Decode and forward polar coding for Half-duplex two-relay channels based on multilevel construction

Polar codes represent an emerging class of error-correcting codes with power to approach the capacity of the physically degraded relay channel and relevant coding schemes have been proposed in the literature. This paper aims to design new cooperative decode-and-forward (DF) polar coding schemes for half-duplex two-relay channel based on the Plotkin’s construction illustrating their performances gain. In these schemes, we consider the use of time-division process in transmission. The source node transmits its polar-coded information to both relays and the destination nodes during the first time slot. Each relay node receives the data from the source and processes it using the DF protocol. For the second transmission period, each relay first decodes the source signal then after reconstruction of the information reduction matrix based on the multilevel characteristics of polar codes, the extracted data at each relay are recoded using another polar code and transmitted to the destination. At destination node, the signals received from each relay and source nodes are processed by using multi-joint successive cancellation decoding for retrieving the original information bits. We demonstrate via simulation results that by carefully constructed polarisation matrix at each relay node, we can achieve the theoretical capacity in the half-duplex relay channel.     

A new double EWMA-t chart with auxiliary information for the process mean

In this paper, we propose an auxiliary-information-based (AIB) double EWMA-$t$ (AIB-DEWMA-$t$) chart for monitoring the process mean. The DEWMA-$t$ chart encompasses the EWMA-$t$ and AIB-EWMA-$t$ charts. The Monte Carlo simulations are used to compute the run length characteristics of the AIB-DEWMA-$t$ chart. Based on detailed run length comparisons, it is found that the AIB-DEWMA-$t$ chart may uniformly and substantially outperform the AIB-EWMA-$t$ chart when detecting different shifts in the process mean. In addition, the AIB-DEWMA-$t$ chart is uniformly more sensitive than the DEWMA-$t$ chart. Similar trends are observed when comparing these control charts with the variable sampling interval feature. A real dataset is also considered to demonstrate the implementation of the proposed chart.     

An electrochemical microfluidic platform for human P450 drug metabolism profiling

This paper is the first report of a P450-electrode in a microfluidic format. A 30 μL microfluidic cell was made in poly(methyl methacrylate) containing the inlet, outlet, and reaction chamber with two electrode strips, one of which contains the human cytochrome P450 3A4 covalently bound to gold via a 6-hexanethiol and 7-mercaptoheptanoic acid (1:1) self-assembled monolayer. The electrochemical response of the P450-electrode in the microfluidic cell was tested using four drugs that are known substrates of P450 3A4: quinidine, nifedipine, alosetron and ondansetron. Titration experiments allowed the electrochemical measurements of K(M) for the four drugs, with values of 2.9, 29.1, 113.4, and 114.1 mM, respectively. The K(M) values are found to be in good agreement and correctly ranked with respect to the published literature on human liver microsomes and baculosomes: [ondansetron ≈ alosetron > nifedipine > quinidine]. The results presented in this paper represent a step forward for a rapid evaluation of the interaction of P450 and drug, requiring small volumes of new chemical entities to be tested.     

POCA: pattern‐oriented channel assignment scheme for wireless cellular networks

This paper presents a new decentralized dynamic channel allocation scheme which uses a ‘clustering’ concept to allocate channels efficiently. Simulation results show that the proposed scheme performs better than fixed channel assignment and some other dynamic channel allocation schemes under low and moderate traffic load conditions. Copyright © 2004 John Wiley & Sons, Ltd.     

Aluminium and cerium co-doped ZnO nanoparticles:Facile and inexpensive synthesis and visible light photocatalytic performances

Facile combustion route synthesized Al and Ce co-doped ZnO nanoparticles photocatalysts were characterized using XRD,SEM,BET,EDS,UV-visible DRS,PL,photocurrent and EIS techniques.XRD and SEM analyses identify that crystallite and particle size is reduced from 13.26 to 11.88 nm with introduction of Al and Ce into ZnO which assists inhibiting the recombination of photo generated charge carriers.UVvisible DRS spectra indicate that optical assimilation of ZnO is significantly increased to visible region(-406 nm)and band gap reduces from 3.18 to 3.06 eV with introduction of Al and Ce co-dopants.Electrochemical impedance spectroscopy analysis under visible light illumination confirms the enhancement in visible light activity of Al and Ce co-doped ZnO nanoparticles as photocatalysts.The enhanced activity of Al and Ce co-doped ZnO photocatalyst can be ascribed to enhanced light assimilation,high surface area and efficient charge transfer process.Our results reveal that by incorporating precise amount of Al(~2%)and Ce(~2%)into ZnO,a highly efficient catalyst can be synthesized that have degraded almost 95%methyl orange(MO)dye in just 45 min.Further,the influence of various operational parameters such as solution pH,catalyst dose,dye concentration,airflow rate and light intensity on photodecomposition of MO was evaluated.Furthe rmore,a possible mechanism for Al and Ce modified ZnO was proposed and designed photocatalysts demonstrates good stability in aqueous medium.     

Metallic and dielectric photonic crystals with chiral elements by combined nanoimprint and reversal lithography in SU-8

We report a novel nanoprocess combining nanoimprint lithography and conventional lithography to fabricate metallic and dielectric nanophotonic crystals with chiral elements in SU-8. The previously developed nanoimprint process was modified for much smaller feature size. Four different types of nanophotonic crystals with different materials in both large and small dimensions are fabricated. The new proposed reversal lithography is used to fabricate one type among the above mentioned four. The success of reversal lithography provides a solution for near-field lithography to achieve nanosize structures with simple conventional lithography. Optical measurements of the laser polarization state from the fabricated photonic crystals indicate an optical chirality which distinguishes the chiral elements from other normal symmetric structures.     

Effect of crosslinker feed content on catalaytic activity of silver nanoparticles fabricated in multiresponsive microgels

We investigated the effect of crosslinking density of poly(N-isopropyl acrylamide-co-acrylic acid) microgels on catalytic activity of silver nanoparticles fabricated hybrid microgels. Multiresponsive poly(N-isopropyl acrylamide-co-acrylic acid) microgels with 2, 4, 6 and 8 mole percentage of N,N-methylene-bis-acrylamide were synthesized by emulsion polymerization. These microgels were characterized by dynamic light scattering and were used as microreactors to synthesize silver nanoparticles. Hybrid system was characterized by ultraviolet-visible spectroscopy. The catalytic activity of hybrid microgels with different crosslinker content was compared by studying the reduction of pnitrophenol as a model reaction. Kinetics of reaction was monitored by spectrophotometry. The value of the apparent rate constant decreases from 0.568 to 0.313min^?1, when content of crosslinker are increased from 2 to 8 mole percentage respectively. This decreases in value of apparent rate constant is due to increase in diffusional barrier offered by high crosslinking of polymer network at high mole percentages of N,N-methylene-bis-acrylamide.     

Patterning the mechanical properties of hydrogen silsesquioxane films using electron beam irradiation for application in mechano cell guidance

Hydrogen silsesquioxane (HSQ) is a material with the potential for studying the effect of surface stiffness on stem cell differentiation. Here, the effects of electron beam dose on the topography and the mechanical properties of HSQ obtained with or without trimethylamine (TMA) development are characterised by atomic force microscopy imaging and indentation. A correlation between the surface stiffness (uniform across the sample) and electron beam exposure is observed. Surface roughness of HSQ samples developed in TMA decreases exponentially with increasing electron beam exposure. Surface coating with plasma polymerised allylamine (ppAAm) leads to an overall decrease in stiffness values. However, the increase in surface stiffness with increasing electron beam exposure is still evident. The ppAAm coating is shown to facilitate human mesenchymal stem cell adhesion.     

Low Resistance Polycrystalline Diamond Thin Films Deposited by Hot Filament Chemical Vapour Deposition

Polycrystalline diamond thin films with outgrowing diamond (OGD) grains were deposited onto silicon wafers using a hydrocarbon gas (CH4) highly diluted with H2 at low pressure in a hot filament chemical vapour deposition (HFCVD) reactor with a range of gas flow rates. X-ray diffraction (XRD) and SEM showed polycrystalline diamond structure with a random orientation. Polycrystalline diamond films with various textures were grown and (111) facets were dominant with sharp grain boundaries. Outgrowth was observed in flowerish character at high gas flow rates. Isolated single crystals with little openings appeared at various stages at low gas flow rates. Thus, changing gas flow rates had a beneficial influence on the grain size, growth rate and electrical resistivity. CVD diamond films gave an excellent performance for medium film thickness with relatively low electrical resistivity and making them potentially useful in many industrial applications.