Performance of Salix viminalis and Populus nigra × Populus maximowiczii in short rotation intensive culture under high irrigation

On a plantation established in 2004 from stem cuttings at a density of 20,000 trees per hectare, we investigated growth and nutritional plant response to a high hydraulic regime for two species (Salix viminalis and Populus nigra × Populus maximowiczii), using a comparative approach with measurements from irrigated and control plots. The plantation was irrigated from June to September 2005 with about 140 mm per day. The equivalent of 120 Kg NO₃–N, 40 Kg P₂O₅–P and 85 Kg K₂O–K per hectare per year was applied by means of irrigation with wastewater. No mortality occurred and stem biomass production of both poplar and willow species were not statistically different on irrigated and control areas. However, S. viminalis revealed to be more tolerant to flooded conditions since these corresponded more closely to its nutritional requirements (foliar concentration of 20 mgN g⁻¹). The capacity of S. viminalis to withstand waterlogged conditions could play an important role in the sustainability of a plantation for the filtration of effluent at low pollutant concentration.     

Well-defined second-order nonlinear optical polymers by controlled radical polymerization,via multifunctional macromolecular chain transfer agent: Design,synthesis, and characterizations

To address the issue of the aggregation in second-order nonlinear optical (NLO) polymers we developed an approach based on the synthesis of a multifunctional macromolecular chain transfer agent. The controlled monomer insertion polymerization into the main chain by a ‘reversible addition-fragmentation chain transfer’ (RAFT) mechanism allows the spatial arrangement of the NLO chromophores along the polymeric chain in order to obtain sequence-ordered polymers. In a first step, a novel trithiocarbonate based macroinitiator containing the disperse red 19 (DR19) units in the main chain was synthesized by polycondensation; in a second step, this polymeric precursor was applied to the synthesis of a sequentially ordered polymer by controlled insertion radical polymerization of styrene. Size exclusion chromatography (SEC), nuclear magnetic resonance (NMR) data revealed that, (i) for the first time, polystyrenes (PS) bearing DR19 dyes covalently bounded were obtained, and (ii) both the insertion reaction and the length of the polystyrene segments were accurately controlled. Whatever the incorporated dye amount, all the copolymers were soluble in common solvents. Second-order optical nonlinearity in corona-poled thin films was evaluated, and second harmonic coefficients up to 80 pm/V were determined for loading ratio lower than 10 wt-% (DR19/PS). This approach opens up opportunities for the incorporation of more efficient chromophores even in apolar matrices.     

Arsenic uptake by common marsh fern Thelypteris palustris and its potential for phytoremediation

Hydroponic and soil cultivations of Thelypteris palustris, the common marsh fern, were used to investigate its potential for use in phytoremediation of arsenic (As) contaminated water or soil. ICP-MS analyses indicate that both roots and fronds accumulated arsenic in levels up to 100 times the concentration of treatment solutions of 250 microg/L and 500 mug/L arsenic, but values varied widely and there was no significant difference in concentrations in fronds between the control (no arsenic) and treatments. Plants exposed to 500 microg/L exhibited necrosis in their fronds, suggesting that Thelypteris palustris is not a good candidate for phyotoremediation of arsenic-contaminated sites.     

Modal method in deep metal-dielectric gratings: the decisive role of hidden modes

The modal method is well adapted for the modeling of deep-groove, high-contrast gratings of short period, possibly involving metal parts. Yet problems remain in the case of the TM polarization in the presence of metal parts in the corrugations: whereas most of the diffraction features are explained by the interplay of an astonishingly small number of true propagating and low-order evanescent modes, the exact solution of the diffraction problem requires the contribution of two types of evanescent modes that are usually overlooked. We investigate the nature and the role of these modes and show that metal gratings can be treated exactly by the modal method.     

Early Dissimilar Fates of Liver Eicosapentaenoic Acid in Rats Fed Liposomes or Fish Oil and Gene Expression Related to Lipid Metabolism

The study was undertaken to determine whether eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3), esterified in phospholipids (PL) as liposomes or in triglycerides (TG) as oil, exhibited comparable fates in liver lipids and whether these fates were associated with gene expressions related to fatty acid (FA) metabolism. PL and TG mixtures with close contents in EPA and DHA were administered to rats over 2 weeks. Most relevant events occurred after 3 days for both treatments. At that time, liposomes, compared with oil, increased the liver content in PL with a FA composition enriched in n-6 FA, comparable in DHA and much lower in EPA. Moreover, liposomes increased the activity and mRNA levels of carnitine palmitoyltransferase (CPT) I. In contrast, fish oil exerted opposite effects on CPT I and increased the genic expression of lipogenic enzymes. Liposomes, unlike fish oil, apparently increased the mRNA levels of acyl-CoA oxidase and the activity of the peroxisomal FA-oxidising system. Concomitantly, mRNA levels of hepatic lipoprotein receptors were increased with both diets, but intracellular proteins involved in free FA uptake and lipid synthesis were up-regulated only with liposome-treated rats. The quasi absence of EPA in hepatic PL of liposome-treated rats on the short term could result from increased β-oxidation activities through metabolic regulations induced by more available free EPA and other PUFA.     

Early stage hydration of slag-cement

The early hydration characteristics of slag cements (blends of separately ground granulated blast furnace slags with portland cement) have been examined. Isothermal calorimetry, chemical shrinkage and compressive strength measurements were made. The kinetics of hydration have been treated; apparent activation energies determined for a slag cement were ～49 KJ/mole compared with ～44 KJ/mole for the portland cement used in the blends.     

α-Al2O3 (0001) Surfaces: Atomic and Electronic Structure

New results on the     R ± 9° reconstructed α-Al₂O₃ (0001) surface, which can be obtained after heating at high temperature (1400°C) under vacuum, are presented. The atomic structure has been studied by combining low-energy electron diffractometry and grazing incidence X-ray scattering. The surface structure is found to be perfectly commensurable with the underlying bulk lattice. The surface consists of hexagonal zones of two, nearly perfect, close-packed Al (111) planes separated by a defect of hexagonal periodicity with a parameter of 26.44 Å. This model is consistent with previous surface studies of this reconstruction. The electronic structure has been investigated using valence band photoemission spectroscopy, X-ray absorption spectroscopy at the O K edge, electron energy loss spectroscopy, and X-ray-induced Auger electron spectroscopy. Interpretation of these experimental data in the frame of a self-consistent, tight-binding calculation leads to the conclusion that the     R ± 9° reconstructed surface is more covalent than the (1 × 1) surface. Significant changes in the; Al-O hybridizations are observed; these are likely due to a difference in the interatomic distances along the [0001] axis (relaxations). The increase of covalent character is mainly due to a strong decrease of the Madelung field on the reconstructed surface.     

Dedicated microprocessors for realtime identification of multivariable systems

In this paper, an algorithm is proposed for identifying multivariable systems in state-space form from noisy data, which is suitable for implementation on dedicated microprocessor systems. The proposed algorithm uses the normalized stochastic approximation criterion which reduces the computational complexity and memory requirements. It is shown that the overall performance of the proposed stochastic approximation algorithm when using a dedicated microprocessor with fixed point arithmetic is superior to the extended least-squares method in terms of memory requirements, execution speed per iteration, and the estimation results.     

Texture as a reflection of microstructure

The perception of texture has been correlated to the microstructure of particulate whey protein gels. A full, two-level, factorial experimental design was used in which the processing conditions, pH, heating rate and addition of salt were used as design factors. The texture of the gels was analysed by a sensory panel, and the microstructure was analysed by light and electron microscopy. The microstructure was quantified by using different types of image analysis.

In this study of particulate whey protein gels, the test principles of analysing texture were divided into two groups: destructive tests and non-destructive tests. The microstructural parameters can also be divided into two groups: overall network dimensions (pore size and particle size) and strand characteristics. The texture as measured with destructive methods was sensitive to overall network dimensions, whereas texture as measured with non-destructive methods was sensitive to the strand characteristics of particulate protein gels.