• Environmental Engineering Research
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• 제20권4호
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• pp.342-346
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• 2015

Haloacetonitriles (HANs) are nitrogenous disinfection by-products (DBPs) that have been reported to have a higher toxicity than the other groups of DBPs. The adsorption process is mostly used to remove HANs in aqueous solutions. Functionalized composite materials tend to be effective adsorbents due to their hydrophobicity and specific adsorptive mechanism. In this study, the removal of dichloroacetonitrile (DCAN) from tap water by adsorption on thiol-functionalized mesoporous composites made from natural rubber (NR) and hexagonal mesoporous silica (HMS-SH) was investigated. Fourier-transform infrared spectroscopy (FTIR) results revealed that the thiol group of NR/HMS was covered with NR molecules. X-ray diffraction (XRD) analysis indicated an expansion of the hexagonal unit cell. Adsorption kinetic and isotherm models were used to determine the adsorption mechanisms and the experiments revealed that NR/HMS-SH had a higher DCAN adsorption capacity than powered activated carbon (PAC). NR/HMS-SH adsorption reached equilibrium after 12 hours and its adsorption kinetics fit well with a pseudo-second-order model. A linear model was found to fit well with the DCAN adsorption isotherm at a low concentration level.

• 폴리머
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• 제34권5호
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• pp.469-473
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• 2010

광경화성 수지인 아크릴레이트의 경화 특성과 메카니즘에 대하여 Photo-DSC와 FTIR, Raman spectrometer를 이용하여 조사하였다. 아크릴레이트 종류, 관능기 수, 광 세기 등에 따른 경화 속도에 관한 정보는 시간에 따른 Photo-DSC curve에서 계산하였고, FTIR과 Raman을 이용하여 경화 반응의 전환율과 반응 메카니즘을 조사하였다. 광경화 반응에서 산소의 영향을 알아보기 위하여 아크릴레이트 수지와 thiol-ene 수지의 경화과정을 비교하였는데, 공기 중 산소가 아크릴레이트의 라디칼 반응에서 금지제로 작용하여 아크릴레이트 수지는 80% 이하의 전환율을 보인 반면 thiol-ene 수지는 산소가 반응에 영향을 미치지 않는 것을 알 수 있었다.

• 한국식품영양학회지
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• 제15권4호
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• pp.331-336
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• 2002

본 연구는 두유에 칼슘을 강화하고자 두유단백질의 칼슘내인성을 높이기 위한 방법으로 단백분해효소를 처리한 경우 효소처리 전, 후에 나타나는 단백질의 구조적 특성을 비교 분석하였다. 표면소수도는 SMP

• Bulletin of the Korean Chemical Society
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• 제24권11호
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• pp.1689-1691
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• 2003

• 대한방사성의약품학회지
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• 제4권2호
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• pp.85-89
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• 2018

We demonstrate a detail protocol for the radiosynthesis of an $^{125}I$-labeled MSTP prosthetic group and its application to the efficient radiolabeling of human serum albumin (HSA). Radioiodination of the precursor (2) was carried out by using $[^{125}I]$NaI and chloramine T as an oxidant at room temperature for 15 min. After HPLC purification of the crude product, the purified $^{125}I$-labeled MSTP ($[^{125}I]1$) was obtained with high radiochemical yield ($73{\pm}5%$, n = 3) and excellent radiochemical purity (>99%). Site-specific reaction between ($[^{125}I]1$) and HSA gave the $^{125}I$-labeled human serum albumin ($[^{125}I]3$) with more than 99% of radiochemical yield as determined by radio-thin-layer chromatography (radio-TLC). These results clearly demonstrate that the present radiolabeling method will be useful for the efficient and convenient radiolabeling of thiol-bearing biomolecules.

• 대한약침학회지
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• 제21권4호
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• pp.249-257
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• 2018

Objectives: The hepatotoxicity induced by Acetaminophen (AAP) mostly mediated by effect on oxidative stress parameters. The Zataria multiflora (Z.M) is an herbal medicine with well-known antioxidant effect. The aim of this study is investigation of preventive effects of Z.M and Carvacrol (CAR) on AAP-induced hepatotoxicity in rats. Methods: Rats were randomly divided into four groups including: 1) Control, 2) Acetaminophen (AAP), 3) and 4) CAR. The saline, Z.M (200 mg/kg) and CAR (20 mg/kg) were administrated orally for 6 days, after that AAP (600 mg/kg) was administrated in the $7^{th}$ day. Blood sampling was performed on the first and last days. Also, the liver tissue was removed for evaluation of Malondyaldehide (MDA), Thiol content, Superoxide dismutase (SOD) and Catalase (CAT). Total Protein (tPro), Glutamic Oxaloacetic Transaminase (GOT), Glutamic Pyruvic Transaminase (GPT) and Alkaline Phosphatase (ALP) in liver tissue were evaluated. The changes (${\Delta}$) of enzymes activities were presented. Results: The ${\Delta}GOT$, ${\Delta}GPT$ and ${\Delta}ALP$ in CAR group significantly decreased compared to AAP group (P < 0.01 to P < 0.001) and ${\Delta}GPT$ in Z.M group was significantly reduced in comparison with AAP group (P < 0.05). Also, MDA, Thiol, SOD and CAT levels in treated groups were attenuated compared to AAP group (P < 0.05 to P < 0.001). Conclusion: Z.M and CAR have a powerful hepatoprotective effect. CAR is more effective than Z.M. Based on the results. Z.M and CAR could be potent supplementary agents against hepatotoxicity of AAP in patients.

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1153-1157
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• 2011

A kinetic study is reported for aminolysis of S-4-nitrophenyl X-substituted thiobenzoates 3a-g in 80 mol % $H_2O$/20 mol % DMSO at $25.0{\pm}0.1^{\circ}C$. Thiol esters 3a-g are 7.8-47.6 fold more reactive than the corresponding oxygen esters (i.e., 4-nitrophenyl X-substituted benzoates 1a-g). Such reactivity order appears to be in accordance with the expectation that 4-nitrothiophenoxide in 3a-g is a better nucleofuge than 4-nitrophenoxide in 1a-g since the former is 2.64 pKa units less basic than the latter. Hammett plot for the reactions of 3a-g exhibit poor correlation coefficients ($R^2$ = 0.977-0.986) with negative deviation by substrates possessing an electrondonating group (EDG), while the Yukawa-Tsuno plots result in excellent linear correlation ($R^2$ = 0.995-0.997) with ${\rho}$ = 0.93-1.23 and r = 0.57-0.67, indicating that the negative deviation shown by substrates possessing an EDG is caused by ground-state stabilization through resonance interactions but not due to a change in ratedetermining step upon changing the nonleaving-group substituent X. The ${\rho}$ value increases as the incoming amine becomes more basic and more reactive, indicating that the RSP is not operative in the current reactions.

• Bulletin of the Korean Chemical Society
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• 제27권3호
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• pp.403-406
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• 2006

The surface structure and electrochemical behavior of self-assembled monolayers (SAMs) formed by aromatic thiols on Au(111) were investigated by scanning tunneling microscopy (STM) and cyclic voltammetry. Benzenethiol (BT) forms disordered phases on Au(111) which are composed of many bright domains, while benzyl mercaptan (BM), with a methylene unit between the aromatic group and sulfur atom, forms twodimensional ordered SAMs on Au(111). In addition, two phase-separated domains consisting of disordered and ordered phases were observed in binary SAMs formed from a 1 : 1 mixed ethanol solution of BT and BM. From STM and CV measurements, we found that the blocking efficiency of aromatic thiol SAMs coated on an Au(111) electrode for an electron transfer reaction decreases as the structural order of the SAMs increases. Molecular-scale STM and CV results obtained here will be very useful in designing functional SAMs for further applications, such as the improvement of corrosion passivation of Au(111) on an aromatic thiolmodified Au(111) surface.

• Mass Spectrometry Letters
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• 제11권3호
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• pp.59-64
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• 2020

Mertansine, a thiol-containing maytansinoid, is a tubulin inhibitor used as the cytotoxic component of antibody-drug conjugates for the treatment of cancer. Liquid chromatography-tandem mass spectrometry was described for the determination of mertansine in rat plasma. 50-μL rat plasma sample was pretreated with 25 μL of 20 mM tris-(2-carboxyethyl)-phosphine, a reducing reagent, and further vortex-mixing with 50 μL of 50 mM N-ethylmaleimide for 3 min resulted in the alkylation of thiol group in mertansine. Alkylation reaction was stopped by addition of 100 μL of sildenafil in acetonitrile (200 ng/mL), and following centrifugation, aliquot of the supernatant was analyzed by the selected reaction monitoring mode. The standard curve was linear over the range of 1-1000 ng/mL in rat plasma with the lower limit of quantification level at 1 ng/mL. The intra- and inter-day accuracies and coefficient variations for mertansine at four quality control concentrations were 96.7-113.1% and 2.6-15.0%, respectively. Using this method, the pharmacokinetics of mertansine were evaluated after intravenous administration of mertansine at doses of 0.2, 0.5, and 1 mg/kg to female Sprague Dawley rats.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3103-3108
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• 2010

Conducting polymers (CPs) are widely used as matrixes for the entrapment of enzymes in analytical chemistry and biosensing devices. However, enzyme-catalyzed polymerization of CPs is rarely used for immunosensing due to the difficulties involved in the quantitative analysis of colloidal CPs in solution phase. In this study, an enzyme-amplified electrocatalytic immunosensor employing a CP as a redox marker has been developed. A polyanionic polymer matrix, $\alpha$-amino-$\omega$-thiol terminated poly(acrylic acid), was employed for precipitation of CP. The acrylic acid group acts as a polyanionic template. The thiol terminus of the polymer was used to produce self-assembled monolayers (SAMs) on Au electrodes and the amine terminus was employed for immobilization of biomolecules. In an enzymeamplified sandwich type immunosensor, the polyaniline (PANI) produced enzymatically is attracted by the electrostatic force of the matrix polymer. The precipitated PANI was characterized by electrochemical methods.