Cloning and characterization of the Inc A/C plasmid RA1 replicon

The Inc A/C plasmids, like Inc P and Inc Q plasmids, have a broad host range. However, their maintenance functions remain to be studied. An autoreplicative region of 2.79 kb named RepA/C, able to replicate both in the family Enterobacteriaceae and in Pseudomonas spp., was isolated and sequenced. The stability, copy number, and incompatibility expression of this replicon were determined. RepA/C and a nonautoreplicative fragment of 16 kb of this replicon were used as probes and showed specific hybridizations with the Inc P3-A/C plasmids from Pseudomonas spp. and members of the Enterobacteriaceae. These probes could be used as tools for identification of the plasmids of this epidemiologically important Inc group.     

Comparative evaluation of platforms for parallel Ant Colony Optimization

The rapidly growing field of nature-inspired computing concerns the development and application of algorithms and methods based on biological or physical principles. This approach is particularly compelling for practitioners in high-performance computing, as natural algorithms are often inherently parallel in nature (for example, they may be based on a “swarm”-like model that uses a population of agents to optimize a function). Coupled with rising interest in nature-based algorithms is the growth in heterogenous computing; systems that use more than one kind of processor. We are therefore interested in the performance characteristics of nature-inspired algorithms on a number of different platforms. To this end, we present a new OpenCL-based implementation of the Ant Colony Optimization algorithm, and use it as the basis of extensive experimental tests. We benchmark the algorithm against existing implementations, on a wide variety of hardware platforms, and offer extensive analysis. This work provides rigorous foundations for future investigations of Ant Colony Optimization on high-performance platforms.     

Nursing records for discharge. Report of the nursing history

The quality of care within our health care system depends upon an active and dynamic communication which bridges the different levels of care (primary and hospital) and will permit a continuity of services between the distinct parts. To insure this success, the authors propose an outpatient nursing record that will follow the patient upon his or her discharge. This record, to be called the "Discharged Patient Report", will be directed to other medical professionals so that they can be informed of previous treatments that the patient has received. Included in the report will be items such as; the previous nursing interactions that were used on the patient, how problems were resolved, possible other solutions, and health care information given to the patient. Using the report in this way will give us a great tool to know our patients and better understand how to serve them.     

Effect of texture and testing conditions on strain localization during cyclic deformation of copper polycrystals

Fatigue tests were performed on pure copper polycrystals with a crystallographic texture different from that produced by ‘standard’ thermomechanical treatments, which emphasize multi-slip 111–100 textures. The texture along the loading axis deviated by 10–15° from these two poles for the samples used here. The experiments were initiated by ramp loading as a mechanical pretreatment and the cyclic stress–strain curve (CSSC) was established by step tests using enough cycles at each step to insure saturation. Under these conditions, a plateau was observed in the CSSC at an appropriate stress level and in a reproducible fashion.     

Metal selectivity of Sargassum spp. and their alginates in relation to their alpha-L-guluronic acid content and conformation

The discovery of a consistent and unusual enrichment in homopolymeric alpha-L-guluronic acid G-blocks in alginates extracted from a suite of Sargassum brown algae is described in this study. 1H NMR spectroscopy was used to characterize these alginates which display homopolymeric guluronic acid block (G-block) frequency values (F(GG)) between 0.37 and 0.81. The presence of these G-blocks results in an enhanced selectivity for cadmium or calcium relative to monovalent ions such as sodium and the proton as well as smaller divalent ions such as magnesium. Results of competitive exchange experiments for the Cd-Ca-alginate system yield selectivity coefficient, K*(Cd)Ca, values between 0.43 +/- 0.10 and 1.32 +/- 0.02 for a range in F(GG) of 0.23 to 0.81. In contrast to the Cd-Ca-alginate system, the Mg-Ca-alginate and Mg-Cd-alginate systems yielded maximum values of K*(Mg)Ca (18.0 +/- 1.4) and K*(Mg)Cd (16.0 +/- 0.9) for the alginates extracted from Sargassum fluitans (F(GG) = 0.81; Cuba) and Sargassum thunbergii (F(GG) = 0.75; Korea), respectively. Selectivity studies with mixed-metal pair alginate systems highlight the importance of the specific macromolecular conformation of the alginate polymer in determining metal binding behavior in multiple-metal systems. Furthermore, they demonstrate the importance of the conformation of the alginate as it occurs within the tissue of Sargassum in determining the metal binding behavior of this algal biosorbent. The unique composition of the alginates present in species of Sargassum may represent a distinct advantage over other brown algal species when considering their implementation for the strategic removal of toxic heavy metals from contaminated and industrial wastewaters.     

Fracture variability and R-curve behavior in yttria-stabilized zirconia ceramics

An assessment of fracture origins is conducted in yttria-stabilized zirconia ceramics containing different grain sizes. As the microstructure coarsens due to the application of heat treatments, fracture origins change from single pores to transformed regions at the free surface which are induced by the applied stress. The observation of an increasing size of failure origins with microstructural coarsening lies as the underlying reason for the finding that specimens containing coarser microstructures and a more pronounced R-curve behavior do not fail at larger stresses. A fracture model is used to link the strength variability of a fully tetragonal zirconia containing a small grain size to its pore size distribution. The increased transformability of zirconia ceramics with coarser tetragonal grains is evaluated by means of quantitative phase analysis, characterizations of fracture surface morphology, and R-curve assessments. It is confirmed that tetragonal grains of up to 4 m may not necessarily undergo a spontaneous t–m transformation upon cooling from sintering.     

Influence of notch radius and R-curve behaviour on the fracture toughness evaluation of WC-Co cemented carbides

In this work the apparent fracture toughness of different grades of WC-Co cemented carbides has been evaluated by means of the single edge V-notched beam (SEVNB) method. The results are analysed, as a function of both the binder mean free path and the maximum steady-state crack shielding value, following a theoretical approach which assumes the existence of a small crack at the notch tip. The experimental findings indicate that larger defects at the notch tip and/or existence of R-curve behaviour imply higher (i.e. less restricted) values of the minimum notch radius required in SEVNB specimens for a reliable assessment of the fracture toughness of cemented carbides.     

Nanoindentation of Al2O3/Al2TiO5 composites: Small-scale mechanical properties of Al2TiO5 as reinforcement phase

The mechanical properties of alumina/aluminum titanate composites (Al₂O₃/Al₂TiO₅) were evaluated and analyzed by nanoindentation. Indentations with different penetration depths were performed, and residual imprints on specimens were located and observed by combining complementary characterization techniques. The mechanical response of composites was found to be determined by grain size of alumina and aluminum titanate, as evaluated from indentations performed at 1500 nm of penetration depth. On the other hand, small indents in individual grains permitted to assess the hardness as well as the elastic modulus of non-cracked particles of Al₂TiO₅ through implementation of different analytical indentation models. The attained values for the local mechanical properties were validated through critical comparison of them with those predicted by the rule of mixtures. Results showed no evidence of microcracking on grains of the reinforcing phase for all the tested composites, before and after low penetration depth indentations. Elastic modulus of Al₂TiO₅ was found to be higher than the values reported on bulk aluminum titanate, presumably because of the absence of microcracking for small grain sizes. The bulk composite mechanical response is finally discussed on the basis of contributions from those of the individual phases.