RESUMEN
The Wulff construction and the theory of Milner and Morse [Phys. Rev. E 54, 3793 (1996)] were used to calculate the shape of grains formed when a lamellar block copolymer phase is formed by a shallow quench into the ordered state. The calculations show that the grains are ellipsoids of revolution, with an aspect ratio rho=2.37. This value is in reasonable agreement with results of transmission electron microscopy and depolarized light scattering experiments, which indicate that the average value of rho of grains formed during the early stages of the disorder-to-order transition is about 2.0.
RESUMEN
Mutations in human immunodeficiency virus type 1 reverse-transcriptase codons 89 and 184 confer inhibitor resistance and alter the mutation spectrum of the enzyme. Six macaques were inoculated with wild-type or mutated derivatives (E89G or E89G and M184V) of simian immunodeficiency virus macaque (SIVmac) 239. Five of the infected monkeys maintained high virus loads; the sixth, which was infected with the E89G mutant strain, maintained viremia at a level below the limit of detection. Sequence analysis demonstrated substantial reversion of the E89G mutation in the animals with progressive infection and preservation of this mutation in the animal with controlled infection. A P272S mutation occurred at high frequency in the viruses containing M184V, which did not revert. These results demonstrate that the E89G mutation has a significant negative impact on SIVmac fitness, whereas SIVmac bearing M184V achieved high, sustained virus loads, perhaps with a compensatory effect of the P272S mutation.