• The Korean Journal of Pharmacology
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• v.13 no.2
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• pp.67-73
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• 1977

The nitrogen sparing effect of intravenous 3% amino acid solution was compared with 5% dextrose solution in 30 patients who were undergoing surgical operations or radiation therapy. Infusion of 3% amino acid solution or 5% dextrose solution was given before and immediately after operations or irradiation and continued for 6 days. Infusion of solutions through peripheral vein was well tolerated and not experienced any specific hematologic or blood chemistry change in all patients subjected throughout the experiment. The patients received 3% amino acid solution showed low blood glucose and insulin level, but significantly high blood urea nitrogen and ketone body. In patients receiving amino acids, as compared with those receiving dextrose, mean cumulative six day nitrogen losses were significantly lower($63.95{\pm}2.12$ Gm and $79.12{\pm}2.43Gm$ respectively). The nitrogen sparing effect of amino acids is probably due to decreased glucose and insulin levels allowing greater endogenous fat mobilization.

• Journal of Veterinary Science
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• v.21 no.1
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• pp.6.1-6.12
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• 2020

Currently, the optimal resuscitation fluid remains debatable. Therefore, in the present study, we designed a trometamol-balanced solution (TBS) for use as a resuscitation fluid for hemorrhagic shock. Hemorrhagic shock was induced in 18 male Wistar-Kyoto rats, which were assigned to normal saline (NS), Ringer's solution (RS), and TBS groups. During the hemorrhagic state, their hemodynamic parameters were recorded using an Abbott i-STAT analyzer with the CG4+ cartridge (for pH, pressure of carbon dioxide, pressure of oxygen, total carbon dioxide, bicarbonate, base excess, oxygen saturation, and lactate), the CG6+ cartridge (for sodium, potassium, chloride, blood glucose, blood urea nitrogen, hematocrit, and hemoglobin), and enzyme-linked immunosorbent assay kits (calcium, magnesium, creatinine, aspartate aminotransferase, alanine aminotransferase, bilirubin, and albumin). Similar trends were found for the parameters of biochemistries, electrolytes, and blood gas, and they revealed no significant changes after blood withdrawal-induced hemorrhagic shock. However, the TBS group showed more effective ability to correct metabolic acidosis than the NS and RS groups. TBS was a feasible and safe resuscitation solution in this study and may be an alternative to NS and RS for resuscitation in hemorrhagic shock patients without liver damage.

• Journal of Sensor Science and Technology
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• v.32 no.3
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• pp.154-158
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• 2023

This study aimed to improve the moisture resistance of salt cores by investigating the suitability of a two-dimensional kaolinite colloidal solution and a commercially available SiO₂ ink solution as coating agents. X-ray diffraction analysis (XRD) results showed that the intercalation of urea into kaolinite did not significantly change its layer structure. Scanning electron microscopy (SEM) images revealed that the dip-coating only affected the surface of the salt core, and the texture of the surface is differ depending on the coating solution. The humidity absorption test results showed that both coatings reduced the hygroscopicity of the salt core by more than 50%. However, in the water-solubility test, the kaolinite dissolved with the salt core, whereas the SiO₂-coated salt core left a residue. These results strongly suggest that with the coating of the exfoliated kaolinite solution, salt core will remain stable in humid environments.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.4
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• pp.292-301
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• 2001

The objectives of this study were to measure the changes in soil moisture regimes and the distribution patterns of inorganic N derived from the fertigated $^{15}N$-labeled urea, and compare them with the results obtained from broadcast-applied soil under the same drip irrigation domain. In fertigated soil, a $^{15}N$-labeled urea solution of $117mg\;N\;L^{-1}$ was applied by surface drip irrigation for 4 weeks. In broadcast-applied soil, no the other hand, 4 g of $^{15}N$-labeled urea(1.87 g N) mixed thoroughly with 5 kg of soil was placed on the surface of packed soil. Soil water status was controlled by drip irrigation scheduled at soil matric potential of -50 kPa. A calibrated time-domain reflectometry probe was installed in the soil vertically 15 cm apart from a drip emitter to control drip irrigation. About 60% of urea-derived inorganic nitrogen was remained in the top zone between 0 and 10 cm depth of fertigated soil, while, most of the inorganic nitrogen (91%) was accumulated in the top zone of broadcast-applied soil. Of inorganic nitrogen derived from urea, the percentage of $NO_3{^-}$ was much higher for fertigation (99%) than for surface application (62%). The relatively lower recovery of urea-derived inorganic nitrogen of broadcast-applied urea-N (51%) than that of fertigated urea-N (89%) was attributable to enhanced $NH_3$ volatilization.

• Composites Research
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• v.16 no.2
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• pp.54-61
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• 2003

In this study, manufacturing process for microcapsules with the self-healing agent was introduced and the characteristics of microcapsules manufactured by varying with various manufacturing process variables were evaluated through a particle size analyzer, an optical microscope, and a TGA. Urea-formaldehyde resin was used for the thin wall of microcapsules and DCPD (dicyclopentadiene) was used for the self-healing agent. The various manufacturing process variables, such as (1) 24hr, 40hr, 48hr, 60hr of the solution time of the EMA copolymer, (2) pH3.5, pH4.0, pH4.5 of the hydrogen ion concentration of the emulsified solution, (3) 400rpm, 500rpm, 600rpm, 1000rpm of the agitation speed of the emulsified solution, (4) $50^{\circ}$, $55^{\circ}$, $60^{\circ}$ of the reaction temperature of the emulsified solution, were considered. According to the results, the particle size distribution of microcapsules was affected on the agitation speed, and the thermal stability of microcapsules was influenced by the solution time of the EMA copolymer, the hydrogen ion concentration, and the reaction temperature of the emulsified solution. Therefore, suitable manufacturing process variables should be applied to obtain thermally stable microcapsules capable of containing the healing agent capable until the thin wall of microcapsules were to be burned.

• Journal of Powder Materials
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• v.8 no.1
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• pp.13-19
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• 2001

Ni and NiO particles were made by a combustion synthesis process. The characteristics of synthesized powders were investigated with various kinds and amounts of fuels such as urea, citric acid and glycine. Ni phase particles without NiO phase were obtained through combustion synthesis process in air atmosphere with-out further calcinations process, when the content of glycine was 2.44 times of the stoichiometric ratio in the precursor solution. Primary particle sizes of synthesized Ni and NiO particles were about 20∼30 nm.

• The Korean Journal of Ceramics
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• v.6 no.1
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• pp.47-52
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• 2000

Lanthanides such as La, Gd and Ce have recognized as elements of high level radioactive wastes immobilized by forming solid solution with $CaTiO_3$. For easy forming solid solution between $CaTiO_3$and lanthanides, the combustion synthesis process was applied and the powder characteristics and sinterability were investigated. The proper selection of the type and the composition of fuels are important to get the crystalline solid solution of $CaTiO_3$and lanthanides. When glycine or the mixtures of urea and citric acid with stoichiometric composition was used as a fuel, the solid solution of $CaTiO_3$with $La_2O_3$or $Gd_2O_3$or $CeO_2$was produced very well by the combustion process. The combustion synthesized powder seemed to have a good sinterability with the linear shrinkage of more than 25% up to $1500^{\circ}C$, while that of the solid state reacted powder was less than 10% at the same condition.

• Journal of the Korean Chemical Society
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• v.32 no.4
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• pp.323-332
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• 1988

The bacteria containing urease convert each molecule of urea into two molecules of ammonia and one molecule of carbon dioxide gas. Bacterial electrodes have been constructed by immobilizing the Proteus vulgaris on an ammonia and a carbon dioxide gas-sensors, and were investigated for the effects of pH, temperature, buffer solution, bacterial amounts and interferences, and life time. NH3-bacterial electrode based on ammonia gas-sensor had linearity in the range of $7.0{\times}10^{-4}\;-\;3.0{\times}10^{-2}$M urea in pH 7.4, 0.05M phosphate buffer at $25^{\circ}C$ with a slope of 116.7 mV/decade. While $CO_{2-}$bacterial electrode based on carbon dioxide gas-sensor bad linearity in the range of $7.0{\times}10^{-4}\;-\;5. 0{\times}10^{-2}$M urea in pH 7.0, 0.1M phosphate buffer at $30^{\circ}C$with a slope of $45.4{\times}45.7mV/decade$. As the clinical application, urea in urine was determined by these devices and this result was compared with spectrophotometric method. Consequently, these electrodes could be used for the analysis of many samples because of simplicity, rapidity and convenience of the experimental procedure.

• The Korean Journal of Physiology
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• v.2 no.2
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• pp.33-43
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• 1968

Histamine, 0.5 mg as histamine base in 4 ml of normal saline solution, was injected into rabbits anesthetized with nembutal and the mean blood pressure was kept in the range of $52{\sim}80\;mmHg$ for over one hour by supplemental additions. Following the injection of the test substances, 300 mg of urea and 200 mg of antipyrine intravenously, serial blood samples were obtained from the femoral artery and the internal jugular vein at $0.5{\sim}3$ minutes interval. The decreasing patterns in the concentrations of arterial and venous blood plasma samples were compared with each other. The ratio of the concentration of brain tissue to that of the final arterial plasma was also studied. By these measures the degrees of penetration of the test substances in the brain in the control and in the histamine treated rabbits were observed. The concentrations of antipyrine and urea in the arterial blood plasma were decreasing exponentially with respect to the time elapsed. The venous concentrations were anticipated to increase initially and to cross the arterial concentration curve in the point of equlibrium between the plasma and the tissue. On the contrary to the expectation venous concentration also revealed the decreasing tendency similar to that of arterial plasma. The similarity between these two curves, arterial and venous, would be atributable to the fact that the cerebral blood flow rate was large enough and the rising phase in the venous concentration curve was instantly over before serial blood samples were taken. Inspite of some similarity in the decreasing tedency in both concentration curves there were appreciable discrepancies between the arterial and venous plasma which would reflect the situation far from the equlibria among several compartments in the brain. Changes in plasma potassium levels caused by the injection of histamine or bleeding were observed, too. Using 8 rabbits as the control and 12 rabbits for the histamine treated group following results were obtained: 1. Both of the concentration curves, arterial and venous, declined rapidly at_first and slowly later on and approached same equilibrium concentration with the passage of time after a single injection. The time at which attained the same concentration was $2.0{\pm}0.54\;min.$ in the control and $4.3{\pm}1.92\;min.$ in the histamine treated group with respect to antipyrine. On the other hand in the case of urea they were $2.4{\pm}0.59\;min.$ in the control and $4.4{\pm}1.31\;min.$ in the histamine group, respectively. In the histamine treated group enlarged spaces for distribution of test substances were postulated. 2. The concentration of antipyrine in the brain tissue water revealed no significant differences between the control and experimental groups, showing $212{\pm}40.2\;mg/l$ in the control and $206{\pm}64.1\;mg/l$ in the histamine treated group. On the other hand urea revealed higher value in the histamine treated group than in the control, showing an enhanced penetration of urea into the tissue after injection of histamine. Urea concentration in the brain water was $32.3{\pm}3.36\;mg%$ in the control and $39.2{\pm}4.25\;mg%$ in the histamine treated group. 3. The distribution ratio of antipyrine in the brain tissue was very close to unity in the histamine treated animals as well as in the control. 4. The average of the distribution ratio of urea in the control animals was 0.77 and it showed the presence of blood-brain barrier with regard to urea. However in the histamine treated animals the distribution ratios climbed up to 0.86 and they were closer to unity than in the control animals. Out of 12 cases 5 were greater than 0.9 and 8 exceeded 0.85. It appeared that histamine enhanced the penetration of urea through the barrier. 5. Histamine injection and or hemorrhage caused an elevation of the concentration of potassium in plasma. In the event that histamine and hemorrhage were applied together the elevation of potassium exceed the elevation seen at the histamine alone. There was no evidence that the leakage of potassium from the brain tissue was dominant in comparison with the general leakage from the whole body.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.1
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• pp.57-61
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• 1992

For testing salts effect on seed germination, nitrogen solutions($(NH_4)_2SO_4$, $NH_4NO_3$, $KNO_3$, $Mg(NO_3)_2$, $Ca(NO_3)_2$, $(NH_2)_2CO$) were treated to chinese cabbage(Brassica rape L.) and lettuce(Lactuca sativa L.) seeding on the quartz sand bed given a tilt to wet by dripping. Electrical conductivities (mS/cm) increased with direct proportion by equivalent gram-molecular weight at $(NH_4)_2SO_4$ and $KNO_3$, $NH_4NO_3$, but those of Mg and Ca salt remained 1 1/2 times higher. And urea solution never showed EC at all. $(NH_4)_2SO_4$ solution appeared to have value of EC with 1.37 times as high as that of $KNO_3$ and it was in order of $(NH_4)_2SO_4>NH_4NO_3>KNO_3>Ca(NO_3)_2>Mg(NO_3)_2$ comparing with same percentage solution. Application of $Mg(NO_3)_2$ and $(NH_4)_2SO_4$ among 6 salts resulted in a severe decreas in germination of both crops, and $NH_4NO_3$ showed light inhibition in comparison to $KNO_3$. Urea showed little effect on germination as the same as $Ca(NO_3)_2$ and $KNO_3$ solution at low concentrations, but the latter two salts reduced germination remarkably at high concentrations. It is likely to show that germination inhibition is not affected by salt salanity but by the sort of salts.