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991.
Agathe Szkola Katrina Campbell Christopher T. Elliott Reinhard Niessner Michael Seidel 《Analytica chimica acta》2013
A novel multiplexed immunoassay for the analysis of phycotoxins in shellfish samples has been developed. Therefore, a regenerable chemiluminescence (CL) microarray was established which is able to analyze automatically three different phycotoxins (domoic acid (DA), okadaic acid (OA) and saxitoxin (STX)) in parallel on the analysis platform MCR3. As a test format an indirect competitive immunoassay format was applied. These phycotoxins were directly immobilized on an epoxy-activated PEG chip surface. The parallel analysis was enabled by the simultaneous addition of all analytes and specific antibodies on one microarray chip. After the competitive reaction, the CL signal was recorded by a CCD camera. Due to the ability to regenerate the toxin microarray, internal calibrations of phycotoxins in parallel were performed using the same microarray chip, which was suitable for 25 consecutive measurements. For the three target phycotoxins multi-analyte calibration curves were generated. In extracted shellfish matrix, the determined LODs for DA, OA and STX with values of 0.5 ± 0.3 μg L−1, 1.0 ± 0.6 μg L−1, and 0.4 ± 0.2 μg L−1 were slightly lower than in PBS buffer. For determination of toxin recoveries, the observed signal loss in the regeneration was corrected. After applying mathematical corrections spiked shellfish samples were quantified with recoveries for DA, OA, and STX of 86.2%, 102.5%, and 61.6%, respectively, in 20 min. This is the first demonstration of an antibody based phycotoxin microarray. 相似文献
992.
《合成通讯》2013,43(15):2107-2114
Abstract This work describes the lipase‐mediated epoxidation of cyclohexene. Lipases were used to generate peroxyoctanoic acid directly from octanoic acid and hydrogen peroxide and applied in situ to obtain cyclohexene oxide. Various parameters, which could affect this reaction, were studied such as lipases from different sources, organic solvents, temperature and acyl donor concentrations. Highest conversions to cyclohexene epoxide were achieved using a two‐phase system of toluene or xylene/water with ROL (Amano F‐Ap15 free Rhizopus orizae lipase) (84 and 80%) or CALB (Novozymes 435®‐immobilized Candida antarctica lipase type B) (>9 and 84%) as biocatalysts. Using PSL (Amano PS‐free Pseudomonas sp) the conversions were in the range of 12–53%, but an improvement was obtained by the use of the ionic liquid 1‐butyl‐3‐methylimidazolium tetrafluoroborate (20 to 41% in water/methyl dichloride). 相似文献
993.
Qi‐jing Lin Shu‐ming Yang Chen‐ying Wang Jian‐jun Ding Zhuang‐de Jiang 《Surface and interface analysis : SIA》2013,45(8):1223-1227
Two bilayer thin films with different stacking sequences, Cu/Ti/Si and Ti/Cu/Si, were deposited by DC magnetron sputtering technique. X‐ray diffraction technique was used to measure the crystallization structures, and scanning electron microscopy and atomic force microscopy were used to measured surface morphology. The multifractal spectra f(α)‐α was used to characterize the surface morphology. The result of |q|max ≤ 53 is obtained by multifractal analysis. The shape of the multifractal spectra f(α) ? α is hook‐like for Cu/Ti/Si and bell jar‐like for Ti/Cu/Si. The spectrum width Δα = αmax ? αmin and Δf(=f(αmin) ? f(αmax)) of the multifractal spectra is able to quantitatively analyze the growth and surface roughness of the Cu/Ti bilayer thin films. The surface of Ti/Cu/Si thin film is more uniform and smoother than the film of Cu/Ti/Si. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
994.
This work describes the dielectric properties of piezoelectric poly(vinylidene fluoride) (PVDF) thin films in the frequency and temperature ranges relevant for usual applications. We measured the isothermal dielectric relaxation spectra of commercial piezoelectric PVDF thin films between 10 Hz to 10 MHz, at several temperatures from 278 K to 308 K. Measurements were made for samples in mechanically free and clamped conditions, in the direction of the poling field (perpendicular to the film). We found that the imaginary part of the dielectric relaxation spectra of free and clamped PVDF samples is dominated by a peak, above 100 kHz, that can be characterized by a Havriliak-Negami function. The characteristic time follows an Arrhenius dependence on temperature. Moreover, the spectra of the free PVDF samples show two additional peaks at low frequencies which are associated with mechanical relaxation processes. Our results are important for the characterization of piezoelectric PVDF, particularly after the stretching and poling processes in thin films, and for the design and characterization of a broad range of ultrasonic transducers. 相似文献
995.
《Journal of Dispersion Science and Technology》2013,34(6):659-663
A new type of surfactant, 3‐alkoxyl‐2‐hydroxylpropyltrimethyl ammonium bromide (CnH2n+1OCH2CH(OH)CH2N(CH3)3 +Br?, abbreviated as RnTAB, n=8, 12, 14, 16) was synthesized. The solubilization of n‐pentanol, n‐hexanol, n‐heptanol, benzyl alcohol, n‐hexane, benzene, toluene, heptane, and carbon tetrachloride in aqueous solutions of RnTAB, sodium dodecyl sulfonic(R12SO3Na), and in the mixed solution of R16TAB/R12SO3Na have been studied by the microtitration method. The experimental results show that the solubilized amounts of the organic compounds increase with the growing of the hydrocarbon chain of RnTAB, and the solubilizing ability of the binary system is lower for polar substances than for a mono‐surfactant aqueous solution. “V” isothermal curves of the solubilized amount of polar substances have been observed, and the minimum solubilized amount is at the molar ratio 1∶1 of R16TAB/R12SO3Na. However, the solubilizing ability of mixed surfactants for non polar substances is higher than that for a mono‐surfactant solution, the solubilizing isotherm curves present a “saddle” shape, and the maximum solubilized amount is at the molar ratio 1∶1 of R16TAB/R12SO3Na too. The length of hydrophobic chains of surfactant and the polarity of the organic compound affect the transfer free energy from aqueous to micelle phase. The longer the hydrophobic chain of RnTAB and the lower the polarity of the organic compound, the more easily will the compound transfer from aqueous phase to micelle phase. 相似文献
996.
A series of functional polyorganosiloxanes containing fluorocarbon side chain and amino groups had been synthesized by ring-opening polymerization. The raw materials used were Octamethyl cyclotetrasiloxane (D4), dodecafluoroheptyl-propyl-trimethoxylsilane (502) and γ-aminopropyltriethoxylsilane (550), respectively. FTIR, 1H-NMR, 13C-NMR, and 19F-NMR were used to characterize the copolymer structures. The surface properties of the functional polyorganosiloxanes emulsions were discussed. The results showed that the functional polyorganosiloxanes containing fluorocarbon and amino side chains had low surface tension and excellent water repellency. 相似文献
997.
T.L.-G. Carlson K. Larsson Y. Miezis 《Journal of Dispersion Science and Technology》2013,34(2):197-208
In connection with studies of technical functionality of lipids in cereals, the aqueous systems of lipids from rye and tri-ticale flour are described and compared to different wheat culti-vars. Rye lipids give a lamellar liquid-crystalline phase with very small ordered regions, and this phase is continuously changed into an L2-phase with increasing water content. Triticale lipids exhibit phase equilibria in between lipids of wheat and of rye. Evidence is given for a significant role of the lamellar liquid--crystalline phase with regard to technical functionality when the cereal flour is worked in water to give a dough. 相似文献
998.
Sandeep Kumar Singh Balkishen Razdan 《Journal of Dispersion Science and Technology》2013,34(4):538-545
This article looks at atomic force microscopy as an important aid to characterize the self-nanoemulsifying formulation of glibenclamide, lovastatin, and carvedilol in conjunction with other sophisticated technique, viz., transmission electron microscopy and photon correlation spectroscopy. Sizes obtained by processing the atomic force microscopy (AFM) image are comparable with those obtained from transmission electron microscope. Although in the present study, the mean particle size obtained from photon correlation spectroscopy does not correlate to the findings of atomic force microscopy and transmission electron microscopy, but the poly-disperse index values correlate well with the findings of AFM and transmission electron microscopy where uniform particle size was observed in aqueous dispersion of self-nanoemulsifying formulation of glibenclamide, lovastatin, and carvedilol. 相似文献
999.
A. Mohammad R. Gupta Nazrul Haq Mu. Naushad G. E. El-Desoky 《Journal of Dispersion Science and Technology》2013,34(8):1179-1184
Aqueous ethylene glycol (ethane 1,2 diol) as a green mobile phase has been used for thin layer chromatographic (TLC) studies of cationic surfactants on alumina layers. Nineteen solvent systems were used to examine the mobility of the surfactants and to discover the best TLC system for the selective separation of dodecyl trimethylammonium bromide (DTAB) from multi-component mixture of other surfactants. Among the TLC systems studied, M3 (ethylene glycol: water, 8:2) was best for achieving the selective separation of DTAB from multi-component mixture of other surfactants because in this mobile phase mobility of all surfactants except DTAB were insignificant. Effect of organic additives in aqueous ethylene glycol mobile phase on the mobility of surfactants was examined. The results obtained on laboratory made alumina TLC plates and commercially available precoated alumina HPTLC plates were compared. The lower limits of detection of DTAB, CPC, CTAB, HDTAC, and TTAB were 0.02, 0.05, 0.04, 0.06, or 0.08 µg per zone respectively. The resolution of mixture of cationic surfactants was also examined in the presence metal cations as an impurity in the analyzed sample. 相似文献
1000.
Sandeep Kumar Singh Balkishen Razdan 《Journal of Dispersion Science and Technology》2013,34(6):771-777
The dynamics of morphological transition in amphiphillic systems such as self-nanoemulsifying drug delivery system (SNEDDS) has become an increasingly active field of research in colloidal science. The present contribution deals with the morphological transition of selected optimized SNEDDS formulations of glibenclamide, carvedilol, and lovastatin on progressive aqueous dilution using transmission electron microscopy. The study emphasizes the structural aspects of the systems and stresses the effect of aqueous dilution under which the systems transform from water-in-oil (L2) phase into bicontinuous structure and, finally, in oil-in-water (L1) nanodroplets. 相似文献