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A high frequency experiment was conducted in the Woods Hole Harbor in Massachusetts to evaluate the effectiveness of Doppler sonar for discriminating targets from reverberation. Using a pulsed linear frequency modulated signal, one finds that the matched filtered outputs are filled with high-level discrete backscattered returns, referred to as clutter, which are often confused with the target echo. The high level non-target returns have an amplitude distribution that is heavy-tailed. Using a Doppler-sensitive binary-phase-shift-keying signal coded with an m-sequence, the target echo and clutter can be separated by Doppler and delay, and tracked using the Doppler spectrogram (Dopplergram). The Doppler filtered time series show a background reverberation with a Rayleigh-like amplitude distribution, with an improved signal-to-(peak) reverberation ratio compared with that without Doppler filtering. The reduced reverberation level with Doppler processing decreases the probability of false alarm (Pfa) for a given threshold level. Conversely, for a given Pfa, the higher signal-to-(peak) reverberation ratio implies a higher probability of detection. Transmission loss measurement was conducted to estimate some of the system parameters, e.g., the source level and target strength relative to the noise level.

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Leukocyte-derived microparticles (LMPs) include neutrophil-, lymphocyte-and monocyte-derived MPs. LMPs act as proinflammatory mediators in autoimmune diseases, infectious diseases and vascular diseases. The present study examined the hypothesis that the percentage of LMPs was increased in patients with inflamed odontogenic keratocysts (OKCs), and investigated the biological effects of Jurkat cell-derived MPs on the fibroblasts of OKCs in vitro. Cyst fluid MPs, obtained by centrifugation of samples from 20 patients with inflamed OKCs, 3 patients with uninflamed OKCs, 15 patients with radicular cysts (RCs) and 12 patients with inflamed dentigerous cysts (DCs), were analyzed by transmission electron microscopy, dynamic light scattering and immunofluorescence staining. The percentages and concentrations of cyst fluid LMPs were further determined by flow cytometry. The cytokine levels of apoptotic Jurkat cell-derived MPs and Jurkat cell supernatants were compared by cytokine antibody arrays. Fibroblasts were isolated from 3 patients with OKC and co-cultured with apoptotic Jurkat cell-derived MPs with or without interleukin (IL)-15Rα to detect the levels of matrix metallopeptidase 9 (MMP-9) and receptor activator of nuclear factor-κB ligand (RANKL) by reverse transcription-quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. The supernatant from Jurkat MPs-treated fibroblasts was collected to make conditioned medium in which the osteoclastogenesis of Raw264.7 cells was determined. Antibodies against human soluble (s)RANKL were added to the conditioned medium to investigate the inhibitory effects. Mean percentages of lymphocyte-and neutrophil-derived MPs were significantly higher in inflamed OKCs than in DCs. Significant elevations in IL-15 were detected in apoptotic Jurkat cell-derived MPs compared with that in Jurkat cell supernatant. Furthermore, higher levels of MMP-9 and RANKL were detected in Jurkat cell MP-treated OKC fibroblasts, and this was partially blocked by IL-15Rα. Increased osteoclast-like cell formation was observed in the Jurkat MPs-treated fibroblast supernatant and Raw264.7 co-culture groups. The anti-human sRANKL antibody in the Jurkat MPs-treated fibroblast supernatant group decreased the osteoclastogenesis of the Raw264.7 cells. These results indicate that LMPs serve as novel communication tools that contribute toward the bone resorption of inflamed OKCs by inducing RANKL of OKC fibroblasts via IL-15.

Distributed underwater sensors are expected to provide oceanographic monitoring over large areas. As fabrication technology advances, low cost sensors will be available for many uses. The sensors communicate to each other and are networked using acoustic communications. This paper first studies the performance of such systems for current measurements using tomographic inversion approaches to compare with that of a conventional system which distributes the sensors on the periphery of the area of interest. It then proposes two simple signal processing methods for ocean current mapping (using distributed networked sensors) aimed at real-time in-buoy processing. Tomographic inversion generally requires solving a challenging high dimensional inverse problem, involving substantial computations. Given distributed sensors, currents can be constructed locally based on data from neighboring sensors. It is shown using simulated data that similar results are obtained using distributed processing as using conventional tomographic approaches. The advantage for distributed systems is that by increasing the number of nodes, one gains a much more improved performance. Furthermore, distributed systems use much less energy than a conventional tomographic system for the same area coverage. Experimental data from an acoustic communication and networking experiment are used to demonstrate the feasibility of acoustic current mapping.

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