Novel class of saccharide-based organogelators: glucofuranose derivatives as one of the smallest and highly efficient gelators

Gluco- and allofuranose derivatives, having unprotected three OH groups, were investigated as potential gelators, showing high gelating ability for a variety of organic solvents and result in new consistent class of organogelators. The minimum gelator concentration reaches 0.03%, which is one of the lowest concentrations achieved so far. The correlation between the saccharide crystal structure and its gelating ability was also examined. The SEM pictures of xerogeles obtained from concentrated and diluted gels (1.0-0.03%) show significant differences in μm-scale structure.     

Geometry of real polynomial mappings

In this paper we study the set of points at which a real polynomial mapping is not proper. Received: 7 May 1999; in final form: 18 September 2000 / Published online: 25 June 2001     

On ramification values of a polynomial mapping

 Let be affine algebraic varieties of dimension n-1. There is a proper polynomial mapping such that the set of its ramification values contains hypersurfaces , which are birationally equivalent to Received: 21 December 2001 Mathematics Subject Classification (2000): 14 D 06, 14 Q 20     

The millimeter- and submillimeter-wave spectrum of the trans-gauche conformer of diethyl ether

The results of a first investigation of the rotational spectrum of the trans-gauche conformer of diethyl ether are reported. Two spectrometers have been used to measure the spectrum in the millimeter-wave and submillimeter-wave regions and a total of 1090 absorption line frequencies in the range 108-366 GHz were obtained and analyzed. Of these lines, 902 were measured with a spectrometer employing the fast scan submillimeter spectroscopic technique (FASSST) at Ohio State and the remaining 188 were measured with the phase-lock two-loop system (PLL) in Warsaw. The spectrum was fit to within experimental accuracy with the use of the A-reduced Watson Hamiltonian. Based on relative intensity measurements, the percentage of diethyl ether at room temperature in the trans-gauche conformer was found to be 30.5(13)%, in good agreement with prior spectroscopic values and an ab initio determination based on an energy difference of 5.40 kJ mol⁻¹ (452 cm⁻¹) between the excited trans-gauche and ground trans-trans conformers. This work also stimulated a critical evaluation of the data acquisition and calibration procedure of the FAAAST spectrometer, the results of which will be discussed.     

Chiral base promoted enantioselective rearrangement of organophosphorus epoxides

Cinchona alkaloids serve as effective chiral bases for enantioselective rearrangement of 3,4-epoxyphospholane oxides resulting in the formation of P,C-chirogenic 4-hydroxy-2-phospholene derivatives with up to 52% ee. A stereochemical course of the epoxide rearrangement involving anti β-proton abstraction is proposed. 3,4-Epoxy-1-phospholane-borane rearranges to 4-hydroxy-2-phospholene-borane of 55% ee on treatment with sec-BuLi/sparteine base system.     

Single-electron and two-electron transfer in the anionic polymerization of vinyl monomers and the ring-opening polymerization of lactones*

Single-electron-transfer (SET) and two-electron-transfer reactions and their mechanisms were examined in the anionic polymerization of vinyl monomers and in the ring-opening polymerization of lactones. SET resulted in the formation of radical anions or enolates at the initiation step of styrene or lactone polymerization with naphthalene sodium as a catalyst. However, alkali-metal supramolecular complexes such as M⁺crown–M⁻ (M = Na or K) were able to transfer two electrons to both these monomers to form carbanions as reactive intermediates. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2158–2165, 2002     

Large deviations in operator form

In this paper we introduce and investigate the so-called operator form of Cramér large deviations of order for a class of transition probability functions.      

Fluorescence-based detection of single nucleotide permutation in DNA via catalytically templated reaction

Templated reduction of low fluorescence azidocoumarin-PNA conjugate to high fluorescence aminocoumarin was achieved using a catalytic amount of DNA with single nucleotide resolution.     

Nucleic acid encoding to program self-assembly in chemical biology

This tutorial review serves as an introduction to the use of oligonucleotides and in particular peptide nucleic acids (PNAs) to encode function beyond heredity. Applications in chemical biology are reviewed starting with the use of nucleic acid tags to program self-assembled microarrays of small and macromolecules, followed by the use of nucleic acid templated reactions for the purpose of DNA or RNA sensing and finally, the use of nucleic acid templates to display ligands.