A traffic model for non-real-time data users in a wireless radionetwork

Based on an analysis of Internet protocols for data communication, we propose a simple model for future data traffic in wireless radio networks. Model parameters are selected so as to resemble traffic from the Worldwide Web (WWW) access and from distributed file systems. By changing a single parameter, the model can be switched between resembling up- or down-link traffic. The model is intended for design and performance analysis of radio resource allocation algorithms in future wireless systems     

Value of diuresis renography in the post-natal period of assumed physiological renal immaturity

The aim of this study was to determine if it is possible to exclude renal obstruction using diuresis renography in the first 6 weeks of life (the period of physiological renal immaturity), thus avoiding unnecessary invasive procedures, such as the Whitaker test or surgery. Diuresis renography with 123I-hippuran was performed in 27 patients aged less than 6 weeks and in 50 older children who acted as a reference group (age 6 weeks to 1 year, n = 28; age 1-10 years, n = 22). All 27 patients had significant dilatation of the pelvicalyceal system on ultrasonography. Renal curves were evaluated by mathematical curve characteristics (split renal function, counts, T-max, etc.) as the visual grade of obstruction. Whole-kidney regions of interest were defined on images summed over 30 min; renal parenchyma on images summed over 5 min. The renal curves of 18/27 patients indicated tracer accumulation and led to frusemide administration. Only two patients showed no significant response to frusemide and had to be further investigated by the Whitaker test. The frequency of kidneys with no response to frusemide revealed no significant differences in the three groups. Whole-kidney evaluation resulted in an overestimation of obstruction in 9/150 kidneys, which matches the lower correlation to the DMSA separation values for this method of evaluation. In contrast with the literature, significant post-renal obstruction can be excluded by diuresis renography in most cases in spite of renal immaturity and can help to avoid invasive procedures.     

Attributed social power and group acceptance: A classroom experimental demonstration.

A classroom demonstration, which illustrates the reaction of group members to the communications and behavior they receive from others, when the nature and direction of the communications are influenced by the amount of power attributed to special members, is described. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective immunoaffinity-based enrichment of CD34+ cells transduced with retroviral vectors containing an intracytoplasmatically truncated version of the human low-affinity nerve growth factor receptor (deltaLNGFR) gene

Human hematopoietic stem cells remain one of the most promising target cells for gene therapeutic approaches to treat malignant and nonmalignant diseases. To rapidly characterize transduced cells and to isolate these from residual nontransduced, but biologically equivalent, cells, we have used a Moloney murine leukemia virus (Mo-MuLV)-based retroviral vector containing the intracytoplasmatically truncated human low-affinity nerve growth factor receptor (deltaLNGFR) cDNA as a marker gene. Supernatant transduction of CD34+ cells (mean purity 97%) in fibronectin-coated tissue culture flasks resulted in 5.5-45% (mean 26%) transduced cells expressing deltaLNGFR (LNGFR+ cells). After transduction, more than 65% of the transduced cells remained CD34+. Compared with control (mock- and nontransduced) CD34+ cells, transduction did not decrease the cloning efficiency of CD34+ cells. Immunomagnetic selection of the transduced cells with a monoclonal anti-LNGFR antibody resulted in >90% LNGFR+ cells. Further phenotypic characterization of these highly enriched LNGFR+ cells indicated that the majority co-expressed the CD34 and CD38 antigens. These results show that transduced cells expressing an ectopic cell-surface protein can be rapidly and conveniently quantitated and characterized by fluorescence-activated cell sorting (FACS) analysis and fast and efficiently enriched by immunoadhesion using magnetic beads. The use of cell-surface reporters should facilitate optimization of methods of gene transfer into more primitive hematopoietic progenitors.     

Wall Layer Formation in Continuously Operated Tubular Reactors for Free-Radical Polymerizations

Polymer fouling is a major problem for the operation of continuous reactors. Therefore, it is important to understand and quantitatively describe the mechanisms leading to formation of fouling deposits. In this work, a CFD model for the radical polymerization of N-vinylpyrrolidone is presented, where the reaction kinetics, a viscosity model, and a transport model for polymer moments are determined from independent experiments. The model is compared to experimental obtained residence time distributions in capillary reactors over a wide range of concentrations. Model predictions are in good agreement with experimental findings.     

Optimization of Liquid Gun Propellants based on nitromethane/methanol by physical and chemical modifiers

Main topics of developing and optimizing liquid gun propellants are the suppression of oscillations, and increase in performance and an improvement of electrical conductivity. Additives for the liquid system nitromethane/methanol will be described, that will change the evaporation and reaction kinetics by varying the physical and chemical properties. This will lead to an improved escillation behavior. Energetic additives, based on organic azido-compounds, will cause a significant enhancement in performance. The electrical conductivity is improved by special compounds on the base of transition metal nitrates. The investigations show a small effect of the physical modifiers. A significant suppression of oscillations is reached by mechnistical additives. Using these additives, the interaction of the specific energy with an accompanying increase in intensity of oscillation - will be minimized. As a consequence, the possibility of an additional enhancement in performance is given, due to the developed energetic additives.