Half-Duplex Relaying for the Multiuser Channel

This work focuses on studying the half-duplex (HD) relaying in the Multiple Access Relay Channel (MARC) and the Compound Multiple Access Channel with a Relay (cMACr). A generalized Quantize-and-Forward (GQF) has been proposed to establish the achievable rate regions. Such scheme is developed based on the variation of the Quantize-and-Forward (QF) scheme and single block with two slots coding structure. The results in this paper can also be considered as a significant extension of the achievable rate region of Half-Duplex Relay Channel (HDRC). Furthermore, the rate regions based on GQF scheme is extended to the Gaussian channel case. The scheme performance is shown through some numerical examples.Comment: 7 pages, 4 figures, conference pape

Revisiting the holographic dark energy in a non-flat universe: alternative model and cosmological parameter constraints

We propose an alternative model for the holographic dark energy in a non-flat universe. This new model differs from the previous one in that the IR length cutoff $L$ is taken to be exactly the event horizon size in a non-flat universe, which is more natural and theoretically/conceptually concordant with the model of holographic dark energy in a flat universe. We constrain the model using the recent observational data including the type Ia supernova data from SNLS3, the baryon acoustic oscillation data from 6dF, SDSS-DR7, BOSS-DR11, and WiggleZ, the cosmic microwave background data from Planck, and the Hubble constant measurement from HST. In particular, since some previous studies have shown that the color-luminosity parameter $\beta$ of supernovae is likely to vary during the cosmic evolution, we also consider such a case that $\beta$ in SNLS3 is time-varying in our data fitting. Compared to the constant $\beta$ case, the time-varying $\beta$ case reduces the value of $\chi^2$ by about 35 and results in that $\beta$ deviates from a constant at about 5$\sigma$ level, well consistent with the previous studies. For the parameter $c$ of the holographic dark energy, the constant $\beta$ fit gives $c=0.65\pm 0.05$ and the time-varying $\beta$ fit yields $c=0.72\pm 0.06$. In addition, an open universe is favored (at about 2$\sigma$) for the model by the current data.Comment: 8 pages, 4 figure

Using Lysine-Reactive Fluorescent Dye for Surface Characterization of a Monoclonal Antibody

The last decade has witnessed a rapid growth in the development of protein pharmaceuticals for diagnostic and therapeutic purposes. The biopharmaceutical industry increasingly demands thorough characterization of protein conformation and conformational dynamics to ensure product quality and consistency. Here we present a chromatography-based method that is able to characterize protein conformation and conformational dynamics at peptide level resolution in a high-throughput manner. The surface lysine residues of the protein were labeled with a fluorescent dye prior to trypsin and Glu-C digestion. The resulting peptide maps were monitored by fluorescence detection and the peak areas of the respective peptides were normalized to protein concentration. The normalized fluorescence peak area for a specific peptide represents the individual lysine solvent accessibility. A higher normalized fluorescence peak area indicates higher solvent accessibility at a specific site. The identity of the peak of interested was determined by LC-MS/MS analysis. We first demonstrated this method is suitable for probing protein surface/conformation by studying the effect of deglycosylation on a recombinant monoclonal antibody (mAb), IgG 1. The results from this method were consistent with previous results obtained by H/D-exchange. We then applied our method to study the interaction of the mAb with a common excipient, polysorbate-20 (PS-20). The interaction between PS-20 and the mAb was generally weak. The presence of PS-20 increased the fluorescent labeling of several lysine residues on the mAb. These lysine residues localized near the protein domains of relatively high hydrophobicity. This result provides a first insight into PS-20-mAb interaction at peptide level resolution