Determining the minimum grain size in severe plastic deformation process via first-principles calculations

Although the stacking fault energy (SFE) is a fundamental variable determining the minimum grain size (d_min) obtainable in severe plastic deformation (SPD) processes, its accurate measurement is difficult. Here we establish the SFEs of binary Pd–Ag, Pd–Cu, Pt–Cu and Ni–Cu solid solutions using the axial interaction model and the supercell model in combination with first-principles theory. The two models yield consistent formation energies. For Pd–Ag, Pd–Cu and Ni–Cu, the theoretical SFEs agree well with those from the experimental measurements. For Pt–Cu no experimental results are available, and thus our calculated SFEs represent the first reasonable predictions. We discuss the correlation of the SFE and d_min in SPD experiments and show that the d_min values can be evaluated from first-principles calculations.     

Analysis of Modified Nucleotide Aptamer Library Generated by Thermophilic DNA Polymerases

One of the pivotal steps in aptamer selection is the amplification of target-specific oligonucleotides by thermophilic DNA polymerases; it can be a challenging task if nucleic acids possessing modified nucleotides are to be amplified. Hence, the identification of compatible DNA polymerase and modified nucleotide pairs is necessary for effective selection of aptamers with unnatural nucleotides. We present an in-depth study of using 5-indolyl-AA-dUTP (TAdUTP) to generate oligonucleotide libraries for aptamer selection. We found that, among the eight studied DNA polymerases, only Vent(exo-) and KOD XL are capable of adapting TAdUTP, and that replacing dTTP did not have a significant effect on the productivity of KOD XL. We demonstrated that water-in-oil emulsion PCR is suitable for the generation of aptamer libraries of modified nucleotides. Finally, high-throughput sequence analysis showed that neither the error rate nor the PCR bias was significantly affected by using TAdUTP. In summary, we propose that KOD XL and TAdUTP could be effectively used for aptamer selection without distorting the sequence space of random oligonucleotide libraries.     

Hydroisomerization of Fischer�CTropsch Wax on Pt/AlSBA-15 and Pt/SAPO-11 Catalysts

A Pt/AlSBA-15 catalyst was investigated in the selective isomerisation of Fischer?CTropsch wax, which type of catalyst have not been studied in detail in this reaction system yet. Its hydroconversion activity was compared with that of the Pt/SAPO-11 catalyst. Based on the results it was concluded that the selective isomerization of the Fischer?CTropsch wax can be a new application of the Pt/AlSBA-15 catalyst.     

Signaling architectures and recovery time scaling for grid applications in IST Project MUPBED

It is now evident to the research community that local computational resources cannot keep up in an economical way with the demands generated by some users/applications. Therefore, distributed computing and the concept of a computational grid are now emerging. Novel transport network concepts are needed to support such visions, and high-speed intelligent optical networking may be the required infrastructure that will enable global grids. Emerging utility grid applications like business continuity and disaster recovery have strong requirements on the dynamic optical networks connecting the distributed grid resources. Supporting grid networking with an intelligent optical network (ION) infrastructure will allow utility grid applications the necessary flexibility with the required QoS (e.g., high bandwidth, reliability, limited delay). Emerging QoS requirements, such as scalable recovery time, highly depend on the ION's signaling architecture. This article gives simple analytical models for the implementation options of optical control plane signaling, shows simulation models for different resilience strategies, and offers some illustrative numerical comparisons to support the aforementioned efforts. This research area is also discussed, among others, in the European research project Multi-Partner European Testbeds for Research Networking (MUPBED).     

Influence of silicon doping on the nanomorphology and surface chemistry of a wood-based carbon molecular sieve

Carbon–silica molecular sieves were prepared by carbonization of Scotch fir (Pinus sylvestris) after impregnation with aqueous waterglass (Na_xSi_yO_z, where x, y and z may take a range of values). Compared to Si-free samples, doping significantly modifies the structure that forms during the carbonization process. For carbonization temperatures between 600 °C and 1000 °C, doped samples shrink less than undoped samples, indicating increased mechanical strength. The specific surface area and pore volume develop in a combined self-activation and chemical vapour deposition (CVD) process. Nevertheless, the presence of the sodium silicates limits self-activation and thus reduces the porosity. Doping drastically reduces the specific surface area, measured both by gas adsorption and small angle X-ray scattering. The latter technique demonstrates that in both doped and undoped samples the specific surface area is isotropic. X-ray photoelectron spectroscopy (XPS) reveals that the spatial distribution of Na and Si atoms within the samples are not identical. The open honeycomb structure, conserved during the heat treatment from the original wood, provides easy access for gas adsorption and separation applications. The ratios of the microporous diffusion time constants of N₂ and O₂ from frequency response (FR) measurements gave separation factors 3.0, 4.3, 2.7 and 1.3 for samples prepared at 600 °C, 700 °C, 800 °C and 900 °C, respectively.     

Dogs' ( Canis familaris ) responsiveness to human pointing gestures.

In a series of 3 experiments, dogs (Canisfamiliaris) were presented with variations of the human pointing gesture; gestures with reversed direction of movement, cross-pointing, and different arm extensions. Dogs performed at above chance level if they could see the hand (and index finger) protruding from the human body contour. If these minimum requirements were not accessible, dogs still could rely on the body position of the signaler. The direction of movement of the pointing arm did not influence the performance. In summary, these observations suggest that dogs are able to rely on relatively novel gestural forms of the human communicative pointing gesture and that they are able to comprehend to some extent the referential nature of human pointing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High Catalytic Activity in CO Oxidation over MnO x Nanocrystals

Manganese oxides of various stoichiometry were prepared via Mn-oxalate precipitation followed by thermal decomposition in the presence of oxygen. A non-stoichiometric manganese oxide, MnO _x (x = 1.61…1.67) was obtained by annealing at 633 K and demonstrated superior CO oxidation activity, i.e. full CO conversion at room temperature and below. The activity gradually decreased with time-on-stream of the reactants but could be easily recovered by heating at 633 K in the presence of oxygen. CO oxidation over MnO _x in the absence of oxygen proved to be possible with reduced rates and demonstrated a Mars—van Krevelen—type mechanism to be in operation. A TEM structural analysis showed the MnO _x phase to form microrods with large aspect ratio which broke up into nanocrystalline manganese oxide (MnO _x ) particles with diameters below 3 nm and a BET specific surface area of 525 m²/g. Annealing at 798 K rather than 633 K produced well crystalline Mn₂O₃ which showed lower CO oxidation activity, i.e. 100% CO conversion at 335 K. The catalytic performance in CO oxidation of various Mn-oxides either studied in this work or elsewhere was compared on the basis of specific reaction rates.     

Laparoscopic hiatal reconstruction and use of harmonic scalpel instrument

The method of laparoscopic repair of hiatal hernia is accepted in surgery. Usually associated with Nissen fundoplication which is the most commonly performed antireflux operation. Within a ten-year period authors have done 90 antireflux operations, 52 was laparoscopic procedures. (30 operations for GERD, 10 for hiatal hernia, 12 for the combination of both.) A patient was submitted to operation with large hiatal hernia. He was treated laparoscopic way with success and good results. The Ultracision Harmonic Scalpel instrument helped their operation in many ways, and provided correct bloodless preparation of cardiac region. The authors demonstrate our procedure and the use of the Harmonic Scalpel. Their patient were completely pleased with the results after discharge, they are still under regular control.