A technique for the isolation of ribonucleic acid (RNA)-rich mutants of Escherichia coli is described. Mutagenized cells were centrifuged to isopycnic equilibrium on potassium tartrate or cesium sulfate gradients. Samples from the region of the gradients slightly denser than the majority of the cells were spread on agar plates, and the resulting clones were tested for increased RNA to protein r...

For the past 50 years, atomic standards based on the frequency of the cesium ground-state hyperfine transition have been the most accurate time pieces in the world. We now report a comparison between the cesium fountain standard NIST-F1, which has been evaluated with an inaccuracy of about 4 x 10(-16), and an optical frequency standard based on an ultraviolet transition in a single, laser-coole...

Non-elutable crystalline silicotitanate (CST) ionexchanger materials have been studied for removing cesium from a variety of radioactive wastes at several U.S. DOE sites over the last decade. For the current pretreatment facility design of the River Protection Project (RPP) Waste Treatment Plant (WTP) in Hanford, the removal of cesium from low activity waste (LAW) is achieved by ion-exchange te...

Matthew Meselson, Franklin Stahl, and Jerome Vinograd, developed cesium chloride, or CsCl, density gradient centrifugation in the 1950s at the California Institute of Technology [5], or Caltech, in Pasadena, California. Density gradient centrifugation enables scientists to separate substances based on size, shape, and density. Meselson and Stahl invented a specific type of density gradient cent...

Neither the infectivity nor the morphology of the mouse mammary tumor virus is appreciably affected by abrupt dilutions from strong solutions of cesium chloride, sodium chloride, or sodium iothalamate. In the purification of this virus by density gradient centrifugation, it is not necessary to use solutions of low osmotic activity. In sucrose, sodium iothalamate, potassium tartrate, or citrate,...

We report valence and conduction band densities of states measured via ultraviolet and inverse photoemission spectroscopies on three metal halide perovskites, specifically methylammonium lead iodide and bromide and cesium lead bromide (MAPbI3, MAPbBr3, CsPbBr3), grown at two different institutions on different substrates. These are compared with theoretical densities of states (DOS) calculated ...

The direct synthesis of aryl triflones, that is, trifluoromethanesulfonyl arenes, was achieved through the trifluoromethanesulfonylation of benzynes. The trifluoromethanesulfonyl group, one of the fluorinated functional groups, is a highly electron-negative and mild lipophilic substituent. Aryl triflones have high potential in the synthesis of bioactive compounds and specialty materials. The tr...

Single channel patch-clamp techniques were used to study nicotinic acetylcholine receptors in cultured rat myotubes. The single channel conductance in pure cesium and sodium levels off at high concentrations, as if a binding site within the channel were saturating. The conductances at very low concentrations, however, are larger than predicted by the simplest one-site transport model fitted to ...

Samples of bacterial deoxyribonucleic acid from bacteria having guanine plus cytosine (GC) contents in the range of 27 to 72 moles per cent GC were analyzed by optical melting (T(m)) and equilibrium buoyant density methods. The relation between these properties is shown to be linear. The relative value of 1.99 moles per cent GC per degree C change in T(m) is calculated, and a reference method f...