Elementary and high-level functions can be computed in hardware using polynomial approximation techniques. There are many techniques in the literature to calculate the coefficients of such polynomials. Remez algorithm [1] provides the optimal polynomial in the Chebyshev sense that is minimizing the maximum error (minimax approximation). This paper presents an algorithm for truncating the coefficients of the minimax polynomials obtained from Remez algorithm using an algorithmic method. A gain of 3 and 4 bits of accuracy over the direct rounding is reported. Muller [2] addressed the same problem but his algorithm is applicable for the second order polynomials only. This paper presents an algorithm that is applicable for any order.

We investigated the effects of the vasoconstrictor angiotensin (Ang) II on the whole cell inward rectifier K(+) (Kir) current enzymatically isolated from small-diameter (<100 microm) coronary arterial smooth muscle cells (CASMCs). Ang II inhibited the Kir current in a dose-dependent manner (half inhibition value: 154 nM). Pretreatment with phospholipase C inhibitor and protein kinase C (PKC) inhibitors prevented the Ang II-induced inhibition of the Kir current. The PKC activator reduced the Kir currents. The inhibitory effect of Ang II was reduced by intracellular and extracellular Ca(2+) free condition and by Gö6976, which inhibits Ca(2+)-dependent PKC isoforms alpha and beta. However, the inhibitory effect of Ang II was unaffected by a peptide that selectively inhibits the translocation of the epsilon isoform of PKC. Western blot analysis confirmed that PKCalpha, and not PKCbeta, was expressed in small-diameter CASMCs. The Ang II type 1 (AT(1))-receptor antagonist CV-11974 prevented the Ang II-induced inhibition of the Kir current. From these results, we conclude that Ang II inhibits Kir channels through AT(1) receptors by the activation of PKCalpha.

BACKGROUND: Inadequate cyclosporine (CsA) blood levels are a major risk factor for acute rejection in transplant recipients. The CsA trough level (C0 level) measured just before the next dose is commonly used to adjust the oral dosage. However, the 2-hour post-CsA dose concentration (C2 level) is favored as the best single-point correlate of CsA area-under-the-curve concentration and may better reflect the immunosuppressive effect of CsA. Because an adequate C2 level has not yet been defined, this study was performed to assess the value of C2 monitoring for the prevention of acute rejection and to define target levels in pediatric heart transplant recipients.

METHODS: C2 levels were assessed in 50 pediatric heart transplant patients with oral CsA therapy and compared with trough C0 levels using full blood sampling, mass spectrometry and a blinded analysis. Acute graft rejection was detected using intramyocardial electrocardiogram (IMEG) and serial conventional and tissue Doppler echocardiography (TDE). Rejection was confirmed or excluded by endomyocardial biopsy.

RESULTS: C2 and not C0 levels were significantly reduced in patients with acute graft rejection (ISHLT Grade > or =2). Patients with a C2 level <600 ng/ml had a significantly higher risk of developing acute rejection (100% sensitivity and 82% specificity). Patients with impaired CsA absorption were identified with C2 monitoring and switched to another calcineurin inhibitor.

CONCLUSIONS: Monitoring of the C2 rather than the C0 level better reflects immunosuppressive efficiency and identifies patients at increased risk of acute rejection. A C2 level of >600 ng/ml should be the target to prevent acute rejection.

This paper presents an adaptive fault location scheme for aged power cables using synchronized phasor measurements from both ends of the cable. The proposed fault location scheme is derived using the two terminal synchronized measurements incorporated with distributed line model, modal transformation theory and Discrete Fourier Transform. The proposed scheme has the ability to solve the problem of cable changing parameters, especially the change of the relative permittivity over its age and thus for the operating positive, negative, and zero-sequence capacitance changes. Extensive simulation studies are carried out using Alternative Transients Program ATP/EMTP. The simulation studies show that the proposed scheme provides a high accuracy in fault location calculations under various system and fault conditions. The results show that the proposed scheme responds very well to any fault insensitive to fault type, fault resistance, fault inception angle and system configuration. The proposed scheme solves the problem of aged cables with the change of the electric parameters. In addition to, it gives an accurate estimation of the fault resistance.