Weak π-rings

In this paper we establish some characterizations for weak π-rings.     

Shock Processing of Amino Acids Leading to Complex Structures—Implications to the Origin of Life

The building blocks of life, amino acids, are believed to have been synthesized in the extreme conditions that prevail in space, starting from simple molecules containing hydrogen, carbon, oxygen and nitrogen. However, the fate and role of amino acids when they are subjected to similar processes largely remain unexplored. Here we report, for the first time, that shock processed amino acids tend to form complex agglomerate structures. Such structures are formed on timescales of about 2 ms due to impact induced shock heating and subsequent cooling. This discovery suggests that the building blocks of life could have self-assembled not just on Earth but on other planetary bodies as a result of impact events. Our study also provides further experimental evidence for the ‘threads’ observed in meteorites being due to assemblages of (bio)molecules arising from impact-induced shocks.     

Polyaniline film formation in hexadecyl trimethyl ammonium bromide admicelles on hydrous zirconia surface

Formation of a thin polyaniline film on hydrous zirconia (ZrO2) surface was carried out using adsorbed surfactant bilayers on ZrO2 as reaction sites. Aniline was adsolubilized in hexadecyltrimethylammonium bromide (HDTAB) admicelles formed on the surface of ZrO2 by adsorption. Subsequent polymerization of the adsolubilized aniline monomer showed effective conversion of aniline to polyaniline. The formation of the polyaniline coated ZrO2 has been confirmed by UV-visible spectroscopy, FT-IR spectroscopy, and conductivity measurements. Various parameters involved during the adsorption process were studied. Selection of pH 9.0 as the pH of all experimental feed solutions was governed by the knowledge of point of zero charge (PZC) of ZrO2. Effect of aniline concentration on HDTAB adsorption was studied and it was observed that increase in aniline concentration decreased the amount of HDTAB adsorbed on ZrO2. Addition of salt (0.05 M NaCl) in the feed solution increased HDTAB adsorption and drastically reduced the effect of aniline concentration on HDTAB adsorption.     

Free energy simulations: Applications to the study of liquid water,hydrophobic interactions and solvent effects on conformational stability

Free energy simulations using the Metropolis Monte Carlo method and the coupling parameter approach with umbrella sampling are described for several problems of interest in structural biochemistry: the liquid water, the hydrophobic interaction of alkyl and phenyl groups in water, and solvent effects on the conformational stability of the alanine dipeptide and the dimethyl phosphate anion in water. Proximity analysis of the results is employed to identify stabilizing factors. Implications of the result with respect to the structural chemistry of proteins and nucleic acids is considered.     

2-Join decomposition lattices

In this paper we characterize principal element lattices and Dedekind domains in terms of 2-join decomposition lattices. Received March 2, 1999; accepted in final form July 10, 2000.     

Some results on almost principal element lattices

In this paper, we explore locally principal element lattices in terms of primary, semiprimary and prime power elements.     

Design and fabrication of an ultraviolet photoelectron spectrometer for the study of free molecules

An ultraviolet photoelectron spectrometer for the study of free atoms and molecules has been designed and fabricated with indigeneous components. The spectrometer consists of a 100 mA HeI discharge lamp, 180° hemispherical electron energy analyser (127 mm mean dia) and electron multiplier ratemeter electron detection systems. The resolution of the spectrometer is 90 meV/and the intensity of N₂ (5σ) band is 10⁵ c/sec. The sample inlet and the collision chamber can be heated to 500 K so that solids of low vapour pressure can be studied. Typical spectra of molecules recorded with the instrument are shown. Contribution No. 373 from the Solid State and Structural Chemistry Unit.