Experimental Observations of Laser-Driven Tin Ejecta Microjet Interactions.

The study of high-velocity particle-laden flow interactions is of importance for the understanding of a wide range of natural phenomena, ranging from planetary formation to cloud interactions. Experimental observations of particle dynamics are sparse given the difficulty of generating high-velocity flows of many particles. Ejecta microjets are micron-scale jets formed by strong shocks interacting with imprinted surfaces to generate particle plumes traveling at several kilometers per second. As such, the interaction of two ejecta microjets provides a novel experimental methodology to study interacting particle streams. In this Letter, we report the first time sequences of x-ray radiography images of two interacting tin ejecta microjets taken on a platform designed for the OMEGA Extended Performance (OMEGA EP) laser. We observe that the microjets pass through each other unattenuated for the case of 11.7±3.2 GPa shock pressures and jet velocities of 2.2±0.5 km/s but show strong interaction dynamics for 116.0±6.1 GPa shock pressures and jet velocities of 6.5±0.5 km/s. We find that radiation-hydrodynamic simulations of the experiments are able to capture many aspects of the collisional behavior, such as the attenuation of jet velocity in the direction of propagation, but are unable to match the full spread of the strongly interacting cloud.

First report of prenatal biochemical diagnosis of Lowe syndrome.

The oculocerebrorenal syndrome of Lowe (OCRL) is a rare X-linked disorder with a severe phenotype characterized by congenital cataracts, renal tubular dysfunction and neurological deficits. The gene has been characterized and mutations have been identified in patients. Owing to the allelic heterogeneity exhibited by this gene, prenatal diagnosis by molecular analysis is limited to families in which the mutation is already known or in which linkage is informative. A more generally applicable diagnostic test would be valuable for families at risk for Lowe syndrome. Since ocrl1 is now known to encode a phosphatidylinositol 4,5-bisphosphate 5-phosphatase (Ptdlns(4,5)P2 phosphatase), we assessed whether biochemical testing could be used for prenatal diagnosis. We report here the first case of prenatal diagnosis for Lowe syndrome by measuring phosphatidylinositol 4,5-bisphosphate 5-phosphatase activity in cultured amniocytes.

Discriminative stimulus effects of butorphanol: influence of training dose on the substitution patterns produced by Mu, Kappa and Delta opioid agonists.

The discriminative stimulus effects of butorphanol were examined in separate groups of pigeons trained to discriminate either a low (0.1 mg/kg), medium (1.0 mg/kg) or high (5.6 mg/kg) dose of butorphanol from saline. The mu-selective opioid antagonist naloxone was considerably more potent than the delta-selective opioid antagonist naltrindole in antagonizing the effects of butorphanol. In each of the training dose groups, the mu opioid agonists morphine, l-methadone and fentanyl, as well as buprenorphine, (-)-pentazocine, nalbuphine, (-)-metazocine and nalorphine, substituted completely for the butorphanol stimulus. The rank order of potency for these compounds in substituting for the butorphanol stimulus was similar across training dose groups and similar to those reported in studies in which fentanyl or morphine were used as training stimuli. (-)-N-allylnormetazocine (NANM) and levallorphan substituted completely for the butorphanol stimulus in the low-dose group, and substituted partially for and antagonized partially the butorphanol stimulus in the medium- and high-dose groups. The kappa opioid agonists spiradoline, bremazocine, U50,488 and U69,593 substituted partially for butorphanol in the low-dose group, an effect that was not reversed by naloxone. In the medium- and high-dose groups, these kappa opioid agonists produced predominantly saline-appropriate responding. The delta opioid agonist BW373U86 substituted completely for butorphanol in the low-dose group, and naltrindole was more potent than naloxone in antagonizing these effects. In the medium- and high-dose groups, BW373U86 substituted partially for the butorphanol stimulus. Unlike the substitution patterns produced by the mu, kappa and delta opioid agonists, the sigma/phencyclidine compounds (+)-cyclazocine and (+)-NANM and the barbiturate pentobarbital produced predominantly saline-appropriate responding in all training dose groups. The present findings suggest that opioids with agonist activity at mu, kappa and delta opioid receptors share similar stimulus effects with a low training dose of butorphanol, whereas only opioids with agonist activity at the mu opioid receptor share stimulus effects with a medium and high training dose of butorphanol.