Equilibrium binding constants as a function of temperature were determined for the binding of 4-amino-N-methylphthalimide (4-AMP) to β-cyclodextrin and to human and bovine serum albumins, and for 6-propionyl-2-(dimethylamino)naphthalene (PRODAN) to β-cyclodextrin, by using phase-resolved fluorimetry to eliminate errors from the significant fluorescence contribution from the free 4-AMP or PRODAN. Enthalpy and entropy values were also calculated from these experimental data. 相似文献
An analysis of the factors controlling the relative intensities of low resolution microwave spectroscopic bands of conformers leads to a formula for ΔG, the free energy difference between two conformers, in terms of the relative intensities of two bands of the same rotational quantum number J. Estimates of the a dipole moment component, and the rotational constants A, B, C, for the two conformers also occur in the formula. A partial experimental test is discussed, which compares two isotopic forms rather than two conformers. 相似文献
Magneto-optic Kerr effect (MOKE) and magnetoresistance (MR) measurements were used to measure the switching characteristics of spin-valve (SV) arrays currently being developed to trap and release superparamagnetic beads within a fluid medium. The effect of SV size on switching observed by MOKE showed that a 1 μm×8 μm SV element was found to have optimal switching characteristics. MR measurements on a single 1 μm×8 μm SV switched with either an external applied magnetic field or a local magnetic field generated by an integrated write wire (current density ranging from 106 to 107 A/cm2) confirmed the MOKE findings. The 1 μm×8 μm SV low field switching was observed to be +8 and −2 mT with two stable states at zero field; the high field switching was observed to be −18 mT. The low switching fields and the large magnetic moment of the SV trap along with our observation of minimal magnetostatic effects for dense arrays are necessary design characteristics for high-force, “switchable-magnet,” microfluidic bead trap applications. 相似文献
Among the various industrial uses of the glow discharge at atmospheric pressure (GDAP), biological applications such as sterilization are under investigation. In this paper, we present images of a liquid medium (Luria-Bertani broth with tetracycline) contaminated by Escherichia coli bacteria (strain PER 322) undergoing plasma treatment. In most cases, it is found that an exposure time of two to 20 minutes leads to nearly a complete kill of a 108/ml E. coli population. The treatment time necessary to obtain a complete kill depends on the plasma power density, the type of gas used, the type of bacteria, and the type of medium 相似文献
Molecular design: The electronic structure of conjugated polyelectrolytes as a function of ionization potential (IP) and electron affinity (EA) is determined using X‐ray absorption and emission spectroscopy (see figure). Different functional groups give rise to dissimilar transport gaps and exciton binding energies.
The synthesis and photophysical properties of 1 and 2, two Ru(II)-polypyridyl based-1,8-naphthalimide Tr?ger's bases, are described; these were found to stabilize double stranded DNA, undergo rapid cellular uptake, displaying good luminescence without affecting cell viability even after 24 hours of incubation. 相似文献
Within the last decade, ionic liquids have come to the fore as environmentally-responsible designer solvents. But what are ionic liquids and what can they offer the analytical scientist? This article addresses these questions and chronicles recent progress made in the application of ionic liquids toward analytical problem-solving. While further progress is required before ionic liquids become mainstream analytical solvents, results to date commend their use in various modes of chemical analysis. It is our aim that the findings reported herein draw other researchers into this area and encourage the increased application of ionic liquids in this manner. 相似文献
