Abstract: A purified thermostable enzyme is derived from the thermophilic archaebacterium Archaeoglobus fulgidus. The enzyme can be native or recombinant, is stable under PCR conditions and exhibits double strand specific exonuclease activity. It is a 3?–5? exonuclease and cleaves to produce 5?-mononucleotides. Thermostable exonucleases are useful in many recombinant DNA techniques, in combination with a thermostable DNA polymerase like Tag especially for nucleic acid amplification by the polymerase chain reaction (PCR).

Abstract: A multi-octave ferrite oscillator topology that utilizes transformer coupling to provide the proper phase shift in the feedback loop. In a specific embodiment, a 10 mil YIG sphere is loosely coupled to 20 mil input and output loops, both of which are connected to a GaAs integrated circuit that includes a Darlington pair of bipolar transistors. The Darlington pair provides high gain, high output power, and low parasitic reactance up to about 10 GHz. A resistor bridge across the base of the input transistor of the Darlington pair insures a substantially real input impedance over a wide bandwidth.