• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2002년도 제9차 국제심포지움 및 추계정기학술발표회
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• pp.53-53
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• 2002

Shoot tips of in vitro propagated plantlets were cryopreserved using encapsulation/dehydration procedures. Shoot tips were excised under filter sterilized antioxidants solution (0.2M phosphate buffer, pH 5.7 supplemented with 5g/1 ascorbic acid and 15g/1 sodium borate). They were drawn up into a sterile 10 $\textrm{cm}^3$disposable pipette and were dropped into the culture medium with 2.5w/v Na-alginate, then into 100mM CaCl$_2$.2$H_2O$. Encapsulated shoot tips were transferred into 10㎤ of liquid culture medium with a range of sucrose concentrations (0.25-1.0M) and were incubated in dark for 24 hours in 18C at 40rpm. Beads were then dehydrated in silica gel for different time intervals (1-24 hours). Then they were freeze dried either rapidly (plunge directly into liquid N2 or in two stages (samples were kept at 20C for 10 minutes, then reduced to 35C at 1C per minute. Then, plunge into liquid $N_2$). The influence of sucrose and silica gel pre-treatment on pre- and post-freeze shoot growth was examined.(중략)

• Bulletin of the Korean Chemical Society
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• 제26권1호
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• pp.38-42
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• 2005

Bis(2-methylbenzaldehyde)butane-2,3-dihydrazone(TDSB) was used as new N-N Schiff's base which plays the role of an excellent ion carrier in the construction of a La(III) membrane sensor. The best performance was obtained with a membrane containing, 30% poly(vinyl chloride), 60% benzyl acetate, 6% TDSB and 4% sodium tetraphenyl borate. This sensor reveals a very good selectivity towards La(III) ions over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The proposed electrode exhibits a Nernstian behavior (with slope of 19.8 mV per decade) over a wide concentration range (1.0 ${\times}$ 10$^{-5}$-1.0 ${\times}$ 10$^{-1}$ M). The detection limit of the sensor is 7.0 ${\times}$ 10$^{-6}$ M. It has a very short response time, in the whole concentration range ($\sim$5 s), and can be used for at least twelve weeks in the pH range of 3.0-9.4. The proposed sensor was successfully applied as an indicator electrode for the potentiometric titration of a La(III) solution, with EDTA. It was also successfully applied in the determination of fluoride ions in three mouth wash preparations.

• Korea-Australia Rheology Journal
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• 제19권1호
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• pp.43-47
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• 2007

The polydiacethylene (PDA) is known to change its color by mechanical shear. The shear-induced color transition has been reported with elastomer or film type of PDA. In this paper, we newly investigated the transition with liposome type of PDAs in polymeric solutions. The liposomes were dispersed in Poly(vinyl alcohol) 2% + Sodium borate 1%, Poly(vinyl alcohol) 15% and Hyaluronic acid 1% (PVA/B, PVA, HA). The shear stress was continuously imposed to each solution by stress control type rheometer with coni-cylinder fixture. The degree of color transition was quantified with the characteristic absorbance peak at 540 nm (blue) and 640 nm (red). As a result, PDA liposome in PVA/B solution changed the color from blue to red upon increasing the magnitude of shear (from 0 to 100 Pa) and the duration of shear-imposed time (from 0 to 5400 sec). Meanwhile, PDA liposome in HA or PVA solution did not noticeably change the color, even though the low shear viscosities of the solutions were kept almost constant. This color transition of PDA liposome is expected to measure the magnitude of shear, and to distinguish different responses of polymeric solutions to the applied shear.

• 한국세라믹학회지
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• 제52권3호
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• pp.180-185
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• 2015

Low-cost ceramic membrane supports with pore sizes in the range of $0.52-0.62{\mu}m$ were successfully prepared by uniaxial dry compaction method using inexpensive raw materials including kaolin, bentonite, talc, sodium borate, and alkaline-earth oxides in carbonate forms (e.g., $MgCO_3$, $CaCO_3$, and $SrCO_3$). The prepared green supports were sintered at $1000^{\circ}C$ for 8 hr in air. The effect of alkaline-earth oxide additives on the flexural strength of clay-based membrane supports was investigated. The porosity of the clay-based membrane supports was found to be in the range of 33-34%. The flexural strength of the clay-based membrane supports with 1% alkaline-earth carbonates was found to be in the range of 42.8-52.7 MPa. The addition of alkaline-earth carbonates to clay-based membrane supports resulted in large increases (47-80%) in the flexural strength of the membrane supports, compared to that of membrane supports without alkaline-earth carbonates. The typical flexural strength of the clay-based membrane support with 1% $SrCO_3$ was 52.7 MPa at 33.8% porosity.

• Archives of Pharmacal Research
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• 제24권6호
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• pp.601-606
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• 2001

A simple assay method of recombinant human epidermal growth factor (rhEGF) in a pharmaceutical preparation was studied and validated by capillary electrophoresis (CE) using micellar electrokinetic chromatography (MEKC) techniques. Factors affecting the migration behavior and separation performances of the peptide; type of buffers pH, butler concentration, and concentration of sodium dodecyl sulfates (SDS) were investigated to optimize the analytical performance. CE was performed using running buffers 50.0 mM borate (pH 8.5) containing 12.5 mM SDS at 20 $mutextrm{V}$ of the applied voltage. Calibration curves for the rhEGF showed good linearity (r>0.999) over the wide dynamic range from 1.25 to $100{\mu\textrm{g}}/ml$. Sample analysis was performed by using standard addition method to eliminate the matrix effects of dosage vehicle. This method is assumed to be useful for quality control (QC) of various forms of pharmaceutical products of the peptide.

• Bulletin of the Korean Chemical Society
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• 제14권2호
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• pp.234-238
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• 1993

The method of study describes the determination of the nanogram amounts of mono-, di-, and tri-butyltin compounds in sea water. The procedure is based on 1) the conversion of tin compounds to non-ionic species by sodium tetraethyl borate as an alkylation reagent, 2) one-step ethylation and 3) extraction. No further purification or concentration of the extract was required before GC-FPD (Flame Photometric Detector). The detection limits for mono-, di- and tri-butyltin were 12.50, 6.02, and 4.19 ng/L. The linear range (0-120 ng/L) was solely dependent on the detector response height. Sea water samples (n=24) were obtained from Masan Bay, Busan, Ullsan, Gunsan, Sockcho, Yeasu, Donghae, Inchun, Kanghwa, and Ahsan in Korea. The samples were collected between June, 1992 to July, 1992 and the distribution of monobutyltintrichloride (MBTC), dibutyltindichloride (DBTC), and tributyltinchloride (TBTC) in sea water was recorded. The concentrations of butyltin compounds in seawater were found to be in the range of N.D. (not detected)-61.93 ng/L for MBTC, N.D.-32.16 ng/L for DBTC, and N.D.-55.76 ng/L for TBTC.

• Bulletin of the Korean Chemical Society
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• 제26권4호
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• pp.579-584
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• 2005

The 3-[(2-furylmethylene)amino]-2-thioxo-1,3-thiazolidin-4-one (FTT) was used as an excellent ionophore in construction of a $Zn^{2+}$ PVC-based membrane sensor. The best performance was obtained with a membrane composition of 30% poly(vinyl chloride), 62% nitrobenzen (NB), 3% FTT and 5% sodium tetraphenyl borate (TBP). This membrane sensor shows very good selectivity and sensitivity towards $Zn^{2+}$ over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The membrane sensor revealed a great enhancement in selectivity coefficients for $Zn^{2+}$ ions, in comparison to the previously reported $Zn^{2+}$ membrane sensors. Theoretical studies also showed the selective interaction of TFF and $Zn^{2+}$ ions. The proposed membrane sensor exhibits a Nernstian behavior (with slope of 29.3 ${\pm}$ 0.3 mV per decade) over a wide concentration range (1.0 ${\times}$ $10^{-6}$-1.0 ${\times}$ $10^{-2}$) with a detection limit of 8.5 ${\times}$ $10^{-7}$ M (52 ng mL$^{-1}$). It shows relatively fast response time, in the whole concentration range ($\lt$ 20 s), and can be used for at least 10 weeks in a pH range of 3.0-7.0. The proposed membrane sensor was successfully used in direct determination of $Zn^{2+}$ ions in wastewater of industrial zinc electroplating companies, and also as an indicator electrode in titration with EDTA.

• 대한화학회지
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• 제27권6호
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• pp.434-440
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• 1983

테트라히드로프란 용액에서 수소화붕소나트륨과 붕산트리페닐을 사용해서 카르복시산, 카르복시산염, 3차아미드 및 술폭시드를 환원하는 새로운 방법을 개발하였다. 즉 카르복시산은 실온에서 6~12시간에 정량적으로 환원될 수 있으며, 지방족 카르복시산염은 실온에서 6시간에 정량적으로 환원되나 방향족 산염은 $65^{\circ}C$에서 24시간이 소요되었다. 3차 아미드는 실온에서 3~6시간에 88∼100%의 좋은 수율로 환원되었으며, 조사한 대부분의 술폭시드는 실온에서 1~6시간에 98∼100%의 수율로 환원되었으나, 디페닐술폭시드는 보다 격렬한 조건에서 48시간에 환원할 수 있었다.

• 방사성폐기물학회지
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• 제8권2호
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• pp.143-150
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• 2010

가압경수로 원전의 농축폐액건조설비에서 발생된 농축폐액 건조물을 유리화 하는 방안이 연구되어 왔다. 중저준위 방사성폐기물을 유리화할 경우 최종 생성물은 내구성이 우수하고 현저한 부피저감 효과의 장점을 가지고 있다. 붕산농축폐액에 대한 유리화 타당성 연구는 분말시료의 전처리 방법 개발, 유리조성 프로그램을 이용한 유리개발 및 실증시험으로 수행되었다. 분말시료에 대한 전처리 방안으로는 유리화설비에 투입하기 전에 고형성을 갖도록 펠렛화하는 것이다. 농축폐액 성분중 Na와 B의 함량 분포는 유리속에 용융되는 정도와 설비로부터의 폐기물 배출 처리에 영향을 주기 때문에 이를 고려하여 유리조성이 개발되어야 한다. 실증시험에서는 폐기물 투입률, 배기체 특성 및 최종 생성물인 유리고화체의 특성이 검토되었다. 본 연구는 붕산농축폐액에 대한 유리고화체의 물리화학적 특성을 검토하고 유리화 타당성을 확인하는데 목적이 있다.

• The Korean Journal of Physiology and Pharmacology
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• 제19권3호
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• pp.249-255
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• 2015

Wnk kinase maintains cell volume, regulating various transporters such as sodium-chloride cotransporter, potassium-chloride cotransporter, and sodium-potassium-chloride cotransporter 1 (NKCC1) through the phosphorylation of oxidative stress responsive kinase 1 (OSR1) and STE20/SPS1-related proline/alanine-rich kinase (SPAK). However, the activating mechanism of Wnk kinase in specific tissues and specific conditions is broadly unclear. In the present study, we used a human salivary gland (HSG) cell line as a model and showed that $Ca^{2+}$ may have a role in regulating Wnk kinase in the HSG cell line. Through this study, we found that the HSG cell line expressed molecules participating in the WNK-OSR1-NKCC pathway, such as Wnk1, Wnk4, OSR1, SPAK, and NKCC1. The HSG cell line showed an intracellular $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) increase in response to hypotonic stimulation, and the response was synchronized with the phosphorylation of OSR1. Interestingly, when we inhibited the hypotonically induced $[Ca^{2+}]_i$ increase with nonspecific $Ca^{2+}$ channel blockers such as 2-aminoethoxydiphenyl borate, gadolinium, and lanthanum, the phosphorylated OSR1 level was also diminished. Moreover, a cyclopiazonic acid-induced passive $[Ca^{2+}]_i$ elevation was evoked by the phosphorylation of OSR1, and the amount of phosphorylated OSR1 decreased when the cells were treated with BAPTA, a $Ca^{2+}$ chelator. Finally, through that process, NKCC1 activity also decreased to maintain the cell volume in the HSG cell line. These results indicate that $Ca^{2+}$ may regulate the WNK-OSR1 pathway and NKCC1 activity in the HSG cell line. This is the first demonstration that indicates upstream $Ca^{2+}$ regulation of the WNK-OSR1 pathway in intact cells.