• 상하수도학회지
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• 제35권6호
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• pp.533-544
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• 2021

전자 및 화학 산업의 초순수 생산 및 원자력 발전소의 부식 제어를 위해 이온교환 수지탑의 성능 파악이 필수적이다. 따라서 본 연구에서는 4종의 H 및 ETAH 형 양이온 교환수지가 채워진 양이온 및 혼상 이온교환수지탑에 미량의 NaCl를 포함하는 에탄올아민(ETA) 및 암모니아(NH₃) 용액을 주입하여 양이온 파과특성을 조사하였다. 조사 결과, 주성분인 ETAH⁺ 및 NH₄⁺와 달리, 미량성분인 Na⁺는 (이론적교환용량의 3배 이상) 시험기간 동안 수지탑 출구에서 파과 및 오버슈팅 현상이 나타나지 않았다. H형 수지탑의 파과현상은 ETAH⁺ 및 NH₄⁺가 순서대로 일어났고, 오버슈팅은 NH₄⁺가 파과할때 ETAH⁺에 대해서 발생했다. 파과영역의 너비로 결정되는 상대적 선택도는 NH₄⁺가 ETAH⁺보다 최대 51.5 % 더 높았다. 유입수 Na⁺ 농도가 높을수록, 선택도는 감소하고 오버슈팅 현상은 증가하였다. 이온교환 수지의 고유 특성을 개선하여 감소시킬 수 있는 Na⁺ 누출은, ETAH형에서 높았고 4종의 양이온수지에 대해 동일하지 않은 것으로 조사되었다.

• Archives of Pharmacal Research
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• 제27권3호
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• pp.305-313
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• 2004

The effect of diazoxide, a $K^{+}$channel opener, on apoptotic cell death was investigated in HepG2 human hepatoblastoma cells. Diazoxide induced apoptosis in a dose-dependent manner and this was evaluated by flow cytometric assays of annexin-V binding and hypodiploid nuclei stained with propidium iodide. Diazoxide did not alter intracellular $K^{+}$concentration, and various inhibitors of $K^{+}$channels had no influence on the diazoxide-induced apoptosis; this implies that $K^{+}$channels activated by diazoxide may be absent in the HepG2 cells. However, diazoxide induced a rapid and sustained increase in intracellular $Ca^{2+}$ concentration, and this was completely inhibited by the extracellular $Ca^{2+}$ chelation with EGTA, but not by blockers of intracellular $Ca^{2+}$ release (dantrolene and TMB-8). This result indicated that the diazoxide-induced increase of intracellular $Ca^{2+}$ might be due to the activation of a Ca2+ influx pathway. Diazoxide-induced $Ca^{2+}$ influx was not significantly inhibited by either voltage-operative $Ca^{2+}$ channel blockers (nifedipinen or verapamil), or by inhibitors of $Na^{+}$, $Ca^{2+}$-exchanger (bepridil and benzamil), but it was inhibited by flufenamic acid (FA), a $Ca^{2+}$-permeable nonselective cation channel blocker. A quantitative analysis of apoptosis by flow cytometry revealed that a treatment with either FA or BAPTA, an intracellular $Ca^{2+}$ chelator, significantly inhibited the diazoxide-induced apoptosis. Taken together, these results suggest that the observed diazoxide-induced apoptosis in the HepG2 cells may result from a $Ca^{2+}$ influx through the activation of $Ca^{2+}$-permeable non-selective cation channels. These results are very significant, and they lead us to further suggest that diazoxide may be valuable for the therapeutic intervention of human hepatomas.

• 대한화학회지
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• 제43권3호
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• pp.280-285
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• 1999

이온크로마토그래피를 이용하여 Pu 화학종의 분리방법을 검토하였다. 환원제(KI, $NaNO_2$) 또는 산화제(KBrO_3$)를 사용하여 Pu의 산화수를 조절한 후 1-octanesulfonate 와 ${\alpha}$-HiBA 용리액을 사용하는 동적계에서 $PuO_2^{2+},\; PC^{4+}$ 및 $Pu^{3+}$의 화학종을 각각 안정하게 개별분리하였다. Iodide와 nitrite를 동시에 사용하여 Pu 화학종들을 $Pu^{3+}$까지 환원한 다음 이온크로마토그래피로 안정하게 분리하였다.

• 한국식품영양과학회지
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• 제33권9호
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• pp.1584-1587
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• 2004

해안가 및 폐염전 등에 서식하며 각종 미네랄, 아미노산 및 유용 생리활성 물질을 함유하고 있는 함초로부터 혈중 동맥경화 및 심장 질환 예방에 유효한 효능을 보일 것으로 예상되는 성분인 betaine을 HPLC를 이용하여 분석하였다. 함초는 양쪽성 물질로 같이 존재하는 다른 이온성 물질들에 의해 방해를 받으며 UV 흡수가 매우 낮아 일반적인 정량방법으로는 분석이 매우 까다롭다. 따라서 본 연구에서는 이러한 문제를 해소하기 위하여 2단계 이온교환수지 컬럼을 이용하여 방해물질을 제거한 후 betaine을 4-bromophenacyl bromide (PBPB)로 유도체화시켜 UV-labelling 한 후 분석하였다. 이온교환수지를 통과한 함초추출물의 회수율은 83.6%이며 함초추출액 mL당 4.85mg의 betaine이 함유되어 있는 것으로 나타났다.

• 자원환경지질
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• 제28권3호
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• pp.231-241
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• 1995

It is well known that hydroxyapatite [$Ca_{10}(PO_4)_6(OH)_2$] have an exchangeability for various heavy metal ions in aqueous solution. To evalute the feasibility of employing the synthetic hydroxyapatites as an eliminatable exchanger for environmentally noxious caions in waste water, the adsorption properties, the removal capacities and the selectivity of the apatites for various cations were investigated in more detailed. The heavy metal cations have been exchanged in calcium part of hydroxyapatite. The order of the degree of amount exchanged of the investigated cations is $Pb^{2+}>Cd^{2+}>Zn^{2+}>Ba^{2+}$. The molar ratios between released $Cd^{2+}$ ions and remeved divalent metal cations in the reacted solution with hydroxyapatite are roughly close to an integer 1.0, suggesting that an ion-exchange reaction could have played a major role in the removal of heavy metals rather then an adsorption effect. The exchangeability of the hydroxyapatite powder of Ca/P molar ratio 1.67, which have specipic surface area of $104.5m^2g^{-1}$, appeared to be better then $237.6{\mu}g$ per g for $Pb^{2+}$ ions. The removal capacity of the heavy metal ions varies directly as particle size of hydroxyapatites. All evidences obtained indicate that the synthesized hydroxyapatite powders by precipitation reaction method can be employed as an effective cation exchanger for eliminating noxious ions in waste water even in some improvemental.

• 분석과학
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• 제14권1호
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• pp.28-33
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• 2001

자연수에 존재할 가능성이 있는 $Pu^{3+}$, $Pu^{4+}$, $PuO_2{^+}$, $PuO_2{^{2+}}$ 상태의 플루토늄을 이온크로마토그래피로 분리하는 방법을 연구하였다. 각각 $SiO^-$, SiO-$SO_3{^-}$작용기를 가진 이온교환체를 충전한 두 컬럼을 이용하는 방법과, Dionex사 AG11컬럼에 oxalate/$HNO_3$ 용리액을 사용하여 IC로 분리하는 두 가지 방법을 시도하였다. 예비실험으로서 플루토늄과 화학적 성질이 유사하며 산화수가 안정한 $Eu^{3+}$, $Th^{4+}$, $NpO_2{^+}$, $UO_2{^{2+}}$을 사용하여 분리조건을 얻었다. 이 분리조건을 플루토늄에 적용시켰을 때, $SiO^-$, SiO-$SO_3{^-}$ 이온교환체를 이용한 방법은 산화수별 플루토늄을 성공적으로 분리할 수 있었다. 그러나 IC를 사용한 방법은 oxalate 용액에서 $Pu^{3+}$가 쉽게 $Pu^{4+}$로 산화되며, $PuO_2{^{2+}}$도 $PuO_2{^+}$로 환원되어 분리가 곤란하였다.

• 폴리머
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• 제24권6호
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• pp.763-769
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• 2000

E-beam 전조사법을 이용하여 아크릴산과 스틸렌 단량체를 폴리프로필렌 섬유에 그라프트 반응시켜 PP-g-(AAc/Sty) 공중합체를 합성하고 술폰화 반응시켜 다관능성 섬유상 양이온 교환체를 합성하였다. 합성체의 그라프트율은 물과 메탄올 혼합비가 30 : 70 vol%인 혼합용매에서 아크릴산과 스틸렌, 단량체비가 30 : 70 vol%일 때 190%로 최대이었으며 혼합용매의 조성비가 일정할 때 아크릴산 단량체의 양이 증가할수록 그라프트율은 감소하였다. 또한 이온교환체의 이온교환용량은 4.6 meq/g이었으며, 술폰화 이온교환체와 아크릴산 이온교환체의 리튬이온에 대한 흡착량을 비교한 결과 본 연구에서 합성한 이온교환체의 흡착성이 우수한 것으로 나타났다.

• 한국식품위생안전성학회지
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• 제7권4호
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• pp.165-172
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• 1992

Among the nutrients of biological importance, minerals are of particular interest in human nutrition because the range of adequate intake is so narrow. As the results of a series of interaction experiments between dietary fiber sources and minerals, there are many inconsistencies in the experimental data regarding the effect of dietary fibers on mineral bioavailability. the mechanism by which dietary fiber might influence mineral absorption is related to its physicochemical properties. These properties involve the ability of dietary fiber to (1) act as a weak cation exchanger, (2) decrease transit time, (3) dilute mineral concentration by increasing fecal bulk and (4) resist digestion in the large bowel. Regardless of the large number of human and animal studies available, a carful review of these publications dose not provide the answer as to whether the adverse effect of dietary fibers on mineral absorption is the fiber itself or some associated dietary factors( e.g. phytate, oxalate, ascorbate, citrate and protein, mineral-mineral interaction, etc) that are responsible for this action. As a result of the complexity of interaction that may take place between minerals. dietary fiber, and other component of food ; it becomes very difficult to blame fiber alone as a negative factor of mineral nutrition. We absolutely need more research with advanced tools rather than metabolic balance study.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권1호
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• pp.61-66
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• 2006

The simple Langmuir isotherm is frequently employed to describe the equilibrium behavior of protein adsorption on a wide variety of adsorbents. The two adjustable parameters of the Langmuir isotherm - the saturation capacity, or $q_m$, and the dissociation constant, $K_d$ - are usually estimated by fitting the isotherm equation to the equilibrium data acquired from batch equilibration experiments. In this study, we have evaluated the possibility of estimating $q_m$ and $K_d$ for the adsorption of bovine serum albumin to a cation exchanger using batch kinetic data. A rate model predicated on the kinetic form of the Langmuir isotherm, with three adjustable parameters ($q_m,\;K_d$, and a rate constant), was fitted to a single kinetic profile. The value of $q_m$ determined as the result of this approach was quantitatively consistent with the $q_m$ value derived from the traditional batch equilibrium data. However, the $K_d$ value could not be retrieved from the kinetic profile, as the model fit proved insensitive to this parameter. Sensitivity analysis provided significant insight into the identifiability of the three model parameters.

• 농업과학연구
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• 제41권3호
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• pp.237-243
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• 2014

Human Glucagon like peptide-1 (GLP-1) is an incretin hormone that promotes secretion of insulin. In order to eliminate the formation of the soluble aggregate, Ala19 in GLP-1 was substituted with Thr, resulting in a GLP-1 mutant GLP-1A19T. The gene synthesis of GLP-1A19T and the fusion of 6-lysine tagged ubiquitin gene were accomplished by using the overlap extension polymerase chain reaction. The ubiquitin fused GLP-1A19T (K6UbGLP-1A19T) is expressed as form of inclusion body with little formation of the soluble aggregation in recombinant E. coli. In order to produce K6UbGLP-1A19T in large amounts, fed-batch fermentation was carried out in a pH-stat feeding strategy. Maximum dry cell weight of 87.7 g/L and 20.4% of specific K6UbGLP-1A19T content were obtained. Solid-phase refolding using a cation exchanger was carried out to renature K6UbGLP-1A19T. The refolded K6UbGLP-1A19T aggregated little and was released GLP-1A19T by on-column cleavage with ubiquitin-specific protease-1. The molecular mass of GLP-1A19T showed an accurate agreement with its theoretical molecular mass.