硫酸溶液中1,1'-硫代羰基二咪唑在碳钢上的吸附及缓蚀影响和碘离子的增强应

The inhibition effect of 1,1'-thiocarbonyldiimidazole (TCDI) on the corrosion behaviors of mild steel impedance spectroscopy(EIS),and linear polarization resistance(LPR)techniques.The effect of immersion time on the inhibition effect of TCDI was also investigated over 72 h.For the long.term tests.hydrogen evolution with immersion time(VH2-t)was measured in addition to the three techniques already mentioned.The thermodynamic parameters.such as adsorption equilibrium constant(Kads) and adsorption free energy(△Gads)values,were calculated and discussed.To clarify inhibition mechanism,the synergistic effect of iodide ion was also investigated.The potential of zero charge (PZC)of the MS was studied by electrochemical impedance spectroscopy method.and a mechanism of adsorption process was proposed.It was demonstrated that inhibition efficiency increased with the increase in TCDI concentration and synergistically increased in the presence of KI.The inhibition efficiency was discussed in terms ofadsorption of inhibitormolecules on the metal surface and protective film formation.     

Electrical wiring of Pseudomonas putida and Pseudomonas fluorescens with osmium redox polymers

Two different flexible osmium redox polymers; poly(1-vinylimidazole)12-[Os-(4,4'-dimethyl-2,2'-di'pyridyl)2Cl2](2+/+) (osmium redox polymer I) and poly(vinylpyridine)-[Os-(N,N'-methylated-2,2'-biimidazole)3](2+/3+) (osmium redox polymer II) were investigated for their ability to efficiently "wire" Pseudomonas putida ATCC 126633 and Pseudomonas fluorescens (P. putida DSM 6521), which are well-known phenol degrading organisms, when entrapped onto cysteamine modified gold electrodes. The two Os-polymers differ in redox potential and the length of the side chains, where the Os(2+/3+)-functionalities are located. The bacterial cells were adapted to grow in the presence of phenol as the sole source of organic carbon. The performance of the redox polymers as mediators was investigated for making microbial sensors. The analytical characteristics of the microbial sensors were evaluated for determination of catechol, phenol and glucose as substrates in both batch analysis and flow analysis mode.     

Adsorption of cinnabarinic acid from culture fluid with magnetic microbeads

In this study, antimicrobial pigment cinnabarinic acid (CA) was produced from Pycnoporus cinnabarinus in laboratory‐scale batch cultures. Magnetic poly(ethylene glycol dimethacrylate‐N‐methacryloyl‐l‐tryptophan methyl ester) [m‐poly(EGDMA‐MATrp)] beads (average diameter = 53–103 µm) were synthesized by copolymerizing of N‐methacryloyl‐l‐tryptophan methyl ester (MATrp) with ethylene glycol dimethacrylate (EGDMA) in the presence of magnetite (Fe₃O₄) and used for the adsorption of CA. The m‐poly(EGDMA‐MATrp) beads were characterized by N₂ adsorption/desorption isotherms (Brunauer Emmet Teller), X‐ray photoelecron spectroscopy, scanning electron microscopy, infrared spectroscopy, thermal gravimetric analysis, electron spin resonance and swelling studies. The efficiency of m‐poly(EGDMA‐MATrp) beads for separation of CA from culture fluid was evaluated. The effects of pH, initial concentration, contact time and temperature on adsorption were analyzed. The maximum CA adsorption capacity of the m‐poly(EGDMA‐MATrp) beads was 272.9 mg g⁻¹ at pH 7.0, 25 °C. All the isotherm data can be fitted with the Langmuir, Freundlich and Dubinin–Radushkevich isotherm models. The adsorption process obeyed pseudo‐second‐order kinetic model. Thermodynamic parameters ΔH = 5.056 kJ mol⁻¹, ΔS = 52.44 J K⁻¹ mol⁻¹ and ΔG = −9.424 kJ mol−¹ to ‐11.27 kJ mol−¹ with the rise in temperature from 4 to 40 °C indicated that the adsorption process was endothermic and spontaneous. Copyright © 2015 John Wiley & Sons, Ltd.     

Cytotoxic and apoptotic effects of Hypericum androsaemum on prostate adenocarcinoma (PC-3) and hepatocellular carcinoma (Hep G2) cell lines with identification of secondary metabolites by LC-HRMS

The study aims to determine the secondary metabolites of Hypericum androsaemum L. extracts by liquid chromatography-high resolution mass spectrometry (LC-HRMS), and investigate the antioxidant and cytotoxic activities of the plant. Cytotoxic activity was evaluated by MTT assay, and apoptosis induction abilities on human prostate adenocarcinoma (PC-3), and hepatocellular carcinoma (Hep G2) cell lines. Accordingly, major secondary metabolites were found as hederagenin (762 ± 70.10 μg/g) in the leaves dichloromethane (LD), herniarin (167 ± 1.50 μg/g) in fruit dichloromethane (FD), (-)-epicatechin (6538 ± 235.36 μg/g) in the leaves methanol (LM), (-)-epigallocatechin gallate (758 ± 20.46 μg/g) in the fruit methanol (FM), and caffeic acid (370 ± 8.88 μg/g) in the fruit water (FW), and (3313 ± 79.51 μg/g) in the leaves water (LW) extracts. LM exerted strong antioxidant activity in DPPH free (IC₅₀ 10.94 ± 0.08 μg/mL), and ABTS cation radicals scavenging (IC₅₀ 9.09 ± 0.05 μg/mL) activities. FM exhibited cytotoxic activity with IC₅₀ values of 73.23 ± 3.06 µg/mL and 31.64 ± 2.75 µg/mL on PC-3 and Hep G2 cell lines, respectively. Being the richest extract in terms of quillaic acid (630 ± 18.9 μg/g), which is a well-known cytotoxic triterpenoid with proven apoptosis induction ability on different cells, FM extract showed apoptosis induction activity with 64.75% on PC-3 cells at 50 μg/mL concentration. The study provides promising results about the potential of Hypericum androsaemum on cancer prevention.     

Synthesis and properties of a novel redox driven chemiluminescent material built on a terthienyl system

A novel redox driven chemiluminescent material built on a terthienyl system, namely 5,7-di-ethylenedioxythiophen-2-yl-2,3-dihydro-thieno[3,4-d]pyridazine-1,4-dione (ETE-Lum), which is soluble in both organic media and basic aqueous solution was synthesized and characterized. Furthermore, its polymer, PETE-Lum, which is one of the most rare examples of chemiluminescent polymeric materials bearing a pyridazine unit, was obtained successfully by electrochemical means. Both of the materials give chemiluminescence either by treatment with oxidants (H₂O₂ and/or KMnO₄) or by the application of a potential pulse.     

Determination of 5‐Aminosalicylic Acid by Catalase‐Peroxidase Based Biosensor

5‐Aminosalicylic acid is an antiinflammatory drug used to treat inflammation of the digestive tract (Crohn's disease) and mild to moderate ulcerative‐colitis. 5‐Aminosalicylic acid is a bowel‐specific aminosalicylate drug. It was developed an amperometric biosensor for determination of 5‐aminosalicylic acid concentration and measurement technique is based on substrate‐competition. The biosensor is more suitable especially for routine 5‐aminosalicylic acid analysis because it is simple to construct and sensitive, specific and does not require any expensive apparatus. This enzyme based biosensor was made with a couple of enzymes which uses the same substrate. The electrode was developed to determine measurement conditions and also characterized.     

Determination of phenolic acids using Trametes versicolor laccase

Two biosensors based on Trametes versicolor laccase (TvL) were developed for the determination of phenolic compounds. Commercial oxygen electrode and ferrocene-modified screen-printed graphite electrodes were used for preparation of laccase biosensors. The systems were calibrated for three phenolic acids. Linearity was obtained in the concentration range 0.1-1.0 μM caffeic acid, 0.05-0.2 μM ferulic acid, 2.0-14.0 μM syringic acid for laccase immobilised on a commercial oxygen electrode and 2.0-30.0 μM caffeic acid, 2.0-10.0 μM ferulic acid, 4.0-30.0 μM syringic acid for laccase immobilised on ferrocene-modified screen-printed electrodes. Furthermore, optimal pH, temperature and thermal stability studies were performed with the commercial oxygen electrode. Both electrodes were used for determination of a class of phenolic acids, achieving a cheap and fast tool and an easy to be used procedure for screening real samples of human plasma.     

硫酸溶液中1,1’-硫代羰基二咪唑在碳钢上的吸附及缓蚀影响和碘离子的增强效应

The inhibition effect of 1,1’-thiocarbonyldiimidazole (TCDI) on the corrosion behaviors of mild steel (MS) in 0.5 mol·L -1 H2SO4 solution was studied with the help of potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and linear polarization resistance (LPR) techniques. The effect of immersion time on the inhibition effect of TCDI was also investigated over 72 h. For the long-term tests, hydrogen evolution with immersion time (VH2-t) was measured in addition to the three techniques already mentioned. The thermodynamic parameters, such as adsorption equilibrium constant (Kads) and adsorption free energy (⊿Gads) values, were calculated and discussed. To clarify inhibition mechanism, the synergistic effect of iodide ion was also investigated. The potential of zero charge (PZC) of the MS was studied by electrochemical impedance spectroscopy method, and a mechanism of adsorption process was proposed. It was demonstrated that inhibition efficiency increased with the increase in TCDI concentration and synergistically increased in the presence of KI. The inhibition efficiency was discussed in terms of adsorption of inhibitor molecules on the metal surface and protective filmformation.     

Electrical properties and photoconductivity of polyaniline/sulfonated poly(arylene ether sulfone) composite films

Temperature dependent electrical conductivity of the polyaniline-sulfonated poly(arylene ether sulfone) with 35 mol percent sulfonation (PANI-BPS35) composite films were investigated in the temperature range of 80–380 K. These composite films showed semiconductor behavior with the exponential variation of inverse temperature dependence of electrical conductivity. Calculated Mott’s parameters showed that variable range hopping mechanism is the dominant transport mechanism for the carriers in low temperature region. Photoconductivity of the PANI-BPS35 composite films having 10, 20, and 40 weight percent conductive filler under various illumination intensities was also studied. Photocurrent of the composite films increased with increasing both polyaniline weight fraction and temperature. Finally, the effect of doping on both electrical conductivity and the photoconductivity of the composite films was investigated.