X ray imaging microscope for cancer research

The NASA technology employed during the Stanford MSFC LLNL Rocket X Ray Spectroheliograph flight established that doubly reflecting, normal incidence multilayer optics can be designed, fabricated, and used for high resolution x ray imaging of the Sun. Technology developed as part of the MSFC X Ray Microscope program, showed that high quality, high resolution multilayer x ray imaging microscopes are feasible. Using technology developed at Stanford University and at the DOE Lawrence Livermore National Laboratory (LLNL), Troy W. Barbee, Jr. has fabricated multilayer coatings with near theoretical reflectivities and perfect bandpass matching for a new rocket borne solar observatory, the Multi-Spectral Solar Telescope Array (MSSTA). Advanced Flow Polishing has provided multilayer mirror substrates with sub-angstrom (rms) smoothnesss for the astronomical x ray telescopes and x ray microscopes. The combination of these important technological advancements has paved the way for the development of a Water Window Imaging X Ray Microscope for cancer research

Methodology and Results of the Near-Earth Object (NEO) Human Space Flight (HSF) Accessible Targets Study (NHATS)

Near-Earth Asteroids (NEAs) have been identified by the Administration as potential destinations for human explorers during the mid-2020s. Planning such ambitious missions requires selecting potentially accessible targets from the growing known population of 8,008 NEAs. NASA is therefore conducting the Near-Earth Object (NEO) Human Space Flight (HSF) Accessible Targets Study (NHATS), in which the trajectory opportunities to all known NEAs are being systematically evaluated with respect to a set of defined constraints. While the NHATS algorithms have identified hundreds of NEAs which satisfy purposely inclusive trajectory constraints, only a handful of them offer truly attractive mission opportunities in the time frame of greatest interest. In this paper we will describe the structure of the NHATS algorithms and the constraints utilized in the study, present current study results, and discuss various mission design considerations for future human space flight missions to NEAs

Measurements of laser-hole boring into overdense plasmas using x-ray laser refractometry(invited)

Copyright 1999 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Review of Scientific Instruments, 70(1), 543-548, 1986 and may be found at http://dx.doi.org/10.1063/1.114938

Exercise-Associated Hyponatremia: The Effects of Carbohydrate and Hydration Status on IL-6, ADH, and Sodium Concentrations

Exercise-associated hyponatremia (serum sodium \u3c 135 mmol/L) is a rare, but serious condition that has been identified in those engaging in prolonged, physical activity conducted in the heat. PURPOSE: The purpose of this study was to evaluate the effect of hydration status and glycogen level on plasma IL-6, ADH, and sodium concentrations during and after prolonged exercise in the heat. METHODS: Ten male participants completed four trials: a glycogen depleted, euhydrated condition (DE); a glycogen depleted, dehydrated condition (DD); a glycogen loaded, euhydrated condition (LE); and a glycogen loaded, dehydrated condition (LD) consisting of cycling 90 minutes at 60% VO2 max in a 35˚C environment followed by a 3-h rehydration (RH) period. During RH, subjects received either 150% of fluid lost (DD & LD) or an additional 50% of fluid lost (DE & LE). Exercise and RH blood samples were analyzed for glucose, IL-6, ADH, and Na+. Sweat and urine samples were analyzed for [Na+]. RESULTS: Post-exercise to post-rehydration [Na+] changes for LD, DD, DE and LE were -6.85, -6.7, -1.45 and 0.10 mM, respectively. Post-exercise [IL-6] for DD, LD, DE, and LE were 5.4, 4.0, 3.7, and 3.49 pg/mL, respectively. Post-exercise [ADH] for LD, DD, DE, and LE were 21.5, 12.8, 7.6, and 1.9 pg/mL, respectively. The number of hyponatremic measurements for all RH samples was 5, 5, 20, and 10 for LD, DD, DE, and LE, respectively. CONCLUSION: Despite our glycogen and hydration manipulations, no regulatory effects of IL-6 and ADH on plasma sodium were observed. The timing of fluid intake did alter plasma sodium since euhydration during exercise combined with an additional 50% intake during RH, and a post-exercise RH volume of 150% of fluid lost both resulted in sodium concentrations below initial levels. Supported by a grant from the Gatorade Sports Science Institute

Observation and Modeling of the Solar Transition Region: II. Solutions of the Quasi-Static Loop Model

In the present work we undertake a study of the quasi-static loop model and the observational consequences of the various solutions found. We obtain the most general solutions consistent with certain initial conditions. Great care is exercised in choosing these conditions to be physically plausible (motivated by observations). We show that the assumptions of previous quasi-static loop models, such as the models of Rosner, Tucker and Vaiana (1978) and Veseckey, Antiochos and Underwood (1979), are not necessarily valid for small loops at transition region temperatures. We find three general classes of solutions for the quasi-static loop model, which we denote, radiation dominated loops, conduction dominated loops and classical loops. These solutions are then compared with observations. Departures from the classical scaling law of RTV are found for the solutions obtained. It is shown that loops of the type that we model here can make a significant contribution to lower transition region emission via thermal conduction from the upper transition region.Comment: 30 pages, 3 figures, Submitted to ApJ, Microsoft Word File 6.0/9

High-Pressure Amorphous Nitrogen

The phase diagram and stability limits of diatomic solid nitrogen have been explored in a wide pressure--temperature range by several optical spectroscopic techniques. A newly characterized narrow-gap semiconducting phase $\eta$ has been found to exist in a range of 80--270 GPa and 10--510 K. The vibrational and optical properties of the $\eta$ phase produced under these conditions indicate that it is largely amorphous and back transforms to a new molecular phase. The band gap of the $\eta$ phase is found to decrease with pressure indicating possible metallization by band overlap above 280 GPa.Comment: 5 pages, 4 figure

Application of Soft X-Ray Lasers for Probing High Density Plasmas

The reliability and characteristics of collisionally pumped soft x-ray lasers make them ideal for a wide variety of plasma diagnostics. These systems now operate over a wavelength range extending from 35 to 400 {Angstrom} and have output energies as high as 10 mJ in 150 ps pulses. The beam divergence of these lasers is less than 15 mrad and they have a typical linewidth of {Delta}{lambda}/{lambda} {approximately} 10{sup -4} making them the brightest xuv sources available. In this paper we will describe the use of x-ray lasers to probe high density plasmas using a variety of diagnostic techniques. Using an x-ray laser and a multilayer mirror imaging system we have studied hydrodynamic imprinting of laser speckle pattern on directly driven thin foils with 1-2 {mu}m spatial resolution. Taking advantage of recently developed multilayer beamsplitters we have constructed and used a Mach-Zehnder interferometer operating at 155 {Angstrom} to probe 1-3 mm size laser produced plasmas with peak electron densities of 4 x 10{sup 21} cm{sup -3}. A comparison of our results with computer simulations will be presented