Galectins are defined by a conserved β-galactoside binding site that has been linked to many of their important functions in e.g. cell adhesion, signaling, and intracellular trafficking. Weak adjacent sites may enhance or decrease affinity for natural β-galactoside-containing glycoconjugates, but little is known about the biological role of this modulation of affinity (fine specificity). We have now produced 10 mutants of human galectin-3, with changes in these adjacent sites that have altered carbohydrate-binding fine specificity but that retain the basic β-galactoside binding activity as shown by glycan-array binding and a solution-based fluorescence anisotropy assay. Each mutant was also tested in two biological assays to provide a correlation between fine specificity and function. Galectin-3 R186S, which has selectively lost affinity for LacNAc, a disaccharide moiety commonly found on glycoprotein glycans, has lost the ability to activate neutrophil leukocytes and intracellular targeting into vesicles. K176L has increased affinity for β-galactosides substituted with GlcNAcβ1–3, as found in poly-N-acetyllactosaminoglycans, and increased potency to activate neutrophil leukocytes even though it has lost other aspects of galectin-3 fine specificity. G182A has altered carbohydrate-binding fine specificity and altered intracellular targeting into vesicles, a possible link to the intracellular galectin-3-mediated anti-apoptotic effect known to be lost by this mutant. Finally, the mutants have helped to define the differences in fine specificity shown by Xenopus, mouse, and human galectin-3 and, as such, the evidence for adaptive change during evolution.

Abstract-We present a narrowband interference (NBI) canceller that suppresses spectral leakage in an orthogonal frequency-division multiplexing (OFDM)-based system caused by a narrowband (NB) signal. In our scenario, we assume that the spectrum of the NB signal is within the spectrum of the OFDM signal. This can be the case, e.g., on digital subscriber lines (DSL) and in new unlicensed frequency bands for radio transmission.The canceller makes linear minimum mean-square error estimates of the spectral leakage by measuring the NBI on a few modulated or unmodulated OFDM subcarriers. It uses a model of the NB signal's power spectral density as a priori information. Using frequency invariant design it is possible to cancel NBI from signals that are changing their frequency location with significantly reduced complexity overhead. The operational complexity of the canceller can be lowered by using the theory of optimal rank reduction and using the time-bandwidth product of the NB signal.Analytical performance evaluations, as well as Monte Carlo simulations, also show that without perfect a priori information this canceller can suppress the spectral leakage from a strong NB signal (e.g., with equal power as the OFDM signal) to well below the background noise floor for typical applications where it causes negligible signal to noise ratio and symbol error rate degradation.Index Terms-Digital subscriber lines (DSL), discrete multitone (DMT), industrial-scientific-medical (ISM) band, orthogonal frequency-division multiplexing (OFDM), radio frequency interference (RFI), wireless local area network (WLAN).

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In this paper, we present a new duplex scheme, called Zipper, for discrete multitone (DMT)-based very high bit-rate digital subscriber line (VDSL) systems on copper wires. This scheme divides the available bandwidth by assigning different subcarriers for the upstream and downstream directions. It has high flexibility to divide the capacity between the up and downstream, as well as good coexistence possibilities with other systems such as ADSL. Simulation results show high bit-rate performance in different environments such as mixed ADSL and VDSL traffic under radio frequency interference and with different background noise sources.