Von Bezold assimilation effect reverses in stereoscopic conditions

Lightness contrast and lightness assimilation are opposite phenomena: in contrast, grey targets appear darker when bordering bright surfaces (inducers) rather than dark ones; in assimilation, the opposite occurs. The question is: which visual process favours the occurrence of one phenomenon over the other? Researchers provided three answers to this question. The first asserts that both phenomena are caused by peripheral processes; the second attributes their occurrence to central processes; and the third claims that contrast involves central processes, whilst assimilation involves peripheral ones. To test these hypotheses, an experiment on an IT system equipped with goggles for stereo vision was run. Observers were asked to evaluate the lightness of a grey target, and two variables were systematically manipulated: (i) the apparent distance of the inducers; and (ii) brightness of the inducers. The retinal stimulation was kept constant throughout, so that the peripheral processes remained the same. The results show that the lightness of the target depends on both variables. As the retinal stimulation was kept constant, we conclude that central mechanisms are involved in both lightness contrast and lightness assimilation

From Cheese Whey Permeate To An Anti-Listeria Food Packaging Device: Bacterial Cellulose Nanocrystals/Sakacin-A Conjugates (Nanosak)

In the present project cheese whey permeate (CWP), the residual by-product obtained by extraction of whey proteins from cheese whey, was used as substrate for the growth of bacterial species that produce two appealing molecules: the anti-listerial bacteriocin sakacin-A and bacterial cellulose (BC). BC is then turned into nanocrystals (BCNCs) that are finally conjugated with sakacin-A to obtain an innovative antimicrobial device for food which could support Listeria monocytogenes growth. Sakacin-A was produced by Lactobacillus sakei DSMZ 6333 in liquid cultures. The highest bacteriocin production (around 300 AU/mL) was achieved after 9 h at 26\ub0C; a food-grade, salt-free enriched sakacin-A extract was obtained by using a gravity reverse phase chromatography. BC was produced by Komagataeibacter xylinus DSMZ 2325 by static fermentation of CWP in presence of 0.5 U/mL of \u3b2-galactosidase at 30\ub0C; after 7 days, BC yield was around 7 g/L. BCNCs were then obtained by acid hydrolysis mediated by sulfuric acid, with the goal of removing the amorphous regions of BC and introduce a net negative charge by esterification on the hydroxyl group on C6. BCNCs/sakacin-A conjugates were prepared by exploiting their opposite charge: enriched sakacin-A extract was mixed with BCNCs and, after incubation, conjugates collected by centrifugation have a specific activity of 100 AU/mg BCNCs. Among all peptides present in the enriched sample, sakacin-A appears to preferentially absorb onto BCNCs, thus allowing its further purification. Sakacin-A as well its BCNCs conjugates were then included in a hydroxypropil-cellulose coating spread onto paper sheets at a concentration of 5 and 25 AU/cm2. The addition of the coating did not bring any significant change in the oxygen barrier properties of the cellulosic substrate. In a similar way, the static contact angle of both uncoated and coated substrate was of approximately 130\ub0. However, the presence of BCNCs seemed to increase the swelling phenomenon of the coating. Sakacin A was also included in whey, caseine and cellulose derived matrices to prepare films and coatings with diverse results. The kinetics of Sakacin-A released from active films to aqueous food was analyzed by immersion of samples in water (as simulant) and measuring the anti-Listeria activity of the simulant after increasing times of exposure. In vitro and in vivo antimicrobial trials were carried out on real food products demonstrated their anti-listerial effectiveness, proving that the developed devices can contribute to increase shelf life, quality and safety of perishable foods

DECREASED LYMPHOCYTE-RESPONSE TO PHA, CON-A, and CALCIUM IONOPHORE (A23187) in PATIENTS WITH RA and SLE, and REVERSAL WITH LEVAMISOLE in RHEUMATOID-ARTHRITIS

ESCOLA PAULISTA MED,DEPT MICROBIOL IMUNOL & PARASITOL,DISCIPLINA IMUNOL,São Paulo,BRAZILESCOLA PAULISTA MED,DEPT MICROBIOL IMUNOL & PARASITOL,DISCIPLINA IMUNOL,São Paulo,BRAZILWeb of Scienc