• 멤브레인
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• 제18권3호
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• pp.250-255
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• 2008

열적, 기계적, 화학적 안정성이 우수한 제올라이트 분리막의 물/에탄올 선택도를 이온교환 실험을 통해 더욱 효과적으로 높이고자 하였다. KA형 제올라이트 분리막을 직접 합성하는 것은 용이하지 않으므로 NaA형 제올라이트 분리막을 합성한 후 이를 다시 이온교환 하여 KA형 제올라이트 분리막을 제조하였다. 공급되는 에탄올의 농도 변화 및 투과 증발실험 온도의 변화가 투과플럭스와 물 선택도에 미치는 영향을 고찰하였다. 이온교환 실험 후 전체 투과플럭스는 감소하였고 물 선택도는 증가함을 관찰할 수 있었다.

• 한국환경농학회지
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• 제20권5호
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• pp.352-357
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• 2001

Cadmium (Cd) has been identified as a potential contaminant in agricultural and environmental soils. Ionic condition in the soils is an important factor to influence Cd availability. In this study, the effect of sulfate or nitrate application on Cd sorption in acidic and calcareous soils was investigated. The Cd, sulfate $(SO_4)$, and nitrate $(NO_3)$ sources were solutions of $CdCl_2$, $K_2SO_4$, and $KNO_3$, respectively. The soil-solution system pH was affected by the application of sulfate or nitrate in both acidic and calcareous soil system, but there was not clear pH difference between pre- and simultaneous applications of sulfate or nitrate (PAS/PAN or SAS/SAN). Solution ionic strength (I) values were similar between the acid and calcareous soil systems after applying the Cd even though it was significantly different in the untreated control soils. However after applying the sulfate or nitrate, the I values increased and were always higher with SAS/SAN treatments. Solution Cd concentration also increased with the application of sulfate or nitrate. However, the Cd concentration in soil solution controlled by Cd sorption in the systems was different between PAS/PAN and SAS/SAN treatments only in the calcareous soil system, but not in the acidic soil system. The difference in Cd concentration between SAS/SAN and PAS/PAN in the calcareous systems may be caused by system pH, ionic strength, complexation, and predominately, competition of the $Cd^{2-}$ with the index $K^+$ ion. Potassium ion-Cd competition in the acidic soil system may be minimized because of the abundance of hydrogen ions.

• The Korean Journal of Physiology
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• 제2권2호
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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.

• 한국수정란이식학회지
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• 제30권4호
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• pp.277-282
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• 2015

Cryopreservation affects osmotic tolerance and intracellular ion concentration through changes in expression levels of water and ion channels. Control of these changes is important for cell survival after cryopreservation. Relatively little is known about changes in $K^+$ channel expression compared to water channel expression. This study was performed to investigate changes in TASK-2 channel (KCNK5: potassium channel, subfamily K, member 5), a member of two-pore domain $K^+$ channel family, in cryopreserved mouse ovaries. Cryopreservation increased TASK-2 mRNA expression in mouse ovaries. In addition, TASK-2 protein expression was upregulated in vitrified and slowly frozen ovaries. TASK-2 protein was expressed in all area of granulosa cells that surround the oocyte within the follicle, except nucleus. Viability of cells overexpressed with TASK-2 was higher than that of vector-transfected cells. Our results found that TASK-2 expression was increased by cryopreservation and overexpression of TASK-2 decreased cryopreservation-induced cell death. These results suggest that TASK-2 upregulation might reduce cryodamage.

• 대한화학회지
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• 제37권8호
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• pp.773-778
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• 1993

Tl$^+$이온 센서로서 크라운 에테르 B15C5와 DB18C6를 중성운반체로 한 PVC 액체막 이온 선택성 전극을 제작하였다. 막용매로는 DOA, NPPE 및 NPOE를 사용하였으며 친유성 염, KTClPB의 농도를 변화시킨 여러가지 조성의 막을 시험하였다. B15C5와 DB18C6 막 전극의 감응전위는 농도범위, 10$^{-1}$∼10$^{-5}$M에서 직선으로 나타났으며 최대 기울기는 전극에 따라서 40∼55 mV/decade였다. 선택계수는 분리용액법으로 결정하였으며 알카리금속 이온, 알칼리토금속 이온 및 일부 전이금속 이온에 대하여 좋은 선택성을 나타냈다. 제작된 액체막 전극은 Ph > 3 에서 안정한 감응전위를 보였다.

• 대한약리학회지
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• 제2권1호
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• pp.31-40
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• 1966

The microsomal fraction is isolated from rabbit heart and skeletal muscle. The fraction is found to contain the $Na^+$-and $K^+$-activated ATPase. The maximal ATPase activity is obtained in $Na^+$ and $K^+$ concentration of 100 mM. Calcium itself stimulates the $Na^+$-and $K^+$-activated portion of ATPase in the presence of $Mg^{++}$. However, calcium does not stimulate ATPase in the absence of $Mg^{++}$.

• 약학회지
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• 제45권1호
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• pp.34-38
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• 2001

The Phellodendri Cortex of Phellodendron amurense (Rutaceae) is known to contain a number of isoquinoline alkaloid, and berberine, palmatine, jateorrhizine, phellodendrine and magnoflorine are the major constituents of protoberberine alkaloids. For the determination of protoberberine alkaloids from Phellodendri Cortex and berberine chloride from the preparation, the new spectrophotometric method was developed with a simple and selective sample clean-up using thiocyanatocobaltate[II] complex ion. Samples were extracted with 0.1 mM hydrochloric acid, potassium biphthalate reagent, thiocyanatocobaltate reagent and 1.2-dichloroethane for 60 min. The absorbance of protoberberine alkaloid complexes in 1.2-dichloroethane solution was measured at 625 nm. Calibration curve for berberine was linear over the concentration range of 0.05~0.30 mg/ml 1.2-dichloroethane. The method proved to be rapid, simple and reliable for the determination of protoberberine alkaloids from Phellodendri Cortex and berberine chloride from the preparation.

• 한국환경과학회지
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• 제12권10호
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• pp.1061-1069
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• 2003

The adsorption behaviors of strontium and cesium ions on fly ash, natural zeolites, and zeolites synthesized from fly ash were investigated. The zeolites synthesized from fly ash had greater adsorption capabilities for strontium and cesium ions than the original fly ash and natural zeolites. The maximum adsorption capacity of synthetic zeolite for strontium and cesium ions was 100 and 154 mg/g, respectively, It was found that the Freundlich isotherm model could fit the adsorption isotherm. The distribution coefficients (K$\_$d/) for strontium and cesium ions were also calculated from the adsorption isotherm data, The distribution coefficients decreased with increasing equilibrium concentration of strontium and cesium ions in solution. By studying the removal of cesium and strontium ions in the presence of calcium, magnesium, sodium, potassium, sulfate, nitrate, nitrite, and EDTA (in the range of 0.01 - 5 mM) it was found that these coexistence ions competed for the same adsorption sites with strontium and cesium ions.

• 대한소아치과학회지
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• 제31권2호
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• pp.314-322
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• 2004

글루캔 형성은 이온, 완충액 및 영양물질 등과 같은 구강 내 존재하는 물질과 이들의 변화에 영향을 받는다. 본 연구에서는 치아 우식증의 중요한 원인균인 Streptococcus mutans를 실험균으로 하여 수용성 글루캔 합성 효소인 GTFD 유전자의 발현에 대한 이온 및 완충액의 영향을 Fluorescent in situ hybridization 방법으로 관찰하여 다음의 결과를 얻었다. 1. $CaCl_2$ 농도가 1.0mM, KCl 농도가 2.5mM, $MgCl_2$의 농도가 0.4mM일 때 생균수가 가장 많았다. 2. 완충액의 경우 sodium bicarbonate 10mM, sodium phosphate 1mM, potassium phosphate 0.1mM에서 생균수가 가장 많았고, 3가지 완충액 모두 100mM 농도에서 생균수가 가장 적었다. 3. 자당이 함유되지 않은 BHI 배지에 비해 1%자당을 첨가한 경우 gtfD 유전자의 mRNA 발현에 따른 녹색형광이 관찰되었다. 4. $CaCl_2$ 0.25mM일 때 gtfD 유전자의 mRNA 발현에 따른 녹색형광이 대조군보다 강하였고, KCl의 경우 10mM일 때 대조군과 유사한 녹색형광을 나타냈으나, 다른 농도에서는 거의 관찰되지 않았다. $MgCl_2$의 경우 각 농도에서 대조군보다 녹색형광이 약하게 나타났다. 5. Sodium bicarbonate, sodium phosphate 완충액의 경우 mRNA 발현에 따른 녹색형광이 각 농도에서 대조군과 유사하게 나타났으며, potassium phosphate 완충액의 경우 100mM에서 녹색형광을 거의 관찰할 수 없었다.

• Bulletin of the Korean Chemical Society
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• 제27권9호
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• pp.1439-1444
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• 2006

A $Cu^{2+}$ ion-selective membrane microelectrode has been fabricated from poly vinyl chloride (PVC) matrix membrane containing a new symmetrical hexadentate Schiff,s base 2-{1-(E)-2-((Z)-2-{(E)-2-[(Z)-1-(2-hydroxyphenyl)ethylidene]hydrazono}-1-methylpropylidene)hydrazono]ethyl}phenol (HDNOS) as a neutral carrier, Potassium tetrakis(4-chlorophenyl) borate (KTpClPB) as an anionic excluder and o-nitrophenyloctyl ether (NPOE) as a plasticizing solvent mediator. The microelectrode displays linear potential response in the concentration range of $1.0\;{\times}\;10^{-5}-1.0\;{\times}\;10^{-11}$ M of $Cu^{2+}$. The microelectrode exhibits a nice Nernstian slope of 25.9 ${\pm}$ 0.3 mV $decade^{-1}$ in the pH range of 3.1-8.1. The sensor has a relatively short response time in whole concentration ranges ($\sim$5 s). The detection limit of proposed sensor is $5.0\;{\times}\;10^{-12}$ M (320 pg/L), and it can be used over a period of eight weeks. The practical utility of the sensor has been demonstrated by using it as an indicator electrode in the potentiometric titration of $Cu^{2+}$ with EDTA. The proposed membrane electrode was used for the direct determining of $Cu^{2+}$ content in black and red pepper, and in waste water samples.