Cerebral Blood Flow and Metabolism Studies Comparing Krypton 85 Desaturation Technique With Argon Desaturation Technique Using the Mass Spectrometer • Average cerebral blood flow determinations were performed 26 times comparing argon desaturation curves measured by mass spectrometry to the krypton 85 desaturation technique of McHenry. During 17 of these studies krypton 85 and argon desaturation...

The use of a noble gas as an inert tracer for mixing studies in combustion systems is investigated. Simultaneous two-photon laser-induced fluorescence (LIF) of krypton and Rayleigh scattering are used for imaging measurements of mixture fraction and temperature in turbulent non-premixed jet flames. The turbulent flames investigated in this study include a piloted CH4/air flame (Sandia flame D) ...

BACKGROUND Low power violet laser diodes (VLDs) have been evaluated as potential replacements for water-cooled argon-ion and krypton-ion ultraviolet and violet lasers for DNA content analysis using the Hoechst dyes and 4,6-diamidino-2-phenylindole (Shapiro HMN, Perlmutter NG: Cytometry 44:133-136, 2001). In this study, we used a VLD to excite a variety of violet-excited fluorescent molecules im...

Long-lived radioactive krypton isotopes, (81)Kr (t1/2 = 229,000 year) and (85)Kr (t1/2 = 10.76 year), are ideal tracers. (81)Kr is cosmogenic and can be used for dating groundwater beyond the (14)C age. (85)Kr is a fission product and can be applied in atmospheric studies, nuclear safety inspections, and dating young groundwater. It has long been a challenge to analyze radio-krypton in small sa...

We use a statistical thermodynamic approach to determine the composition of clathrate hydrates which may form from a multiple compound gas whose composition is similar to that of Titan’s atmosphere. Assuming that noble gases are initially present in this gas phase, we calculate the ratios of xenon, krypton and argon to species trapped in clathrate hydrates. We find that these ratios calculated ...

The abundance and isotopic composition of all noble gases are reported in the Wellman chondrite, and the abundance and isotopic composition of xenon and krypton are reported in the gases released by stepwise heating of the Tell and Scurry chondrites. Major changes in the isotopic composition of Xe result from radiogenic Xe129 and from variations in the isotopic mass fractionation pattern in the...

Feeding currents of free-swimming calanoid copepods, observed through an expanded krypton laser beam and a back-focus dark-field optical system, show that these planktonic animals generate a double shear field to help in detecting food. The interrelation between flow field, perception of food items, and body orientation explains why these animals are generally negatively buoyant.

Experiments demonstrating the feasibility of Kr-edge MAD on frozen crystals as a routine method for structure determination are reported. Approximately 50% of protein crystals can be successfully derivatized by pressurization with the noble gases xenon or krypton. While Xe has produced many useful derivatives for MIR phasing over the last several years, the Xe edges (K edge = 34.6 keV, L(I) = 5...