			Home About us Contact

Measurements Only (measurement + only)

Distribution by Scientific Domains

Engineering	50%

Selected Abstracts

Adefovir dipivoxil for wait-listed and post,liver transplantation patients with lamivudine-resistant hepatitis B: Final long-term results

LIVER TRANSPLANTATION, Issue 3 2007
Eugene Schiff
Wait-listed (n = 226) or post,liver transplantation (n = 241) chronic hepatitis B (CHB) patients with lamivudine-resistant hepatitis B virus (HBV) were treated with adefovir dipivoxil for a median of 39 and 99 weeks, respectively. Among wait-listed patients, serum HBV DNA levels became undetectable (<1,000 copies/mL) in 59% and 65% at weeks 48 and 96, respectively. After 48 weeks, alanine aminotransferase (ALT), albumin, bilirubin, and prothrombin time normalized in 77%, 76%, 60%, and 84% of wait-listed patients, respectively. Among posttransplantation patients, serum HBV DNA levels became undetectable in 40% and 65% at weeks 48 and 96, respectively. After 48 weeks, ALT, albumin, bilirubin, and prothrombin time normalized in 51%, 81%, 76%, and 56% of posttransplantation patients, respectively. Among wait-listed patients who underwent on-study liver transplantation, protection from graft reinfection over a median of 35 weeks was similar among patients who did (n = 34) or did not (n = 23) receive hepatitis B immunoglobulin (HBIg). Hepatitis B surface antigen was detected on the first measurement only in 6% and 9% of patients who did or did not receive HBIg, respectively. Serum HBV DNA was detected on consecutive visits in 6% and 0% of patients who did or did not receive HBIg, respectively. Treatment-related adverse events led to discontinuation of adefovir dipivoxil in 4% of patients. Cumulative probabilities of resistance were 0%, 2%, and 2% at weeks 48, 96, and 144, respectively. In conclusion, adefovir dipivoxil is effective and safe in wait-listed or posttransplantation CHB patients with lamivudine-resistant HBV and prevents graft reinfection with or without HBIg. Liver Transpl 13:349-360, 2007. © 2007 AASLD. [source]

Stability improvement in power systems with non-linear TCSC control strategies

EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 6 2000
X. Lei
In this paper, a non-linear control scheme for the TCSC (thyristor-controlled series compensator) to dampen power oscillations and to improve the transient stability of power systems is presented. Based on an one-machine-infinite-bus system, a non-linear mathematical model is established which is proven as an affine nonlinear system. With the help of the feedback linearization technique, the affine non-linear model is exactly transferred to a linear model, and then the control scheme is designed for the TCSC based on the global linearization, where the input signal uses local measurements only. The effectiveness and robustness of the proposed non-linear control scheme are demonstrated with an one-machine test system, where the TCSC modelling and power system simulations are performed by using the program system NETOMAC. In comparison with a conventional control scheme, significant improvements of dynamical performance in the test power' system are achieved by the proposed non-linear control strategy for the TCSC. [source]

Adaptive tracking control of flexible-joint manipulators without overparametrization

JOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 7 2004
Min S. Kim
In this paper, an adaptive controller is designed for rigid-link flexible-joint robot manipulators based on link and actuator position measurements only. It is based on the adaptive integrator backstepping method and the link and actuator velocity filters are used to estimate the unknown velocity terms. Moreover, the proposed controller exploits the estimate of the joint stiffness matrix inverse to overcome the overparametrization problem, which has been a significant drawback in adaptive partial state feedback controllers. It achieves asymptotic tracking of link positions while keeping all states and signals bounded. The tracking capability of the presented method is shown through simulation results of one- and two-link flexible joint manipulators. © 2004 Wiley Periodicals, Inc. [source]

Two-step growth of InGaN quantum dots and application to light emitters

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2007
T. Yamaguchi
Abstract A two-step growth method for creating InGaN quantum dots (QDs) was developed by using a combination of an InxGa1,xN nucleation layer (NL) without island structures and an InyGa1,yN formation layer (FL) with an indium content lower than that of the InxGa1,xN NL. The realization of QDs was confirmed by micro-photoluminescence (,-PL) measurements only for the sample with both the InxGa1,xN NL and the InyGa1,yN FL. The spectral position of the QD ensemble recombination was controlled mainly by the deposition time of the InxGa1,xN NL. Green (,520 nm) and amber (,600 nm) LEDs with the QD layers grown by the two-step growth method as the active region were also fabricated and compared with that having InGaN QW layers, reported previously. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]