A uniform solution to the independent set problem through tissue P systems with cell separation

Membrane computing is an emergent branch of natural computing, which is inspired by the structure and the functioning of living cells, as well as the organization of cells in tissues, organs, and other higher order structures. Tissue P systems are a class of the most investigated computing mod- els in the framework of membrane computing, especially in the aspect of efficiency. To generate an exponential resource in a polynomial time, cell separation is incorporated into such systems, thus obtaining so called tissue P systems with cell separation. In this work, we exploit the computational efficiency of this model and construct a uniform family of such tissue P systems for solving the independent set problem, a well-known NP-complete problem, by which an efficient so- lution can be obtained in polynomial time.

Influence of the synthesis method parameters used to prepare nickel-based catalysts on the catalytic performance for the glycerol steam reforming reaction

The influence of the synthesis method parameters used to prepare nickel-based catalysts on the catalytic performance for the glycerol steam reforming reaction was studied.A series of Al2O3-supported Ni catalysts were synthesized,with nickel loading of 8 wt%,using the incipient wetness,wet impregnation,and modified equilibrium deposition filtration methods.The catalysts＇ surface and bulk properties were determined by inductively coupled plasma（ICP）,N2 adsorption-desorption isotherms（BET）,X-ray diffraction（XRD）,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,and temperature-programmed reduction（TPR）.Used catalysts were characterized by techniques such as elemental analysis and SEM in order to determine the level of carbon that was deposited and catalyst morphology.The results indicated that the synthesis method affected the textural,structural and surface properties of the catalysts,differentiating the dispersion and the kind of nickel species on alumina＇s surface.The formation of nickel aluminate phases was confirmed by the XRD and TPR analysis and the β-peak of the Ni/Al-edf catalyst was higher than in the other two catalysts,indicating that the nickel aluminate species of this catalyst were more reducible.Both Ni/Al-wet and Ni/Al-edf catalysts showed increasing CO2 selectivities and approximately constant CO selectivities for temperatures above 550℃,indicating that these catalysts successfully catalyze the water gas shift reaction.It was also confirmed that the Ni/Al-edf catalyst had the highest values for glycerol to gaseous products conversion,hydrogen yield,allyl alcohol,acetaldehyde,and acetic acid selectivities at 650℃ and the lowest carbon deposition of the catalysts tested.The correlation of the catalysts＇ structural properties,dispersion and reducibility with catalytic performance reveals that the EDF method can provide catalysts with higher specific surface area and active phase＇s dispersion,that are easier to reduce,more active and selective to hydrogen production,and more resistant to carbon deposition.

Possibility of Evolution in Culture of the <i>Oryctes</i>Nudivirus of the Coconut Rhinoceros Beetle <i>Oryctes rhinoceros</i>(Coleoptera: Scarabaeidae: Dynastinae)

It is suggested that the isolates of Oryctes Nudivirus (OrNV), cultured for decades in cells of Heteronychus arator (F.) (HA), be checked to verify genomic changes have not occurred which adapt them to culture but reduce or cancel their ability to infect the target pest, the coconut rhinoceros beetle (CRB), Oryctes rhinoceros (L.). Full genomes of field-caught OrNV isolates, and their infectivity against larvae and adults, could be compared with those of HA-cultured isolates. Further data to correlate OrNV dosage indices with doses in number of virions/ml could be advantageous so as to explore if CRB larvae or adults may resist infection by a sub-threshold dose. Also the possibility of changes in the HA culture cells which alter the outer coat of the resulting virion, hence perhaps its infectivity towards CRB cells, could be checked. Might it be possible to move beyond HA-culture and develop tissue culture of Oryctes rhinoceros cells for mass production of OrNV as this beetle species is the target? Nuclear genomes of OrNV-resistant and OrNV-susceptible strains of the CRB could be examined for changes perhaps correlated with resistance. The possibility of endosymbiotic bacteria affecting CRB susceptibility to OrNV might be checked.