On the Suitability of Almond Shells for the Manufacture of a Natural Low-Cost Bioadsorbent to Remove Brilliant Green: Kinetics and Equilibrium Isotherms Study.

Almond production generates a large number of coproducts, but the farmer's interest mainly focuses on the nutritional and commercial aspects of the kernel for getting the best return from their harvests. Thus, almond coproducts such as almond shells that represent more than 70% of biomass remain underexplored. In this work, the suitability of almond shell powder (ASP) as a natural low-cost adsorbent was evaluated in the adsorption of brilliant green dye (BG), which is known as a chemical pollutant. Brunauer-Emmett-Teller (BET) method, for the determination of specific surface area, Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) techniques were performed to characterize the ASP adsorbent. The batch adsorption kinetic study for the removal of BG dye was carried out by varying pH, temperature, initial concentration of the dye, bioadsorbent dose, and contact time. It was found that 98% of BG dye is removed under the following optimal experimental conditions: ASP bioadsorbent dose of 1 g/L at T = 25°C, pH = 6.8, and C 0 = 1 g/L, which proves that ASP can be used as an excellent low-cost bioadsorbent for the removal of BG dye from wastewater. The experimental isotherm data were analyzed using Freundlich and Langmuir models. The results show the best correlation with single-layer adsorption, and the adsorption kinetics seems to follow a pseudo-second-order model.

Charge recovery during concurrent stimulation for a vision prosthesis.

Parallel or concurrent stimulation in an epiretinal neuroprosthesis is likely necessary in order to deliver sufficient phosphenes for effective vision. Important issues with concurrent stimulation are the effect of current distribution which introduces current leakage or 'cross talk' between adjacent electrodes and charge recovery which determines balanced charge being delivered/recovered at each electrode from the previous phase. In this paper, we present the effect of concurrent stimulation of two hexagonally arranged platinum electrode arrays on charge recovery. Balanced and imbalanced (unequal) currents were delivered to the hexagonal arrays when they were immersed in physiological saline. Both simulation and experimental results revealed that charge was not recovered at individual electrodes, particularly when imbalanced currents were delivered. However, total charge injected to both hexagonal arrays was recovered.

Differential accumulation of monolignol-derived compounds in elicited flax (Linum usitatissimum) cell suspension cultures.

Lignin and lignans share monolignols as common precursors and are both potentially involved in plant defence against pathogens. In this study, we investigated the effects of fungal elicitors on lignin and lignan metabolism in flax (Linum usitatissimum) cell suspensions. Cell suspension cultures of flax were treated with elicitor preparations made from mycelium extracts of Botrytis cinerea, Phoma exigua and Fusarium oxysporum F ssp lini. Elicitors induced a rapid stimulation of the monolignol pathway, as confirmed by the increase in PAL (phenylalanine ammonia-lyase, EC 4.1.3.5), CCR (cinnamoyl-CoA reductase EC 1.2.1.44) and CAD (cinnamyl alcohol dehydrogenase EC 1.1.1.195) gene expression and PAL activity. At the same time, CCR activity only increased significantly in F. oxysporum-treated cells 24 h post elicitation. On the other hand, CAD activity measured for coniferyl alcohol formation was transiently decreased but a substrate-specific activation of CAD activity was observed in F. oxysporum-treated cells when using sinapyl alcohol as substrate. The accumulation of monolignol-derived products varied according to the elicitor used. B. cinerea or P. exigua-elicited cell cultures were characterised by a reinforcement of the cell wall by a deposit of 8-O-4'-linked non-condensed lignin structures and phenolic monomers, while at the same time no stimulation of 8-8'-linked lignan or 8-5'-linked phenylcoumaran lignan accumulation was observed. Additionally, elicitation of cell cultures with F. oxysporum extracts even triggered a strong incorporation of monolignols in the non condensed labile ether-linked lignin fraction concomitantly with a decrease in lignan and phenylcoumaran lignan accumulation. Several hypotheses are proposed to explain the putative role of these compounds in the defence response of flax cells against pathogens.

ESTs from the fibre-bearing stem tissues of flax (Linum usitatissimum L.): expression analyses of sequences related to cell wall development.

In order to learn more about the diversity of genes expressed during flax fibre cell wall formation, expressed sequence tags (ESTs) were obtained from a cDNA library derived from the outer fibre-bearing tissues of flax (Linum usitatissimum) stems (cv Hermes) harvested at the mid-flowering stage. After elimination of vector and unreadable sequences, 927 ESTs were grouped into 67 clusters and 754 singletons. The flax ESTs have been submitted to the dbEST and GenBank databases with the accession numbers 25939634 - 25940560 (dbEST) and CV478070 - CV478996 (GenBank). Functional analysis allowed the grouping of ESTs into 13 functional categories and revealed that 62 % of ESTs were similar to known sequences, while 12.4 % of ESTs presented no similarity to any known sequences and 25.6 % of ESTs corresponded to proteins of unknown function. The most highly expressed transcripts belonged to four functional categories: protein maturation and metabolism (31 ESTs), signalling (22 ESTs), the cell wall (21 ESTs) and photosynthesis (19 ESTs). 4.4 % (41) of the total ESTs were potentially related to cell wall formation and maturation. The most highly expressed cell wall EST (15 ESTs) corresponded to a beta-xylosidase gene--potentially involved in cell wall remodelling during growth and development. Other cell wall-related ESTs corresponded to cellulose synthase, xyloglucan endotranglucosylase/hydrolase (XTH), beta-galactosidases, and peroxidases. The expression patterns of different cell wall-related ESTs were determined at different developmental stages in flax plants grown under different field conditions. The potential roles of gene products associated with cell wall related ESTs in fibre cell wall development is discussed.