Bond interchange reactions in functionalized triglyceride oil/poly(ethylene terephthalate) compositions

Naturally functionalized triglyceride oils are renewable resources which contain reactive chemical groups, hydroxyl in the case of castor oil, and epoxide in the case of vernonia oil. In this article, the reaction of these groups, and the ester linkages between the glycerol and acid residue portions of the oil molecule with poly(ethylene terephthalate) (PET) is investigated through a variety of means. Multiple reactions are possible in the triglyceride–PET system, some of which form a copolymer that increases miscibility, and if allowed to continue, forms a completely random copolymer mixture. Among the numerous reactions possible, PET–ester exchange with the hydroxyl or epoxide functionality of the triglyceride oils is found to be the most significant, and the effects of these and other reactions are observed and structural implications discussed. © 1993 John Wiley & Sons, Inc.     

Allene cross-metathesis: synthesis of 1,3-disubstituted allenes

[reaction: see text] Grubbs catalyst, Cl2(Cy3P)2Ru=CHPh, was found to catalyze the cross-metathesis of monosubstituted allenes to 1,3-disubstituted allenes in varying yields.     

A cell model of a liquid droplet

An expression for the free energy of a droplet composed of attracting hard spheres is found using a simple cell model. The hard-sphere repulsion is assumed to act only between molecules in the same cell, whereas attraction extends over many cells. A maximum term analysis gives rise to a mean-field free energy which includes terms proportional to the first and second power of the droplet radius R with coefficients which can be related to the planar surface tension and Tolman length. Certain Gaussian fluctuations about the maximum term are also considered, corresponding to droplet translation and capillary wave fluctuations. Inclusion of these fluctuations is necessary to ensure that the nucleation rate is proportional to the system volume. They also reduce the planar surface tension and introduce a logarithmic term, -4/3 ln R, into the free energy. The inclusion of other fluctuations and the relationship between these equations and those arising in density-functional theories of nucleation is discussed.     

Novel peripherally functionalized seco-porphyrazines: synthesis, characterization and spectroscopic evaluation

Co-macrocyclizations of 2,3-dipropylmaleonitrile and 2,3-di-(4-(methoxycarbonyl)phenyl)maleonitrile, respectively, with N,N′-dibenzyl-N,N′-di-(11-tetrahydropyranyloxy-3,6,9-trioxo-undecyl))maleonitrile and N,N,N′,N′-tetramethylmaleonitrile were used to prepare derivatives of the 4,5-diamino-porphyrazine systems including the zinc(II) complexes. Subsequent oxidation of the macrocycles with potassium permanganate gave the corresponding seco-porphyrazines. These were shown to be efficient sensitizers for the production of singlet oxygen (Φ_Δ=0.15-0.57) by the determination of their photophysical properties.     

An intermediate spherical model of a ferromagnet

A one-parameter family of partition functions is considered which for zero value of the parameter reduces to the spherical model of a ferromagnet. The model for > 0 is closer to the usual discrete lattice spin model of a ferromagnet than is the spherical model. The first four terms in of the limiting value of the partition function are calculated above and below the critical temperature for arbitrary interactions using the saddle point method to calculate certain correlation functions for the spherical model. These calculations indicate that the critical temperature is independent of for small and certain interactions.Part of this research appeared in the author's doctoral thesis.⁽³⁾     

Amino acid analysis by micellar electrokinetic chromatography with laser-induced fluorescence detection: application to nanolitre-volume biological samples from Arabidopsis thaliana and Myzus persicae

Amino acids were derivatised with 4-fluoro-7-nitrobenzo-2,1,3-oxadiazol (NBD-F), separated by micellar electrokinetic chromatography (MEKC), and detected by argon-ion (488 nm) laser-induced fluorescence. The optimised MEKC background electrolyte conditions were: 40 mM sodium cholate, 5 mM beta-cyclodextrin in 20 mM aqueous borate buffer, pH 9.1, with 7% v/v acetonitrile. Using these conditions, 19 amino acids were separated within 17 min. The limits of detection were in the range of 7.6-42.2 pmol/mL and limits of quantitation from 0.05-0.14 nmol/mL. The method was systematically validated for injection volume error, migration time variation, calibration linearity, accuracy, precision, and recovery. Nanolitre volume samples of phloem sap of individual sieve element cells from the plant Arabidopsis thaliana and honeydew from the aphid Myzus persicae were directly analysed with this method. Quantitative amino acid concentrations in these two biological matrices were profiled for the first time. This method is particularly important because it allows the complete profile of the amino acids obtained from individual phloem elements, allowing cell to cell and plant to plant variation to be quantified, which to date has not been possible with Arabidopsis thaliana.     

Capillary and microelectrophoretic separations of ligase detection reaction products produced from low-abundant point mutations in genomic DNA

Capillary gel electrophoresis (CGE) and polymer-based microelectrophoretic platforms were investigated to analyze low-abundant point mutations in certain gene fragments with high diagnostic value for colorectal cancers. The electrophoretic separations were carried out on single-stranded DNA (ssDNA) products generated from an allele-specific ligation assay (ligase detection reaction, LDR), which was used to screen for a single base mutation at codon 12 in the K-ras oncogene. The presence of the mutation generated a ssDNA fragment that was >40 base pairs (bp) in length, while the primers used for the ligation assay were <30 bp in length. Various separation matrices were investigated, with the success of the matrix assessed by its ability to resolve the ligation product from the large molar excess of unligated primers when the mutant allele was lower in copy number compared to the wild-type allele. Using CGE, LDR product models (44 and 51 bp) could be analyzed in a cross-linked polyacrylamide gel with a 1000-fold molar excess of LDR primers (25 bp) in approximately 45 min. However, when using linear polyacrylamide gels, these same fragments could not be detected due to significant electrokinetic biasing during injection. A poly(methylmethacrylate) (PMMA) microchip of 3.5 cm effective column length was used with a 4% linear polyacrylamide gel to analyze the products generated from an LDR. When the reaction contained a 100-fold molar excess of wild-type DNA compared to a G12.2D mutant allele, the 44 bp ligation product could be effectively resolved from unligated primers in under 120 s, nearly 17 times faster than the CGE format. In addition, sample cleanup was simplified using the microchip format by not requiring desalting of the LDR prior to loading.