Problem areas in the use of the firefly luciferase assay for bacterial detection

By purifying the firefly luciferase extract and adding all necessary chemicals but ATP in excess, an assay for ATP was performed by measuring the amount of light produced when a sample containing soluble ATP is added to the luciferase reaction mixture. Instrumentation, applications, and basic characteristics of the luciferase assay are presented. Effect of the growth medium and length of time grown in this medium on ATP per viable E. coli values is shown in graphic form, along with an ATP concentration curve showing relative light units versus ATP injected. Reagent functions and concentration methods are explored. Efforts to develop a fast automatable system to detect the presence of bacteria in biological fluids, especially urine, resulted in the optimization of procedures for use with different types of samples

Evanescent Black Holes

A renormalizable theory of quantum gravity coupled to a dilaton and conformal matter in two space-time dimensions is analyzed. The theory is shown to be exactly solvable classically. Included among the exact classical solutions are configurations describing the formation of a black hole by collapsing matter. The problem of Hawking radiation and backreaction of the metric is analyzed to leading order in a $1/N$ expansion, where $N$ is the number of matter fields. The results suggest that the collapsing matter radiates away all of its energy before an event horizon has a chance to form, and black holes thereby disappear from the quantum mechanical spectrum. It is argued that the matter asymptotically approaches a zero-energy ``bound state'' which can carry global quantum numbers and that a unitary $S$-matrix including such states should exist.Comment: 14 page

Quantum algorithm for the Boolean hidden shift problem

The hidden shift problem is a natural place to look for new separations between classical and quantum models of computation. One advantage of this problem is its flexibility, since it can be defined for a whole range of functions and a whole range of underlying groups. In a way, this distinguishes it from the hidden subgroup problem where more stringent requirements about the existence of a periodic subgroup have to be made. And yet, the hidden shift problem proves to be rich enough to capture interesting features of problems of algebraic, geometric, and combinatorial flavor. We present a quantum algorithm to identify the hidden shift for any Boolean function. Using Fourier analysis for Boolean functions we relate the time and query complexity of the algorithm to an intrinsic property of the function, namely its minimum influence. We show that for randomly chosen functions the time complexity of the algorithm is polynomial. Based on this we show an average case exponential separation between classical and quantum time complexity. A perhaps interesting aspect of this work is that, while the extremal case of the Boolean hidden shift problem over so-called bent functions can be reduced to a hidden subgroup problem over an abelian group, the more general case studied here does not seem to allow such a reduction.Comment: 10 pages, 1 figur

Laboratory procedures manual for the firefly luciferase assay for adenosine triphosphate (ATP)

A manual on the procedures and instruments developed for the adenosine triphosphate (ATP) luciferase assay is presented. Data cover, laboratory maintenance, maintenance of bacterial cultures, bacteria measurement, reagents, luciferase procedures, and determination of microbal susceptibility to antibiotics

HfC(310) High Brightness Sources for Advanced Imaging Applications

The authors report on electron emission from HfC(310) operating in extended Schottky emission mode. Data are gathered from test stands as well as through operation in a commercial scanning electron microscope. Emitter end-form geometry consisted of rounded, via electrochemical etching, and truncated, via ion milling. The authors demonstrate high angular intensity operation of \u3e60 mA/sr especially for the rounded end-form emitters. Advantages include robustness of the material, which is not reliant on material supply as is the case with standard ZrO/W(100) sources. Hence, operation is available over a much larger range of temperatures, fields, and potentially pressures. Operation in a commercial scanning electron microscope gave ten times higher beam currents for identical operational parameters over a standard Schottky source

Colliding axisymmetric pp-waves

An exact solution is found describing the collision of axisymmetric pp-waves with M=0. They are impulsive in character and their coordinate singularities become point curvature singularities at the boundaries of the interaction region. The solution is conformally flat. Concrete examples are given, involving an ultrarelativistic black hole against a burst of pure radiation or two colliding beam- like waves.Comment: 6 pages, REVTeX, some misprints are correcte

Normalizers of tori

We determine the groups which can appear as the normalizer of a maximal torus in a connected 2-compact group. The technique depends on using ideas of Tits to give a novel description of the normalizer of the torus in a connected compact Lie group, and then showing that this description can be extended to the 2-compact case.Comment: Published by Geometry and Topology at http://www.maths.warwick.ac.uk/gt/GTVol9/paper31.abs.htm

Perfect category-graded algebras

In a perfect category every object has a minimal projective resolution. We give a criterion for the category of modules over a categorygraded algebra to be perfect.Comment: A sufficient condition is replaced by a criterion. Several references added. 17 page