Sorption and diffusion properties of volatile phenols into cork

The sorption and diffusion properties of seven common volatile phenols in hydro-alcoholic medium placed in contact with natural cork were investigated to determine the influence of cork closures on the concentration of these compounds in wine. Weighted cork samples were immersed in model wine solutions containing selected concentrations of each compound and were sampled over time. Sorption coefficients ranged between 125 and 306 mg of aroma compound per kg of cork, while diffusion coefficients varied from 0.8 to 4.1 × 10⁻¹¹ m²/s. Sorption isotherms of guaiacol and 4-propylguaiacol, respectively, the lowest and highest sorbed compounds of an homologous series of guaiacol, accurately fit Henry’s model. Hydrophobicity of aroma compounds seems to be a determining factor in both diffusion and sorption. This could indicate a preferential pathway for diffusion through suberin, the more hydrophobic constituent of cork.     

Temperate and virulent Lactobacillus delbrueckii bacteriophages: Comparison of their thermal and chemical resistance

The aim of this work was to study the efficiency of diverse chemical and thermal treatments usually used in dairy industries to control the number of virulent and temperate Lactobacillus delbrueckii bacteriophages. Two temperate (Cb1/204 and Cb1/342) and three virulent (BYM, YAB and Ib3) phages were studied. The thermal treatments applied were: 63 °C for 30 min (low temperature – long time, LTLT), 72 °C for 15 s (high temperature – short time, HTST), 82 °C for 5 min (milk destined to yogurt elaboration) and 90 °C for 15 min (FIL-IDF). The chemical agents studied were: sodium hypochlorite, ethanol, isopropanol, peracetic acid, biocides A (quaternary ammonium chloride), B (hydrogen peroxide, peracetic acid and peroctanoic acid), C (alkaline chloride foam), D (p-toluensulfonchloroamide, sodium salt) and E (ethoxylated nonylphenol and phosphoric acid). The kinetics of inactivation were drew and T₉₉ (time necessary to eliminate the 99% of phage particles) calculated. Results obtained showed that temperate phages revealed lower resistance than the virulent ones to the treatment temperatures. Biocides A, C, E and peracetic acid showed a notable efficiency to inactivate high concentrations of temperate and virulent L. delbrueckii phages. Biocide B evidenced, in general, a good capacity to eliminate the phage particles. Particularly for this biocide virulent phage Ib3 showed the highest resistance in comparison to the rest of temperate and virulent ones. On the contrary, biocide D and isopropanol presented a very low capacity to inactivate all phages studied. The efficiency of ethanol and hypochlorite was variable depending to the phages considered. These results allow a better knowledge and give useful information to outline more effective treatments to reduce the phage infections in dairy plants.     

Old and endangered tomato cultivars under organic greenhouse production: effect of harvest time on flavour profile and consumer acceptance

The influence of two different harvest times (optimal and 4 days earlier) on thirty flavour compounds, titratable acid and sugars as well as consumer acceptance of four old and endangered tomato cultivars (‘Ananas’, ‘Auriga’, ‘Green Zebra’ and ‘Lukullus’) was analysed. In most cases, cultivar type had a greater effect on the volatiles profile than harvest times. Sugar contents were mostly higher at optimal harvest compared with early harvest, whereas acid content was in most cases not affected by harvest time. Consumers perceived differences in several visual and sensory aspects between cultivars as well as harvest times. The optimal harvest was regularly preferred to or at least regarded as equal to the early‐harvest time. Sensory evaluation was poorly related to the aroma volatile profile and only partly to the acid and reducing sugar contents of tomatoes. This was probably owing to the special external characteristics of the tomatoes: differing in size, shape and colour from the ‘normal’ red types.     

Computing with energy and chemical reactions

Taking inspiration from some laws of Nature—energy transformation and chemical reactions—we consider two different paradigms of computation in the framework of Membrane Computing. We first study the computational power of energy-based P systems, a model of membrane systems where a fixed amount of energy is associated with each object and the rules transform objects by manipulating their energy. We show that if we assign local priorities to the rules, then energy-based P systems are as powerful as Turing machines; otherwise, they can be simulated by vector addition systems, and hence are not universal. Then, we consider stochastic membrane systems where computations are performed through chemical networks. We show how molecular species and chemical reactions can be used to describe and simulate the functioning of Fredkin gates and circuits. We conclude the paper with some research topics related to computing with energy-based P systems and with chemical reactions.     

The influence of attrition milling on carbon dioxide sequestration on magnesium–iron silicate

Present work evaluates the structural changes in olivine (Mg,Fe)₂SiO₄ (deposit Åheim, Norway) generated by mechanical treatment as well as its adsorption properties for carbon dioxide. The high-energy attrition milling was applied for mechanical activation. Identification of the mechanically-induced changes in the mineral was carried out applying various techniques: scanning electron microscopy, Mössbauer spectroscopy, specific surface measurements, carbon dioxide adsorption and Fourier-transformed infrared spectroscopy. The observed changes in the physico-chemical properties illustrate the possibility of the applied activation to modify the surface and/or bulk properties of olivine. Sensitivity for atmospheric CO₂ sequestration as well as sequestration of CO₂ by chemisorption can be derived from the obtained results.     

Effect of Residual Water Content on the Physico-Chemical Properties of Sucralfate Dried Gel Obtained by Microwave Drying

The purpose of this study was to investigate the physico-chemical characteristics of sucralfate humid gel dried by microwaves, in relation to the residual water content. Differential scanning calorimetry (DSC) allowed for the determination of the water state in sucralfate samples. Fourier-transform infrared (FT-IR) spectroscopy was used to monitor the changes in sucralfate gel structure induced by the microwave drying. A boundary value of total water content for sucralfate gel samples was found at 42% (w/w). Below this value only bound water was present, whereas above this value, the increase in total water was due to free water. In the physical form of gel, the strength of the coordination between sulfate anions and the positively charged aluminum hydroxide was dependent on the residual water content. The study of the sedimentation behavior of water suspensions prepared with dried sucralfate allowed for the evaluation of the retention of gel properties. We found that the microwave drying process affected the sedimentation of sucralfate dried gel suspensions independent of the residual water content: when suspensions were prepared from sucralfate dried gel powders containing more than 42% (w/w) of residual water, the sedimentation ratio was higher than 0.9. The non-gel powder suspension showed a sedimentation ratio of 0.68 ± 0.02, whereas the sucralfate humid gel suspension did not sediment.     

Shuttle‐Mediated Nanoparticle Delivery to the Blood–Brain Barrier

Many therapeutic drugs are excluded from entering the brain due to their lack of transport through the blood–brain barrier (BBB). The development of new strategies for enhancing drug delivery to the brain is of great importance in diagnostics and therapeutics of central nervous diseases. To overcome this problem, a viral fusion peptide (gH625) derived from the glycoprotein gH of Herpes simplex virus type 1 is developed, which possesses several advantages including high cell translocation potency, absence of toxicity of the peptide itself, and the feasibility as an efficient carrier for delivering therapeutics. Therefore, it is hypothesized that brain delivery of nanoparticles conjugated with gH625 should be efficiently enhanced. The surface of fluorescent aminated polystyrene nanoparticles (NPs) is functionalized with gH625 via a covalent binding procedure, and the NP uptake mechanism and permeation across in vitro BBB models are studied. At early incubation times, the uptake of NPs with gH625 by brain endothelial cells is greater than that of the NPs without the peptide, and their intracellular motion is mainly characterized by a random walk behavior. Most importantly, gH625 peptide decreases NP intracellular accumulation as large aggregates and enhances the NP BBB crossing. In summary, these results establish that surface functionalization with gH625 may change NP fate by providing a good strategy for the design of promising carriers to deliver drugs across the BBB for the treatment of brain diseases.