Novel characterization of capsule x-ray drive at the National Ignition Facility.

Indirect drive experiments at the National Ignition Facility are designed to achieve fusion by imploding a fuel capsule with x rays from a laser-driven hohlraum. Previous experiments have been unable to determine whether a deficit in measured ablator implosion velocity relative to simulations is due to inadequate models of the hohlraum or ablator physics. ViewFactor experiments allow for the first time a direct measure of the x-ray drive from the capsule point of view. The experiments show a 15%-25% deficit relative to simulations and thus explain nearly all of the disagreement with the velocity data. In addition, the data from this open geometry provide much greater constraints on a predictive model of laser-driven hohlraum performance than the nominal ignition target.

Measurement of high-pressure shock waves in cryogenic deuterium-tritium ice layered capsule implosions on NIF.

The first measurements of multiple, high-pressure shock waves in cryogenic deuterium-tritium (DT) ice layered capsule implosions on the National Ignition Facility have been performed. The strength and relative timing of these shocks must be adjusted to very high precision in order to keep the DT fuel entropy low and compressibility high. All previous measurements of shock timing in inertial confinement fusion implosions [T. R. Boehly et al., Phys. Rev. Lett. 106, 195005 (2011), H. F. Robey et al., Phys. Rev. Lett. 108, 215004 (2012)] have been performed in surrogate targets, where the solid DT ice shell and central DT gas regions were replaced with a continuous liquid deuterium (D2) fill. This report presents the first experimental validation of the assumptions underlying this surrogate technique.

Atrial natriuretic peptide in the preterm newborn.

Atrial natriuretic peptide (ANP), plasma renin and renin substrate concentrations (PRC and PRS) were measured in 31 preterm infants with idiopathic respiratory distress syndrome. Infants were studied at a mean of 1.4 days; 17 infants were also studied 2 days later. A 6-hour urine collection was made from 13 male infants on the first day of sampling to assess renal function. Both ANP and PRC were elevated and showed wide ranges of values (geometric means of 620 pg/ml and 18.4 ng/ml/h). Plasma ANP was significantly correlated with pH, PaCO2 and base excess. No correlations with parameters of cardiovascular or renal function were found. Plasma ANP rose in 13 of the 17 paired samples. We suggest that the very high ANP concentrations in these babies are a consequence of the pulmonary haemodynamic disturbances which accompany respiratory distress in the newborn.

Release of cartilage proteoglycan degrading enzyme activity by thioglycollate stimulated mouse peritoneal macrophages in culture.

Media from cultured mouse peritoneal macrophages were tested for cartilage proteoglycan degrading activity using S35-labelled rabbit ear cartilage. Media samples collected at 2-day intervals contained increasing amounts of activity between days two and six. This activity was activated by trypsin and antagonized by chelating agents. The macrophage products induced release of the proteoglycan component of cartilage as determined by biochemical and histological methods without affecting the collagen component. Media from cells incubated with hydrocortisone were devoid of proteoglycan degrading activity.

Topical betamethasone 17-valerate is an anticorticosteroid in the rat. 1. Dermal atrophy.

In the albino rat, topical betamethasone 17-valerate acts as an anticorticosteroid. This steroid is inactive in a dermal atrophy assay over a dose range where betamethasone and hydrocortisone display atrophogenic activity. At appropriate concentrations betamethasone 17-valerate competitively inhibits the atrophogenic effects of both betamethasone and triamcinolone acetonide. Since betamethasone and betamethasone 17-valerate penetrate rat skin in vivo at essentially the same rate, it is concluded that the latter compound is relatively resistant to hydrolysis during penetration, and that it binds to rat corticosteroid receptor proteins in such a manner as to prevent expression of corticosteroid activity. Therefore, the rat cannot be used as a model species to predict activity in man for this compound.

Corticosteroid-induced dermal atrophy in the rat.

Corticosteroid-induced dermal atrophy has been studied in the rat using daily application of ethanolic solutions to small areas of flank skin. After 12 days of treatment, the degree of atrophy was determined by comparing the weights of skin plugs (16 mm diameter) taken from the treated areas with contralaterally paired control areas. Doses can be adjusted so that systemic effects are minimized and only local effects are observed. Hydrocortisone, hydrocortisone butyrate, dexamethasone, betamethasone, desonide and triamcinolone acetonide all produce atrophy in the rat, and the degree of thinning is dose dependent. Potencies in the dermal atrophy assay compare directly with topical anti-inflammatory potencies in the rat, and the presence of fluorine in the steroid molecule is not a determining factor in the production of atrophy.