• Title/Summary/Keyword: Liquid-Liquid Biphasic

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Diffusional Behavior of Rodlike Poly(${\gamma}-benzyl$ L-glutamate) in Concentrated Solution as Studied by the Field-Gradient $^{1}H$ NMR Methods

  • Kuroki, Shigeki
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.345-345
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    • 2006
  • It is well known that poly(glutamate)s with long n-alkyl side chains form thermotropic liquid crystalline state by melting of the side-chain crystallites and also poly(glutamate)s such as poly(${\gamma}-benzyl\;L-glutamate$ )(PBLG), poly(${\gamma}-n-alkyl\;L-glutamate$), etc. in solvent form the isotropic, biphasic and liquid crystalline phases which contains cholesteric and columnar liquid crystalline forms depending on the polypeptide concentration. Although there is no diffusion study for PBLG in liquid crystalline state, because it is difficult to observed $^{1}H$ spectrum of PBLG in liquid crystalline state for its very short $^{1}H\;T_{2}$. In this study, the diffusional behavior of rodlike PBLG in concentrated solution is successfully elucidated as studied by the field-gradient $^{1}H$ NMR methods.

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Extraction of Biomolcules by Ionic Liquids (이온성 액체를 이용한 생물분자의 추출)

  • Lee, Woo Yun;Lee, Yong Hwa;Lee, Jun;Hong, Yeon Ki
    • Journal of Institute of Convergence Technology
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    • v.4 no.2
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    • pp.23-26
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    • 2014
  • As an effective separation method for biomolecules, aqueous two-phase systems based on ionic liquids were suggested. Hydrophobic ionic liquids are more expensive and viscous in spite of their usage in the ionic liquid/water biphasic extraction compared with hydrophilic ionic liquids. In case of aqueous two-phase systems using hydrophilic ionic liquids, they can be diluted in aqueous phase. Experimental results show that aqueous two phase systems can be formed by adding appropriate amount of ionic liquids to aqueous salts solutions. The viscosity of ionic liquid aqueous phase is proportional to the cation chain length in ionic liquids. It is founded that the ionic liquid based aqueous two phase systems are effective for the separation of biomolecules such as acrylic acid.

Effects of Hydrocarbon Additions on Gas-liquid Mass Transfer Coefficients in Biphasic Bioreactors

  • Silva, Teresa Lopes da;Calado, Vitor;Silva, Nadia;Mendes, Rui L.;Alves, Sebastiao S.;Vasconcelos, Jorge M.T.;Reis, Alberto
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.11 no.3
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    • pp.245-250
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    • 2006
  • The effects of aliphatic hydrocarbons (n-hexadecane and n-dodecane) on the volumetric oxygen mass transfer coefficient $(k_L\;a)$ were studied in flat alveolar airlift reactor and continuous stirred tank reactors (CSTRs). In the flat alveolar airlift reactor, high aeration rates (>2vvm) were required in order to obtain efficient organic-aqueous phase dispersion and reliable $k_La$ measurements. Addition of 1% (v/v) n-hexadecane or n-dodecane increased the $k_La$ 1.55- and 1.33-fold, respectively, compared to the control (superficial velocity: $25.8{\times}10^{-3}m/s$, sparger orifice diameter: 0.5 mm). Analysis of the gas-liquid interfacial area a and the liquid film mass transfer coefficient $k_L$ suggests that the observed $k_La$ increase was a function of the media's liquid film mass transfer. Addition of 1% (v/v) n-hexadecane or n-dodecane to analogous setups using CSTRs led to a $k_La$ increase by a factor of 1.68 and 1.36, respectively (superficial velocity: $2.1{\times}10^{-3}m/s$, stirring rate: 250 rpm). These results propose that low-concentration addition of oxygen-vectors to aerobic microbial cultures has additional benefit relative to incubation in purely aqueous media.

In vitro Folding of Recombinant Hepatitis B Virus X-Protein Produced in Escherichia coli: Formation of Folding Intermediates

  • Kim, Sun-Ok;Sohn, Mi-Jin;Jeong, Soon-Seog;Shin, Jeh-Hoon;Lee, Young-Ik
    • BMB Reports
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    • v.32 no.6
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    • pp.521-528
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    • 1999
  • The folding of recombinant hepatitis B virus X-protein (rHBx) solubilized from Escherichia coli inclusion bodies was investigated. By sequential dialysis of urea, rHBx was folded into its native structure, which was demonstrated by the efficacy of its transcriptional activation of the adenovirus major late promoter (MLP), fluorescence spectroscopy, and circular dichroism (CD) analysis. The decrease in CD values at 220 nm and a corresponding blue shift of the intrinsic fluorescence emission confirmed the ability of rHBx to refold in lower concentrations of urea, yielding the active protein. Equilibrium and kinetic studies of the refolding of rHBx were carried out by tryptophan fluorescence measurements. From the biphasic nature of the fluorescence curves, the existence of stable intermediate states in the renaturation process was inferred. Reverse phase-high performance liquid chromatography (RP-HPLC) analysis further demonstrated the existence of these intermediates and their apparent compactness.

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Effect of Isopropanol on CO2 Absorption by Diethylenetriamine Aqueous Solutions (이소프로판올을 포함한 디에틸렌트리아민 상분리 흡수제의 CO2 흡수 특성)

  • Lee, Hwa Young;Seok, Chang Hwan;Hong, Yeon Ki
    • Clean Technology
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    • v.27 no.3
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    • pp.255-260
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    • 2021
  • A drawback in the CO2 capture process using an aqueous amine solution is the high energy requirement for the regeneration process. In order to overcome this disadvantage, this study investigated CO2 capture characteristics using a biphasic absorbent in which isopropanol (IPA) was introduced into an aqueous solution of diethylenetriamine (DETA). When the IPA composition exceeded 20 wt% in 20 wt% DETA aqueous solution, the absorbent phase was liquid-liquid separated into a CO2-rich phase and a CO2-lean phase because of the low solubility of the salt formed by the reaction of CO2 with DETA in isopropanol. When the isopropanol composition in the DETA aqueous solution increased, the phase volume ratio of the CO2-rich phase to the volume of the CO2-lean phase increased; and, accordingly, the CO2 in the CO2-rich phase was more concentrated. The results of absorbing CO2 in a packed tower using 20 wt% DETA + IPA + water absorbent confirmed that both the CO2 absorption capacity and the absorption rate were higher than that of the 20 wt% DETA aqueous solution. When a biphasic absorbent composed of DETA + IPA + water is applied to CO2 capture, it can be expected to concentrate CO2 because of phase separation and thereby reduce regeneration energy owing to volume reduction of the CO2-rich phase.

Effect of the Constituents of Angelicae dahuricae Radix on Hepatic Drug Metabolizing Enzyme Activity (백지근(白芷根) 성분(成分)이 간(肝)의 약물대사효소활성(藥物代謝酵素活性)에 미치는 효과(效果))

  • Shin, Kuk-Hyun;Kim, Ok-Nam;Woo, Won-Sick
    • Korean Journal of Pharmacognosy
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    • v.19 no.1
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    • pp.19-27
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    • 1988
  • The hexane and ether extracts from the roots of Angelica dahurica caused a significant inhibition of hepatic drug-metabolizing enzyme (DME) activity. Through systematic fractionation by $SiO_2\;column$ and vacuum liquid chromatography monitoring by bioassays, three furanocoumarins, phellopterin, byakangelicin and tert-O-methylbyakangelicin were isolated as active principles. These components have biphasic responses, both inhibitory and inducing effects on DME system. Tert-O-methyl byakangelicin was found to have the strongest enzyme inhibitory potency.

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Synthesis of Biodiesel from Soybean Oil Using Lewis Acidic Ionic Liquids Containing Metal Chloride Salts (금속염화물을 첨가한 루이스산 이온성 액체 촉매를 이용한 대두유로부터 바이오디젤 합성)

  • Choi, Jae Hyung;Park, Yong Beom;Lee, Suk Hee;Cheon, Jae Kee;Choi, Jae Wook;Woo, Hee Chul
    • Korean Chemical Engineering Research
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    • v.48 no.5
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    • pp.643-648
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    • 2010
  • Production of biodiesel from soybean oil catalyzed by Lewis acidic ionic liquids(ILs) containing metal chloride salts was investigated in this study. Metal chloride salts, such as $SnCl_2$, $ZnCl_2$, $AlCl_3$, $FeCl_3$ and CuCl, were screened for oil transesterification in the range of 363-423 K. Among these metal chlorides, tin chloride showed particularly high catalytic property for the oil transesterification. Similarly, among these Lewis acidic ionic liquid catalysts, $[Me_3NC_2H_4OH]Cl-2SnCl_2$ resulted in a high fatty acid methyl esters(FAMEs) content of 91.1% under the following reaction conditions: 403 K, 14 h, and a molar ratio of 1:12:0.9 (oil:methanol:catalyst). Unlike the pure tin chloride catalysts, Lewis acidic ILs containing tin chloride $[Me_3NC_2H_4OH]Cl-2SnCl_2$ catalyst could be recycled up to five times without any significant loss of activity by separating from the FAMEs with simple decantation. The Lewis acidity and high moisture-stability of this catalyst appeared to be responsible for the excellent catalytic performance. The effects of reaction time and the molar ratio of methanol/catalyst to oil on the FAMEs production were also studied in this work.

Development and validation of an analytical method to quantify baphicacanthin A by LC-MS/MS and its application to pharmacokinetic studies in mice

  • Jeon, So Yeon;Kim, San;Park, Jin-Hyang;Song, Im-Sook;Han, Young Taek;Choi, Min-Koo
    • Analytical Science and Technology
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    • v.35 no.2
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    • pp.60-68
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    • 2022
  • In this study, we developed and validated a sensitive analytical method to quantify baphicacanthin A in mouse plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The standard calibration curves for baphicacanthin A ranged from 0.5 to 200 ng/mL and were linear, with an r2 of 0.985. The inter- and intra-day accuracy and precision and the stability fell within the acceptance criteria. Besides, we investigated the pharmacokinetics of baphicacanthin A following its intravenous (5 mg/kg) and oral administration (30 mg/kg). Intravenously injected baphicacanthin A showed biphasic elimination kinetics with high clearance and volume of distribution values. Furthermore, baphicacanthin A showed a rapid absorption but low aqueous solubility (182.51±0.20 mg/mL), resulting in low plasma concentrations and low oral bioavailability (2.49 %). Thus, we successfully documented the pharmacokinetic properties of baphicacanthin A using this newly developed sensitive LC-MS/MS quantification method, which could be used in future lead optimization and biopharmaceutic studies.

Preparation of Biodegradable PHBV Devices Containing Gentamicin Sulfate (PHBV를 이용한 황산겐타마이신 서방성 제형의 제조와 방출거동)

  • 최학수;김상욱;윤덕일;강길선;이종문;김용식;이해방
    • Polymer(Korea)
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    • v.25 no.3
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    • pp.334-342
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    • 2001
  • Gentamicin sulfate (GS)-loaded poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV) devices were prepared for controlled-release of antibiotics. In this study, the effects of thickness, hydroxyvalerate (HV) content, initial drug-loading ratio, and additive content on the release profile have been investigated. The morphology of devices was examined with scanning electron microscope (SEM) before and after in vitro release; their highly porous surface and cross-sectional were observed. It could be suggested that device would be affected by the packing of the HV and additive content, which would depend on their structure. A high performance liquid chromatography (HPLC) was used to detect and quantify the release of GS from the device. The drug release from all the devices showed biphasic release patterns, and some matrices released the incorporated antibiotic throughout 30 days with a near zero-order release rate. The release patterns were shown to be changed by altering the thickness, copolymer ratio, and additive content.

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