Phytodegradation Potential of <Emphasis Type="Italic">Erythrina crista-galli</Emphasis> L., Fabaceae,in Petroleum-Contaminated Soil

This work aimed at investigating both the tolerance and the phytodegradation potential of Erythrina crista-galli L. in petroleum-contaminated soil. It consisted in analyzing E. crista-galli germination, surviving, growth, and development when cultivated at different contaminant concentrations and pollutant degradation rates. This specimen was selected because it presented a special behavior among others also exposed to petroleum in an accident that occurred in the Araucaria region (south of Brazil), resulting in a four-million-liter oil spill. The experiment was carried out in a greenhouse containing non-contaminated soil (NCS), vegetated contaminated soil (VCS), and non-vegetated contaminated soil (NVCS) at the following petroleum concentrations: 25 g kg⁻¹ (VCS-25), 50 g kg⁻¹ (VCS-50), and 75 g kg⁻¹ (VCS-75). After 60 days, the soil samples were analyzed by gas chromatography. Germination was more and more evident as higher petroleum concentrations were observed. The surviving rates of groups NCS, VCS-25, VCS-50, and VCS-75 were 64%, 70%, 61%, and 96%, respectively. The VCS group growth was reduced when compared to the control group (NCS). The individuals exposed to petroleum pollution presented differences in the anatomic structure of their roots when compared to the NCS group. It was observed that the petroleum degradation rate was higher for VCS group than for NVCS. E. crista-galli is potentially recommended for petroleum-contaminated soils because of its positive association in the presence of contamination.     

A survey for the quadratic assignment problem

The quadratic assignment problem (QAP), one of the most difficult problems in the NP-hard class, models many real-life problems in several areas such as facilities location, parallel and distributed computing, and combinatorial data analysis. Combinatorial optimization problems, such as the traveling salesman problem, maximal clique and graph partitioning can be formulated as a QAP. In this paper, we present some of the most important QAP formulations and classify them according to their mathematical sources. We also present a discussion on the theoretical resources used to define lower bounds for exact and heuristic algorithms. We then give a detailed discussion of the progress made in both exact and heuristic solution methods, including those formulated according to metaheuristic strategies. Finally, we analyze the contributions brought about by the study of different approaches.     

Aromatic nitro substitution reaction between 4‐nitro‐N‐n‐butyl‐1,8‐naphthalimide and n‐heptanethiol in water–methanol binary mixtures

The second‐order rate constants of thiolysis by n‐heptanethiol on 4‐nitro‐N‐n‐butyl‐1,8‐naphthalimide (4NBN) are strongly affected by the water–methanol binary mixture composition reaching its maximum at around 50% mole fraction. In parallel solvent effects on 4NBN absorption molar extinction coefficient also shows a maximum at this composition region. From the spectroscopic study of reactant and product and the known H‐bond capacity of the mixture a rationalization that involves specific solvent H‐donor interaction with the nitro group is proposed to explain the kinetic data. Present findings also show a convenient methodology to obtain strongly fluorescent imides, valuable for peptide and analogs labeling as well as for thio‐naphthalimide derivatives preparations. Copyright © 2008 John Wiley & Sons, Ltd.     

Anti-inflammatory/infection PLA nanoparticles labeled with technetium 99m for in vivo imaging

Despite advancements in treatment of infectious diseases, opportunistic pathogens continue to pose a worldwide threat. Identifying a source of infection/inflammation is often challenging which highlights the need of improved diagnostic agents. Using a model of local S. aureus infection, here we evaluated the potential of betamethasone or dexamethasone loaded in poly (lactic acid) nanoparticles and radiolabeled with 99mTc to detect an infection/inflammation site in vivo. A betamethasone and dexamethasone nanoparticles (NPs) with 200 and 220 nm in size, respectively, were created with a 98% 99mTc radiolabeling efficiency. When injected in infected mice, betamethasone NPs presented a higher accumulation in the infected hind paw in comparison with dexamethasone NPs. Our results suggest that this nanosystem may be a valid nanoradiopharmaceutical for the detection of inflammation/infection foci in vivo.

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Graphical abstract Nanoradiopharmaceutical for inflammation

     

Some Long-Range Dependence Processes Arising from Fluctuations of Particle Systems

Several long-range dependence, self-similar Gaussian processes arise from asymptotics of some classes of spatially distributed particle systems and superprocesses. The simplest examples are fractional Brownian motion and sub-fractional fractional Brownian motion, the latter being intermediate between Brownian motion and fractional Brownian motion. In this paper we focus mainly on long-range dependence processes that arise from occupation time fluctuations of immigration particle systems with or without branching, and we study their properties. Some long-range dependence non-Gaussian processes that appear in a similar way are also mentioned. Mathematics Subject Classifications (2000) Primary 60G15, 60G18; secondary 60F17, 60G20, 60J80.Research partially supported by CONACyT grant 37130-E (Mexico).     

Spin-wave theory for the dynamics induced by direct currents in magnetic multilayers

A spin-wave theory is presented for the magnetization dynamics in a ferromagnetic film that is traversed by spin-polarized carriers at high direct-current densities. It is shown that nonlinear effects due to four-magnon interactions arising from dipolar and surface anisotropy energies limit the growth of the driven spin wave and produce shifts in the microwave frequency oscillations. The theory explains quantitatively recent experimental results in nanometric point contacts onto magnetic multilayers showing downward frequency shifts (redshifts) with increasing current, if the external field is on the film plane, and upward shifts (blueshifts), if the field is perpendicular to the film.