Fabrication of DNA-magnetite hybrid nanofibers for water detoxification

DNA-magnetite hybrid nanofibers were fabricated by electrospinning a spin dope consisting of oleic acid coated magnetite nanoparticles and DNA-CTMA in ethanol/chloroform mixed solvent. The fabricated nanofibers exhibit superparamagnetic behaviour owing to embedded magnetite nanoparticles. It is demonstrated that these nanofibers can be used as effective detoxification materials in aqueous media as a combined result of DNA's affinity to both organic and inorganic toxicants, high surface area of the nanofibers and the fast and easy separation due to magnetite nanoparticles under external magnetic field. In addition to detoxification, these novel hybrid nanofibers have potential applications in many technological areas such as catalysis and drug delivery.     

Between-person comparison of metabolite fitting for NMR-based quantitative metabolomics

Nuclear magnetic resonance (NMR) spectroscopy is widely used as an analytical platform for metabolomics. Many studies make use of 1D spectra, which have the advantages of relative simplicity and rapid acquisition times. The spectral data can then be analyzed either with a chemometric workflow or by an initial deconvolution or fitting step to generate a list of identified metabolites and associated sample concentrations. Various software tools exist to simplify the fitting process, but at least for 1D spectra, this still requires a degree of skilled operator input. It is of critical importance that we know how much person-to-person variability affects the results, in order to be able to judge between different studies. Here we tested a commercially available software package (Chenomx' NMR Suite) for fitting metabolites to a set of NMR spectra of yeast extracts and compared the output of five different people for both metabolite identification and quantitation. An initial comparison showed good agreement for a restricted set of common metabolites with characteristic well-resolved resonances but wide divergence in the overall identities and number of compounds fitted; refitting according to an agreed set of metabolites and spectral processing approach increased the total number of metabolites fitted but did not dramatically increase the quality of the metabolites that could be fitted without prior knowledge about peak identity. Hence, robust peak assignments are required in advance of manual deconvolution, when the widest range of metabolites is desired. However, very low concentration metabolites still had high coefficients of variation even with shared information on peak assignment. Overall, the effect of the person was less than the experimental group (in this case, sampling method) for almost all of the metabolites.     

Inert-marker studies during high-temperature formation of FeS2 from FeS1 + x

Marker experiments were made during the growth of FeS₂ upon FeS_1.128 at 650 °C. From the position of the markers in the scale, it was determined that the sulphur motion in FeS₂ was similar to that of the iron motion. Such motion may have occurred from solid-state diffusion in the FeS₂ or from gaseous transport in the micropores present in the FeS₂.     

Modeling the evolution of the dynamic mechanical properties of a commercial epoxy during cure after gelation

The cure kinetics for a commercial epoxy have been established and the influence of the degree of cure on the glass transition determined. Time‐temperature and time‐conversion superposition principles have been built into a model that successfully predicts the development of the viscoelastic properties of the epoxy during isothermal cure from gelation to after vitrification. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 495–508, 2000     

Synthesis,characterization, and cure of allyl and propargyl functionalized indene as a thermoset composite matrix resin

Two highly functionalized resins were synthesized by the phase transfer reaction of indene with propargyl bromide or allyl chloride in the presence of strong base. The resins consisted of a mixture of tri- and tetrafunctional indenes with 60–80% of the product being tetrafunctional. The allylated (AL) and propargylated (PL) indene resins were thermally cured without added catalysts. Both resins exhibited a broad, highly exothermic cure with a peak energy at 320°C for AL resin and 282°C for PL resin. Thermal degradation of cured AL resin was found to begin at approximately 400°C with a carbon yield of 20% of its initial weight at 1000°C. Carbon yields for cured PL resin were excellent, with 68% retention of weight at 1000°C. Unidirectional, carbon fiber composites were fabricated from the substituted indene resins. AL–carbon fiber composites gave modulus values of 126 GPa and strength values of 967 MPa, while PL–carbon fiber composites gave modulus values of 116 GPa and strength values of 935 MPa in three-point bending tests. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 475–482, 1998