• 대한약리학회지
• /
• 제13권2호
• /
• pp.67-73
• /
• 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
• /
• 제21권1호
• /
• pp.6.1-6.12
• /
• 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.

• 센서학회지
• /
• 제32권3호
• /
• pp.154-158
• /
• 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.

• 한국토양비료학회지
• /
• 제34권4호
• /
• pp.292-301
• /
• 2001

본 연구는 점적관수시 토양수분 영역의 변화를 측정하고 이에 따른 관비와 표면시비로 투입된 중질소 표지요소에서 유래한 무기태 질소의 분포 양식을 비교하기 위하여 수행되었다. 이를 위해 비닐하우스 내에서 6주간 포트실험을 수행하였다. 관비구는 $117mg\;N\;L^{-1}$ 수준으로 4주간 1.41 g N 을 투입하였으며 표면시비구는 토양 5 kg에 1.81 g N 을 고루 섞어 표면 (3 cm) 에 충진하였다. 관개는 -50 kPa의 토양 수분 장력을 관수점으로 하여 유속 $0.5L\;hr^{-1}$로 공급하였다. 질소 동위원소비의 분석결과 관비구의 경우 투입된 1.41g N 중 89% 에 해당하는 1.25 g N 이 토양에서 무기태 질소로 회수되었으며 표면시비구의 경우 1.87 g N 중 단지 51% 만이 회수되었다. 이는 낮은 농도의 관비로 공급된 요소가 습윤구역에 분포하여 가수분해, 질산화가 일어나는데 반해 표면시비는 고농도로 집적된 요소가 지표에서 가수분해되어 암모니아 휘산이 많이 일어나기 때문이다. 관비로 공급된 요소에서 유래한 무기태 질소의 60%가 0-10 cm 깊이에 있었으며 깊어짐에 따라 농도가 점차 감소하였다. 반면 표면시비된 요소에서 유래한 무기태 질소는 91%가 지표에 집중되어 10 cm 밑으로는 거의 발견되지 않았다. 관비의 경우 요소에서 유래한 무기태 질소의 99%가 질산태 질소로 회수된 반면 표면시비된 요소에서 유래한 무기태 질소는 38%가 암모늄태로 남아있었으며 대부분 습윤구역 바깥쪽 표면에서 회수되었다. 이는 수분이동이 적고 건습이 반복되는 지표, 특히 습윤구역 외부에 투입된 요소의 경우 이동성이 적으며 질산화가 지연되기 때문이다. 본 실험의 결과로 보아 관비로 요소를 투입할 때 암모니아 휘산에 의한 질소의 손실을 최소화할 수 있었으며 발견된 요소유래 무기태 질소의 분포로 보아 식물이 흡수하기 용이한 무기태 특히 질산태 질소를 지속적으로 공급할 수 있었다.

• Composites Research
• /
• 제16권2호
• /
• pp.54-61
• /
• 2003

본 연구에서는 자가치료제가 저장된 마이크로캡슐의 제조공법을 소개하였으며 제조공정변수를 달리하여 제조된 마이크로캡슐의 특성을 입도분석기, 광학현미경, TGA 등을 통해 평가하였다. 이때 자가치료용 마이크로캡슐은 요소-포름알데히드 수지로 구성된 박막으로 되어 있으며 마이크로캡슐의 내부에는 자가치료제인 DCPD가 충전되어 있는 경우를 고려하였다. 마이크로캡슐의 제조공정변수로는 (1) 24시간. 40시간. 48시간, 60시간의 EMA copolymer 용해시간, (2) pH3.5, pH4.0, pH4.5의 수소이온농도, (3) 400rpm, 500rpm, 600rpm. 1000rpm의 교반속도, (4) $50^{\circ}$, $55^{\circ}$, $60^{\circ}$의 반응온도 등을 고려하였다. 연구결과에 따르면 마이크로캡슐의 입도분포는 교반속도에 따라 달라지며, EMA copolymer의 용해시간, 수용액에서의 수소이온농도 및 반응온도 등은 마이크로캡슐의 열안정성에 큰 영향을 미친다. 따라서 마이크로캡슐의 내부에 저장된 자가치료제의 증발을 억제할 수 있는 우수한 열안정성을 갖는 마이크로캡슐을 제조하기 위해서는 적절한 제조공정변수가 적용되어야 한다.

• 한국분말재료학회지
• /
• 제8권1호
• /
• pp.13-19
• /
• 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
• /
• 제6권1호
• /
• pp.47-52
• /
• 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.

• 대한화학회지
• /
• 제32권4호
• /
• pp.323-332
• /
• 1988

요소는 박테리아가 가지고 있는 urease에 의해 2분자의 $NH_3$와 1분자의 $CO_2$ 기체를 생성한다. Proteus vulgaris를 $NH_3\;와\;CO_2$ 기체 감응전극에 고정시켜 박테리아 전극을 조립하고, pH, 온도, 완충용액, 박테리아(균)의 양 및 여러가지 방해불질의 영향과 전극의 수명등에 관하여 조사하였다. $NH_{3-}$박테리아 전극은 $25^{\circ}C$에서 pH 7.4인 0.05M phosphate완충용액을 사용하였을 때 직선범위는 $7.0{\times}10^{-4}\;-\;3.0{\times}10^{-2}$M 이었고, 감응 기울기는 116.7 mV/decade였다. 한편, $CO_{2-}$박테리아 전극은 $30^{\circ}C$, pH 7.0, 0.1M phosphate완충용액을 사용하였을 때 $7.0{\times}10^{-4}\;-\;5. 0{\times}10^{-2}$M내에서 감응 기울기는 $45.4{\sim}45.7mV/decade$로 나타났다. 실제 임상적인 응용으로서 요속에 들어 있는 요소를 정량하고 분광광도법과 비교하였다. 결과적으로 이 전극의 경우는 실험과정이 간단하고 편리하여 신속하게 많은 양의 시료 분석이 가능하였다.

• The Korean Journal of Physiology
• /
• 제2권2호
• /
• pp.33-43
• /
• 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.

• 한국토양비료학회지
• /
• 제25권1호
• /
• pp.57-61
• /
• 1992

질소염(窒素鹽)들의($(NH_4)_2SO_4$, $NH_4NO_3$, $KNO_3$, $Mg(NO_3)_2$, $Ca(NO_3)_2$, $(NH_2)_2CO$) 농도별(濃度別) 염강도(鹽强度)를 비교하고 영양액연속유출경사사경재배장치(營養液連續流出傾斜砂耕栽培裝置)를 이용하여 배추와 상치에 대한 발아장해정도(發芽障害程度)를 조사하였다. 그람분자량으로 동일농도(同一濃度)의 EC(electrical conductivity, mS/cm)를 측정한 결과 황산암몬은 1가염(價鹽)의 2배수준(倍水準)을 나타냈으나 질산고토, 질산석회는 1.5배정도 이었고 요소(尿素)는 전연 측정되지 않았다. 그리고 동일백분률(同一百分率) 농도(濃度)에서는 황산암몬(1.37)>질산암몬(1.22)>질산칼리(1.0)>질산석회(0.72)>질산고토(0.64)의 순(順)으로 EC치의 비율을 보였다. 배추와 상치의 발아에 가장 심한 장해를 주는 염(鹽)은 질산고토, 황산암몬이었으며 질산암몬도 질산칼리에 비하여 장해정도가 컸고 요소(尿素)는 질산칼리, 질산석회와 같이 가장 낮은 영향을 주었으나 농도가 짙어지면서 질산칼리, 질산석회도 장해를 나타냈다. 그리고 상치가 배추보다 발아장해에 더 예민한 편이었다. 발아장해(發芽障害)는 염농도(鹽濃度)보다 질소염(窒素鹽)의 종류(種類)에 더 큰 영향을 받는 것으로 나타났다.