Conformational flexibility of the 1,4-dihydropyridine ring in calcium channel agonists and antagonists molecules

Conformational flexibility of the 1,4-dihydropyridine ring in 4-aryl derivatives of the 2,6-dimethyl-3,5-dicarbmethoxy-1,4-dihydropyridine has been studied using the MM3 molecular mechanics method. Change of the C=C---C---C= endocyclic torsion angle of dihydrocycle in the range of 35° entails an increase of energy less than 1 kcal mol⁻¹. The energy levels below 99% of the molecular population for each molecule were estimated. The interval of the torsion angle change for these regions is about 60°.     

Clearing mechanism of organic phototropic shutters for ruby lasers

The clearing of organic phototropic shutters under irradiation by ruby lasers is considered. The effect of the atomic constants of solutions on the clearing process is examined.     

Exclusive reactions in pp interactions at 32 GeV/c

The cross sections of several exclusive reactions in $\text{p}\text{p}$ interactions are given. In the channels $\text{p}\text{p}\text{→}\text{p}\text{p}\text{π}{}^{\mathrm{+}}\text{π}{}^{\mathrm{?}}\text{and}\text{p}\text{p}\text{→}\text{p}\text{p}\text{2π}{}^{\mathrm{+}}\text{2π}{}^{\mathrm{?}}$ which dominate the interactions, the single and double diffractive dissociations are analysed and compared to the results obtained with K^±p interactions at the same energy, pp and $\text{p}\text{p}$ interactions at other energies. The test of factorization at the p → pπ⁺π^? vertex is well verified. The process $\text{p}\text{p}\text{→ Δ}{}^{\mathrm{++}}\text{Δ}{}^{\mathrm{++}}$ is studied and the cross sections of $\text{Δ}{}^{\mathrm{++}}\text{,}\text{Δ}{}^{\mathrm{++}}\text{, ?}{}^0\text{and}\text{f}{}^0$ production are also given.