Solubilization of M2 Transmembrane Peptide of Influenza A in Pure Water: Implications for Emergence of Proteins and Protein-embedded Primeval Membranes in Unsalted Oceans

We demonstrated that M2 transmembrane peptide, one of the most hydrophobic sequences in nature, can be solublized to at least ~100 µM in unsalted water without any lipid molecules. Strikingly, the M2 peptide also forms a highly-helical conformation in water which remains almost unchanged even at 95 ºC, as characterized by CD spectroscopy. Our result has critical implications in understanding emergence of proteins and protein-embedded primeval membranes in unsalted oceans

Analysis of shielded and open microstrip lines of double negative metamaterials using spectral domain approach (SDA)

Double-negative (DNG) metamaterials, refer to artificially created materials both having negative permittivity and effective permeability at a given frequency. In the last several years, double negative metamaterials attract a great deal of attention from scientists. In the area of high frequency application, transmission line serves as the fundamental building blocks. Due to the different application purposes, two kinds of microstrip are widely studied, shielded and open. In 2003, Krowne published his numerical results for shielded microstrip line with double negative metamaterials. In this research, Chebyshev polynomials are chosen for the current basis functions and diverse model structures are analyzed. Spectral domain approach (SDA) is used to explore the electric guiding-wave properties of specific structures with DNG metamaterials, containing dispersion curves, field distributions, power flow, and characteristic impedance. Convergence test of the dispersion constant over different sizes of current basis is analyzed for the open microstrip. The numerical results show that propagating mode or complex mode is found at different frequencies and geometric setups. Field distributions show the significant difference from that of double positive (DPS) materials. To improve the calculation efficiency, numerical acceleration techniques are included and implemented. The numerical analysis implies that the shielding walls have great impact on the propagating properties in the shielded microstrip line. The open microstrip line filled with DNG metamaterials exhibits significant loss in its fundamental mode, indicating that it is not a good candidate for transmission lin

Optimal Partitioned Cyclic Difference Packings for Frequency Hopping and Code Synchronization

Optimal partitioned cyclic difference packings (PCDPs) are shown to give rise to optimal frequency-hopping sequences and optimal comma-free codes. New constructions for PCDPs, based on almost difference sets and cyclic difference matrices, are given. These produce new infinite families of optimal PCDPs (and hence optimal frequency-hopping sequences and optimal comma-free codes). The existence problem for optimal PCDPs in ${\mathbb Z}_{3m}$, with $m$ base blocks of size three, is also solved for all $m\not\equiv 8,16\pmod{24}$.Comment: to appear in IEEE Transactions on Information Theor

List Decodability at Small Radii

$A'(n,d,e)$, the smallest $\ell$ for which every binary error-correcting code of length $n$ and minimum distance $d$ is decodable with a list of size $\ell$ up to radius $e$, is determined for all $d\geq 2e-3$. As a result, $A'(n,d,e)$ is determined for all $e\leq 4$, except for 42 values of $n$.Comment: to appear in Designs, Codes, and Cryptography (accepted October 2010