Design of differential amplifier with negative impedance compensation

Design of differential amplifier with high gain accuracy and high linearity is presented in the paper. The amplifier design is based on the negative impedance compensation technique reported by the authors in [1]. A negative impedance with high precision, low sensitivity, wide input signal range and simple structure is used for the compensation of differential amplifier. Analysis and simulation results show that gain accuracy and linearity can be improved significantly with the negative impedance compensation

Stability analysis of the amplifier with negative impedance compensation

A novel amplifier design technique based on negative impedance compensation has been proposed in our recent paper. In this paper, we investigate the stability of this amplifier system. The parameter space approach has been used to determine system parameters in the negative impedance circuit such that the stability of the amplifier system can be guaranteed in a certain region represented by those parameters. The simulation results have demonstrated that stable circuit behavior for the amplifier can be achieved

Challenges to Slovakia and Poland health policy decisions: use of investment treaties to claim compensation for reversal of privatisation/liberalisation policies

Investment treaties, and possibly the EU Treaty itself, are being used by multinational companies Penta and Eureko to try and force the Slovak government to pay compensation for reversing health privatisation and liberalisation policies. Similar action has been used against the Polish government by Eureko to win compensation worth nearly 2 billion Euros and a policy commitment to further privatisation.

Structure and denaturation of 4-chlorobenzoyl coenzyme A dehalogenase from Arthrobacter sp. strain TM-1

The secondary structure of the trimeric protein 4-chlorobenzoyl coenzyme A dehalogenase from Arthrobacter sp. strain TM-1, the second of three enzymes involved in the dechlorination of 4-chlorobenzoate to form 4-hydroxybenzoate, has been examined. E(mM) for the enzyme was 12.59. Analysis by circular dichroism spectrometry in the far uv indicated that 4-chlorobenzoyl coenzyme A dehalogenase was composed mostly of alpha-helix (56%) with lesser amounts of random coil (21%), beta-turn (13%) and beta-sheet (9%). These data are in close agreement with a computational prediction of secondary structure from the primary amino acid sequence, which indicated 55.8% alpha-helix, 33.7% random coil and 10.5% beta-sheet; the enzyme is, therefore, similar to the 4-chlorobenzoyl coenzyme A dehalogenase from Pseudomonas sp. CBS-3. The three-dimensional structure, including that of the presumed active site, predicted by computational analysis, is also closely similar to that of the Pseudomonas dehalogenase. Study of the stability and physicochemical properties revealed that at room temperature, the enzyme was stable for 24 h but was completely inactivated by heating to 60 degrees C for 5 min; thereafter by cooling at 1 degrees C min(-1) to 45 degrees C, 20.6% of the activity could be recovered. Mildly acidic (pH 5.2) or alkaline (pH 10.1) conditions caused complete inactivation, but activity was fully recovered on returning the enzyme to pH 7.4. Circular dichroism studies also indicated that secondary structure was little altered by heating to 60 degrees C, or by changing the pH from 7.4 to 6.0 or 9.2. Complete, irreversible destruction of, and maximal decrease in the fluorescence yield of the protein at 330-350 nm were brought about by 4.5 M urea or 1.1 M guanidinium chloride. Evidence was obtained to support the hypothetical three-dimensional model, that residues W140 and W167 are buried in a non-polar environment, whereas W182 appears at or close to the surface of the protein. At least one of the enzymes of the dehalogenase system (the combined 4-chlorobenzoate:CoA ligase, the dehalogenase and 4-hydroxybenzoyl coenzyme A thioesterase) appears to be capable of association with the cell membrane.