Synthetic studies towards the novel diterpenoid rameswaralide: RCM mediated acquisition of the tricyclic core

A synthetic approach towards the novel anti-inflammatory diterpenoid rameswaralide from the cis-Corey lactone involving a tandem RCM and Diels-Alder reaction has been conceived and endeavors so far have led to the acquisition of the BCD ring fragment of the natural product.     

Potential formation and high density plasma production on the tandem mirror GAMMA 10

GAMMA 10 experiments have advanced in high density experiments after the last EPS Workshop where we reported high density plasma production by using an ion cyclotron range of frequency heating at a high harmonic frequency and neutral beam injection in the central cell. Recently a high density plasma was obtained with much improved reproducibility than before and without degradation of diamagnetic signal. The high density plasma was attained by adjusting the spacing of the conducting plates installed in the anchor transition regions. Dependencies of particle confinement time, ion energy confinement time and plasma confining potential on plasma density were obtained for the first time in the high density region. Presented at 5th Workshop “Role of Electric Fields in Plasma Confinement and Exhaust”, Montreus, Switzerland, June 23–24, 2002.     

Quest for inosito-inositols: synthesis of novel, annulated and conformationally locked inositols

A new family of annulated inositols (inosito-inositols) has been conceptualized. Naphthalene has been elaborated into novel cyclohexa-annulated neo- and chiro-inositols, with two additional hydroxyl functionalities, through a series of stereoselective oxyfunctionalization protocols. The trans-ring fusion present in these new annulated inositols ensures conformational locking.     

Enantioselective total synthesis of epoxyquinone natural products (−)-phyllostine, (+)-epoxydon, (+)-epiepoxydon and (−)-panepophenanthrin: access to versatile chiral building blocks through enzymatic kinetic resolution

A new enzyme mediated protocol to access versatile chiral building blocks for the synthesis of epoxyquinone natural products is delineated. Total syntheses of (−)-phyllostine, (+)-epoxydon, (+)-epiepoxydon and (−)-panepophenanthrin have been accomplished to demonstrate the efficacy of this approach.     

Model spectral function and superconductivity in BaxK1−xBiO3 (x=0.5-0.7)

The Eliashberg spectral density function is constructed for the superconducting compound Ba_xK_1−xBiO₃ with x=0.5, 0.6, 0.7. The functions, besides yielding some prominent structures, show widely spreading spectra that inhibit lattice instability by yielding not too large values of λ(<1.32). The resulting spectral functions show similar shape as other results, where available, and also successfully reproduce the observed critical temperature, isotope exponent, gap ratio and several other parameters.     

Lithium insertion into YBa2Cu3O7

Atomistic computer simulation techniques are used to investigate the effects of lithium insertion into YBa₂Cu₃O₇. Attention is focused on various possible lattice sites occupied by the inserted lithium ions and pathways for their migration. The square-planar position in the Cu(2) layer is calculated to be the most energetically favorable. This is supported by the structural modeling of the ordered lithiated phase Li_0.33YBa₂Cu₃O₇. The calculated activation energies derived from migration profiles are in accord with experimental values and suggest fairly mobile lithium ions.     

Synthesis and studies of antibacterial activity of pongaglabol

Pongaglabol [8-hydroxy-5-phenyl-furo[2,3-h]benzo(b)pyran-7-one] was synthesized and tested for antibacterial effects againstShigella dysenteriae, Salmonella typhi, Streptococcus β-haemolyticus andStaphylococcus aureus. The synthesized compounds were characterized using UV, IR and¹H NMR spectral data     

The optical-mechanical analogy in general relativity: Exact Newtonian forms for the equations of motion of particles and photons

In many metrics of physical interest, the gravitational field can be represented as an optical medium with an effective index of refraction. We show that, in such a metric, the orbits of both massive and massless particles are governed by a variational principle which involves the index of refraction and which assumes the form of Fermat's principle or of Maupertuis's principle. From this variational principle we derive exact equations of motion of Newtonian form which govern both massless and massive particles. These equations of motion are applied to some problems of physical interest.