High‐performance liquid chromatographic analysis: applications to nutraceutical content and urinary disposition of oxyresveratrol in rats

A high‐performance liquid chromatographic (HPLC) method was developed for the analysis of the stilbene, oxyresveratrol. This method involves the use of a Luna® C₁₈ column with ultraviolet detection at 320 nm. The mobile phase consisted of acetonitrile, water and formic acid (30 : 70 : 0.04 v/v) with a flow rate of 0.6 mL/min. The calibration curves were linear over the range of 0.5–100.0 μg/mL. The mean extraction efficiency was between 98.9 and 109%. The precision of the assay was 0.069–18.4% (RSD%), and within 20% at the limit of quantitation (0.5 μg/mL). The bias of the assay was <15% and within 15% at the limit of quantitation. This assay was successfully applied to pre‐clinical pharmacokinetic samples from rat urine and to nutraceutical product analysis. Copyright © 2009 John Wiley & Sons, Ltd.     

Dispersion properties of high-contrast grating hollow-core waveguides

We present unique dispersion characteristics of high-contrast grating (HCG) hollow-core waveguides and show that slow light can be facilitated using internal resonances developing inside the waveguide walls. In addition, we show a fast and precise method of inferring the dispersion information from the waveguide angular reflectivity spectrum.     

Local surface damage and material dissolution in 45S5 bioactive glass: Effect of the contact deformation

Bioactive glasses react with the human physiological solution in control of their biofunctionality. The stress state in bioactive glasses determines the chemomechanical reaction and their biofunctionality. Using the microindentation technique, the effect of the indentation deformation on the surface damage and material dissolution of 45S5 bioglass was investigated. The indentation-induced local surface damage, including ring cracks and radial cracks, was revealed before and after the immersion tests in phosphate buffer solution (PBS). There existed a critical load for the formation of the radial cracks, which emanated from the periphery of the outmost ring crack. The growth of the radial cracks in the PBS solution displayed the stress-corrosion behavior with the crack-growth speed being a linear function of the indentation load. Fast dissolution occurred at the edges of the surface-damaged zone due to stress-assisted dissolution under the action of local tensile stress, which was different from the dissolution behavior of stress-free 45S5 bioglass.     

Polymer cushions functionalized with lipid molecules

This Letter reports a novel approach to the fabrication of a biomimicking surface by modification of an end-functionalizable smooth polymer cushion constructed via chemoselective ligation with a phospholipid-like molecule containing oxyamine groups. The mobility of a phospholipid bilayer formed by vesicle fusion on the phospholipid-like molecule terminated polymer film was characterized by fluorescence recovery after bleaching. Platelet adhesion, as one measure of biocompatibility of the film was also studied and compared to other surfaces such as polyethylene or poly(dimethylsiloxane). The results show that the end-functionalized smooth polymer cushion has potential as a biocompatible platform to reconstitute membrane proteins.     

Investigations into the interactions between DNA and conformationally constrained pyridylamineplatinum(II) analogues of AMD473

The syntheses of [PtCl(2)(amp)] (amp = 2-pyridylmethylamine) and enantiomerically pure [PtCl(2)(R-pea)] and [PtCl(2)(S-pea)] (pea = 1-(2-pyridyl)ethylamine) and the crystal structure of [PtCl(2)(R-pea)] are reported. The reactions of [PtCl(2)(amp)] and of the enantiomers of [PtCl(2)(pea)] with d(GpG) and with a 52-base-pair oligonucleotide were investigated. Each of the reactions with d(GpG) resulted in the formation of three platinated bifunctional d(GpG) species in a ratio of 1:2:1. These species were shown to be a pair of isomers, one of which exists as a pair of slowly interconverting rotamers that can be separated by HPLC but reequilibrate after 5 days at 37 degrees C. The pyridyl moieties of the pyridylalkylamine ligands are constrained to lie in the coordination plane, and as a consequence, the rotation about the Pt-N7 bond of the adjacent guanine is highly restricted. 2D NMR investigations were carried out on the isomer of [Ptd(GpG)(amp)] that did not form separable rotamers and identified it as the isomer having the pyridine adjacent to the 5'-guanine of the d(GpG). The reaction of each of the three [PtCl(2)(py-R)] complexes (py-R = amp or pea) with a 52-base-pair oligonucleotide resulted in the formation of the same three bifunctional d(GpG) adducts in approximately the same ratios as the reactions with d(GpG), indicating that negligible stereoselectivity results from interactions between the complexes and duplex DNA.     

Putting the Fun Into Functions Through the Use of Manipulatives,Computers, and Calculators

For six years, the authors have conducted a series of professional development workshops for teachers in Grades K-8. This article summarizes some of the research from those workshops and gives an overview of the approach taken. The institutes emphasized basic reasoning skills based upon the NCTM Standards and the Kentucky Education Reform Act, integrating manipulative materials and technology. The article demonstrates the integration of manipulatives and technology using patterns, relations and functions as examples.     

A plasma source for Fourier transform mass spectrometry

A plasma source has been designed so as to inject plasma directly into a Fourier transform mass spectrometer analysis cell. The source is a small radio-frequency cavity in which gas is ionized with RF. The source is coupled to the analysis cell through a small orifice. Argon irons from an argon plasma produced in the source have been injected, trapped and heated (excited), and detected in the analysis cell.     

On the extraction of optical sums from experimental generalized oscillator strengths and the experimental determination of the x-ray incoherent scattering factory by electron scattering

The connection between an experimentally measured Bethe surface and certain optical sum rules is discussed. The simplest procedure for constructing optical sums involves summing (integrating) the generalized oscillator strength over energy loss at a fixed scattering angle. This involves an approximation and an error formula is developed to estimate the magnitude of the correction involved. The approximation is shown to be extremely accurate in the limit of high incident energy and large momentum transfer. The sum S(?1,K) which is simply related to the X-ray incoherent scattering factor is found to have a small first order correction in the case of electron scattering from He with 25 keV electrons even at angles as small as 1°.     

Baker’s yeast (Saccharomyces cerevisiae) mediated transformations of C-aryl-N-phenylnitrones

C-Aryl-N-phenylnitrones are transformed to a mixture of azoxybenzene and aryl aldehydes when treated with a mixture of Baker’s yeast and sucrose in pH = 6.0 phosphate buffer medium at 32 °C.