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Micellar Phase (micellar + phase)
Selected AbstractsLength-dependent DNA separations using multiple end-attached peptide nucleic acid amphiphiles in micellar electrokinetic chromatographyELECTROPHORESIS, Issue 13 2008Jeffrey M. Savard Abstract End-labeled free-solution electrophoresis (ELFSE) is an alternative approach to gel-based methods for size-based electrophoretic separation of DNA. In ELFSE, an electrically neutral "drag-tag" is appended to DNA to add significant hydrodynamic drag, thereby breaking its constant charge-to-friction ratio. Current drag-tag architecture relies on covalent attachment of polymers to each DNA molecule. We have recently proposed the use of micellar drag-tags in conjunction with sequence-specific hybridization of peptide nucleic acid amphiphiles (PNAAs). This work investigates the effect of multiple PNAA attachment on DNA resolution using MEKC. Simultaneous PNAA hybridization allows for the separation of long DNA targets, up to 1012,bases, using micellar drag-tags. Each PNAA handle independently interacts with the micellar phase, reducing the overall mobility of this complex relative to individual PNAA binding. The sequence- and size-based dependence of this separation technique is maintained with multiple PNAA binding over a range of DNA sizes. Results are accurately described by ELFSE theory, yielding , = 54 for single-micelle tagging and , = 142 for dual-micelle tagging. This method is the first example of a non-covalent drag-tag used to separate DNA of 1000,bases based on both size and sequence. [source] Milk Protein Analysis Using a Micro Fabricated Sieve: A Promising PossibilityJOURNAL OF FOOD SCIENCE, Issue 3 2001C.S. Rao ABSTRACT: In cheese making, proteins present in the micellar phase, i.e., ,, ,, ,, , casein and their variants, determine the yield and properties of the final product (Walsh and others 1995). The current milk prices are based on solid components, that is, fat, total protein and other solids. However, the cheese yields are extremely sensitive to variations in protein sub-components. Thus, total protein content, although a simple measure of yield, is not the most accurate one. In the future, the food industry might require simple tools to analyze protein components in a given sample of milk. Two features of such a tool, portability and accuracy, would be invaluable. In this article, a protocol for design of a micro-scale sieve for the separation of proteins is conceived. [source] Study of the solubilization of gliclazide by aqueous micellar solutionsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 4 2003Khouloud A. Alkhamis Abstract It was of interest to increase the solubility of gliclazide in aqueous media. Therefore, solubilization of gliclazide in a variety of surfactants was investigated. Anionic and cationic surfactants exhibited dramatic solubilizing ability for gliclazide, whereas nonionic surfactants showed significantly lower solubilizing ability. It was found that gliclazide solubility increases with increasing the carbon chain length of cationic surfactants and decreases with increasing the carbon chain length of anionic surfactants. The solubilization data were analyzed on the basis of a pseudo-phase model with gliclazide exhibiting moderate partition coefficients into the micellar phase. The possible sites of solubilization of gliclazide in the micelle were examined by studying the effect of NaCl on solubilization and by comparing the absorption spectra of gliclazide in different solvents. The results obtained from these two experiments indicated that gliclazide is solubilized mainly in the inner core of the cationic surfactant micelles and in the outer regions of the anionic surfactant micelles. © 2003 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 92:839,846, 2003 [source] Fluorescence saturation of dye molecules in water pools of reversed micellesLASER PHYSICS LETTERS, Issue 10 2005A. V. Potapov Abstract Rhodamine 6G has been used as a fluorescence probe in AOT reversed micelles systems with the different amounts of solubilized water (hydratation power ,). The saturation of fluorescence and the lifetime of dye molecules were measured. The absorption cross section values were calculated from the saturation curves. We showed the differences in values of the absorption cross section, lifetime and velocity of fluorescence saturation in micellar phase with different , and in comparison to bulk phase. Additionally, the structure of hydrated reversed micelles has been studied by the method of correlation spectroscopy. The influence of , on size and shape of micelles was detected. (© 2005 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] Temperature Effect on the Fluroescence Anisotropy Decay Dynamics of Coumarin-153 Dye in Triton-X-100 and Brij-35 Miscellar Solutions,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2005Manoj Kumbhakar ABSTRACT The fluorescence anisotropy decay dynamics of the fluorescent probe Coumarin-153 (C153) have been investigated in two neutral micelles, Triton-X-100 (TX-100) and Brij-35 (BJ-39, at different temperatures and analyzed on the basis of the wellknown two-step model. Because steady-state fluorescence spectra of the above probe do not show any noticeable changes with respect to temperature, for either of the studied micelles, suggests a similar polarity in the microenvironment around the probe at all the temperatures studied. The anisotropy results indicated that, for both the micelles, the fluidity inside the Palisade layer increases with temperature. However, the temperature effect on the anisotropy decay is relatively more pronounced in TX-100 than in BJ-35. It is inferred that the temperature effect on the anisotropy decay in the BJ-35 micelle is mainly due to the thermal effect on the microviscosity in the micellar phase. In the case of TX-100, the results indicate that, along with the above thermal effect, an additional effect is observed due to the increased size and hydration of the micelle with temperature, with the result being that the fluorescence anisotropy decay in TX-100 is more sensitive to temperature than in BJ-35. In the TX-100 micelle, our studies show that with an increase in temperature, even though the micellar size increases substantially, the distance of the probe from the micellar core does not increase that significantly. Thus, with increasing temperature, the probe undergoes a relative migration toward the micellar core to avoid the increased hydration in the micellar Palisade layer. [source] Characteristics of protein partitioning in an aqueous micellar-gel systemBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2006L.J.P. van den Broeke Abstract Partitioning of proteins has been studied experimentally in a system combining a gel-bead phase and a nonionic micellar phase. The micellar phase consists of cylindrically shaped micelles, which are completely excluded from the gel-bead phase. Partitioning of single-component protein solutions (myoglobin, ovalbumin, and BSA) is determined by excluded-volume interactions in the micellar phase, and as a result the proteins prefer the gel-bead phase to the micellar phase. The protein concentration inside the gel beads increases with an increase in volume fraction of the micelles and increases with an increase in the size of the proteins. The protein partition coefficients obtained for a binary mixture of myoglobin and bovine serum albumin (BSA) show the same protein concentration dependence as the single-component protein partition coefficients. © 2005 Wiley Periodicals, Inc. [source] Mineral contents and distribution between the soluble and the micellar phases in calcium-enriched UHT milksJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2004Miguel Angel de la Fuente Abstract A study concerning the content of mineral elements (calcium, magnesium, sodium, potassium and phosphorus) and the distribution between the soluble and the micellar phases has been carried out on mineral,mainly calcium,enriched UHT milks. Total calcium contents were 1371,1793 mg l,1 in the 10 brands examined. Percentages of calcium in the soluble phase varied from 23.6 to 37.2%, whereas ionic calcium concentrations found were within a very wide range (44,91 mg l,1). The different forms of phosphorus were studied by 31P-NMR. Spectra indicated that the majority of the brands employed polyphosphates as stabilizers. Ingredients used to fortify these products consisted of dairy fractions and calcium salts. The modifications in salt balance as consequence of these practices are discussed. Copyright © 2004 Society of Chemical Industry [source] | |||||||||||||