Chimerism analysis in long-term survivor patients after bone marrow transplantation for severe aplastic anemia

BACKGROUND AND OBJECTIVE: Allogeneic bone marrow transplantation (BMT) is the most common treatment for young patients with severe aplastic anemia (SAA). Late graft failure represents one of the possible unfavorable outcomes in this setting. Mixed chimerism might represent a risk factor for late graft failure. We examined this relationship by studying chimerism in long-term survivor SAA patients after allogeneic BMT. METHODS: We analyzed long-term hematopoietic chimerism in 15 patients who received BMTs for SAA: 9 with an irradiation-based conditioning regimen and 6 with ATG. We used a PCR method targeting VNTR loci. Sensitivity of the technique ranged between 0.5 and 1.5%. RESULTS: All patients conditioned with radiation-based schemes showed complete donor chimerism. Conversely, out of six patients who received cyclophosphamide and ATG as a conditioning regimen, only one of them had late graft failure (day +168). In this patient, durable mixed chimera status was first detected two months after BMT. INTERPRETATION AND CONCLUSIONS: Our results suggest that in long-term survivors of SAA after BMT there is almost always complete donor chimerism in both irradiated and ATG-conditioned recipients. Mixed chimerism might predict graft failure in these patients.     

Measurement of mobility in HEMT devices using high-order derivatives

In this paper, a novel approach to the measurement of mobility of GaAs HEMT devices is presented. The new approach employs high-order derivatives as a means of determining the parameters of the proposed new mobility equation. The new approach is compared to established mobility measurement methods, and shown to offer better accuracy. The results presented also consider the behavior of mobility in the linear and saturation bias regions. The mobility value extracted by this new method has permitted improvements to the MESFET/HEMT model when simulating the behavior of the device in the linear region. This is critical in many applications, such as in low current linear-mixing applications.     

Performance Indices for Surface N Fertigation

The application of N fertilizers mixed with a surface irrigation stream (surface N fertigation) is widely practiced in the southwestern United States. Procedures for the optimal design and management of surface N fertigation systems are needed. The purpose of this work is to identify and define a set of performance indices that can be used to assess the relative merits of alternative design and management scenarios. Equations and solutions for quantifying the performance indices are proposed. Sample performance calculations are presented for a fertigation field experiment in which bromide ion was used as a tracer to simulate the movement of nitrate on the surface and through the soil profile.     

A Java/Matlab-based environment for remote control system laboratories: illustrated with an inverted pendulum

In this paper, a novel environment is described that provides 24-h-a-day access to a Web-based lab for the remote control of different didactic setups. The control of an inverted pendulum is used to demonstrate the use of such an environment. The main attributes of this Web-based lab are: 1) the on-line interactivity with the didactic setup, 2) the possibility of defining different experiments by using parameter files, and 3) the open architecture of the environment which allows easy development of new experiments with other didactic setups. The structure of this Web-based lab not only provides students with quantitative information feedback but also allows visual supervision. Now, a remote-controlled camera plays an important role within a remote experimentation environment with mobile parts. Students can handle the camera on-line, just as they can control the didactic setup over the Internet.     

Actinoplanic acids A and B as novel inhibitors of farnesyl-protein transferase

Actinoplanic acids A and B are macrocyclic polycarboxylic acids that are potent reversible inhibitors of farnesyl-protein transferase. Actinoplanic acids A and B were isolated from Actinoplanes sp. MA 7066 while actinoplanic acid B was isolated from both MA 7066 and Streptomyces sp. MA 7099. Actinoplanic acids A and B are competitive with respect to farnesyl diphosphate and are selective inhibitors of farnesyl-protein transferase because they do not inhibit geranylgeranyl-protein transferase type 1 or squalene synthase. MA 7066 is believed to be a novel species of actinomycetes while MA 7099 is believed to be a novel strain of Streptomyces violaceusniger on the basis of morphological, biochemical and chemotaxonomic characteristics as well as its production of actinoplanic acids.