Subcarrier modulation for transmission of 1-Gbit/s channels over 500 m of 62.5-μm multimode fiber

The use of two different subcarriers at frequencies up to 5.5 GHz each transmitting 1 Gbit/s over 500 m of multimode fiber (MMF) is demonstrated. By transmitting the two subcarrier channels simultaneously alongside the baseband signal, an aggregate bit rate of 2.8 Gbit/s is possible.

An improved technique to measure axial variation in wall flow along the channels of a diesel particulate filter

A technique to measure wall flow variation in Diesel Particle Filters (DPFs) is described. In a recent paper, it was shown how the flow distribution in DPFs could be measured in a non-destructive manner. This involved measuring the progressive dilution of a tracer gas introduced at the "outlet" channel upstream end. In the present paper, a significant further improvement to this technique is described, in which only a single probe is required, rather than the two of the previous technique. The single, traversable, probe consists of a controllable flow sink, and slightly downstream, a tracer gas supply. By controlling the sink flow rate such that a very small concentration of tracer gas is aspirated into it, the total flow up to that location in the channel is determined. Typical results showing the axial variation in the wall flow for known wall blockage cases are presented. It is suggested that this technique could be used to interpret the soot loading in the filter channels in a non-intrusive way.

Functionalisation of microfluidic channels with in situ grown carbon nanotubes

We present a new route towards customizing the surface properties of microfluidic channels, by a forest of in situ grown multiwalled carbon nanotubes (CNT). Local distortions of the electrical field direction are used to control the direction of the carbon nanotube growth. © 2005 Materials Research Society.

Characterization of acid-sensing ion channels in dorsal horn neurons of rat spinal cord

Acid-sensing ion channels (ASICs) are ligand-gated cation channels activated by extracellular protons. In periphery, they contribute to sensory transmission, including that of nociception and pain. Here we characterized ASIC-like currents in dorsal horn neurons of the rat spinal cord and their functional modulation in pathological conditions. Reverse transcriptase-nested PCR and Western blotting showed that three ASIC isoforms, ASIC1a, ASIC2a, and ASIC2b, are expressed at a high level in dorsal horn neurons. Electrophysiological and pharmacological properties of the proton-gated currents suggest that homomeric ASIC1a and/or heteromeric ASIC1a + 2b channels are responsible for the proton-induced currents in the majority of dorsal horn neurons. Acidification-induced action potentials in these neurons were compatible in a pH-dependent manner with the pH dependence of ASIC-like current. Furthermore, peripheral complete Freund's adjuvant-induced inflammation resulted in increased expression of both ASIC1a and ASIC2a in dorsal horn. These results support the idea that the ASICs of dorsal horn neurons participate in central sensory transmission/modulation under physiological conditions and may play important roles in inflammation-related persistent pain.