To investigate the possible involvement of nitric oxide (NO) in haemodialysis hypotension, we measured plasma concentrations of nitrate anion (NO3-), a metabolite of NO, in 114 patients undergoing maintenance haemodialysis. Mean plasma NO3- concentrations before dialysis were greater in subjects with lower blood pressure (155 +/- 16 micromol L-1) than in those with middle (117 +/- 8 micromol L-1) or higher blood pressure (105 +/- 12 micromol L-1) before dialysis. Further, mean plasma NO3- concentrations before dialysis were greater in subjects with lower blood pressure (186 +/- 13 micromol L-1) than in those with middle (112 +/- 7 micromol L-1) or higher blood pressure (64 +/- 11 micromol L-1) after dialysis. Plasma NO3- concentrations before dialysis were inversely correlated with mean blood pressure before dialysis (r=0.318, P=0.0006), and showed a strong inverse correlation with mean blood pressure after dialysis (r=0.608, P=0.0001). In the selected participants who had equal range of mean blood pressure before dialysis, mean plasma NO3- concentrations were greater in subjects with severe hypotension during dialysis (180 +/- 14 micromol L-1) than in those with mild hypotension (99 +/- 11 micromol L-1) or without hypotension (53 +/- 12 micromol L-1); plasma NO3- concentrations before dialysis were inversely correlated with changes in mean blood pressure during dialysis and mean blood pressure after dialysis. Results indicate that enhanced NO production may be involved in acute hypotension during dialysis, and suggest the possible involvement of NO in the pathogenesis of chronic hypotension associated with maintenance haemodialysis.
A decrease in the watermark detection rate is a fatal problem in employing audio watermarks for applications in which a watermarked signal is transmitted through the air. The enforcement of watermarks using an error-correcting code is a solution to this problem. Low-density Parity Check (LDPC) coding is a recent error-correcting code; it shows good performance close to Shannon's limit. Therefore, in the present study, watermark detection rates when the watermarks were coded combined with and without LDPC coding were evaluated through computer simulations and experiments in a real room. The results showed that employing LDPC coding raised the watermark detection rate by around 15 percentage points for an additive white Gaussian noise and by around 20 points from around 60% to around 80% in an actual reverberation environment.
Recently, many efforts have been made to develop more efficient Inter-Vehicle Communication (IVC) protocols for ondemand route planning according to observed traffic congestion or incidents, as well as for safety applications. Because practical experiments are often not feasible, simulation of network protocol behavior in Vehicular Ad Hoc Network (VANET) scenarios is strongly demanded for evaluating the applicability of developed network protocols. In this work, we discuss the need for bidirectional coupling of network simulation and road traffic microsimulation for evaluating IVC protocols. As the selection of a mobility model influences the outcome of simulations to a great extent, the use of a representative model is necessary for producing meaningful evaluation results. Based on these observations, we developed the hybrid simulation framework Veins (Vehicles in Network Simulation), composed of the network simulator OMNeT++ and the road traffic simulator SUMO. In a proof-of-concept study, we demonstrate its advantages and the need for bidirectionally coupled simulation based on the evaluation of two protocols for incident warning over VANETs. With our developed methodology, we can advance the state-of-the-art in performance evaluation of IVC and provide means to evaluate developed protocols more accurately.
-There is considerable interest to develop new time-of-flight detectors using micro-channel-plate photomultiplier tubes (MCP-PMTs). The question we pose in this paper is whether available waveform digitizer ASICs, such as the WaveCatcher or TARGET, operating with a sampling rate of 2-3 GSa/s, can compete with 1GHz BW CFD/TDC/ADC electronics. We have performed a series of measurements with these waveform digitizers connected to MCP-PMTs operating at low gain and with a signal equivalent to ~40 photoelectrons. These tests were performed using a laser diode to illuminate the photodetectors under conditions comparable to those used in previous SLAC and Fermilab beam tests. Our measurement results indicate that one can achieve similar timing resolution with both methods. Although commercial CFD-based electronics are readily available and perform very well, they are impractical for large scale systems. In contrast, ASIC-based waveform recording electronics are well-suited to such applications, and do not require analog delay lines that otherwise make CFDs difficult to incorporate in ASIC designs.
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