84 research outputs found

    Fano Interference in Microwave Resonator Measurements

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    Resonator measurements are a simple but powerful tool to characterize a material's microwave response. The losses of a resonant mode are quantified by its internal quality factor QiQ_\mathrm{i}, which can be extracted from the scattering coefficient in a microwave reflection or transmission measurement. Here we show that a systematic error on QiQ_\mathrm{i} arises from Fano interference of the signal with a background path. Limited knowledge of the interfering paths in a given setup translates into a range of uncertainty for QiQ_\mathrm{i}, which increases with the coupling coefficient. We experimentally illustrate the relevance of Fano interference in typical microwave resonator measurements and the associated pitfalls encountered in extracting QiQ_\mathrm{i}. On the other hand, we also show how to characterize and utilize the Fano interference to eliminate the systematic error

    Adaptation of plasminogen activator sequences to known protease structures

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    AbstractThe sequences of urokinase (UK) and tissue-type plasminogen activator (TPA) were aligned with those of chymotrypsin, trypsin, and elastase according to their ‘structurally conserved regions’. In spite of its trypsin-like specificity UK was model-built on the basis of the chymotrypsin structure because of a corresponding disulfide pattern. The extra disulfide bond falls to cysteines 50 and 111d. Insertions can easily be accommodated at the surface. As they occur similarly in both, UK and TPA, a role in plasminogen recognition may be possible. Of the functional positions known to be involved in substrate or inhibitor binding, Asp 97, Lys 143 and Arg 217 (Leu in TPA) may contribute to plasminogen activating specificity. PTI binding may in part be impaired by structural differences at the edge of the binding pocket

    Granular aluminium nanojunction fluxonium qubit

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    Mesoscopic Josephson junctions, consisting of overlapping superconducting electrodes separated by a nanometre-thin oxide layer, provide a precious source of nonlinearity for superconducting quantum circuits. Here we show that in a fluxonium qubit, the role of the Josephson junction can also be played by a lithographically defined, self-structured granular aluminium nanojunction: a superconductor–insulator–superconductor Josephson junction obtained in a single-layer, zero-angle evaporation. The measured spectrum of the resulting qubit, which we nickname gralmonium, is indistinguishable from that of a standard fluxonium. Remarkably, the lack of a mesoscopic parallel plate capacitor gives rise to an intrinsically large granular aluminium nanojunction charging energy in the range of tens of gigahertz, comparable to its Josephson energy. We measure coherence times in the microsecond range and we observe spontaneous jumps of the value of the Josephson energy on timescales from milliseconds to days, which offers a powerful diagnostics tool for microscopic defects in superconducting materials

    Pharmacokinetics and pharmacodynamics of saruplase, an unglycosylated single-chain urokinase-type plasminogen activator, in patients with acute myocardial infarction

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    We examined in patients with acute myocardial infarction (AMI) the pharmacokinetics of saruplase, an unglycosylated, single chain, urokinase-type plasminogen activator (rscu-PA) by measuring urokinase-type plasminogen activator (u-PA) antigen and total u-PA activity, its conversion to active two-chain urokinase-type plasminogen activator (tcu-PA) and evaluated its effect on haemostatic parameters. Twelve patients were studied during and after administration of 20 mg bolus plus 60 mg continuous 1 h i.v. infusion of saruplase. For u-PA antigen and total u-PA activity (expressed as protein equivalents), where 234 U corresponds to 1 microgram, respectively, steady state plasma concentrations were 2.75 +/- 8.3 and 2.50 +/- 7.0 micrograms/ml (mean +/- standard deviation) and were reached within 20 min, t1/2 lambda 1 was 9.1 +/- 1.8 and 7.8 +/- 1.3 min, t1/2 lambda 2 1.2 +/- 0.2 and 1.9 +/- 0.5 h, and the total clearance was 393 +/- 110 and 427 +/- 113 ml/min. Inactivation of saruplase in plasma was negligible. After 15 min, tcu-PA was detected in plasma. From the ratio of the areas under the curve of tcu-PA and total u-PA activities it was calculated that 28 +/- 9.3% of the saruplase dose is converted into active tcu-PA. Systemic plasminaemia occurs as shown by a decrease in alpha 2-antiplasmin and fibrinogen and an increase in fibrinogen degradation products. Thrombin-antithrombin complex formation indicated activation of the clotting system. Saruplase is eliminated rapidly from plasma in AMI patients.(ABSTRACT TRUNCATED AT 250 WORDS
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