On-chip microwave photonic beamformer circuits operating with phase modulation and direct detection.

We propose and experimentally demonstrate the working principles of two novel microwave photonic (MWP) beamformer circuits operating with phase modulation (PM) and direct detection (DD). The proposed circuits incorporate two major signal processing functionalities, namely a broadband beamforming network employing ring resonator-based delay lines and an optical sideband manipulator that renders the circuit outputs equivalent to those of intensity-modulated MWP beamformers. These functionalities allow the system to employ low-circuit-complexity modulators and detectors, which brings significant benefits on the system construction cost and operation stability.

Hydrogen exchange of individual amide protons in the E. coli lac repressor DNA-binding domain: a nuclear magnetic resonance study.

Proton exchange in lac repressor headpiece was studied by COSY and 2D NOE spectroscopy. The exchange rates of amide protons, stabilized by the hydrogen bonds of the three alpha-helices of the headpiece, could be determined quantitatively. The exchange rates in these helices showed repetitive patterns of about three to four residues.

Comparative studies on salivary kallikrein from cystic fibrosis patients and controls.

Kallikrein (EC 3.4.21.

The purification of kallikrein from human whole saliva.

A quick and simple procedure is described for purifying kallikrein from human whole saliva. The enzyme has been purified about 2700-fold with a yield of approx. 30%.

The purification and partial characterization of human salivary kallikrein.

The major arginine esterase activity in human saliva has been purified. This enzyme lowers the blood pressure of a rabbit and produces kinins in acid treated dog plasma. It is therefore a kallikrein.