Search

Research over the last ten years has resulted in attempts toward single-chip CMOS RF circuits for Bluetooth, global positioning system, digital enhanced cordless telecommunications and cellular applications. An overview of the use of CMOS for low-cost integration of a high-end cellular RF transceiver front-end is presented. Some fundamental pitfalls and limitations of RF CMOS are discussed. To circumvent these obstacles, the choice of transceiver architecture, circuit topology design, and systematic optimization of the different transceiver blocks is necessary. Moreover, optimization of the transceiver as one single block by minimizing the number of power-hungry interface circuits is emphasized. As examples, a fully integrated cellular transceiver front-end, a low-power extremely low noise-figure low-noise amplifier, and a very efficient power amplifier are demonstrated. Index Terms--CMOS, low power, low voltage, receiver, RF, transceiver, wireless.

Insertion loop 256-268 in coagulation factor IX is discussed. It restricts enzymatic activity where factor VIII is absent. a study has shown that the loop restricts the activity of factor IXa toward synthetic and natural substrates. Complex formation of factor VIIIa cuts back on the inhibitory effect of the insertion loop on activation of FX.

The interaction between plasminogen activator inhibitor 1 (PAI-1), thrombin and glycosaminoglycans was investigated. It was shown that only high molecular weight heparin, containing at least 14 monosaccharide units, acts as an efficient cofactor for thrombin inhibition by PAI-1. A dye displacement assay was used to measure difference spectra between haprin/proflavine vs proflavine. The displacement of the dye by thrombin, but not by PAI-1, indicated that high molecular weight heparin accomodates separate binding sites for thrombin and PAI-1.

The role of interface between the second epidermal growth factor (EGF2) domain and the protease domain of activated factor IX (FIXa) was studied with particular focus on the putative interdomain contacts in the FIXa structure and for this recombinant FIX variants with mutations at residue Asn92, Phe98, Tyr295 and Phe299 were analyzed. Results suggest that putative interdomain contacts involving residues Asn92, Phe98, Tyr295 and Phe299 affect reactivity toward activate factor (FX).