23 research outputs found
Novel mannitol based non-ionic surfactants from biocatalysis - part two - Improved synthesis
Asymmetric color perception in the shopping aisle: some implications for merchandising
Purpose: To investigate the perception of colored items in the aisle of a virtual store and establish whether it may be affected by their position on shelves.
Methods: 50 apparently healthy, right-handed university students, recruited on a voluntary basis, were included in this study. Inclusion criteria included: 1) visual acuity ≥ 20/20 in each eye; 2) normal color vision; 3) right-handedness, assessed by the Edinburgh inventory; 4) no history of ophthalmic and/or neurological disorders. Each subject was asked to look at 3 series of 18 images each on a plasma screen; the images showed a virtual modern store aisle, as it would be seen by a customer standing at one end in a central position and looking straight ahead. On both sides, the virtual aisle had 5 shelves, each containing 39 items of the same size and shape. In each image, apart from one single colored item, all other items were gray. In each series, the colored item was always of the same color, namely blue, red or green. All colors were monochromatic and had the same level of saturation. To avoid perceptive bias, all the images shown were perfectly symmetrical to the vertical axis. For each image, subjects were asked to locate as quickly as possible the colored item. Correctness and response time of answers were recorded. Statistical analysis was performed by ANOVA.
Results: Statistical analysis showed that the coloured items were perceived significantly more accurately and rapidly when they were located on the left.
Conclusion: Results support the idea of an asymmetric perception of colored items in the shopping aisle, suggesting that item location on store shelves may have important implications for merchandising.</br
Hofmeister Series: The hydrolytic activity of Aspergillus niger lipase depends on speciofic anion effects
The specific activity of lipase A (Aspergillus niger) toward the hydrolysis of p-nitrophenyl acetate (p-NPA) is shown to increase as a result of sodium salt addition according to specific ion effects of the Hofmeister series. This shows explicitly that the Hofmeister effect is due to the different specific interactions between anions and the enzymatic surface
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Hofmeister Series: The Hydrolytic Activity of Aspergillus niger Lipase Depends on Specific Anion Effects
The specific activity of lipase A (Aspergillus niger) toward the hydrolysis of p-nitrophenyl acetate (p-NPA) is shown to increase as a result of sodium salt addition according to specific ion effects of the Hofmeister series. This shows explicitly that t
Effects of on-demand feeding on sea urchin larvae (Paracentrotus lividus; Lamarck, 1816), development, survival and microalgae utilization
This study compared the growth of sea urchinParacentrotus lividuslarvae cultured using two different rearing methods: a variable method based on a variable amount of feed (microalgae) and seawater exchange (30% or 50%) established according to the phytoplankton concentration in the larval cultures and a fixed method characterized by a fixed amount of feed and seawater exchange. Three microalgae diets,Isochrysissp. (Tahitian strain, T-Iso),Chaetoceros gracilisand a 50:50 mixed diet, were tested with both rearing methods. Larval development and survival were assessed at the 6-arm pluteus stage (P6), competence (Cp) and metamorphosis (Mt). Data showed that the variable method reduced the requirements for phytoplankton and seawater exchange. Indeed, through the optimization of feed rations, it was possible to reduce the production of debris and settled phytoplankton, minimizing the need for water exchanges. Higher larval survival resulted at Cp and Mt stages for those reared with the variable method as opposed to the fixed one. Survival and development were also influenced by the tested dietary treatments: at Mt stage, the mixed diet resulted in a higher larval survival (63.3±8.9%) than T-Iso (19.7±12.1%) andC. gracilis(23.4±15.1%) (P<0.05). These results suggest that the use of the variable method improves the larval survival and development and also it reduces resource consumption (phytoplankton, seawater use and work effort), which in turn could potentially improve the hatchery production ofP.lividus
Specific Anion effects on glass electrode pH measurements of Buffer solutions: Bulk and surface phenomena
The effect of electrolytes on pH measurements via glass electrodes is explored with solutions buffered at pH 7 (phosphate and cacodylate). Salt and buffer concentrations are varied. Direct and reverse Hofmeister effects are observed. The phenomena are significant for salt concentrations above 0.1 M and for buffer concentrations below 20 mM. Changes in measured pH show up most strongly with anions. They can be related to the usual physicochemical parameters (anion molar volumes, molar refractivity, and surface tensions) that are characteristic of Hofmeister series. They correlate strongly with anionic excess polarizabilities; this suggests the involvement of non-electrostatic, or dispersion, forces acting on ions. These forces contribute to ionic adsorption at the glass electrode surface, and to the liquid junction potential