Manipulation of microalgal lipid production using genetic engineering

Applied Biochemistry and Biotechnology - Genetic transformation of two species of diatoms has been accomplished by introducing chimeric plasmid vectors containing a bacterial antibiotic resistance...     

Polymerization of allyldimethyldodecylammonium bromide in micellar and isotropic media

To study the effect of micellar aggregation upon polymerization and polymer products, the polymerization of the micelle forming monomer allyldimethyldodecylammonium bromide (I) was investigated under both micellar and isotropic conditions. NMR spectroscopy and fluorescence quenching were employed to elucidate the structural characteristics and molecular weight of the polymer obtained by γ-ray irradiation. It was found that (I) undergoes effective polymerization in the micellar state, producing a polymer which consists of a mixture of head to tail and head to head configurations at the ratio 85/15, and has a mean molecular weight of 11,000 ± 1000 daltons.     

Polymerization of head and tail methacrylate micelle-forming surfactants and thermotropic liquid-crystalline character of these monomers and their polymers

The polymerization in micellar and isotropic media of a head-tail pair of surfactants, i.e. of monomers bearing the methacrylate group either at the polar head or at the end of the lipophilic chain is investigated in this study. Owing to the tailor-made structure of these monomers, any differentiations observed in their polymerization can be primarily attributed to topochemical effects resulting from the different location of the polymerizable group in the two monomers. Both monomers exhibited mesomorphic-like textures, which were examined by optical microscopy and DSC studies. Also, their respective polymers showed mesomorphic behaviour, which was found to be dependent on the position of the backbone relative to the polar head.     

Exact analytical expressions for diatomic rotational and centrifugal distortion constants for a Kratzer-Fues oscillator

The exact closed-form expression for the vibrational-rotational eigenvalues of the Kratzer-Fues oscillator served as the starting point for a derivation of exact analytical expressions for the rotational constant B_υ, and the set D_υ to S_υ of centrifugal distortion constants up to 11th-order. The derivations employed the MAPLE symbolic algebra coprocessor. The expressions for B_υ to S_υ were then employed in the calculation of a set of constants for a Kratzer-Fues potential with specified dissociation energy and equilibrium internuclear separation for a hypothetical diatomic molecule with a reduced mass of unity. The tabulated constants serve as a benchmark against which the reliability of various existing or future numerical methods for the determination of rotational and centrifugal distortion constants may be assessed. The near-dissociation behaviour of the calculated constants was also examined and is useful in predicting the behaviour of such constants for real electronic states having pure ionic long-range form.     

Polymerization of oriented monomers. VI. Polymerization of monomeric di(undecenyl) phosphate vesicles to stable polymeric vesicles

The synthesis of a novel vesicle-forming surfactant monomer, i.e., of di(undecenyl) phosphate is reported. Vesicles formed from this monomer were irradiated by γ rays for the production of polymeric vesicles. Polymerization was studied in conjunction with the model of the monomeric vesicles and the structure of the polymers was primarily studied with ¹H-NMR spectra. It was further established that polymerized vesicles retain the structure of their monomeric counterparts while exhibiting higher stability than the unpolymerized vesicles.     

On crepant resolutions of 2-parameter series of Gorenstein cyclic quotient singularities

An immediate generalization of the classical McKay correspondence for Gorenstein quotient spaces ? ^r /G in dimensions r ≥ 4 would primarily demand the existence of projective, crepant, full desingularizations. Since this is not always possible, it is natural to ask about special classes of such quotient spaces which would satisfy the above property. In this paper we give explicit necessary and sufficient conditions under which 2-parameter series of Gorenstein cyclic quotient singularities have torus-equivariant resolutions of this specific sort in all dimensions.     

Further studies on homopolymers and copolymers resulting from the reaction of polymaleic anhydride with alcohols and amines

Polymaleic anhydride prepared by γ-rays irradiation of maleic anhydride was used as a reactive polymer and reacted with certain long-chain aliphatic amines and/or alcohols as well as with the mesogenic biphenylamine. The homopolymers and copolymers that were prepared, i.e., derivatives of N-alkyl polymaleamic acid, monoesters of polymaleic acid, or mixed amide-ester derivatives, were primarily investigated as far as their property to show thermotropic liquid crystalline character is concerned. By this investigation the structural features for the exhibition of mesomorphism by these polymers were determined.     

The B 1sigma+ and X 1sigma+ electronic states of hydrogen fluoride: a direct potential fit analysis

All literature pure rotational and vibration-rotational spectroscopic data on the ground X (1)Sigma(+) electronic state of HF and DF, together with the entire set of spectroscopic line positions from analyses of the B (1)Sigma(+) --> X (1)Sigma(+) emission band systems of HF and DF, have been used in a global least-squares fit to the radial Hamiltonian operators, in compact analytic form, for both electronic states. With a data set consisting of 6157 spectroscopic line positions, the reduced standard deviation of the fit was sigma = 1.028. Sets of quantum mechanically significant rotational and centrifugal distortion constants were calculated for both electronic states using Rayleigh-Schr?dinger perturbation theory.     

An extended Lennard-Jones potential energy function for diatomic molecules: Application to ground electronic states

A new simple analytical diatomic potential energy function that can be considered an extension of the prototypical Lennard-Jones model is proposed and tested. Five- and six-parameter models are considered and these can be easily constructed from widely available low-order vibrational-rotational constants and the dissociation energy. Accuracy tests are carried out on the ground electronic states of sixteen diatomic molecules. The proposed six-parameter function is found to be more accurate than other available few-parameter analytical models for the diatomic potential energy, and has accuracy comparable to that of modern high-level ab initio functions.     

Polymerization of oriented monomers. V. Radiation-induced polymerization of 3n-dodecyl-1-vinylimidazolium iodide in micellar aggregates

In the present study radiation-induced polymerization of 3n-dodecyl-1-vinylimidazolium iodide (I) in micellar aggregates was investigated. For comparison, the corresponding isotropic polymerization of I was also studied. Micellization was obtained in concentrated aqueous solutions; that is, above the monomer's critical micelle concentration (CMC) polymers obtained by both modes of polymerization were treated similarly and subsequently subjected to physical characterization. The main purpose of this study was to investigate whether the degree of organization of the monomer in micelles would affect polymer properties. Attempts to determine tacticity by ¹³C-NMR spectrometry failed because of the particular structure of the polymer. Crystallization of these polymers from ethyl alcohol or acetone was not possible as indicated by x-ray powder diffraction patterns that were characteristic of amorphous polymers. On the other hand, viscosity data of polymers do not depend on the mode of polymerization. It is therefore concluded that micellar aggregates are not sufficiently organized to affect polymer properties.