An argument against routine percutaneous biopsy, ERCP, or biliary stent placement in patients with clinically resectable periampullary masses: a surgical perspective

We have determined the nucleotide sequence of the HIV-1 vif gene in viruses obtained from symptomatic patients of distinct risk groups in Madrid. The genetic diversity among the isolates was estimated in 4.6% (+/- 1.4 standard deviation), a similar value to that obtained for the gag gene 3.9% (+/- 0.8 standard deviation) and env 4.1% (+/- 1 standard deviation) (Rojas et al., Virus Res 31, 331-342, 1994). Amino acid sequence analysis revealed the presence of hypermutable residues at positions 101 and 167, close to antigenically relevant sequential epitopes (comprising amino acids 87-94 and 172-178). Phylogenetic analysis supports the existence of two virus lineages circulating preferentially within different risk groups.     

Mechanical properties and adhesion of TiN monolayer and TiN/TiAlN nanolayer coatings

In this work, TiN monolayer and TiN/TiAlN nanolayer coatings were deposited on 100C6 (AISI 52100) steel substrate by Physical vapor deposited (PVD) magnetron sputtering system. The morphological characterization was evaluated using an atomic force microscopy. The mechanical properties were determined by nanoindentation test. The adhesion was investigated by both microindentation and scratch test. The results show that the TiN/TiAlN nanolayer coating have the more rough surface and the better mechanical properties and adhesion compared to TiN monolayer coating. The effect of microstructural and mechanical proprieties on the adhesion behavior was further discussed. It was found that the improvement in adhesion of nanolayer system is in part due to the increase in plastic deformation resistance and the enhancement of mechanical properties (hardness and elastic modulus) and to the structure with a small grain size and a high number of interfaces.     

Modelling recombination current in polysilicon solar cell grain boundaries

The recombination current in grain boundaries is theoretically investigated for a polycrystalline silicon solar cell n–p junction operating either in short-circuit or in open-circuit configurations. The analysis is carried out using results performed in earlier works, by means of numerical simulations including the presence of grain boundaries. The variation of grain boundary recombination current density with exciting light wavelength is reported for different cell parameters like grain boundary recombination velocity, base dopant density and base thickness.The objective of the present paper is to understand to what extend the light wavelength and the junction configuration allow an optimal measure of the grain boundary recombination parameter.     

Dynamic bandwidth management in IEEE 802.11-based multihop wireless networks

In this paper, we propose a new protocol named dynamic regulation of best-effort traffic (DRBT) which supports quality of service (QoS) throughput guarantees and provides a distributed regulation mechanism for best-effort traffic in multihop wireless networks. By adapting dynamically the rate of best-effort traffic at the link layer, DRBT increases the acceptance ratio of QoS flows and provides a good use of the remaining resources through the network. Our protocol also provides an accurate method to evaluate the available bandwidth in IEEE 802.11-based ad hoc networks which is able to differentiate QoS applications from best-effort traffic. Through extensive simulations, we compare the performance of our proposal scheme with some others protocols like QoS protocol for ad hoc real-time traffic for instance.     

Novel aerobic perchloroethylene degradation by the white-rot fungus Trametes versicolor

Perchloroethylene (PCE) is one of the most important groundwater pollutants around the world. It is a suspected carcinogen and is believed to be recalcitrant to microbial degradation. We report here, for the first time, aerobic degradation of PCE by the white rot fungus, Trametes versicolor, to less hazardous products. Aerobic degradation rate of PCE was 0.20 and 0.28 nmol h(-1) mg(-1) dry weight of fungal biomass. Trichloroacetic acid (TCA) was identified as the main intermediate using [2-13C]-PCE as the substrate. Chloride released and TCA produced were stoichiometric with PCE degradation. Our studies using 1 -aminobenzotriazole (ABT), an inhibitor of cytochrome P-450, suggested that a cytochrome P-450 system may be involved in PCE degradation by T. versicolor. These results are of particular interest because TCA production from PCE has not been reported to date in bacteria or fungi.     

Time-resolved diffusing wave spectroscopy beyond 300 transport mean free paths

We presented theoretical and experimental demonstrations of the possibilities of performing time-resolved diffusing wave spectroscopy: We successfully registered field fluctuations for selected photon path lengths that can surpass 300 transport mean free paths. Such performance opens new possibilities for biomedical optics applications.     

Chemical treatment of sludge: in-depth study on toxic metal removal efficiency, dewatering ability and fertilizing property preservation

The presence of toxic metals in municipal sewage sludge restricts the application of this biomass in agricultural area. A chemical leaching process using a combination of inorganic acid and two oxidants has been developed for sludge decontamination. The present study investigated the effects of the concentrations of sulphuric acid (H2SO4), hydrogen peroxide and ferric chloride on metal solubilization from sewage sludge, as well as preservation of fertilizing properties (nutrient content) and dewatering ability of the treated sludge. The analysis of the results from batch leaching tests has allowed to define the optimal conditions for the reagent concentrations, which are 56 kg Fe3+ tonne(-1) of dry sludge solids (tds), 8 kg H2O2 tds(-1), and enough H2SO4 to reach a pH between 2.0 and 2.5 but less than 142 kg H2SO4 tds(-1). Finally, under these conditions, oxidoreduction potential values are found to be between 450 and 475 mV.     

Mechanical characterization and modeling of poly (β‐hydroxybutyrate)‐co‐poly(β‐hydroxyvalerate)–Alfa fiber‐reinforced composites

The mechanical properties of biobased composites of poly(β‐hydroxybutyrate)‐co‐poly(β‐hydroxyvalerate) biopolymer continuously reinforced with unidirectional Alfa fibers are investigated via tensile testing of oriented composite laminates. Simple mechanical models for the elastic stiffness, strength, and nonlinear hardening of the biobased composites are proposed with an emphasis on techniques that only require the independent properties of the fiber and matrix to facilitate composite design. Rule of mixtures (ROM) approaches are found to effectively predict the elastic properties of the composites but generally overestimate strength. Modified ROM approaches that discount the contribution of the matrix in the fiber loading direction and the contribution of the fiber in the transverse loading direction provide the most accurate strength predictions. Apparent elastic properties for composites with varying fiber orientations are predicted using a modified orthotropic laminate plate method which was found to overestimate composite stiffness in off‐axis loading directions. Postyield nonlinear hardening is modeled using a calibrated continuum yield and plasticity model and demonstrated to provide a close match of the experimental results. POLYM. COMPOS., 35:1758–1766, 2014. © 2014 Society of Plastics Engineers