Adsorptive, thermodynamic and kinetic performances of Al/Ti and Al/Zr-pillared clays from the Brazilian Amazon region for zinc cation removal

Smectite clay samples from the Amazon region, Brazil, were pillarized by intercalating the species obtained from the chemical reactions: (i) AlCl₃·6H₂O/NaOH, (ii) titanium ethoxide in hydrochloric acid and (iii) direct use of ZrOCl₂·8H₂O solution. The natural matrices and the pillaring solutions were maintained under vigorous stirring at 298 K for 3 h and then subjected to calcination at temperatures of 723 and 873 K. Natural and pillared matrices were characterized by XRD, FTIR, TG–DTG and nitrogen adsorption–desorption isotherms. The resulting materials were used for zinc adsorption from aqueous solution at room temperature. The Langmuir, Freundlich and Temkin adsorption isotherm models have been applied to fit the experimental data and the Freundlich model is limited for higher concentrations. The pillaring process increases the thermal stability, the basal spacing of the natural clay sample (A₁) from 1.55 to 2.06 nm and the surface area from 44.30 to 223.73 m² g⁻¹. Kinetic studies demonstrated an equilibrium time of 180 min for zinc adsorption on the pillared matrices. Pseudo-first-order, Lagergren pseudo-second-order and Elovich equations demonstrated a better agreement with second-order kinetics was obtained with K₂ = 4.17–10.43 × 10⁻³ g mg⁻¹ min⁻¹ for the A₁ sample.     

Acceleration of cheese ripening at elevated temperature. An estimation of the optimal ripening time of a traditional Argentinean hard cheese

The effect of elevated ripening temperature on physicochemical, biochemical and sensory characteristics in Reggianito Argentino cheese was evaluated to determine the optimal time for cheese ripening at 18 °C that ensures typical cheese characteristics. Cheeses ripened at 12 or 18 °C and 85% relative humidity were analysed at 2, 4 and 6 months. Seventy-eight variables (as determined by urea-PAGE, RP-HPLC of the water-soluble at pH 4.6 fraction, free amino acids, free fatty acids and sensory analysis) were considered for the principal component analysis. The statistical analysis allowed determination of the optimal time for ripening Reggianito Argentino cheese at 18 °C, which was ranged between 2 and 3 months. In conclusion, the results obtained were not only useful in characterising the ripening of an Argentinean hard cheese, but also in evaluating the effect of an increase of ripening temperature on the main physicochemical, biochemical and sensory changes of Reggianito Argentino cheese.     

Acute oral safety study of rosemary extracts in rats

Increasing interest in rosemary plants is due to their antioxidant and health-enhancing properties. The aim of this study was to evaluate the potential acute toxicity of two supercritical fluid extracts of rosemary. An acute safety study of rosemary extracts was conducted in Wistar rats at a single oral gavage dosage of 2,000 mg/kg of body weight. Rosemary extracts were well tolerated; no adverse effects or mortality were observed during the 2-week observation period. No abnormal signs, behavioral changes, body weight changes, or change in food and water consumption occurred. Two weeks after a single oral rosemary extract dose of 2,000 mg/kg of body weight, there were no changes in hematological and serum chemistry values, organ weights, or gross or histological characteristics. Rosemary extracts appear to have low acute toxicity, and the oral lethal doses (LD50) for male and female rats are greater than 2,000 mg/kg of body weight.     

Detection, occurrence, and characterization of Escherichia coli O157:H7 from raw ewe's milk in Spain

A study was carried out in the Castilla y León region of Spain to investigate the presence of Escherichia coli O157:H7 in raw ewe's milk samples collected from several cheese factories during 1 year. All specimens were examined for E. coli O157:H7 by selective enrichment at 41.5 +/- 1.0 degrees C, after both 6 and 22 h of incubation, and then immunomagnetically separated and plated on cefixime-potassium tellurite-sorbitol MacConkey agar. No growth was obtained in the enrichment broth after a 6-h incubation. Presumptive colonies obtained after 22 h of incubation were screened by a multiplex PCR assay for the presence of rfbO157 and fliCH7 genes. Of all the ewe's milk samples studied, three were positive for E. coli O157:H7. The E. coli O157:H7 strains that were positive for the rfbO157 and fliCH7 genes were then analyzed by multiplex PCR for the presence of virulence genes (stx1, stx2, ehxA, and eaeA). All E. coli O157:H7 isolates were Shiga toxigenic and harbored additional genes related to virulence (ehxA and eaeA). The predominant Stx toxin type was stx2. These results demonstrate that raw ewe's milk used in cheesemaking may be sporadically contaminated with E. coli O157:H7 strains that are potentially pathogenic for humans.     

Saliva and Plasma Neutralizing Activity Induced by the Administration of a Third bnt162b2 Vaccine Dose

The BNT162b2 vaccine induces neutralizing activity (NA) in serum, but no data are available on whether a third-dose activates specific-immunity within the oral mucosa, representing the primary route of viral-entry. To carefully address this issue, we investigated if such immunity is boosted by SARS-CoV-2-infection; how long it is maintained over-time; and if it protects against the SARS-CoV-2 lineage B.1 (EU) and the emerging Delta and Omicron variants. NA was measured in plasma and saliva samples from: uninfected SARS-CoV-2-Vaccinated (SV), subjects infected prior to vaccination (SIV), and subjects who were infected after the second (SIV2) or the third (SIV3) vaccine dose. Samples were collected immediately before (T0), 15 days (T1), and 90 days (T2) post third-dose administration (SV and SIV), or 15 days post-infection (SIV2 and SIV3). In all the enrolled groups, NA in plasma and saliva: (i) was higher against EU compared to the other variants at all time-points (SV: T0 and T1, EU vs. both Delta and Omicron p < 0.001; T2 p < 0.01) (SIV: T0, EU vs. Delta p < 0.05; EU vs. Omi p < 0.01; T1 and T2 EU vs. Delta p < 0.01; EU vs. Omi p < 0.001); (ii) was boosted by the administration of the third dose; iii) declined over-time, albeit being detectable in almost all subjects at T2. The monitoring of NA over time will be important in clarifying if different NA levels may influence either acquisition or course of infection to properly plan the timing of a fourth vaccine dose administration.     

Robust Full-Spectral Color Tuning of Photonic Colloids

Creation of color through photonic morphologies manufactured by molecular self-assembly is a promising approach, but the complexity and lack of robustness of the fabrication processes have limited their technical exploitation. Here, it is shown that photonic spheres with full-color tuning across the entire visible spectrum can be readily and reliably achieved by the emulsification of solutions containing a block copolymer (BCP) and two swelling additives. Solvent diffusion out of the emulsion droplets gives rise to 20–150 µm-sized spheres with an onion-like lamellar morphology. Controlling the lamellar thickness by differential swelling with the two additives enables color tuning of the Bragg interference-based reflection band across the entire visible spectrum. By studying five different systems, a set of important principles for manufacturing photonic colloids is established. Two swelling additives are required, one of which must exhibit strong interactions with one of the BCP blocks. The additives should be chosen to enhance the dielectric contrast, and the formation kinetics of the spheres must be sufficiently slow to enable the emergence of the photonic morphology. The proposed approach is versatile and robust and allows the scalable production of photonic pigments with possible future applications in inks for cosmetics and arts, coatings, and displays.