decrease or no change in the value of $C_L$. For a model with A=2/3, the tendency of $C_L$ was similar to the case of a model with A=1/2. For a model with A=1, an increase in B caused an increase in $C_L$ until $C_L$ has reached the maximum. And the tendency of $C_L$ didn't change dramatically. For a model with A=1.5, the tendency of $C_L$ as a function of B was changed very small as 0.75${\sim}$1.22 with 20$^{\circ}$B${\leq}$50$^{\circ}$. For a model with A=2, the tendency of $C_L$ as a function of B was almost the same in the triangular model. There was no considerable change in the models with 20$^{\circ}$B${\leq}$50$^{\circ}$. 3. The inverted model's $C_L$ as a function of increase of B reached the maximum rapidly, then decreased gradually compared to the non-inverted models. Others were decreased dramatically. 4. The action point of dynamic pressure in accordance with the attack angle was close to the rear area of the model with small attack angle, and with large attack angle, the action point was close to the front part of the model. 5. There was camber vertex in the position in which the fluid pressure was generated, and the triangular canvas had large value of camber vertex when the aspect ratio was high, while the inverted triangular canvas was versa. 6. All canvas kite had larger camber ratio when the aspect ratio was high, and the triangular canvas had larger one when the attack angle was high, while the inverted triangluar canvas was versa.

• Korean Journal of Medicinal Crop Science
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• v.4 no.2
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• pp.126-131
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• 1996

Plant regeneration from the stem tissue of Houttuynia cordata Thunberg was investigated. The medium supplemented with the combination of 2, 4-D 1 mg/L and kinetin 0. 5 mg/L was the most effective for the embryogenic callus formation. The internode segment produced more callus formation than the leaf segment. ${\frac{1}{2}}\;MS$ medium was the most effective for the embryogenic callus formation. The medium supplemented with the 1% activated charcoal produced the whole plant directly without the callus formation from the nodes. The medium supplemented with the combination of NAA 0. 2 mg/L and BA 1 mg/L was the most effective for the plant regeneration from the embryogenic callus.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.1
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• pp.107-113
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• 2004

Several transition metal complexes, [$M(L)X_2$](M=Pd(II), Ni(II); X=CI, Br) are prepared with aminophosphine ligands such as 1,2-bis{(diphenylphosphino)amino}ethane{$Ph_2PNHCH_2CH_2NHPPh_2$}($L_1$), 1,2-bis{(diphenylphosphino)amino}propane{$Ph_2PNHCH(CH_3)CH_2NHPPh_2$}($L_2$), trans-1,2-bis{(diphenylphosphino)amino}cyclohexane{$Ph_2PNHC_6H_{10}NHPPh_2$}($L_3$) and 1,2-bis{(diphenylphosphino)amino}benzene{$Ph_2PNHC_6H_4NHPPh_2$}($L_4$). The properties of these complexes are characterized by optical spectroscopic methods including UV/vis spectroscopy, CD, IR, $^1H$- and $^{31}P-NMR$ together with conductometer and elemental analysis. All complexes are stable under atmospheric environment. Catalytic reactivity for C-C coupling between [$M(L)X_2$] and Grignard reagents(RMgX; R=phenyl, propyl, buthyl) by thermolysis were investigated utilizing GC/mass, $^1H$- and $^{13}C-NMR$. When mol scale is 1:20 at [$Pd(L)Cl_2$] and Grignard reagents, the high catalytic activity for C-C coupling is apparent. The [$M(L)X_2$](X=Cl, Br) complexes which have strong bond at M-P exhibit high yields for C-C coupling reactions. When the central metal ion is Pd(II), the high catalytic activity for C-C coupling is apparent. The complex coordinated with Br shows higher catalytic activity for C-C coupling reactions compared to Cl.

• FLOWER RESEARCH JOURNAL
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• v.16 no.4
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• pp.239-246
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• 2008

This study was conducted to establishment of in vitro micropropagation through induction of multiple shoots from axillary bud culture in Calanthe discolor Lindl. Shoots initiation from axillary bud was the most effective on half strength MS medium supplemented with $0.5mg{\cdot}L^{-1}$ NAA and $2.0mg{\cdot}L^{-1}$ TDZ during four weeks of dark culture followed by culture under a 16-h photoperiod. Multiple shoots (12.5 shoots per explant) were proliferated on half strength MS medium containing $4.0mg{\cdot}L^{-1}$ TDZ and $2.0mg{\cdot}L^{-1}$ IBA. On the other hands, the abnormally emerged shoots during the multiple shoot proliferation stage were recovered to normal shoots on half strength MS hormone free medium. Multiple shoots were well elongated and rooted on half strength MS medium with $0.1mg{\cdot}L^{-1}$ NAA. The plantlets were acclimatized up to 100% on TKS substrate after pretreating with $10mg{\cdot}L^{-1}$ NAA for 30 min. and these plantlets showed good growth as well.

• Journal of the Korean Data and Information Science Society
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• v.21 no.6
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• pp.1311-1317
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• 2010

A continuous time asymmetric power GARCH(1,1) model is suggested, based on a single background driving L$\'{e}$vy process. The stochastic differential equation for the given process is derived and the strict stationarity and kth order moment conditions are examined.

• The Korean Journal of Pain
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• v.2 no.2
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• pp.135-144
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• 1989

Celiac plexus block is recommended in patients with intractable upper abdominal cancer pain. The success rate of a celiac plexus block is variable among the authors. One of the causes of this is the anatomical variations of the celiac plexus. There has not been a study concerning anatomical observations of the celiac plexus in Korean cadavers. So, anatomical dissections were performed and observations were made of the celiac plexus and related structures in Korean cadavers. The results were as follows: 1) The subjects were 21 male bodies and 5 female bodies. The mean age at death was $69.9{\pm}15.5$ years (range 37~93). The mean height was $155.5{\pm}8.3\;cm$ (range 143~172). 2) The number of celiac ganglia ranged from 1~4. The mean numbers were $2.3{\pm}1.9$ in the right plexus and $1.9{\pm}0.8$ in the left, and the mean sizes were $18.9{\pm}7.7{\times}8.0{\pm}3.8\;mm^2$ and $18.5{\pm}8.3{\times}9.5{\pm}3.9\;mm^2$ respectively. 3) Celiac ganglia were most frequently located at the level of the upper third and middle third of L1 in both sides (65.5% in right, 64.0% in left). The vertical range of celiac ganglia ranged from 1 space, which is one third the height of one vertebral body, to 4 spaces. Mean vertical ranges were $1.5{\pm}0.6$ spaces in the right plexus and $1.6{\pm}0.7$ spaces in the left. The celiac ganglia located at the level of the upper third of L1 in the right and the lower third of L1 in the left side, had the largest vertical ranges respectively ($1.8{\pm}0.5$ spaces in right, $2.3{\pm}0.6$ spaces in left) 4) Right side celiac ganglia were located near the midline of the vertebrae compared to the left ones (mean 5.0 mm) The horizontal dimension was greater in the right ganglia ($24.2{\pm}9.2\;mm$) than in the left ganglia ($l8.8{\pm}7.0\;mm$). 5) There was no vertebral level difference between both celiac ganglia in most cases (60%). However, of the 40% of cases at different levels, in half of these (20%) the right ganglia were located higher than the left ganglia; and in the other 20%, this was reversed. 6) The origin sites of the celiac artery were most frequently in the upper third and middle third of L1 (61.6%). The celiac ganglia were usually located at the same level as the site of origin of the celiac artery (61.6% in right, 52.0% in left). 7) The vertebral level of the splanchnic nerves piercing the abdominal surface of the diaphragm was most frequently in the upper third and middle third of L1 (66.6% in right, 66.7% in left). 8) The level of the origin of diaphragmatic crura from the anterior surface of the vertebral bodies varied from the L1-L2 interspace to the L3-L4 interspace. Right crura most frequently originated at the level of the lower third of L2 to the upper third of L3 (57.6%), while left crura originated from the level of the L2-L3 interspace to the middle third of L3 (69.3%). From the above results, we realized that there were some anatomical variations of the celiac plexus and its relations to adjacent structures in Korean bodies. However, when the needle point is behind the anterior margin of the upper third of L1, it is possible to perform a successful retrocrural splanchnic nerve block.

• Journal of the Korean Society of Radiology
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• v.15 no.1
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• pp.63-70
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• 2021

Radiographic contrast agents are used for diagnostic purposes and are one of the factors affecting measured values in bone density tests. They are absorbed into tissues and have an effect of increasing the measured values of bone density, so they are avoided as much as possible before performing a bone density test. MRI contrast agents, which have different physical properties and mechanisms of action than radiographic contrast agents, are based on gadolinium, a metal element. They have radiopacity characteristics, so MRI are generally performed prior to examination using radiation. The purpose of this study was to investigate the effects of MRI contrast agents on bone mineral density examination using dual energy X-ray absorption. Two types of gadolinium based MRI contrast agents were injected into an acrylic water tank for each volume, and the humanoid spine phantom was inserted and the BMD and T-score from (L1-L4) were analyzed by scanning a total of 30 times, 5 times for each injection type. The average value of the measured total (L1-L4) bone density for each of the two contrast agents was 0.952±0.052, 0.957±0.050, and 0.956±0.05g/㎠, respectively, for the Gadoterate Meglumine component 0mL, 7.5mL and 15mL, when the gadobutrol components were 0mL, 5mL, and 10mL, there was no statistically significant difference at all sites at 0.953±0.001, 0.954±0.001, and 0.945±0.001g/㎠, respectively(p>0.05). The average value of total T-score was -0.46±0.05, -0.4±0, -0.42±0.04 when the Gadoterate Meglumine component was 0mL, 7.5mL and 15mL, respectively. When the Gadobutrol ingredients were 0mL, 5mL and 10mL, there was no statistically significant difference in all areas, with -0.46±0.05, -0.46±0.05, and 0.5±0.00, respectively. In this experiment, the MRI contrast agent was found to have no effect on bone density tests, using the dual-energy X-ray absorption method. There is a limitation in that physical conditions such as kidney and health conditions etc. were not taken into consideration, so further clinical research is expected to be conducted in the future.

• Journal of Bio-Environment Control
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• v.33 no.1
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• pp.55-62
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• 2024

This study aimed to compare the nutrient uptake rate, growth and yield of strawberry grown under the aquaponic and hydroponic systems in a plant factory. For aquaculture, 12 of fish (Cyprinus carpio cv. Koi) were raised in an aquaponics tank (W 0.7 m × L 1.5 m × H 0.45 m, 472.5 L) filled with 367.5L of water at a density of 5.44 kg·m^-3. The 30 seedlings of strawberry were planted in ports filled with perlite substrate and then were placed on the bed (W 0.7 m × L 1.5 m × H 0.22 m) at the top of the aquaponics system, and the 30 seedlings were planted in net-pots and then placed on the holes of acrylic plates (140 cm × 60 cm, Ø80 mm) on the bed (W 0.7 m × L 1.5 m × H 0.22 m) at the deep flow technique (DFT)- hydroponics. The pH and EC of the aquaponic solution was ranged from 4.3 to 6.9 and 0.32 to 1.14 dS·m^-1, respectively, while those of hydroponics were ranged from 5.1 to 7.5 and 1.0-1.8 dS·m^-1, respectively. The NO₃-N and NH₄-N concentration of the aquaponic solution were higher about 3.6 and 2.2 me·L^-1 than those of the standard hydroponic solution for strawberry cultivation. The P, Ca, Mg, and S ions in the aquaponic solution were also higher about 0.76, 3.1, 0.8, and 0.9 me·L^-1 than those of standard hydroponic solution, respectively, while the K and Fe were lower about 0.8 me·L^-1 and 0.5 mg·L^-1, respectively. The mineral contents of the strawberry leaves grown on aquaponics did not differ from that of hydroponics, and K content in the leaves were in an appropriate range. Uptake rates of T-N and P between the 58 and 98 days after transplant (DAT) were 1.5 and 1.9-fold higher in the aquaponics than those of hydroponics, respectively with no significant difference in the uptake rate of K. The crown diameter, plant height, and leaf length and width in the 98 DAT were significantly higher in aquaponics. The number of fruits per plant was significantly higher in aquaponics than those in hydroponics, and the fresh and dry weights of fruit and length and width of fruit were significantly higher in hydroponics. The results suggest that plants in aquaponics continuously utilize fertilizer components of solid particles from fish and feed wastes.